M1 Adjustable Gas system?

[tele_mark]

http://www.gokart.net/shop-utopia/mccann/scope/parts.html

Does anybody have any experience with this accessory for the M1? I haven't received the rifle from CMP yet, but when I do, I'd like the flexibility of being able to use a wider range of ammo, both commercial, surplus, and hand-loaded, without risking damage to the rifle.

 

[rscalzo]

They aren't CMP legal so if you intend on using the rifle in competition I would say no. I never saw the need for it. My hand loads are within acceptable guidelines and I use mil. surp. ammo from the CMP in most cases.

 

[bpm990d]

I believe you are correct that they are illegal for use in the CMP Garand Matches, but I'm pretty sure the vented plugs are perfectly legal in CMP EIC Matches, The National Trophy Matches and NRA Matches. All of our M-14s we had wore vented plugs and I didn't see any mention of it in the CMP rulebook in Rule 6.2.

With that being said, the vented plugs are really special use items and may take a while to adjust properly. When you get your Garand, replace all the springs. It might be money better spent.

Enjoy the rifle.

B

 

[rscalzo]

My understanding of the M-14 gas system was that it vented excess pressure through the stock gas system. There was no need for vented plugs.

The one to ask is Dan O'Neill over at West Texas Armory. All he does is rebuild M-1 and M-14 (M1A) mainly. He is always happy to help answer questions.

www.westtexasarmory.com

or post a message at his forum at...
http://www.westtexasarmory.com/phpbb2/

 

[bpm990d]

Yes that is correct, The M-14 has a vent at the bottom of the gas cylinder, however the NM guns were not shooting 147gr bullets that would typically be used by GI rifles. They typically digested a steady diet of 168s & 173s and some much heavier. The AMU did a variety of modifications to the gas system to include a slotted piston and sometimes they drilled a small hole in the end of the gas cylinder plug. All of the receivers were lugged as well.

They set them up this way so that they could use much heavier bullets (180 & 190 gr. Sierra HPBTs and sometimes Lapuas) at the longer yard lines for NRA matches. The guns all functioned fine with with the issued M852 for the National Trophy Matches.

B

 

[rscalzo]

180 & 190 gr. Sierra HPBTs

Never knew they used a bullet that heavy in a match load.

 

[bpm990d]

Mostly for wind resistance at 600, but also for accuracy at 1000 yards. The M852 would not shoot well at 1000 because the bullet (Sierra 168) goes subsonic before it gets to the target and the M118 Match was no longer being made and even if it was, it was never a real performer in the accuracy department.

The older style Sierra 180 with the boat tail the same dimensions of the 190 would stay supersonic as would the 190. The newer style 180 with the boat tail like the 168 was marginal. Why they changed it I don't know. Sierra claimed it shot better with the new boat tail. The 175s would probably have been the first choice if it was around back then.

B

 

[tele_mark]

Thanks for the input everyone! I'm not sure I'm going to do CMP competition, but even if I do, this little device looks to be easily removed. I'm mostly looking at it as a way to be able to use modern, off the shelf ammo without fear of damaging the gas system, if I choose to. It just makes sense not to be limited to surplus ammo for reasons of practicality. Looks like this'll be another accessory waiting here ahead of the rifle itself.