mdmiller
Well-Known Member
Sherm, what bullet and twist and how long is barrel on bottom target???
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Neck Tension Lapua 300prc
- Thread starter LocalJW
- Start date
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That was a heck of a shot at both targets my friend.2 times shows it was not a fluke shot!
Boy there a-lot of really good info on this thread, Keep it coming.
mrdinapoli
Member
- Joined
- Dec 5, 2015
- Messages
- 18
A COLLECTION OF THOUGHTS TO CONSIDER ON NECK TENSION (NT): This thread is a summarized treasure chest of info on a complicated topic. It has taken me years of reading, trials, and measurements, as equipment and techniques have progressed over the same time frame to gain some of this info. First of all, thank you "QuietTexan" — that was the best explanation and summary of the differences and functions of the Redding Dies that I have ever seen. Redding should use that info on their website since they do make such a wide range of dies that allow one to separate the reloading process into different parts.
Below is a summary of what I have learned and some additional thoughts on neck tension:
1. Your final step to set neck tension should be done with an expander mandrel — especially if the necks are not turned for consistent and uniform thickness. This will set the NT more accurately, usually reduce runout, and will push any irregularities to the outside of the neck.
2. To set neck tension correctly, the staff at K&M Shooting (kmshooting.com) suggests reducing neck ID by 0.002 - 0.003" below the desired final ID to allow the neck expander mandrel to adequately and consistently expand the neck to the correct ID.
3. Setting the correct neck ID prior to expansion with a mandrel is typically done with a sizing die with the expander mandrel removed, in a press. This will squeeze the outside of the neck sufficiently to allow the expander mandrel to work. It has been suggested that using a non-bushing die will give the most uniform results and least runout due to the fact that there is less machining and parts required to produce the die, and there are no bushings to move or misalign. However, sizing dies with bushings allow one to test and adjust neck sizing with the use of different bushings. Also, bushing dies from reputable manufacturers (ie. SAC, Whidden, Redding) have been proven to be as at least as consistent as non-bushing dies when set up correctly, in addition to providing the benefits of interchangeable bushings.
4. Powder ignition and burn uniformity must be consistent for optimal velocity SD/ES and best accuracy. For proper powder ignition and burn uniformity, a certain amount of pressure must build up in the case prior to bullet release. Any variation in this process will lead to variations in velocity SD/ES and accuracy.
5. This pressure build and therefore burn consistency is affected by neck tension and the distance of bullet jump prior to engraving in the lands (along with other variables, such as bullet weight, powder charge, powder type, primers, neck drag, etc). Interestingly, NT in various shooting disciples ranges from "zero" (benchrest) to 0.005"+ (magnums and heavy recoiling rifles), as examples.
6. In benchrest, "zero" NT is often used. In fact, at least some competitors do not even even resize their cases, as they have a tight chamber neck and maintain their turned necks so precisely that after a bullet is fired, a new bullet will fit "perfectly" (finger tight) into the unsized neck. However, these shooters single load their rounds and often seat their bullets long, and allow contact of the bullets with the lands to seat their bullets to the correct length (at "zero" distance between the bullet and lands). This contact with the lands causes a pressure spike and allows proper powder ignition to allow the powder to burn uniformly. This pressure caused by the bullet seated into the lands serves a similar function to NT in promoting powder burn uniformity. However, this is neither possible nor practical for rounds fed through a magazine or used for hunting in most cases due to restrictions imposed by magazine length and functional requirements.
7. For rounds fed from a magazine or used in hunting, a NT of 0.003" is likely about optimal. This will prevent the bullet from seating deeper in the case while in the magazine during recoil, and will also prevent bullets from getting "stuck" in the lands if seated too long. Some get excellent results using a NT of 0.002", but there is more risk of bullet setback and bullets sticking in the lands.
8. Many advocate using even more NT (0.004-0.005") in magnums and large capacity cases. One reason is to prevent bullet setback during recoil. However, other sources suggest that it allows more pressure to build in the case prior to bullet release, which allows the powder to burn more efficiently and consistently (ie. Nosler Reloading Manual #8, p 408: "Our lab has found moderate to heavy neck tension, or use of a crimp may be necessary to provide more reliable powder ignition. This may lower standard deviation numbers and improve accuracy on Weatherby cartridges"). In fact, Glen Zediker reported that he and David Tubb both found that the best velocity consistency was obtained with NT > 0.002", and that he personally uses 0.004" NT in his competition loads ("Handloading for Competition").
