Sizing for minimum headspace in M1A?

[Fatelvis]

Please tell me if this would work to size for minimum headspace in a M1A.:
1) Fire a cartridge with gas system turned off.
2) Neck size and reload catridge.
3) Fire again with gas system turned off.
4) Run this case up into your press using the #10 Redding Comp shellholder.
5) Screw a Forster Shoulder bump die (w/o bushing) into press until the case's shoulder touches the die's shoulder.
6) Lock die in place using die's lockring.
7) Replace #10 shellholder with #8 shellholder.
8) Install proper bushing.
9) Size case.
Would this be a good way of sizing a case, and giving .002" headspace in a given M1A? Please let me know of any problems, tips, or corrections you can see. Thanks!

 

[insight3b]

Re: Sizing for minimum headspace in M1A?

The second firing after neck sizing with the spindle valve turned off will require repeated beating of the op rod handle with a rubber mallet to extract the case from the chamber

 

[Fatelvis]

Re: Sizing for minimum headspace in M1A?

Would just one firing be sufficient?

 

[insight3b]

Re: Sizing for minimum headspace in M1A?

Still very difficult to extract after 1 firing bit would give a truer reading of your chamber. Do you still have the hang tag from the trigger guard. SA always fills out a hang tag with exact chamber spec for each new rifle. A much safer and easier way to get your chamber dimension s to cerrosafe mold the chamber and measure the cast

 

[RyanMcIntyre]

Re: Sizing for minimum headspace in M1A?

Those are accurate rifles, but I think you're overestimating the potential and getting too concerned over techniques that aren't going to give you positive results.

Fire the case once, get yourself some headspace gauges, and full-length size your brass to push the shoulder back 2-3 thou.

 

[M14 Shooter]

Re: Sizing for minimum headspace in M1A?

Use the Hornaday Tool to Measure fired cases from your M1-A.Size them .002-.003 under that size.You probably want to use a small base die with your match M1-A chamber.I like to use Imperial Sizing Wax for sizing.It help give me consistent results sizing.Its also good to wait a second on the bottom down stoke on your press.It helps with consistency.
It helps starting with new brass.IMHO LC-Match,LC LR and Lapua are the best brass for use in gas gun.Stay away from Federal or Winchester and remington for second firing.

Regards,Mike

 

[ksthomas]

Re: Sizing for minimum headspace in M1A?

Tons of potential problems here. Forget about setting headspace at .001" or .002" in an M1A, that's not enough. These are Service Rifles, not Benchrest guns, and the loading procedures are totally different. Several of the steps for accuracy oriented bolt guns can actually become hazards when they're used in a gas gun. Setting the headspace this close is one of those potential problem areas, and can easly lead to slam fires or possibly out of battery firing.

What are you trying to accomplish by setting the headspace this closely, anyway?

 

[K2Ballistics]

Re: Sizing for minimum headspace in M1A?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kevin Thomas</div><div class="ubbcode-body">Tons of potential problems here. Forget about setting headspace at .001" or .002" in an M1A, that's not enough. These are Service Rifles, not Benchrest guns, and the loading procedures are totally different. Several of the steps for accuracy oriented bolt guns can actually become hazards when they're used in a gas gun. Setting the headspace this close is one of those potential problem areas, and can easly lead to slam fires or possibly out of battery firing.

What are you trying to accomplish by setting the headspace this closely, anyway? </div></div>

Exactly. I run all of my gas guns at .004-.005. Cuts down dramatically on the FTF and FTE's with no discernable change in accuracy.

 

[Fatelvis]

Re: Sizing for minimum headspace in M1A?

I am looking primarily to extend brass life, and maybe tweak a little more accuracy out of the load. I had a Match M1A previously that I had case head seps after just two loadings, and although I have a different rifle now, I really would like to get more life out of my cases in this rifle! Lol

 

[FLIGHT762]

Re: Sizing for minimum headspace in M1A?

For an M1-A/M-14, you should toss the brass after 4 firings. The M1-A beats the brass badly. Firing any more than that and you risk separations. I would turn off the gas and fire 5 or so rounds, measure the headspace and bump the shoulder .003"-.005".

Read these two downloads; Reloading for the M-14 and Once fired twice fired.

http://www.zediker.com/downloads/m14.html

I've owned and reloaded for an M1-A since the early 1970's.

It is what it is.

 

[Michael]

Re: Sizing for minimum headspace in M1A?

I head space mine to .002. Should say did, cuz I haven't shot since 2008.
Anyway, I have a springfield -21 in which they were carefull to cut a nice chamber so I paid attantion.
Didn't help accuracy, and with the aid of an adjustable gas plug to slow the action I did manage to get 8 reliable firings from my cases before paranoia set it and I tossed them at that point.
I would dremel cut 1 case after each firing to do a visual inspection of the case head. At firing 8 one could see the start of a thinning band which eventually would cause failure.
This timeline was fairly consistant using BH brass and 40.1 grains H4895 behind 175 smk's for 2550 fps chrono reading.

Have not tried other brands of brass, or any milsusrp so I don't know how that would have looked.

To the point of the original poster, one can extend brass life and delay onset web fatigue by paying attention to the head space settings. But having had a standard grade M1A fire with an undersized case and bolt that "looked" locked but was not fully engaged,I would urge caution. It's a decidedly unpleasent experience emphasizing the need for shooting glasses, a new magazine and a bunch of trigger group parts.