New Reloading Method for me

[nicholasjohn]

Bolt lift

or I do it by the Hodgdon method...LINK,
I find their max to be a bit conservative...

When you employ the Hodgdon method, are you using a blade micrometer ? Also, how do you make sure that you're measuring at the same distance from the case head every time ? This has all been a bit tricky for me in the past, and any tricks you can tell me about would be greatly appreciated.

 

[nksmfamjp]

When you employ the Hodgdon method, are you using a blade micrometer ? Also, how do you make sure that you're measuring at the same distance from the case head every time ? This has all been a bit tricky for me in the past, and any tricks you can tell me about would be greatly appreciated.

In all of the rounds I do this for, I'm measuring the max diameter at the head, not including the rim. A normal micrometer works for me.

 

[User4302021]

How are you guys measuring case head expansion ?

Mitutoyo micrometer.

 

[nicholasjohn]

In all of the rounds I do this for, I'm measuring the max diameter at the head, not including the rim. A normal micrometer works for me.

I've found that the pressure ring on the case body is slightly bigger around than the case head is just ahead of the extractor groove. ( So is the rim.) If I use a regular micrometer, I'm not really measuring the case head diameter. What is being is measured is the expanded case WALLS. How do you get around measuring that diameter, and get a clean measurement of the case head diameter ?

I use a blade micrometer, C-clamped to a table top, and stand the cartridge case on a flat piece of steel that elevates the case off the table just enough to put it between the blades at a repeatable height each time. I also mark each case, so that I'm measuring the same spot around its circumference that was measured before firing. ( Most cases aren't perfectly round, nor do they all measure the same size.) This is providing repeatable results, but it is sure a lot of monkeying around to do so. I haven't yet found a way to do this more handily, and still get good measurements.

There's a detailed write-up about this process in Nick Harvey's Practical Reloading Manual. He stresses the importance of using a case that has not been fired ( and work-hardened ) for making these measurements. He also recommends filing a flat spot on two opposing sides of the rim of the case, so that it won't interfere with the micrometer posts. ( This negates the need for the blade micrometer.) While this enables the accurate measurement of the largest diameter of the case head, it pretty much ruins the case for further use.

Lastly, what do these measurements mean ? Dave Skovill did a study years ago, with a wildcat cartridge based on the 9.3 X 62mm cartridge, which is very similar dimensionally to the 30-06 case at the head end. He did actual pressure measurements of his loads, as well as case head measurements, to see how they coincided. As I recall, .0005" of expansion at the case head coincided with 60,000 PSI with extreme regularity. He showed other values as well, and I have found that most factory loads on the 30-06 case head cartridges expanded .0003" in my rifles. I use .0005" as maximum for my use, and have been doing this for a couple of decades without any trouble. I may be leaving something on the table for velocity, but I have never stuck a case in a chamber. At this level of expansion, I have also gotten a little bit better than advertised factory load velocities - usually 50 to 60 fps. The only thing I really don't like about this process is that it is very tedious, and it's difficult to do on cold days.

 

[P7M13]

Dood, my eyes glazed over at the number of strings and the need for a calculator. If your method works great, rock on. I prefer KISS.

#2 How does someone determine the best powder/primer combo

This sometimes works.

[edit to add] I think using Hodgdon's case expansion rule of thumb, given the variability I've seen in brass alloys from manufacturer to manufacturer, is little better than good ol' Kentucky Windage.

 

[nksmfamjp]

Dood, my eyes glazed over at the number of strings and the need for a calculator. If your method works great, rock on. I prefer KISS.


This sometimes works.
View attachment 195642

[edit to add] I think using Hodgdon's case expansion rule of thumb, given the variability I've seen in brass alloys from manufacturer to manufacturer, is little better than good ol' Kentucky Windage.

I'm kind of doing lucky eight ball now. I'm hoping to get better!

 

[Patriot007]

""Run a ladder of my lowest acceptable velocity thru a couple grains over max""

The term " a couple of grains over max " just scares me to death. May I suggest you start with a LOAD DATA MANUAL.
Then start your ladder test some where in the middle of the suggested weight charge. Then work up to the max charge
looking for pressure signs.
If you are using a chrono, log your data and look for a nod. You should see a low nod and a high nod. I would work around the high nod to find my load, and I'm always looking for pressure signs.
As far as bullet seating, I would suggest starting at least .0025 to .0030 of the lands. This will help with throat erosion, and barrel life. Just my 2 cents.

 

[nksmfamjp]

May I suggest you start with a LOAD DATA MANUAL

I have 3 plus, all the manufacturers online and my subscription to loaddata.com. I'm pretty well covered, but might get the Berger book soon.

I should be a bit more clear. When I load in longer barrels, with longer free bore and with other change points, grabbing a book load isn't bad, but it is usually a hair off ideal. I can see loads getting hot. I can feel bolt lift. I don't shoot loads after I feel bolt lift. Counter productive, IMO.

