[Edward429451]

I picked up a slew of 180 gr bullets of different makes at a yard sale. Presumably for use in my M1A. I'm told not to use them in my M1A or I may damage my op rod. Something about peak pressure being longer with this heavy of a bullet which would batter or even bend my op rod. I should stay with 175 gr bullets as a max weight to be safe.

Ok, I can dig that. But what if I shut off the gas valve? I'd have to cycle it manually, as a straight throw bolt action sorta. I'd really like to use these 180's but just want to be sure no suprises that I failed to consider.

Anybody know of any problems with doing this? I've heard of people getting a specially vented gas cap and being able to shoot 200 gr bullets in them with no ill effects, so why couldn't I just shut it off for using heavies? I'd only use em for hunting and paper punching, where fast follow up shots wouldnt require semi auto.

Ideas? Comments? THX.

 

[shayne_44657]

Hello Edward,
With the m14/m1a you don't need to worry about bending your op rod. They are limited which means after the bullet passes the gas port in the barrel it vents into the piston where it builds pressure until it gets enough to work the action. Then the piston moves back and blocks the rest of the gas from entering the piston area. On the m1 Garand it continues to build until the bullet actually leaves the barrel. So if you shoot heavier than 165 regularly you can bend the op rod on a Garand, but not the m14. I did see a article on line somewhere about the m14 that said you would bend your op rod but he must have been confused or someone gave him bad info. Anyways if you wanted to make double extra sure you can shut off gas system (turn it to grenade mode) and shoot all you want. Well happy shootin' Shayne

 

[Edward429451]

Thanks Shayne! :usa:

 

[Mark whiz]

Edward,

Shayne is right in the fact that the M1A gas system is a ported system and not AS subject to op rod problems like the Garand is..............but it can still happen with the heavier bullets, depending on what powder type & load is used. Keep your loads on the very light side of the load chart if you use the 180s. And I wouldn't pump a bunch of them through the gun on any given day.

On the issue of closing off the gas port for shooting these bullets....................... one word - DON'T!! I've made the mistake of not opening the port after cleaning and the 1st shot at the range was fired on the closed port. It literally takes a hammer to knock open the bolt in order to get the fired case out . You do not want to make a habit out of doing this - it's a great way to break bolt pieces and bend/break op arms.