Military 308 Reloading Problem

[sjmills6901]

I recently purchased 1000 rds of once fired Military 308 brass from a reputable source. Product was advertised as being processed with primer crimp removed. Using Magtech large rifle primers and a Lee hand held priming tool, I proceeded to load a box of 147 FMJs and IMR 4895 for some fun at the range with my M1A. Got to the range and the majority of the ammo did not fire due to an extremely light primer strike. I also had several boxes of factory 308 ammo with me. All factory ammo fired without any problems. Upon inspection of the reloaded ammo which did not fire, it appears that the primer is seated a bit deeper than flush causing a light primer strike. I have always used the Lee hand primer in all of my ammo reloading and have never had this occur. with all that said I have a few questions:

1. Is it possible/probable that the brass I purchased is "defective" due to a primer pocket that is too deep maybe caused by the process used to remove the military primer crimp?
2. Is my hand priming method to blame? If so, how does one measure the extent of primer seating on a rifle case?
3. Is the brand of primer to blame for my misfortune? If so, what is the best primer to use when loading 308 ammo (147FMJ & IMR 4895) for my M1A
4. What other factors could have led to my problem at the range.

My M1A is obviously not the issue since it fired factory ammo (several different types) during this shooting session.

Your expertise is most appreciated!!!

 

[Dumpster Baby]

The most probable cause is that the shoulder has been set too far back by the sizing die, resulting in long headspace. Compare those rounds to factory ammo, dummy rounds, whatever, and see where the shoulder is compared to unfired ammo. I'll bet you see the shoulders on those lower than on factory ammo.

Primers must be no more than flush, and are usually recessed slightly. This is very rarely a problem.

 

[Grump]

1. Nope. Your cases are fine. In that design, it takes a defective firing pin or a primer more than 1/16-inch (!) too deep (as in metal is getting crushed) to create a firing pin strike light enough to do what you describe.

2. Nope.

3. Nope.

I suggest checking your resized cases' headspace dimension, AND the case OAL.

4. The other factor I would suspect is something in your reloads is stopping the bolt from fully locking closed. When the hammer falls, the camming tank on its left side hits the camming surface at the rear of the bolt and twists it the rest of the way locked. Hammer energy is so dissipated that you are either getting NO strike at all (Normal cycle-chambering leaves a tiny FP mark from the FP rattling around BEFORE locking), or the strike is, well, weak just like you diagnosed.

How hard was it to unchamber your duds? How does that compare with the factory ammo?

In a safe place and manner, put one of your duds in the chamber and drop the bolt FROM ONLY ABOUT AN INCH back from the chamber. No "slam-fires", please. What little has been conclusively-enough proven for me on that little problem includes a higher incidence with long ammo and short chambers combined...

Does the bolt rotate all the way locked? If not, ammo problem. If yes, see if it will THEN fire (better be on the range or out in the bush for this...) and then check the next dud...

Cases not sized quite enough is the usual culprit, followed by cases too long in OAL case (not cartridge) length--the casemouth jams on the front of the chamber, followed by bullets seated too long (or out of spec--too big) so they jam in the leade.

With 147 FMJs, I presume you loaded them to the crimp groove? Thought so.

If you don't have a Wilson case gage, get one. I love them simple things.

 

[Grump]

Oh, I forgot to mention what has caused clicks most often in MY reloads (the above is combined experience from everyone I've seen it happen out in the field).

The crimping operation *will* buckle the case shoulder back into the case body *when* you get a case that's longer than the ones you used to adjust your dies. The larger diameter jams the round just a hair back from fully seated in the chamber and prevents bolt rotation to the full-locked position.

Thus, we have the joys of trimming cases. *sigh*

If it's not one of those problems, I'm stumped.

 

[Wildfire]

Primers, Etc.

Hey There:
Maybe this will help you. The proper primer depth should be .003" to .005" below the surface. The Firing pin protrusion should be about .055" ....

