View Full Version : Commercial to USGI upgrades

December 06, 2008, 09:05
Have an M1A Scout and got some USGI parts back when CMP was selling them. So far I've upgraded the Op Rod, Trigger Group, and Bolt.

I've read that the cast bolt catches are soft and will wear out and they're cheap so that's simple decision, provided I can get the old one out.

So what else should I go after? I'm mostly interested in upgrading where it matters. I am less interested in upgrading for the sake of it. I'm thinking gas cylinder assembly might be a good upgrade but is there an advantage to the USGI version? How can one ID USGI vs commercial?


December 06, 2008, 11:50
It's very hard to distinguish new production GCs from the USGI versions.

The ones made by Springfield are cast stainless, and I can't recall ever hearing of one having a problem. Smith Ent. and LRB are making new production forged stainless gas cylinders, to USGI specifications.

I would replace the gas cylinder, but that's because I'm neurotic. YMMV.

December 06, 2008, 13:33
Well, with USGI bolt, op rod, and trigger group maybe I'll call it good. Maybe change some small things like op rod guide, bolt hold-open clip, etc. While there are definite metallurgical differences between castings and forgings I wonder if a quality cast part will have any shorter service life. I'm not shooting this thing every day or relying on it to save my life.


December 06, 2008, 22:30
Might want to upgrade to a match quality spring guide and mag catch. Should be fluted for reduced friction and give more consistent mag catch pressure. I'm sure you've found that different mags will produce a slight change in POI because of latch up pressure and the change in vibes to the spring guide, etc. That's why you'll see serious hi power shooters with numbered or marked mags for the rapid fire series.
Might also want to upgrade the flashhider to a GI or GI spec one. The cast ones have been known to crack. Get one reamed to match spec while you are doing that as well.