Inconsistent shoulder bump driving me crazy….help?

[BoydAllen]

A couple of things that I would like to know:
How are you annealing? Have you seen any advantage that you attribute to annealing, for this rifle?

Another thing, a friend was having trouble getting consistent bump with a press that does not cam over, a Lee Classic cast iron. He switched to his Rock Chucker, that does, and the problem was reduced considerably.

I don't follow the trends of reloading for semiautomatics, so I may be off base, but before this thread, I had not heard of annealing for a semiautomatic. It would seem to me that shoulders could become too soft, and be set back by forceful chambering. It would be interesting to do some shooting where two shots were fired, from the magazine, the first letting the bolt/carrier strip the round from the magazine, the second loaded by semiautomatic function as a result of the first round firing, and what would be the third unloaded after chambering by semiautomatic function (by the firing of the second) and measured for "headspace". Of course the rounds would have to be measured and recorded when the magazine was loaded. From this, you could learn is annealing was having any effect on the shoulder position of rounds as they were chambered, not the question that this thread was written to address, but nevertheless related.

What ever you do, having a setup that has the shell holder making contact with the die, while at the same time having the die set for the proper amount of bump, is an advantage as far as bump consistency is concerned, especially for springy brass that has a lot of variability of hardness. If it turns out that annealing makes shoulders too soft (the purpose of the above test), and you think that differences in bump show up on the target, your only alternative may be to resize the springier brass (a second time) with a slightly lower die setting, to get to where the rest of the cases are.

For a bolt rifle, this issue is easily solved by consistent annealing. A friend bought an annealing machine to address the problem for his 7mm WSM and .338 Lapua, and it solved the problem, but if there are other problems associated with annealing for your application, or you are creating problems with inconsistent annealing, you may need to stop annealing, or find a way to do it in a more consistent manner.

Personally, I think that most semiautomatic shooters never anneal, and are not concerned with variation of shoulder bump, as long as the cases with the longest "headspace" have the minimum required clearance. This may be because rifles of this type are mostly fired supported in a manner that would let the differences that annealing, and closer control of bump might provide, get "lost in the noise".

 

[jlow]

Hi Boyd,

Yes, my loads are for a semi-auto but most of the shooting I am doing requires me to single load, so I actually rarely fire from the mag except for the 2-gun tactical matches I shoot but those I shoot off my 16” carbine with Wolfs.

I have seen benefits from annealing as my shoulder bumps are better, but obviously not where I want them to be yet. My neck tension with my neck turn brass has also been much more consistent and I can get my roundout to 1-2 thousands and SDEV now down to the teens which is much better than the old days. Groups are now consistently sub-MOA but could benefit from further improvement. I am still learning and so picking at my problems one at a time.

I have never used a cam over press and so cannot tell you if it is any better. I started reloading with a turret and switched over to the current Lee and have been happy with it. Not likely to switch unless the changes I listed above does not get me to where I want to go. It’s a learning/evolution process for me and I like to take it one step at a time so that I know if I change something, it really matters. If I need to switch to a different press, I will.

I have similar questions about firing some of my rounds in semi-auto fashion vs. single load but frankly it is on the back burner. My neck tension is intentionally high than normal i.e. slightly greater than 2 thousands with this anticipated test in mind. What I can say is that both the current loads I have for my 223 and 308 will fit in a mag so the test will come.

As mentioned previously, I hand anneal with a socket/drill setup using a stopwatch to gauge the time. I acknowledge that this will not be as reproducible as using either a Bench-Source or Giraud, but again, this is part of my learning/evolving with reloading.

I may be a closet bolt action/benchrest shooter but thus far I am having fun and the learnings and limited success I have makes me happy.