How anal to be over M1 brass?

[Khornet]

I've always done no more than resize, clean primer pocket, and reload. I use an X-die so trimming isn't needed so far.

For a bolt gun I usually sort brass by weight (all same headstamp) then uniform the primer pocket, ream the flash hole, and turn the neck. 'course, these are always neck-sized with a Sinclair hand die.

A commenter elsewhere said he uniforms pockets for his AR for match shooting. My M1 is match barrelled, glass bedded, etc. Anybody take this much trouble with their M1 brass?

 

[USSR]

I heartily recommend primer pocket uniforming brass for an M1, if for no other reason than to ensure that the primer is seated deep enough to preclude a slamfire.

Don

 

[Khornet]

Don,

looks like you did the pockets on all that LC M1 brass you sold me. If so, bless you. That makes it an even better deal. That's a tedious job.

Anyway, last night I did the full process on some of that brass, weighing until I had 30 cases between 192.5 and 193 grains, then all the other steps. Now to load 'em with 168 match bullets and Federal Match primers.

 

[USSR]

Yeah, flash hole was deburred on that brass as well. Then, sorting them by weight as you have done, and you are good-to-go. BTW, it wouldn't hurt anything to expand the case weight variability from .5gr to 1.0gr with those cases. What powder you using?

Don

 

[Khornet]

IMR 4895

47.5 or 48 gr for 150 gr bullet, 44.2 for 168 gr. Haven't experimented all that much since getting the rifle rebarreled.

 

[USSR]

Let me know how it turns out. Especially interested in knowing what velocities you get if you have a chrony.

Don

 

[Khornet]

Yep, I have a chrono

with this brass, and no other treatment than what you gave it, using 173 gr M72 pulldown match bullets from Bartlett, and 46 gr 4895, I clocked 'em at 2550 fps average, with standard deviation of 18. Same brass, same treatment, 48 gr 4895 and 150 gr FMJBT goes 2720 average. 48.9 gr gives me about 2800.

I have trouble shooting for groups through a chrono; either I misalign with respect to the photocells or I chrono well but don't group. Plus I can't see all that well with iron sights. I'd like to get my target loads right around 2600. Primed 'em up last night, hope to shoot 'em tomorrow.

 

[P-32]

Uniforming the primer pockets on GI brass reduced my group the most out of everything I do for prep for my M-1's. Uniforming the primer pocket also helps keeps the primer from sitting too high or even flush.

Khornet, I have to suggest not using the Federal primers in the M-1. The reason for this is the M-1 has a free floating firing pin as does all auto loading USGI rifles. Because of this, the firing pin hits the primer and "dimples" it (very light but easy to see) when the round is chambered. I'm sure you've seen it, even when using USGI ball. Out of all the common primer makers the Federals are the most sensitive. I understand the reason why someone would what to use them as they do reduce group size. I have had good luck with CCI standard large rifle primers. I have not tried the CCI large rifle B/R primers and maybe one of these days I will just to see. It seems in the 20 or so years of owning and shooting an M-1, all of the slam fires I have heard of are with Federal primers and most likely to happen during single loading rounds. I use a S.L.E.D. device for single loading which seems to have stopped the slam fire issue. These are availible from Creedmore Sports or Champions Choice. Even using a SLED I can not recommend Federal Primers.

I do have a 308 M-1 which has been match tuned. The gun plummer sprung the firing pin when he worked it over. (sorta slick too) I do use the Federal match primers in this rifle. But I am very careful and check each round for the primer to be below flush. The primers are still dimpled when chambered but to a lesser degree. (still use the SLED)

I also have a tuned up match AR which I'm currently shooting. I try to use Rem 7 1/2 BR primers for this rifle, but my favorite store ran out of them. So I tried Federal small rifle match primers. My loads are not real hot like some of the other AR shooters use but I had 4 pierced primers which took out my firing pin. Yeah, I dressed it up but no more Federal small rifle primers for me. And really there is no real difference in group size when compairing CCI B/R's to the Rem 7 1/2's.

Sorry for the long rant. I would shoot what you have loaded but not use the Federals any more. Oh, and one more thing......sorting brass by weight might help with the 600 yard line, but for 2 and 300 yards you are not going to see much difference. And it will just get you mad when the brass gods take one or two.

 

[Dave P]

"expand the case weight variability from .5gr to 1.0gr with those cases"

I agree, I think I go about +- 2 grains even.

Don't tell anyone, but I also turn the necks on my match brass. I shot this M1 in a 600 yrd match last week, and was scoring 180-185's (Expert level).

Dave

 

[Grumulkin]

M1 Brass

You might also check the brass to see if the primer pockets are centered in the flash hole. I can't think that uncentered flash holes would do anything but hurt accuracy and in a recent batch of M1 brass I went through, a large proportion had this defect.

 

[Khornet]

Firing pin is sprung

and I don't single load anyway. Chambered rounds do have a faint- and I maen faint-dimple now, which I'd never have noticed had I not been looking for it. I'm not worried about Federal primers.

 

[P-32]

and I don't single load anyway. Chambered rounds do have a faint- and I maen faint-dimple now, which I'd never have noticed had I not been looking for it. I'm not worried about Federal primers.

You need to get that thing in a match then. Sounds like all the work has been done. Who did the plumming?

 

[30Cal]

I uniform primer pockets, but only for slamfire concerns. I also deburr flashholes, mostly because it's pretty quick and easy to do.

Those 173gr FMJ "Match" bullets will vary in weight by as much as +/- 1.5grs. If you are weighing anything, you should be weighing them, and even then a commercial match bullet still work better.

I don't have an M1 that shoots consistant enough to tell anything meaningful about sorting brass by weight, but with my match M1A, I've shot 197's on the slow prone reduced targets (194 is my best at 600yds)--without culling brass and without weighing charges.

Ty

 

[Khornet]

P32,

work was done by Roland Beaver, Old Corps Weaponry.

30 Cal, I've gotten 1.2" 5-shot 100 yd groups with those bullets, two back to back. On a second occasion I got only 2-3". However, the light was poor that day and I was having trouble seeing. It was foggy, also. At least that's my story.

 

[Grump]

If you can get an aperature front sight for that M1, use it for your ammo testing. Some guy out of Reno or Sparks or Gardnerville NV used to make 'em, but I forgetted his name. There's nothing like just putting that fuzzy bull inside a crisp black donut centered in your rear sight to make the vision complications irrelevant to your group sizes!

By using stick powder, you are eliminating one very dangerous type of slam-fire--the high primer blocked by spherical powder inside the primer pocket. The breechface of the bolt by itself *will* bang your primers on seating the cartridge if that happens. Yes, it requires a high primer. I had to pull a bunch of brass once 'cause the pockets were loose (once-fired stuff!!!) and they were otherwise destined for use in a semiauto.

No real need to get all that anal with M1 brass if you're shooting 173s. One test I saw from the 1980s showed those bullets could do 3/4 MOA or maybe less--from custom barrel bolt guns. In the M14-type, they were between 1 and 1.5 MOA, IIRC.

 

[USSR]

Never could get those 173gr M72/M118 Match bullets to shoot good, even after sorting them by weight. Maybe if I sorted them by ogive-to-base measurements -- but commercial bullet are so much better.

Don

 

[30Cal]

Some batches of those 173's are probably a lot better than others. I've got one big can I got from the CMP back when they carried them. I get some good groups out of them, but not consistantly (not like a Sierra).

 

[P-32]

Khornet, I sent you a PM. Roland does a nice job of it.