Springfield Armory M1A and operating rod and ammo question

[TexasPatriot.308]

I have a SI M1A Loaded model, usually shoot 150, 168 grain bullets. I got hundreds of factory Remington Core Lokts in 180 grain I bought during the Hussein obumma ammo scare. Any input on shooting 180 grain in this rifle? I hear it is not good for the operating rod....will adjusting the gas block help?

 

[Tommygunn]

I dunno about the heavy bullets.... but you can turn off the gas system and use it as a straight-pull repeater, I should think.

I will leave the question of heavy bullets to a M1A Guru.

 

[Nature Boy]

I asked tech support at SAI about comercial hunting loads in my M1A back when I first got it.

1. Nothing over 180g - limits for op rod safety
2. No reduced recoil loads - might not cycle reliably
3. No soft points like corelokts - might shave off lead from the tip when feeding

 

[Slamfire]

Unless the ammunition is advertised as M1a safe, it is better not to run the stuff through your rifle.

 

[Tommygunn]

Unless the ammunition is advertised as M1a safe, it is better not to run the stuff through your rifle.

I don't think I've even seen that listed on 147 grain ball ammo 7.62 X 51 I have seen, reportedly A-OK for the M1A.

 

[AlexanderA]

but you can turn off the gas system and use it as a straight-pull repeater

That's right. The gas system has a cut-off that was originally designed for the firing of rifle grenades. You just turn the switch to the horizontal position using the rim of a cartridge as a tool.

Keep in mind that the military M80 cartridge uses 147 gr. bullets. The M1A, as the civilian equivalent to the M14, is best used with ammunition that is close to the military standard. Save your 180 gr. bullets for a bolt action rifle.

 

[Tommygunn]

That's right. The gas system has a cut-off that was originally designed for the firing of rifle grenades. You just turn the switch to the horizontal position using the rim of a cartridge as a tool.

Keep in mind that the military M80 cartridge uses 147 gr. bullets. The M1A, as the civilian equivalent to the M14, is best used with ammunition that is close to the military standard. Save your 180 gr. bullets for a bolt action rifle.

I only buy 7.62●51 ammo in fmj and @150gr. and no heavy stuff. I was unclear as to use of the heavy (longer) bullets being used with the gas system cut off ... the rounds might not work if they're too long, or feed right.
I doubt the gas system, including the actuator arm, would be affected as a straight pull.
But I do agree that one should never abuse any rifle ... and if one isn't positive that it can safely fire heavy bullets, then stick to only those approved for the gun.
We've all seen photos of rifles with banana-peeled barrels . That ain't no fun to be around!

 

[Slamfire]

I don't think I've even seen that listed on 147 grain ball ammo 7.62 X 51 I have seen, reportedly A-OK for the M1A.

This is a Federal 168 Match box, don't recall seeing a 150 grain box:



Velocities are not that high with this ammunition. I try to keep my match 168's around 2600 fps to 2625 fps. There is 150 grain ammunition that will push bullets 2800 fps, but I recommend keeping 150 grain bullets at or below 2700 fps.



I can't find my picture of M118, which was the 174 FMJBT Match load, but I have chronographed the stuff, and it goes out of a M1a exactly as the box states, 2550 fps.

Commercial ammunition and even military ammunition are often unknowns in terms of gas port pressures and breech pressures. While the locking mechanism is strong, the gas system is going to be over accelerated when port pressures are too high. I did have an operating rod actually bend in the saddle area, that was due to a misaligned operating rod guide, but, I can see it happening with hot ammunition. Might as well as buy extra extractors as you can bust extractors with hot ammunition.

I really recommend reloading for the things. Small base size the cases, use Wilson type cartridge headspace gages to set up the sizing dies. Size to gage minimum, and use CCI #34 primers. Seat all primers below the case head. The powders I prefer are the 4895 type, which is IMR 4895, H4895, and AA2495. The cartridge was developed with IMR 4895 so it is hard to beat that powder in that case, and in that rifle. My match loads out to 300 yards were a 168 SMK with 41.0 grains IMR 4895, LC case, CCI #34. At 600 yards I either bumped the load up to 41.5 gains with a 168, or I used a 175 SMK at 40.5 to 41.0 grains IMR 4895. Loads for this rifle are not as hot as commercial loads, the thing will operate better and longer by not using the highest velocity and highest pressure ammunition possible.

I will say, disable the gas system, and don't be surprised to find that extraction is hard. The rifle is not great as a single shot straight pull.

 

[Tommygunn]

Ok....it exists. Perhaps it specifies M1A safe since it's 168 grain?
I'm still sticking with lighter loads myself .....

 

[Flatbush Harry]

Three comments:

1. SAI has a limited lifetime warranty on their M1As. Contact their customer service and ask them any questions because they'll stand behind proper use of their gun. They'll tell you what ammo is acceptable. Don't use that which they say is unacceptable if you expect them to honor their warranty (I'm not a lawyer but I have slept in Holiday Inn Express hotels).

2. Military gas action rifles are designed to function with a certain range of gas pressures at the gas port. The acceptable powders are medium-rate burning powders used with a range of charge loads varying with bullet weights. Typically, hunting ammo doesn't use those powders or those bullet types or bullet weights. Using an adjustable gas plug allows use of ammo outside of design ranges but, if you want reliable, damage free function, stick to designed or specified loads. Using the rifle as a single-shot, pull-action rifle works fine but does defeat the purpose of the gun as designed as a semi-auto rifle.

3. I have shot M14s in the service beginning in 1969 and have used, with no trouble, an M1A Super Match that I bought at the factory in Geneseo, IL in 1979 and an M1A Loaded acquired a couple of years ago, with either M14/M1A specific factory ammo or handloads as specified in the Hornady .308 Win Service Rifle data. I also have an e-mail from SAI customer service specifying what is within their design/acceptable range. In regular use since 1969 with one or another of these rifles and ammo, I have never had a problem. I would suggest that you request manufacturer guidance and then follow it.

Now I have studied this issue fairly extensively and followed the advice of the company, military armorers, and qualified gunsmiths and have a pretty good sense of what parameters may be extended. I choose to stick with proven data (NRA load data, Hornady load data, military load data and factory ammo specific to the M1A). I'd recommend that you stay within those parameters and limits. YMMV but it probably shouldn't.

Good luck and good shooting,