The crimping problem is the die is set to far down. you should not need that much crimp. And yes you may have to trim to get them all the same.
A long one will buldge at the shoulder.

While you should know what your head spacing is, I do not think that is your problem from what you have said.

 

[Wildfire]

Well now.

I just read your post again. Maybe you could have a head space issue also.

 

[Jacka L Ope]

Primers must be no more than flush...

Not quite so...

To duplicate and improve upon military cartridge primer/bolt face clearance, I ream and uniform the primer pocket depth to .131" (industry specification is .132" max.), square the bottom corners and seat primers to a uniform depth of approximately .006" below flush (industry max. seating depth is .008"). I do this as an extra margin of safety against slam-fires. Performing this operation is well enough within industry standards and those cartridges perform just fine.

 

[Dumpster Baby]

That's what I meant, just didn't say it right. A flush primer would be worst case for me. All mine are seated below flush, and are seated with a Lee hand priming tool so I can feel what's going on.

A high primer would never get loaded here.

 

[Jacka L Ope]

Gotchya. Cool...

 

[USSR]

The most probable cause is that the shoulder has been set too far back by the sizing die, resulting in long headspace.

Agree. If the firing pin is being tripped (and assuming it is ok), then it is probably a case of excessive headspace caused by the shoulder being pushed too far back.

Don

 

[rcmodel]

+1 to grumps advice in posts #3 & #4.

I would suspect shoulder buckling from crimping resulting in partial locking.

A deep primer, within reason, would not make an M1/M-14 type rifle even miss a beat.

Excess headspace (caused by rifle or resizing) bad enough to cause mis-fires would result in case separations on the ones that did fire.

rcmodel

 

[Grump]

I think my original setup had resized cases having almost .040 head clearance in my chamber, based on comparisons with fired cases.

About 15% (IIRC) started separating after the second reload.

The short-loaded rounds all fired A-OK, to the tune of 2-inch groups, benched and with iron sights, at 200 measured yards.

I resize them all to max cartridge headspace now instead of minimum. Cases last longer.

 

[Grump]

I think it's now time for us to all wait for SJMills6901 to return and report.

 

[sjmills6901]

Trimming recommendation

Everyone,

Thank you for your quick replies. Obviously, I need to try again but with Trimmed cases and a close look at how the resizing die is adjusted.

QUESTIONS:
- What trimmer do you recommend for turning out a fair amount of military cases?
- What load do you recommend for 147GR FMJ using IMR 4895? Does primer choice really matter?
- Does the trim die from RCBS work well?

Thanks in advance.

PS - I will report back once I complete my mission!

 

[uneasy_rider]

I had the exact same problem when I first started reloading 308 for my M1A. My problem was case sizing and I suspect yours may be also.

I would recommend you get a case gauge and see if your resized cases fit in it properly. If they won't fit in the gauge, they probably won't work in your rifle. That as the case with my M1A, but interesting, my FAL can fire 308 ammo that doesn't quite fit in the gauge.

What kind of press are you resizing on? What lube are you using?

When I started I was using a Lee Classic Turret, and Hornady spray on One Shot Lube. I felt like there was too much flex in the Turret press to size good, so I started sizing on a single stage Lee Press and using Imperial wax, and my sizing problems went away.

 

[USSR]

Thank you for your quick replies. Obviously, I need to try again but with Trimmed cases and a close look at how the resizing die is adjusted.

QUESTIONS:
- What trimmer do you recommend for turning out a fair amount of military cases?
- What load do you recommend for 147GR FMJ using IMR 4895? Does primer choice really matter?
- Does the trim die from RCBS work well?

You do understand that trimming is only done AFTER the brass has been properly resized? Your first step should be determining what your case headspace is. This can be done with an RCBS Precision Mic. If you don't have one, or don't want to buy one, you can send a couple cases to me and I will measure them and return them to you. As for a trimmer, I like and use a Wilson trimmer. With a 144-147gr FMJBT bullet in military brass, I use 43.0gr of IMR4895 with a Winchester primer. Hope that helps.