 

[nicholasjohn]

Dood, my eyes glazed over at the number of strings and the need for a calculator. If your method works great, rock on. I prefer KISS.


This sometimes works.
View attachment 195642

[edit to add] I think using Hodgdon's case expansion rule of thumb, given the variability I've seen in brass alloys from manufacturer to manufacturer, is little better than good ol' Kentucky Windage.

Have you ever tried it ?

 

[Patriot007]

I have 3 plus, all the manufacturers online and my subscription to loaddata.com. I'm pretty well covered, but might get the Berger book soon.

I should be a bit more clear. When I load in longer barrels, with longer free bore and with other change points, grabbing a book load isn't bad, but it is usually a hair off ideal. I can see loads getting hot. I can feel bolt lift. I don't shoot loads after I feel bolt lift. Counter productive, IMO.

LOL, I'm glad to see I'm not the only one on here that is a member of Loaddata.com. I don't think I fully got the point in your 1st post. I kind of see where your coming from now. I will say this, I have never found any load data that worked perfect in my rifles. I had to use them as a reference point and work from there. When I get a heavy bolt lift, I bump my shoulder back about .0002, but then again, part of my case prep is bumping the shoulder back .002, so that is never an issue.
One thing is a fact. When you fire a shot and the bolt is sticking, you probably surpassed the max pressure point.
There's nothing like the site of bolt slap on the base of the case.
Back when I first started reloading, no chrono, and magic spells, I was trying to perfect my loads similar to your post.
That was a many rabbit holes and grey hairs ago. The way I would approach your problem would be find the max load with no signs of pressure and work my loads down in .0003 gn increments and watch for point of impact on the target.
once I found a load with a good small group. I would work with that charge weight and try adjusting my bullet seating death. Hopefully, I found an acceptable load for that rifle, and bullet, with a small group.
Also, if you change a component like a primer, bullet, case, powder you will have to start you latter test all over again.
I'm CCI primer fan, but I fined my self shooting more Federal match magnum primers in my CreedMoor and 308.
They give me the most bang for the buck and there **** good primers. That way primers will not be an issue for you.

 

[Skimbleshanks]

I start with seating depth at a min load. Then I move to 3 shot groups at 100 with either .5 or .2 grain increments depending on case size. A couple groups will probably be promising. Reload those charge weights and re shoot groups farther out. Nothing fancy.

 

[P7M13]

Have you ever tried it ?

Vague question, so I'll take multiple stabs.
Eight ball? Yes, when considering dating chicks in college and whether to eat the food my kids brought me.
His work-up method? No, but I'm not working up loads for 600 or 1000 yard PRS.
The Hodgdon case head expansion rule of thumb? Definitely not and never will.

 

[nicholasjohn]

Vague question, so I'll take multiple stabs.
Eight ball? Yes, when considering dating chicks in college and whether to eat the food my kids brought me.
His work-up method? No, but I'm not working up loads for 600 or 1000 yard PRS.
The Hodgdon case head expansion rule of thumb? Definitely not and never will.

It actually works quite well, and it's based on the old copper crusher pressure measuring methodology that used to be employed in the ammunition manufacturing industry. It doesn't require the use of a calculator, as you mentioned in your first response. It is a tedious process, but no more so than most of the other brass preparation tasks we routinely do. I think it's probably somewhat more precise than your preferred eight-ball method.

 

[P7M13]

It actually works quite well, and it's based on the old copper crusher pressure measuring methodology that used to be employed in the ammunition manufacturing industry. It doesn't require the use of a calculator, as you mentioned in your first response. It is a tedious process, but no more so than most of the other brass preparation tasks we routinely do. I think it's probably somewhat more precise than your preferred eight-ball method.

I mean no offense.
Problem is, CUP uses known, calibrated alloys, methodology and equipment.
IMO, chamber differences, brass alloy differences and measurement methodology make enough variables that, for someone not familiar or inexperienced, is an invitation to potential disaster.
As to alloys, look at the differences in brass behavior between Hornady, Lapua and PPU brass. While I havent measured case expansion, I have recent tests where the same load in the same rifle ruptured R-P and PPU brass but not Lapua or Norma brass.
Years ago, I stopped obsessing about velocity and with that, stopped pushing the limits, and no more pressure signs.
Ultimately it's about precision and accuracy.
I imagine your measurements are valid for your methods and rifle. Do your thing.
I know men who can lick their finger and tell you wind speed, who can look at different flags or mirages and accurately gauge how it will affect their shot. I am in awe of them. My personal favorites are the golfers I knew as a caddie who could read the green and had the skill to place their shot so it rolled close to the cup. When they could do it 10 out of 18 times, it wasn't luck.