Ultralight Ultralight Rifles

[Thegman]

Might the aluminum be less rigid/ more malleable and flex more, allowing the brass to expand more?

The only part of the bolt carrier group interacting with the cartridge during firing is the bolt itself, so I wouldn't think so.

My guess is the larger diameter cases have more surface area to stick against the chamber walls and/or their larger diameter bases increasing the force back against the bolt and forward against the chamber shoulder, resulting in the case itself locking the bolt lugs more tightly against lugs on the barrel extension, and those frictional forces increasing the force required to get the bolt to turn and unlock.

In a gas system, the gasses first hold the bolt as far forward as possible as the bolt carrier starts its rearward movement. That might reduce the friction between the bolt lugs and the extension during extraction, but those bigger cases are harder on extractors in gassers as well, so I imagine there's still more of those frictional forces being overcome with a gasser.

 

[JBradley500]

I wonder if a chrome lined chamber would help

 

[KyleR1985]

I think one of the problems is the side charger, if I’m thinking about it right. Especially if you have a chopped down bcg.

If you have a fully guided bcg, the side loading from side charger isn’t as bad.

 

[robtattoo]

Yeah, I tried 7.62x39 in a BCA () barrel.
It wasn't stupidly sticky, but it was bad enough that I decided that it was worth the effort & expense to build a .300 Ham'r with a Wilson barrel instead.

Speaking of barrels, if anyone decides to try & persuade X-Caliber to do a discount on a group buy of spaghetti profile, portless 6x45 barrels, I'm 100% in for one

 

[KyleR1985]

Yeah, I tried 7.62x39 in a BCA () barrel.
It wasn't stupidly sticky, but it was bad enough that I decided that it was worth the effort & expense to build a .300 Ham'r with a Wilson barrel instead.

Speaking of barrels, if anyone decides to try & persuade X-Caliber to do a discount on a group buy of spaghetti profile, portless 6x45 barrels, I'm 100% in for one

Working on it with Satern.

Emails asking about it might help…

 

[Luke S]

I just turned the gas block around on my 7.5 inch AR pistol and shot it suppressed while manually operating the regular bolt. Definitely felt less loud than when gas operated. I don't think I'd want to shoot it without ear pro but it's "less bad."

 

[robtattoo]

Working on it with Satern.

Emails asking about it might help…

I just sent them this:

"I was wondering if it's possible to have a barrel specially built.

There are a few guys on the Rokslide hunting forum that have built, or are building, ultra-utralight non gassed ARs as hunting rifles. I'm presently shooting a sub 5lb rifle, based on a TN Arms carbon lower & Solo 300 upper, chambered in .300 Ham'r, but I would really like a 6x45 for the extra range & bullet availability. Not that there are any flies on the .300, but it's really a 200yd cartridge.

I know that a bunch of us would jump all over a very light (16-18oz) 16" barrel. Especially if it had no gas journal or port! Currently nobody offers anything like this. I know it would be a very limited run, but would a run of, say, 10 or 12 be possible?

Thanks for your time & attention,

All the best,

Rob Peel"

Fingers crossed!