M1A caliber conversions.

[pinotguy]

So I've got a couple of things to run by the M1A crowd here. Back in gunsmithing school, a few of us started to talk about the possibilities of different calibers in the M1A platforms. With that in mind, would it be possible to convert an M1A to another 308 Win. based cartridge? Specifically, I'm thinking of 358 Win. Has this kind of conversion even been attempted in the past? As far as I can tell, the barrel would be the only major component that would need to be changed. This would be a "just because" type of rifle and would serve no other purpose. The other potential obstacle that came to mind was getting 358 Win. ammo to function properly. In other words, would loading 200-250 gr. bullets complicate cycling, feeding, etc?

Thanks in advance.

 

[General Geoff]

You'd need a new barrel, and depending on the gas port size and the internal ballistics properties of .358 Winchester, you might need to get a weaker or stronger op rod return spring. But other than that, I don't see any problems with the idea.

 

[ShunZu]

My SA national match M1A doesn't shoot .308 worth a hoot, regardless of load. Have considered taking it down to .243 just to try something different. Don't know if that's even possible, but it's based on the same cart, just a smaller neck and bullet.

 

[GunTech]

SA turned out a few 243 M1A some years ago. I've long wanted a 260 M1A but haven't found anyone willing to build me a barrel. As long as you has a similar cartridge with a similar pressure profile, there's no reason it wouldn't work.

 

[azredhawk44]

I've also heard of SA, inc doing .243 rifles.

I'd worry about .358 though. That bullet will be moving a lot slower, and offer considerably greater pressure to the gas port and op rod. Definitely would invest in a gas plug that vents overpressure for such an experiment.

On a similar note, I've had an itch for the last few months to have a Romanian PSL rechambered from 7.62x54R to .30-30. I really want a semiauto in .30-30, and there aren't any choices out there.