9. This dichotomy in NT practices beckons a deeper look. Again, some of the best benchrest shooters achieve the smallest groups ever recorded at 100-200 yds with NT so light they can seat bullets with their fingers. However, other accuracy competitors in other disciplines (ie. F-class, High Power, PRS) report using heavy NT (0.003-0.005") to get excellent accuracy and consistent velocities. Although some competitors do report excellent results at 0.002" NT, few if any report using NT between 0.000" and 0.002." At least theoretically, It is possible that a "danger zone" for less consistent powder ignition and velocities may exist in the low NT range between 0.000" and 0.002". To understand this further, we must first consider that when we use the term "neck tension," we are actually referring to the "friction" or resistance to movement between the bullet and case neck, of which neck tension is only one measurable component. There are many factors that contribute to bullet friction. These include: brass quality and structure, brass hardness, annealing, neck thickness, neck surface smoothness, neck cleanliness and the presence of carbon buildup or lube, bullet jack composition, bullet composition, bearing surface length, seating depth, chemical reaction between neck brass and bullet jacket, length of time between loading and shooting, as well as the difference between neck ID and bullet diameter. Some of these factors we can measure and control to some extent, and some we can't. Herein lies a hypothetical problem with obtaining consistency in the low NT range. Mathematically any small inconsistencies in any of these variables will cause a statistically greater affect on overall friction in the low NT range; while at higher NT, any variations will become statistically less significant. EXAMPLE: Assume that variances in any of the above factors lead to a combined effective tension/friction range equivalent to a NT of +/- 0.0005," for a total spread of 0.001". For BR shooters that set their tension to essentially 0.000, that tension can not fall below zero, so the negative range of variance disappears. In addition, on the positive side of variance, they will feel any tension when seating a bullet, and can discard that round. Therefore, their tension will likely not vary much and can only vary on the positive side, therefore remaining around 0.000 to 0.0005. This provides a total spread of 0.0005. Once you start applying tension, it becomes harder to feel small variations and, in addition, tension can now decrease below the goal setting. This is where the problems arise and statistics come into play. If your goal tension is 0.001, your range will be from 0.0005 to 0.0015 with a total spread of 0.001 (0.0015 - 0.0005). This range is essentially equal to your goal (0.001/0.001 = 1), but the highest number is 3 times the lowest (0.0015/0.0005 = 3). If your goal is 0.002, your range will be 0.0015 to 0.0025. The total spread is still 0.001, but now this is half your goal (0.001/0.002 = 0.5), but the highest number is now less than 2 times the lowest (0.0025/0.0015 = 1.67). If you increase your goal to 0.004, your range will now be 0.0035 to 0.0045. The range is now only a quarter of your goal (0.001/0.004 = 0.25), and the difference between the highest and lowest has dropped to 1.29 (0.0045/0.0035 = 1.29). Therefore, statistically, the lighter your goal neck tension, the statistically larger a fixed variance interval will become. As mentioned, this likely has little effect on the benchrest / "zero" NT community because: a) they are at the lowest end of the NT scale, and can't get less than zero tension, thus limiting their total variance; b) they can readily feel any tension greater than zero, which allows them to discard those rounds; c) they are using bullet to land contact to provide a pressure spike for consistent powder burn; d) they typically single load and do not have to worry about magazine constraints. Conversely, the higher the goal neck tension, the statistically smaller a fixed variance interval will become. At some point there will be a point of diminishing returns and safety factors to be considered. I have not heard of anyone consistently recommending a NT of greater than 0.005" under standard circumstances and with standard cartridges.
I hope that all this information is of interest and helps in making your decisions. I also hope it provides food for thought for others to pursue. I typically run 0.003" NT in my 6mm CM through my 300 Win Mag. I have settled on using SAC, Whidden, and Redding FL dies with neck bushings, but with the expander removed, to set my initial NT (and to slightly bump my shoulder back 0.001-0.002"). I then use K&M expander mandrels to set my final neck ID to provide a final NT of 0.003" (measured as the OD of a loaded round and the OD of an expanded case prior to bullet seating.) Best wishes.