Don

 

[dmftoy1]

Everyone,

Thank you for your quick replies. Obviously, I need to try again but with Trimmed cases and a close look at how the resizing die is adjusted.

QUESTIONS:
- What trimmer do you recommend for turning out a fair amount of military cases?
- What load do you recommend for 147GR FMJ using IMR 4895? Does primer choice really matter?
- Does the trim die from RCBS work well?

Thanks in advance.

PS - I will report back once I complete my mission!

What's your budget for a trimmer? That's the determining factory. The Giraud is the best (IMHO) if you have that kind of money. I use a Lyman Universal that I picked up used for $35 and a cheap cordless drill and can do a fair amount pretty easily. Even a manual trimmer isn't too bad if you're doing say 100 . . . .if you need to trim 300-400-500 then you will be pretty damn sick of trimming by the time you get done . .even with a cordless drill. (Never used the Giraud . .)

If I was starting out loading from scratch for the M1A (or any rifle with a free floating firing ping) then I'd be using CCI #34's as you're less likely to experience a slamfire.

Just my .02

Regards,
Dave

 

[86thecat]

If the brass was processed when purchased the seller may have used a small base die which also set the shoulder back, causing an excess headspace condition.

 

[strat81]

For a trimmer, Giraud is top of the line. If you can't swing that, the Possum Hollow Kwick Case Trimmer with Power Adapter is the way to go.

Go to dillon.com and buy a stainless steel gage too.

 

[davecampperry]

Also possible, when the GI crimp was removed, the brass 'flowed' out and back, creating a ridge on the base of the case. Set a case base down on a piece of glass and see if it 'rocks'.Just imagine this and you will 'see' how this would prevent the hammer from fully engaging the firing pin, and the bolt from closing fully. Most likely, as stated above the brass is from an M60 and is too long, preventing full bolt closure, and causing an aneurism in the case about one inch forward of the base. This weak spot will cause excessive 'seal' in the chamber and prevent extraction.

 

[sjmills6901]

M1A Reloading Challenge - Updated

Based on the advice provided I have obtained some Imperial Sizing Wax. After all of this adivce I am convinced that my problem is in the resizing of the cases. I also obtained a L.E. Wilson Cartridge Headspace Gage in .308 which revealed a difference between factory ammo and my reloaded ammo. Here is my new question:

** I am using Lee dies. Would I be better served with a "small base" resizing die from Redding for example than the Lee standard die??
** My M1A is a "loaded" version with a stainless NM barrell. Doe s this barrell require me to do anything different when reloading ammo for it??

 

[uneasy_rider]

I have resized several thousand machine gun fired 7.62 cases in the last couple of months. Several people had recommended a small base die, so I got one from RCBS. I did not find it helpful. Nearly every case would size just fine on the Lee die. And this is machine gun brass, which is notoriously hard to resize because it has been fired in a sloppy machine gun chamber. Of those that did not fit after being sized with the Lee die, very few could be resized with the RCBS small base die so they would fit in the gage. So few in fact were corrected by the small base die, that I stopped using it completely, and just throw cases that the Lee die can't resize in the recycle bucket. The small base die could not salvage enough brass to pay for itself.

If your Lee die will size your brass so it fits in your case gage, then it will chamber in your M1A. If it fits, it fits, and doesn't need to go through a small base die.

Your barrel does not require anything special. Trim your brass to 2.005" and load to an OAL that allows you to still get the cartridges in your magazine, and you will be fine.

 

[Roadkill]

I had exactly the same problem with my Polytech M14S. I put primers in about ten empty cases. I ran one through the sizing die then chambered it and pulled trigger. No strike. Backed the sizing die off a half turn and did the same with the next primed case. No ignition, light strike. Backed sizing die off 1/4 turn. No ignition, heavier strike. Backed off again. Next case POP! Backed it off 1/4 turn more, got solid ignition for remainder of cases. Using 43g IMR4895 with pulled .308s the gun functions flawlessly now.