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Fine tuning loads lee factory crimp die
- Thread starter JDD
- Start date
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Actually, military ammo isn't crimped to prevent bullets getting bumped out of round. That ammo is mass produced, just like all commercial ammo. They apply crimp for a couple reasons. Reason one is because that's what the criteria states in their contract to be NATO spec ammunition. The other reason is the same reason commercial ammo manufacturers do it. It's to compensate for inconsistencies in the brass and to ensure adequate bullet tension.
For mass produced ammo that isn't painstakingly made at a bench and sorted and inspected individually, etc, etc, it's a good idea. For hand loaders, making high quality ammo custom tailored to their rifles, for the intent of using it for long range hunting, forgoing the crutch that is a crimp, and tuning actual uniform neck tension is the best practice.
Again, yes, a crimp can absolutely work. It's been proven to work. I won't argue that. What I will argue, based on extensive tests done by myself and others, is that it is inferior to a good annealed neck that is sized uniformly with adequate and uniform tension on the bullet. Inferior in that crimped rounds are susceptible to being knocked out of round more so than rounds with .002-.003" of uniform tension along the entire surface contacting the bullet.
That contradicts your claim as to why the military crimps their long range ammo.
ar10ar15man
Well-Known Member
i am retired
i build and shoot guns for retirement
i have wins at 600/1000
i have a national championship at 600
i built competitive/target ar's for nearly 20 years.
anything but a keyboard shooter
when i say something, it has well over 50 years of loading and shooting behind the comments.
the only data so far is too small and in an ar.
not a long range hunting rifle
i agree that uniform neck tension is a big clue to low es/sd
BUT
without annealing every time, there is no uniformity.
not with a bushing, a mandrel or a lee fcd
i build and shoot guns for retirement
i have wins at 600/1000
i have a national championship at 600
i built competitive/target ar's for nearly 20 years.
anything but a keyboard shooter
when i say something, it has well over 50 years of loading and shooting behind the comments.
the only data so far is too small and in an ar.
not a long range hunting rifle
i agree that uniform neck tension is a big clue to low es/sd
BUT
without annealing every time, there is no uniformity.
not with a bushing, a mandrel or a lee fcd
my reloading process flows this way. I use a Dillion 650 with the powder measure removed. In place I put a powder dump die used for a 550 in its place. I set up one or two electric powder despensers. My rounds are shot ,ejected with out allowing any trauma to the case. I hand de-prime. I purchased a heated large hydroponic cleaner that I intend to use (I read such cleaning can have a effect on bullet pull. testing will be in order, I do not lube case necks but may have to start) The Dillion lack of height caused some problems with the 6.5x280 so I might move the process over to the hornady lock and load , I been avoiding the press because it won't deprime and reprise cases very long due to primer residue. The its extra hight may be asset though.. When running smoothly I can run a 100 rounds of match grade with individual weighed charges in a hour after cleaning with out breaking a sweat.
I am not sure How to incorporate the double sizing. If somebody made a collet sizer and crimper with a spring loaded dial reading foot lbs . The sizer would indicate neck thickness/stiffnes problems. and the crimper could be dialed in a repeatable manner
You're right about data from what is need in a AR type rifle not being pertinent to this discussion. I have had ar's that would shoot bug hole groups if loaded one at a time with out using the mag. same gun and loads feed from the magazine barely a moa. Neck thickness, stiffness and degree of crimp are more about stopping damage during the loading process. I image that the relationship of the upper to the lower, how high the mag sits , the shape of the mag lips and spring tension and were that round sits in the stack can all have a bearing on the loading process and how much runout can be induced during the loading cycle.
This whole discussion comes down to neck tension, my plan is to test benchrest prepped case with neck tension adjustment due to different bushing size. .003 .004 neck reduction measured runout noted. compared to same brass using minimal neck sizing along with a light crimp induced by a collet run out noted . then to fire said brass multiple times to determine when annealing may be required again to determine if crimping reduces the need to anneal.
Jeffrey Van Zandt
Well-Known Member
Based on feed back I read. I have planed my experiment. My hypothesis is using bench rest prepared cases " miminal neck sizing along with a light crimp applied by a collet die" will exhibit less run out while lowering es and sd. Then similar cases prepared using just adjustments made to neck tension alone by bushing size. Any else wishing to run similar test are welcome to and invited to report back.
ar10ar15man
Well-Known Member
I deprime with my Hornady LnL AP and case feeder using a universal decapping die. Then I wet tumble the brass clean. After they dry, they get annealed. After annealing, they're ready to be resized. Which press I use for the remaining steps really just depends on how I feel or what I'm doing. Load development rounds get done on the single stage. If I'm loading up 100 rounds or more of a developed load, I'll likely use the progressive with the case feeder, but sometimes I load on the single stage as well.
I'll put the Lee FL die without the expander ball into the first station, then the mandrel die in station two. My mandrels are made to produce .003" of bullet tension, which has proven to give me an excellent balance of speed and low SD/ES and doesn't require any sort of crimp to prevent bullet setback from recoil, even in semi-auto rifles.
After that, they all get trimmed, deburred, and chamfered. After that, they're ready to be sorted. I sort cases by weight. I've ran a test to see if sorting by weight vs sorting by H2O capacity works better and the differences were minimal enough that I decided to just weigh them since it's so much faster.
Depending on what cartridge it is (size of the case), I sort them in batches with a plus or minus range of half of a grain to a full grain.
