Obsessing about M1 brass

[Khornet]

Alert readers may recall a thread I started awhile back about how much brass prep is necessay for M1 shooting. I had bought a bunch of LC brass from USSR (Don), and I sorted by weight until I had 25 cases all within 0.5 grains, then uniformed the primer pockets, reamed the flash hole, and turned the necks. I then loaded them with 46.5 gr I4895, a Federal match primer, and Hornady 168 gr. match bullet. Then I laoded another batch the same way with no brass prep.

The rifle is a 1950s H&R, glass bedded, rebarreled with a Douglas barrel, trigger job, NM sights, etc. by Roland Beaver.

Finally got a good day to do a comparison shoot. The loads chrono 2550 on average, with a standard deviation in the mid-teens.

The top target is prepped brass. Each is one 8-round clip from sandbags at 100 yd.

Unprepped brass gave a roughly 4" group extreme spread. Prepped gave me a hair over 2". Worth it? You be the judge.

 

[Khornet]

I should add

that I haven't had time to work up the optimal load for this bullet yet, and I don't see all that well anymore. I need to get a younger shooter to test these loads.

 

[USSR]

Khornet,

Ya got me sold on the benefits of match prepping brass.

Don

 

[30Cal]

I don't think anyone doubts the benefits of prepping brass. The big question is: which steps make a significant difference in accuracy and which ones don't.

I trim, uniform primer pockets, and deburr the flashholes, but that's it. I get the same results out of my bedded M1 whether I use LC72NM brass culled by weight as I do with mixed LC66 & LC69--a little over a minute when I'm doing my part. FWIW, I shoot 45.5grs IMR4895 with the 168--a little bit lighter than most folks use, but it works well across the board in my M1's and 03's.

 

[YellowLab]

It looks that only 1 shot out of the unprepped brass (the one at about 2 oclock) widened the group excessivly.

Take that ONE shot out and they are pretty much the same size.

All that work, not really that much improvement from the limited testing.

I'll just ram the brass into the sizing die and leave it at that.

 

[Grump]

I'm curious about this--I never had a 4-inch M1 group with match bullets, even when it was the stock H&R barrel.

You gotta match tube.

My 168-gr load is 47.5 4064. I had only one batch with flash holes chamfered (and one or two old FA batches with raggedy-old sorta chamfering because the punch knocked the corners off the insides...think what happens when you're slicing to the end of that block of cheese). With the stock barrel and no case prep, SMKs and Hornadys ran 2.5 MOA or better. With an Armscorp medium-heavy match barrel, it went to 1.66 MOA no matter what I did with the cases...average...best was maybe 1.1 inches, 5-round groups.

 

[Khornet]

Yes, that one shot

ruins the group. But that kind of thing happens with EVERY clip for me, except with the batch of match-prepped brass. So there is definitely a significant gain. Whether it's worth the effort is up to the shooter. It's a HOBBY for gosh sakes.

Grumpy, it's a Douglas match barrel. Before I sent it to be accurized, it had a Springfield barrel, and the best I could do was 4 MOA. I have fired 1.2 MOA twice, back to back, since it was accurized. But in general, the problem is I can't see well enough anymore to really know what this rifle can do. That's why I said I'll have to get a younger shooter to try it.