Below is a summary of what I have learned and some additional thoughts on neck tension:
1. Your final step to set neck tension should be done with an expander mandrel — especially if the necks are not turned for consistent and uniform thickness. This will set the NT more accurately, usually reduce runout, and will push any irregularities to the outside of the neck.
2. To set neck tension correctly, the staff at K&M Shooting (kmshooting.com) suggests reducing neck ID by 0.002 - 0.003" below the desired final ID to allow the neck expander mandrel to adequately and consistently expand the neck to the correct ID.
3. Setting the correct neck ID prior to expansion with a mandrel is typically done with a sizing die with the expander mandrel removed, in a press. This will squeeze the outside of the neck sufficiently to allow the expander mandrel to work. It has been suggested that using a non-bushing die will give the most uniform results and least runout due to the fact that there is less machining and parts required to produce the die, and there are no bushings to move or misalign. However, sizing dies with bushings allow one to test and adjust neck sizing with the use of different bushings. Also, bushing dies from reputable manufacturers (ie. SAC, Whidden, Redding) have been proven to be as at least as consistent as non-bushing dies when set up correctly, in addition to providing the benefits of interchangeable bushings.
4. Powder ignition and burn uniformity must be consistent for optimal velocity SD/ES and best accuracy. For proper powder ignition and burn uniformity, a certain amount of pressure must build up in the case prior to bullet release. Any variation in this process will lead to variations in velocity SD/ES and accuracy.
5. This pressure build and therefore burn consistency is affected by neck tension and the distance of bullet jump prior to engraving in the lands (along with other variables, such as bullet weight, powder charge, powder type, primers, neck drag, etc). Interestingly, NT in various shooting disciples ranges from "zero" (benchrest) to 0.005"+ (magnums and heavy recoiling rifles), as examples.
6. In benchrest, "zero" NT is often used. In fact, at least some competitors do not even even resize their cases, as they have a tight chamber neck and maintain their turned necks so precisely that after a bullet is fired, a new bullet will fit "perfectly" (finger tight) into the unsized neck. However, these shooters single load their rounds and often seat their bullets long, and allow contact of the bullets with the lands to seat their bullets to the correct length (at "zero" distance between the bullet and lands). This contact with the lands causes a pressure spike and allows proper powder ignition to allow the powder to burn uniformly. This pressure caused by the bullet seated into the lands serves a similar function to NT in promoting powder burn uniformity. However, this is neither possible nor practical for rounds fed through a magazine or used for hunting in most cases due to restrictions imposed by magazine length and functional requirements.
7. For rounds fed from a magazine or used in hunting, a NT of 0.003" is likely about optimal. This will prevent the bullet from seating deeper in the case while in the magazine during recoil, and will also prevent bullets from getting "stuck" in the lands if seated too long. Some get excellent results using a NT of 0.002", but there is more risk of bullet setback and bullets sticking in the lands.
8. Many advocate using even more NT (0.004-0.005") in magnums and large capacity cases. One reason is to prevent bullet setback during recoil. However, other sources suggest that it allows more pressure to build in the case prior to bullet release, which allows the powder to burn more efficiently and consistently (ie. Nosler Reloading Manual #8, p 408: "Our lab has found moderate to heavy neck tension, or use of a crimp may be necessary to provide more reliable powder ignition. This may lower standard deviation numbers and improve accuracy on Weatherby cartridges"). In fact, Glen Zediker reported that he and David Tubb both found that the best velocity consistency was obtained with NT > 0.002", and that he personally uses 0.004" NT in his competition loads ("Handloading for Competition").
