The dream: M1a and hunting

The round is capable, the rifle is capable, it a matter of getting it to where the shot can be taken.

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That sums up the problem very nicely.

Okay, the why nots. Let's get that out of the way. Assuming that it is legal to use a semi-auto for hunting in your area, we will bypass that argument. Rather, the main reason not to is that they tend to be several pounds heavier than a bolt action rifle in the same cartridge with the same barrel weight and contour. Even without a 20 round magazine inserted (and that's the only type of M1A magazine I acknowledge exists), you're still talking about a 9 or 10 pound rifle, empty, and without optics. You could easily set up an 18 inch barrel bolt action rifle with optics at under 8 pounds.

However, if you don't mind the weight, there is absolutely no reason not to use it hunting. I have used mine and have taken several deer with it. Sorry no elk. I use iron sights and found that in my rifle, Federal's Fusion 150 gr JSP shot safely and reliably, and out to about 300 yards, to the same point of impact as the WWB 147 gr FMJ I use for practice.

You have to be careful with load selection in a gas gun. The pressure at the port is at least as important as the pressure in the chamber with this design. I would avoid High Energy and other suped up loads. And I would stick with loads between 147 and 175 grains.

But keeping this in mind and eating your Wheaties in the morning makes the M1A and excellent companion in the woods.

The M1A and the M14 are self-regulating. You will note the FAL and several other designs have adjustable gas systems, while the M14 has none, because it doesn't need one.

The M1A and M14 pistons are hollow, like a water glass with the open end pointing toward the muzzle. The gas port in the barrel aligns with the gas port in the gas cylinder, which aligns with a gas port in the piston. So when the rifle is fired, the gas is vented inside the piston, where it expands, driving the piston backward. As the piston moves back, the gas ports come out of alignment and the gas flow is shut off.

If your gas pressure is a bit low, the ports stay aligned a bit longer and allow more gas to enter the piston. If your gas pressure is high, the piston moves more quickly and shuts off the gas flow earlier.

In addition, of course, the M14/M1A is a short stroke piston design. The piston moves only a short distance and strikes a weight, driving it backward. So it is the momentum of this weight that operates the action, not gas pressure.

a few problems:

1: it's heavy...especially with a scope.
2. it's loud (the safety and chambering a round)
3. did i mention it's heavy?

the good:

1: it's accurate.
2: it's reliable.

i set one up to hunt with, but once i compared it to a bolt action, i never brought it along. if you're hunting long range, the noise won't be an issue, but if you're up close and personal with the game, they'll hear you switch the safety off or chambering a round.

ETA - in reply to Vern's statement.

All true in theory, but in practice, high pressure loads and/or slower powder curves will beat up your action. The self regulating stacked cups make the M14 action much more tolerant than the old M1 Garand, as far as different load specs, but you're still best off using the bullet weights previously mentioned. And powders of the H/IMR4895/Varget variety, if you handload. Nothing slower than 4064, and not too heavy at that. Your op-rod and receiver will thank you...

M1A you say??? Hunting you say??? Well, here's my buck taken last fall at 423 meters with my DMR clone usign 168 grain BTHP match ammo:



Now some folks will complain that BTHP ammo was designed for punching holes in paper and not deer but really, I've never had a problem with it. The only regulations in ND is no FMJ ammo and no explosive points or some other weird crap like that. So what does a 168 grain BTHP do? Well, here's the same buck with his suit taken off and a pretty good view of the exit wound. BTW, for the record, he took 2 steps before laying down and calling it quits.

Honestly, its very easy to get around the limitations on powder type and bullet weight with an M1a (other than those imposed by barrel twist rate), all you have to do is turn off the gas system, it takes about two seconds and its designed to be operated using the rim of a 7.62 mm case.

Yes, the weapon is no longer a semi auto, but its still reasonably quick to operate as a straight pull bolt action. Besides, as I said in my first post, semi automatic operation isn't going to be much of an advantage on an elk hunt anyway.

I'm not advocating that anyone do anything unsafe, but look at the size of the locking lugs on an M1a bolt, the limitations of the design are in the gas system, not the mechanical strength of the action itself.

ETA - in reply to Vern's statement.

All true in theory, but in practice, high pressure loads and/or slower powder curves will beat up your action. The self regulating stacked cups make the M14 action much more tolerant than the old M1 Garand, as far as different load specs, but you're still best off using the bullet weights previously mentioned. And powders of the H/IMR4895/Varget variety, if you handload. Nothing slower than 4064, and not too heavy at that. Your op-rod and receiver will thank you...

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The M14 doesn't really have an op rod in the same sense as the M1 -- there is no direct connection with the gas system and the bolt system.

And yes, you can beat up any self-loading rifle by firing large quantities of high-pressure ammo with heavy bullets, but the M14 is more damage-resistant than others. I know a Navy gunsmith who used to pull the 150 to 172 grain bullets from match ammo and load a 190 grain bullet over the same powder charge. Now these rifles had to be overhauled every couple of thousand rounds -- but how many hunters fire that much ammo in a life time?

Vern:
I tend to agree with you. Although I don't do it anymore, in my younger, dumber days, I routinely pushed 150 grain bullets around 3000 fps out of my M1a Standard Model. I was using reputable, printed load data and in those innocent pre internet days, I honestly wasn't aware that that it was a problem with the M1a.

The rifle held together through several hundred, possibly as many as a thousand of those rounds with no apparent ill effects. This was in addition to several thousand rounds of various surplus ammo.

The saddest part is, with the reloads, I was mostly shooting pulled M-61 AP bullets because they were so cheap! When I look at what people pay for them now, it almost makes me want to cry.

Don't cry for rounds shot -- be thankful for skill gained.

So, went shooting yesterday with a BUNCH of handloads to try. Did ladder-loads at .5gr increments, using 155 SMK's, 168 SMK's, and Hornady 165 SST's over IMR4895. Took my PTR, my friend brought his M1A.
I'll cut to the pertinent part. In my hand i'm holding a target with a 5rd group fired from a mostly rack-grade GI-spec 22" M1A that measures 1.740" center to center including one outlier. Throw out the outlier, and the other 4 measure 1.082". Round was a 165 SST over 42.0gr that ran 2650 over the chrono.

In the real world, that's perfectly acceptable performance for deer or elk out to 300yd, IMHO.

Very sorry i can't prove with pics.

You betcha it is, even for a bolt gun. I'd love to have an M1A that would shoot that well.

The same load produced a 1.587" group from my PTR, at just under 2500 fps, while the bump to 42.5gr produced a 1.774" group, but with 4 of the shots strung into a .571" hole.

Sorry, that was gratuitous bragging, but the point is that rough load development produced a round that got both rifles into the 1.5MOA or less range, with a bullet and velocity that should work quite well on most medium-large game.

So, consider me to be actively encouraging the OP's idea. Sorry for the minor threadjack, but i'm stoked with our results, and there's some fine-tuning yet to do.

I love .308 battle rifles...

For heavier bullets...180 to 220 brownells sells a Adjustable gas plug for the M14 to relieve pressure an fine tune the rifle for more accuaracy. I didn't know about this until the other day. Think Midway also sells them, so I'm told. It works just like on the Garand for heavier bullets an modern 30/06 ammo.




http://www.brownells.com/.aspx/pid=20456/Product/ADJUSTABLE-GAS-SYSTEM