Maximum Bullet weight in an m14

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scooby_d

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I know this info was covered at some point on this forum but my exhaustive search of old posts was unsucessful. I know that the M14 was designed to fire a 168 gr bullet but I was wondering what the heaviest bullet is that can be shot without damaging the gas system? I seem to recall there being a way to upgrade it to fire heavier rounds also?

Thanks
 
scooby_d said:
I know this info was covered at some point on this forum but my exhaustive search of old posts was unsucessful. I know that the M14 was designed to fire a 168 gr bullet but I was wondering what the heaviest bullet is that can be shot without damaging the gas system? I seem to recall there being a way to upgrade it to fire heavier rounds also?

Thanks
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175 gr LC M118 LR is fed to the M14EBR-RI issued by the US ARMY - no problems noted.

I guess you could shoot heavier projectiles if you shut off the gas valve.
 
I wouldn't put anything heavier than 165-168gr in mine.

They were designed for the 147gr FMJ projectile ie the 7.62mm NATO cartridge and that's the projectile/load it seems to like the best and shoots best with.

I'm pretty sure the U.S. isn't feeding 175gr M118 to a stock condition M14 with regularity. I'm not expert here but I would assume they are modified to use this much heavier load and different projectile?
 
It isn't so much a heavy bullet issue, but the slower powder typically used with heavy bullets. The slower powder has a higher port pressure, and this beats up the gas system.

If you handload, load 180s if you like and just use 4895 powder.
 
Get a Sadlak grooved piston for lower gas pressures. I have one and I do not fire a bullet heaver than 168 gr. Apparently there is an adjustable gas system that can be installed in your rifle but I can not speak to it as I have no experience with that system. I do have a Sadlak grooved piston in my rifle and I shoot 168 gr pills with IMR 4895 reloads. This grooved piston allows for lower gas pressures. Sadlak says that it will not cycle reliably with regulation Nato ball ammo because there is not enough pressure to operate the gas system, but mine does must fine with 147 gr ChiCom Norenco 7.62X51 Nato ammo with the Sadlak grooved piston and only occasionally do I have a failure to cycle, like once in 40-50 rounds. Your mileage may vary.
 
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H2O MAN is right, the US has been running the XM-118, M-118 and M-118 LR as far back as 1964. The 1964 National Match shoot was the first National Match that the M-1 Garand in both 7.62 and 30-06 were used along side the M-14. The M-118 runs at 2550 fps and works flawlessly in M14's. From the on set of the use of the XM-21 in Vietnam, the XM-118 and m-118 match ammo was the preferred choice of ammo as the long range ballistic characteristics of the 173 grn. bullet were far superior to that of the 147 grn. and the 168 grn. The US Military didn`t adopt the 168 grn. Match Load untill the 90`s.
 
It was said earlier, but it's technically true that you could fire whatever you want as long as your reload stays under max pressure at the gas port. Obviously at a certain point that becomes pointless since you can't properly optimize a load...and H20 and McPherson are right about he M118R. Been in use for a while now.
 
Thanks for all the info guys. I am looking at getting a grooved piston from sadlak. Has anyone used one in a Chinese gas assembly or would I need to replace that as well as Northman suggested?
 
H2O MAN said:
175 gr LC M118 LR is fed to the M14EBR-RI issued by the US ARMY - no problems noted.

I guess you could shoot heavier projectiles if you shut off the gas valve.
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Yes the US Army and the US Marine Corps shoot 175 grain bullets out of their M14 super match grade rifles. They also have an armorer that repairs and rebuilds them frequently with no charge to the shooter, They have unlimited budgets for such things. When I was at 29 Palms Calif with the USMC, my buddy was the Armorer there and I spent many an hour in the armory with him watching him rebuild rifles and shooten the bull.
 
I think H2O and I are well aware of the pounding the M14s take under use. I can't speak for H2O, but I recall reading an article on an M14 match gun that dated back ti the mid to late 60's. And after years of constant use, it high ordered. An M14 is just like a 1911, if you want to use the standard Ball ammo, then use the standard weight springs, and if you intend to change your bullet weight higher or lower, the recoil spring should be changed accordingly. It isn't just the pressure range to watch out for.