9. This dichotomy in NT practices beckons a deeper look. Again, some of the best benchrest shooters achieve the smallest groups ever recorded at 100-200 yds with NT so light they can seat bullets with their fingers. However, other accuracy competitors in other disciplines (ie. F-class, High Power, PRS) report using heavy NT (0.003-0.005") to get excellent accuracy and consistent velocities. Although some competitors do report excellent results at 0.002" NT, few if any report using NT between 0.000" and 0.002." At least theoretically, It is possible that a "danger zone" for less consistent powder ignition and velocities may exist in the low NT range between 0.000" and 0.002". To understand this further, we must first consider that when we use the term "neck tension," we are actually referring to the "friction" or resistance to movement between the bullet and case neck, of which neck tension is only one measurable component. There are many factors that contribute to bullet friction. These include: brass quality and structure, brass hardness, annealing, neck thickness, neck surface smoothness, neck cleanliness and the presence of carbon buildup or lube, bullet jack composition, bullet composition, bearing surface length, seating depth, chemical reaction between neck brass and bullet jacket, length of time between loading and shooting, as well as the difference between neck ID and bullet diameter. Some of these factors we can measure and control to some extent, and some we can't. Herein lies a hypothetical problem with obtaining consistency in the low NT range. Mathematically any small inconsistencies in any of these variables will cause a statistically greater affect on overall friction in the low NT range; while at higher NT, any variations will become statistically less significant. EXAMPLE: Assume that variances in any of the above factors lead to a combined effective tension/friction range equivalent to a NT of +/- 0.0005," for a total spread of 0.001". For BR shooters that set their tension to essentially 0.000, that tension can not fall below zero, so the negative range of variance disappears. In addition, on the positive side of variance, they will feel any tension when seating a bullet, and can discard that round. Therefore, their tension will likely not vary much and can only vary on the positive side, therefore remaining around 0.000 to 0.0005. This provides a total spread of 0.0005. Once you start applying tension, it becomes harder to feel small variations and, in addition, tension can now decrease below the goal setting. This is where the problems arise and statistics come into play. If your goal tension is 0.001, your range will be from 0.0005 to 0.0015 with a total spread of 0.001 (0.0015 - 0.0005). This range is essentially equal to your goal (0.001/0.001 = 1), but the highest number is 3 times the lowest (0.0015/0.0005 = 3). If your goal is 0.002, your range will be 0.0015 to 0.0025. The total spread is still 0.001, but now this is half your goal (0.001/0.002 = 0.5), but the highest number is now less than 2 times the lowest (0.0025/0.0015 = 1.67). If you increase your goal to 0.004, your range will now be 0.0035 to 0.0045. The range is now only a quarter of your goal (0.001/0.004 = 0.25), and the difference between the highest and lowest has dropped to 1.29 (0.0045/0.0035 = 1.29). Therefore, statistically, the lighter your goal neck tension, the statistically larger a fixed variance interval will become. As mentioned, this likely has little effect on the benchrest / "zero" NT community because: a) they are at the lowest end of the NT scale, and can't get less than zero tension, thus limiting their total variance; b) they can readily feel any tension greater than zero, which allows them to discard those rounds; c) they are using bullet to land contact to provide a pressure spike for consistent powder burn; d) they typically single load and do not have to worry about magazine constraints. Conversely, the higher the goal neck tension, the statistically smaller a fixed variance interval will become. At some point there will be a point of diminishing returns and safety factors to be considered. I have not heard of anyone consistently recommending a NT of greater than 0.005" under standard circumstances and with standard cartridges.
I hope that all this information is of interest and helps in making your decisions. I also hope it provides food for thought for others to pursue. I typically run 0.003" NT in my 6mm CM through my 300 Win Mag. I have settled on using SAC, Whidden, and Redding FL dies with neck bushings, but with the expander removed, to set my initial NT (and to slightly bump my shoulder back 0.001-0.002"). I then use K&M expander mandrels to set my final neck ID to provide a final NT of 0.003" (measured as the OD of a loaded round and the OD of an expanded case prior to bullet seating.) Best wishes.
- Joined
- Jan 4, 2013
- Messages
- 84
Good tread! I too enjoy learning different methods and results that everyone gets…helps my reloading process.
So to bring the circle all the way around. This is my current process and I do not do any neck tension currently. I would like to use mandrels as I do not us annealing.