Once sorted, I hand prime the cases. I prefer hand priming so I can feel every primer being seated and I know they're consistent and not getting crushed by too much leverage from a press. I use Federal Gold Medal Match primers in all my loads too.
Once primed, they're ready to be charged. I use a GemPro 250 to weigh my charges. If I'm using my progressive press, I use a powder drop die with a funnel. My bullets get seated using either a Redding Competition micrometer seating die, or a Forster Ultra micrometer seating die. Both of those dies have proven to do extremely well. I verify my seating depth using a comparator and measuring my OAL from the base of the case to the ogive of the bullet.
This method has produced extremely consistent and accurate ammo that I can count on.
I only use temp stable extruded powders as well. I've experimented with uniforming primer pockets, deburring flash holes, etc as well. I still do it with some brass, but not all.
I've done a lot of experimenting when it comes to reloading. It's something I have a passion for. I also have a passion for ballistics, especially terminal ballistics. I'm always testing and researching bullets and how they perform on animals, especially at long range/low impact velocities. That's a big reason I'm a member here.
CRaTxn
Well-Known Member
Bench rest guys load individually so that their rounds are not subjected to bullet seating depth variances caused by rounds bouncing around in the magazine of hunting rifles. You just had to make a snide remark to that newbie to show how smart you aren't. By comparing his LRH question to the benchrest environment, it merely shows you do not have the depth of knowledge you thought you had.
Some brass, like Lapua, Peterson, Alpha, etc are made to high quality standards and can be trusted to not require annealing out of the package. You can also get away with not annealing them after several firings. If you want absolute consistency though, annealing after every firing is best. That way it resets any work hardening.
Other brands of brass would highly benefit from a good annealing right away.
Brass is made by a series of draws. As in the brass starts out as a cup and is gradually drawn out to its cylindrical shape. That process makes thicknesses uneven. It's just the nature of the beast. Because if this, if you use a bushing die without turning the necks, you're pushing those inconsistent thicknesses to the inside diameter of the neck. That results in an inconsistent amount of tension on the bullet which equals inconsistent pressure and velocity.
A mandrel pushes those inconsistencies to the outside diameter and leaves a uniform amount of tension on the bullet. No neck turning really required.
An expander ball/button is inferior to a mandrel because it pulls and stretches the neck and shoulder back out as it exits the case. Mandrels size in a downward motion and do not stretch the neck or shoulder as they exit the case.
As we all know, the neck of the case opens up when firing. You want the neck to release the bullet evenly and consistently from one round to the next. That's why it matters having the inside wall of the neck uniform.
Once the round fires, the pressure pushes the case into the chamber walls, and pushing any inconsistencies in thickness back to the inside of the case. At that point it really doesn't matter though because you'll have to resize everything again anyways.
If you turned the necks, you don't need to do it again. If you didn't, like I said, the chamber will have pushed those uneven thicknesses back to the inside of the neck. That technically doesn't matter though, because FL sizing without an expander ball will do the same thing. The mandrel is what fixes that.
It is good practice to anneal though. A mandrel can't defeat spring-back of the metal as it work hardens. Once work hardened, those inconsistent thicknesses will spring back and tension will once again be uneven. Annealing will undo the work hardening and allow the mandrel to set uniform tension once again.
If you turn your necks, a bushing can do the same thing a mandrel does. Turning your necks is what ensures the necks are even thickness and makes it so there's not more pressure on the bullet from thicker areas of brass.
A mandrel pushes those inconsistencies to the outside diameter and leaves a uniform amount of tension on the bullet. No neck turning really required.
An expander ball/button is inferior to a mandrel because it pulls and stretches the neck and shoulder back out as it exits the case. Mandrels size in a downward motion and do not stretch the neck or shoulder as they exit the case.
As we all know, the neck of the case opens up when firing. You want the neck to release the bullet evenly and consistently from one round to the next. That's why it matters having the inside wall of the neck uniform.
Once the round fires, the pressure pushes the case into the chamber walls, and pushing any inconsistencies in thickness back to the inside of the case. At that point it really doesn't matter though because you'll have to resize everything again anyways.
If you turned the necks, you don't need to do it again. If you didn't, like I said, the chamber will have pushed those uneven thicknesses back to the inside of the neck. That technically doesn't matter though, because FL sizing without an expander ball will do the same thing. The mandrel is what fixes that.
It is good practice to anneal though. A mandrel can't defeat spring-back of the metal as it work hardens. Once work hardened, those inconsistent thicknesses will spring back and tension will once again be uneven. Annealing will undo the work hardening and allow the mandrel to set uniform tension once again.
If you turn your necks, a bushing can do the same thing a mandrel does. Turning your necks is what ensures the necks are even thickness and makes it so there's not more pressure on the bullet from thicker areas of brass.
I don t have any mandrel dies. I measure wall thickness double then add dia of bullet subtract the desired amount of neck tension to come up with bushing size. I have K and M mandrels . I would have to determine if it adds run out, and have no way to judge if it increase the rate work harding occurs. could be a interesting side test.
Run your tests. I highly encourage anyone to do their own experimenting. It's joe you'll know for sure what matters and what matters to you. Your actual results are what matter, and most everyone's results tend to vary. Anything you read or any advice you get online or in books is essentially just speculation. Yes, it might come from experience, but how well can you trust the info?
Bryan Litz is pretty trustworth when it comes to shooting and reloading. He's published a ton of trustworthy data, but he will also tell you to run your own tests and decide for yourself. I agree with him 100%