Addition if forgot-

The military boys and girls don't have to pay for the ammo they feed through these guns, so, yeah, they put LOT and LOTS of rounds down range through the M14s and other such guns, and that means heavy wear and tear. Your average shooter can't afford that ammo bill and there for doesn't put the same round count down range in the same time span.
 
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There are a number of ways to go about using heavy bullets for long range. It's common for match shooters to drill a 1/64" hole in the face of the gas plug to help vent excessive pressure. There's also the grooved gas piston which can be used in conjunction with the vented plug. Another shooter I know bored a small hole in the OFF position of his spindle valve so that when he turns it to the OFF position, it reduces the gas flow to the piston allowing him to use hotter and heavier loads.

The key is not to shoot hot/heavy loads in an M14 with an unmodified gas system. It will batter the operating rod and the receiver heel.

I'm in the process of building a rifle that will shoot 165 gr Berger Hybrids and 185gr Berger Juggernauts at very high speeds for the purpose of 600 to 1000+ yards. The 185's will be too long to load in a magazine so they will be exclusively single feed.

The adjustable gas plug you're asking about is a Schuster gas plug. They make a metric version too. http://www.schustermfg.com/

Tony.
 
I don't think you should load your rounds in single feed. If you drop the bolt on a chambered round, you can cause a slam fire, and a really nasty one too.
 
7.62 NATO ammo was invented for the M-14 and M-60 MG, then jammed down other NATO country's throats by the U.S. government. The M118 ammo was introduced in 1964 with the National Match M14, also introduced then. Uses the same 174.5 grain FMJBT bullet used by the M1 National Match Rifle. http://www.snipercentral.com/m118.phtml
Literally millions of rounds of commercial .308 hunting ammo was fired and reloaded for semi'd M-14's and M1A's long before there was an internet with no fuss. 180's work just fine and do not bother the rifle. However, how heavy do you want to go? There's nothing in Canada that needs more than a 180, but there's also nothing that needs a 180 either. The .308/7.62NATO loves 165 grain hunting bullets and a 165 will kill anything you care to hunt.
 
Gobc said:
I don't think you should load your rounds in single feed. If you drop the bolt on a chambered round, you can cause a slam fire, and a really nasty one too.
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I guess I should define single feed. We actually just barely start the bullet tip into the chamber and you click the back of the case into the magazine which disengages the mag follower from the bolt stop. Your basically starting a feed from the magazine. Then you pull back on the operating rod handle and let your operating rod fly home and let the bolt strip the case from the magazine and complete the feed cycle. DO NOT INSERT THE ROUND ALL THE WAY INTO THE CHAMBER! I agree, that could cause a slam-fire.

But since you're already starting the bullet into the chamber, it doesn't matter how long your COL is. Obviously, you want to keep it off the lands, but you're no longer limited to magazine length.

local High Power matches are single-feed only from the 600 yard line and this is the method M1A users use.

Tony.
 
Gobc said:
I don't think you should load your rounds in single feed. If you drop the bolt on a chambered round, you can cause a slam fire, and a really nasty one too.
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I hate to point this out, but this comment is pure bull. If you can't release the bolt on to a single loaded round in the chamber or striping one off the top of the mag with out concern of having a slam fire... then that gun isn't safe to shoot. A Garand/M14 is not a control round feed system, rather the bullet is stripped out of the feed system and rides in front of the bolt/extractor not even touching the bolt face until the round is seated and the bolt cams into place.

The only three ways to have a Slam fire with this system is, with primers that are to soft, primers that haven't been seated properly, and or build up of grease/oil/ dirt/ or other obstructions causing the firing pin to be locked in a forward position.

The reason way people are told not to drop one into the chamber if for the purpose of... what was I talking about? Oh right I need to feed one into the mag, release bolt and... you have just successfully fed a pointed bullet into the back end of a live round in the chamber. A mistake like this might just ruin your lip stick...
 
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