1) FL Size w/Redding and expander ball (decaping)
2) Tumble and clean
3) Size/Trim/Debur
4) Prime
5)Powder
6) Seat bullet with redding competition die
Where would I use the mandrel in this process instead of expander ball? Or what should my steps be
1) FL Size w/Redding and expander ball (decaping)
2) Tumble and clean
3) Size/Trim/Debur
4) Prime
5)Powder
6) Seat bullet with redding competition die
Where would I use the mandrel in this process instead of expander ball? Or what should my steps be
Annealing has nothing to do with whether to use a mandrel or not.
I've migrated away from annealing on my LR stuff unless I'm fireforming AI brass after its pushed the shoulder forward before I FL size it.
I do anneal my 17 and 20 cal brass through, but I'm after a different scenario and that brass gets shot alot more than my LR stuff.
Whatever you do be consistent and test it.
If your one that cleans the carbon off the inside of your necks then I would use a mandrel and neck lube.
Your tumbling and cleaning so I would use a mandrel and neck lube and do it between 3 and 4
mrdinapoli
Member
- Joined
- Dec 5, 2015
- Messages
- 18
I agree with L.Sherm -- Annealing has nothing directly to do with setting neck tension specifically. However, it WILL have an effect -- it is supposed to improve case life and consistency of operations, and to reduce case spring back. Case spring back can run as much as 0.001" at each step and therefore will have an affect on final results. In the meantime, annealing may only result in minimal benefits for the first several firings, so don't worry about it now. I currently do not anneal either, although I would like to in the future, but the cost of the AMP has me holding tight right now.
Just to be clear, LocalJW, you ARE setting and controlling neck tension with the Redding FL sizer and expander ball. It is just that you have left the decisions of the amount of down sizing, then upsizing to final dimensions to Redding and the die. We suggest that you can get more control by separating the processes.
The first thing that I would do is get a good micrometer, not a caliper, because you will need precise measurements to see how the different parts of the process effect the final results.
I would then get a BASELINE of what your current set up is producing. You will need this to evaluate the quality of your current set up and process, as well as to plan any changes to this set up and then make comparisons between your current set up and your changes. To do this, I would do the following:
1. Fire-form 20 cases, and divide into 4 sets.
2. Select 5 fired cases to take through your current process, making measurements at each step along the way -- I would measure the neck OD, neck ID and neck run-out (R/O). (You can measure neck wall thickness and consistency also if you have a good ball micrometer.)
3. Remove your decapping rod and expander ball from your FL sizing die.
4. Measure the diameter of the expander ball.
5. Decap your fired cases with a dedicated decapping die, or remove your expander button from your decapping rod and remove the primers when you size your cases (next step) -- just do not re-expand the case necks with the expander ball.
6. Run your cases through the FL sizing die without the expander. This will size the necks from the outside to the diameter set by Redding. (It will be more than needed.)
7. Measure the neck OD, ID, and R/O of the 5 cases and also get an average.
8. Replace the decapping rod and expander button in your FL die.
9. Take the next set of 5 fired but unsized cases and run them through the FL die with the expander ball and rod. They will now by FL sized, having had their necks squeezed down by the die and then expanded by the expander ball to the final dimension.
10. Measure the neck OD, ID, R/O on these cases and get an average.
Now you know what your current set up is giving you with regards to downsizing the neck, upsizing the neck, final dimensions, and consistency of results -- are your measurements consistent and giving you good results and minimal R/O. You also have an ideas of what ID a certain size expander ball (and therefore mandrel) will give you when used to expand your cases. Finally, you have a baseline as to the neck ID in relation to your bullet to see what Redding thinks is adequate, and to allow you make adjustments up or down.
To select a mandrel, I would start with the same diameter mandrel as your expander button, unless you are deliberately trying to increase or decrease neck tension. Typically, factory dies and expanders are set to provide about 0.003" NT, which is a good general place to start.
Now to get back to your initial question regarding steps in the process along with some comments.
