308 sizing help using bulk machine gun brass

[Ray123]

The last year or so I have a buddy that bought a few AR10's, and then bought bulk machine gun brass to reload.
I ran the brass through my normal 308 sizing die, trimmed it to length (to 2.005), and it is still does not chamber in his rifles.
Factory rounds do. I measured the base of the cases that I had resized, and they all measure .468 (same as my new factory Lapua brass).

If you have had experience with before, can you point me in the right direction?

Will a small base die size the bottom of the case a few thousands more? I have never used one before, so not sure what to expect.

I am loading 168grn amax to OAL of 2.800

Machinegun brass? How can ya tell?... some machineguns leave vertical grooves in the brass not suitable for reloading. I use lots of military brass, LC 2018 the last 500 batch...All of my 5 308s chamber the same military brass, 2 target rifles, 1 hunting rifle and 2 ar 10s from the same dies. I have Lee, RCBs, Redding, and now use mostly Wilson dies in 308 Win., None are small base dies... same die setting for all rifles... I chambered the 3 bolt guns, same reamer... but the AR 10s are factory 1 Schilen, and 1 Hanson. I use a Wilson 308 chamber gauge and set the die to minimum, with a drop indicator on a surface plate. All the bolt guns are at Minimum...the auto then have about .002 to .003 heads head space play, all 308s chamber the same ammo except some of the over length target ammo 200 CN Sierra MK & 225 ELDM etc...but "regular" ammo fits all the .308 Win chambers. Weight sort them and shot the LC mil brass side by side with Lapua brass...same powder charge, same bullet...
The Lapua brass only slightly beat out the weight sorted Military brass in this one experiment. This cheap brass has shot 10 shots into an inch out of an 18" AR 10, with cheap 168 Speer bullets, at 100 yds. Only my 224 Valkyrie and the 6 mm ARC are small base dies. The rest are standard base dies...if it fits the minimum ledge of the Wilson chamber gauge it will fit any properly chanbered rifle...308 or .223, thats been my experience for 50 years. I have seen chamber/ die miss matches... and worn chamber reamers used.. in these high production times...and returned a couple of barrels and an AR Barrel from reputable manufacturers and kept one barrel but rechambered it ...have several AR barrels that are just crap they will never shoot replace with Proof Research barrels, ...a bore scope is a handy tool.

 

[Uncle Ed]

Resized brass after sizing wants to "spring back" to its fired size, length, and diameter.

This is no problem with new cases fired in your chamber with a proper size die. "BUT" the spring back from cases not fired in your chamber can cause a problem.

To reduce brass spring back, pause at the top of the sizing operation for 3 to 5 seconds. This will make the "mixed" brass more uniform in diameter and shoulder location after sizing.

 

[PracticalTactical]

The last year or so I have a buddy that bought a few AR10's, and then bought bulk machine gun brass to reload.
I ran the brass through my normal 308 sizing die, trimmed it to length (to 2.005), and it is still does not chamber in his rifles.
Factory rounds do. I measured the base of the cases that I had resized, and they all measure .468 (same as my new factory Lapua brass).

If you have had experience with before, can you point me in the right direction?

Will a small base die size the bottom of the case a few thousands more? I have never used one before, so not sure what to expect.

I am loading 168grn amax to OAL of 2.800

I do the same thing... I buy bulk once fired military brass but I process it for competition. No, I'm not crazy... I just have a process...

There's lots of hate in this thread for such a practice but I think guys just haven't thought it through from a bang for your buck perspective. If you know what your doing, you can overcome the obstacles.

To address your concern, the result you are having should be expected actually and I would not suggest that you should be using a progressive press for the first time processing the brass.

Instead I would suggest that you do like I do and size the brass twice... Once with a regular sizing die, then again with a small base sizing die. This means no progressive press. If you begin with a small base sizing die, you will likely get cases stuck in the die. So the two sizing die process saves you from that frustration.

You can buy such brass and effectively use it for competition if you buy and process alot of it, then sort it into lots of identical weight. Personally I buy quantities of at least 3,000 and process all of it. In the end I will get about half of it in lots of 300 or so that are within 0.1 grains. The rest break into lots of maybe 50 or so that are within about 0.1 grains but once put together makes lots of 100 within 0.2 grains which is still very close.

I personally neck turn and anneal all the cases after sizing, but that's up to you.

Once you fire it once in your rifle it's a good as anything.

If you do what I describe here you can use such brass even for F Class... I do and cannot see a functional difference compared to Lapua at ten times the cost.

 

[Ray123]

The last year or so I have a buddy that bought a few AR10's, and then bought bulk machine gun brass to reload.
I ran the brass through my normal 308 sizing die, trimmed it to length (to 2.005), and it is still does not chamber in his rifles.
Factory rounds do. I measured the base of the cases that I had resized, and they all measure .468 (same as my new factory Lapua brass).

If you have had experience with before, can you point me in the right direction?

Will a small base die size the bottom of the case a few thousands more? I have never used one before, so not sure what to expect.

I am loading 168grn amax to OAL of 2.800

The last year or so I have a buddy that bought a few AR10's, and then bought bulk machine gun brass to reload.
I ran the brass through my normal 308 sizing die, trimmed it to length (to 2.005), and it is still does not chamber in his rifles.
Factory rounds do. I measured the base of the cases that I had resized, and they all measure .468 (same as my new factory Lapua brass).

If you have had experience with before, can you point me in the right direction?

Will a small base die size the bottom of the case a few thousands more? I have never used one before, so not sure what to expect.

I am loading 168grn amax to OAL of 2.800

Most all military brass is Machinegun brass, as most have semi auto or full auto selector...except the bolt action sniper rifles. The problem is all the old worn chambers in many of the rifles. A no go gauge is perfectly fine if it chambers...they have a larger field gauge to check the chamber...and if that goes in the weapon is still serviceable.. then last is emergency use authorization...the chamber is way out but considered safe enough to use, until it can be repaired. The military doesn't care if the brass is hard for you to resize. The fired military brass cases come in a variety of sizes in spec and out of spec for civilian use. So get a Wilson or similar 308 chamber gauge for the 308 in your case. Next a Redding 308 shoulder bump die, if there seems to be too much spring back with regular dies. Use the gauge along with your dies to get the minimum head space and that which fits your chamber. I use regular base sizing dies and the chamber Guage, to get my head space, plus I have the shoulder bump die to push it back even farther if necessary...but that's not nessary in most cases. Min or .001 above fits all 5 308s I have with all range fired brass including 2 AR 10s., Fired in full auto or semi from the same gun or a SAW depending on the age and condition of the weapon, the military brass comes in all shapes and sizes...some much better than others, so ya gotta work with what ya get, and even discard a few.