Several things to keep in mind that I do differently in my process to at last think about. I do not tumble my cases. There are reasons to hand clean or to tumble either before or after sizing. This is just preference, especially since I run limited numbers of cases per batch. Instead, I wipe the cases with a clean microfiber cloth, clean the outside of the necks with light brass wool, clean the inside of the necks with a brush, then reclean my primer pockets with a primer pocket uniformer to keep all pockets clean, square, and at a consistent depth. This does not take long, although if you were doing 100+ cases at a time, tumbling may be quicker. Tumbling will perform many of the same tasks that I do manually. Since tumbling does clean the case body and inside/outside of the necks, I would DEFINITELY tumble before I size and expand the cases. If you want the primer pockets cleaned too, you will need to decap the cases first with a decapping die prior to tumbling. However, I do feel that tumbling may lead to dings and changes in the case necks. Therefore, if you do tumble, I would do so BEFORE you set your necks to final size.
If you had all the equipment mentioned above, along with an expander mandrel to set neck tension, this is the expanded process I would use. I will break each step down and explain so you can decide what works best for you.
1. Hand clean or tumble the cases, as discussed above.
2. Wipe the cases clean from any dust and carbon.
3. Decap the cases with a separate decapping die (unless you are going to decap the cases as part of step 5 without an expander ball).
4. Lube the cases.
5. Run the cases through a FL sizing die without the expander ball. (This will size the necks from the outside to prepare them for the expander mandrel.)
6. Measure and trim/debur/chamfer cases if needed. (Use a VLD chamfer inside the case mouth.)
7. Clean the primer pockets with a primer pocket uniformer to ensure clean, square, and consistent depth.
8. Brush inside of case necks if not done previously to ensure that they are clean and smooth.
9. Dip case necks (mouth down) in Imperial Dry Lube to lubricate for the expander. (You can use other lubes, but then you will need to clean the necks well after expansion and prior to bullet seating.)
10. Expand the cases to final ID neck tension with your expander mandrel. (I like doing this after trimming because I feel that it will iron out any burs left after the trim/debur/chamfer. This can also be done after the full length sizing step instead of here.)
11. Confirm correct ID with a Pin Gauge (or calipers if you don't have a pin gauge).
12. Prime the cases.
13. Charge with powder.
14. Seat the bullet.
As before, though, the first time you do this process, I would take take 5 fired cases and take measurements of each of them along the way to see how the process is working and to make comparisons with your prior set up.
1. FL size the cases -- measure neck ID, OD, R/O, calculate average.
2. Expand the necks -- measure neck ID, OD, R/O, calculate average.
3. Seat the bullets -- measure neck OD, bullet R/O, calculate average.
Not only will taking all of these measurements for your initial set of cases let you compare your process and results with your prior process, it will let you trouble shoot your current process to see if there are problems along the way leading to excessive inconsistency or R/O.
Pay close attention and take some measurements and notes when you make changes, and you will get a sense of how well your process works and what may need tweaking.
I know the explanation was long, but I hope it helps.
Just to be clear, LocalJW, you ARE setting and controlling neck tension with the Redding FL sizer and expander ball. It is just that you have left the decisions of the amount of down sizing, then upsizing to final dimensions to Redding and the die. We suggest that you can get more control by separating the processes.
The first thing that I would do is get a good micrometer, not a caliper, because you will need precise measurements to see how the different parts of the process effect the final results.
I would then get a BASELINE of what your current set up is producing. You will need this to evaluate the quality of your current set up and process, as well as to plan any changes to this set up and then make comparisons between your current set up and your changes. To do this, I would do the following:
1. Fire-form 20 cases, and divide into 4 sets.
2. Select 5 fired cases to take through your current process, making measurements at each step along the way -- I would measure the neck OD, neck ID and neck run-out (R/O). (You can measure neck wall thickness and consistency also if you have a good ball micrometer.)
3. Remove your decapping rod and expander ball from your FL sizing die.
4. Measure the diameter of the expander ball.
5. Decap your fired cases with a dedicated decapping die, or remove your expander button from your decapping rod and remove the primers when you size your cases (next step) -- just do not re-expand the case necks with the expander ball.
6. Run your cases through the FL sizing die without the expander. This will size the necks from the outside to the diameter set by Redding. (It will be more than needed.)
7. Measure the neck OD, ID, and R/O of the 5 cases and also get an average.
8. Replace the decapping rod and expander button in your FL die.
9. Take the next set of 5 fired but unsized cases and run them through the FL die with the expander ball and rod. They will now by FL sized, having had their necks squeezed down by the die and then expanded by the expander ball to the final dimension.
10. Measure the neck OD, ID, R/O on these cases and get an average.
Now you know what your current set up is giving you with regards to downsizing the neck, upsizing the neck, final dimensions, and consistency of results -- are your measurements consistent and giving you good results and minimal R/O. You also have an ideas of what ID a certain size expander ball (and therefore mandrel) will give you when used to expand your cases. Finally, you have a baseline as to the neck ID in relation to your bullet to see what Redding thinks is adequate, and to allow you make adjustments up or down.
To select a mandrel, I would start with the same diameter mandrel as your expander button, unless you are deliberately trying to increase or decrease neck tension. Typically, factory dies and expanders are set to provide about 0.003" NT, which is a good general place to start.
Now to get back to your initial question regarding steps in the process along with some comments.
Several things to keep in mind that I do differently in my process to at last think about. I do not tumble my cases. There are reasons to hand clean or to tumble either before or after sizing. This is just preference, especially since I run limited numbers of cases per batch. Instead, I wipe the cases with a clean microfiber cloth, clean the outside of the necks with light brass wool, clean the inside of the necks with a brush, then reclean my primer pockets with a primer pocket uniformer to keep all pockets clean, square, and at a consistent depth. This does not take long, although if you were doing 100+ cases at a time, tumbling may be quicker. Tumbling will perform many of the same tasks that I do manually. Since tumbling does clean the case body and inside/outside of the necks, I would DEFINITELY tumble before I size and expand the cases. If you want the primer pockets cleaned too, you will need to decap the cases first with a decapping die prior to tumbling. However, I do feel that tumbling may lead to dings and changes in the case necks. Therefore, if you do tumble, I would do so BEFORE you set your necks to final size.
If you had all the equipment mentioned above, along with an expander mandrel to set neck tension, this is the expanded process I would use. I will break each step down and explain so you can decide what works best for you.
1. Hand clean or tumble the cases, as discussed above.
2. Wipe the cases clean from any dust and carbon.
3. Decap the cases with a separate decapping die (unless you are going to decap the cases as part of step 5 without an expander ball).
4. Lube the cases.
5. Run the cases through a FL sizing die without the expander ball. (This will size the necks from the outside to prepare them for the expander mandrel.)
6. Measure and trim/debur/chamfer cases if needed. (Use a VLD chamfer inside the case mouth.)
7. Clean the primer pockets with a primer pocket uniformer to ensure clean, square, and consistent depth.
8. Brush inside of case necks if not done previously to ensure that they are clean and smooth.
9. Dip case necks (mouth down) in Imperial Dry Lube to lubricate for the expander. (You can use other lubes, but then you will need to clean the necks well after expansion and prior to bullet seating.)
10. Expand the cases to final ID neck tension with your expander mandrel. (I like doing this after trimming because I feel that it will iron out any burs left after the trim/debur/chamfer. This can also be done after the full length sizing step instead of here.)
11. Confirm correct ID with a Pin Gauge (or calipers if you don't have a pin gauge).
12. Prime the cases.
13. Charge with powder.
14. Seat the bullet.
As before, though, the first time you do this process, I would take take 5 fired cases and take measurements of each of them along the way to see how the process is working and to make comparisons with your prior set up.
1. FL size the cases -- measure neck ID, OD, R/O, calculate average.
2. Expand the necks -- measure neck ID, OD, R/O, calculate average.
3. Seat the bullets -- measure neck OD, bullet R/O, calculate average.
Not only will taking all of these measurements for your initial set of cases let you compare your process and results with your prior process, it will let you trouble shoot your current process to see if there are problems along the way leading to excessive inconsistency or R/O.
Pay close attention and take some measurements and notes when you make changes, and you will get a sense of how well your process works and what may need tweaking.
I know the explanation was long, but I hope it helps.
I run a mandrel on the last step of brass prep.I then prime, measure powder and fill cases and fit bullet in case
I may have missed it but sometimes I and others have found the best results by using a FL die with neck honed to desired final size , no mandrel no bushings. Some die makers will hone for you for $10-$20 or you can do yourself with expandable hone and cordless.
Is your FL die using a neck bushing or no neck bushing?
I guess does a standard FL die already bring in the neck with out bushing?
