AR PARTS INTERCHANGE

Rosie

Will any of the Bushmaster AR15 parts interchange with Colt? How about S&W aka Stag Arms?

dcs shooters

They should,most AR'S are made to gov. specs.

Wehrmacht_45

As long as the AR is built to mil specs all internals should interchange within brands.

cpermd

No, many will not.
Front hinge pin, some triggers and hammers and pins are larger in a Colt.

CP

shooter10

Answering the second question: The S&W's until recently were made by Stag and finished by Smith. Now S&W is totally doing the process. So all parts should interchange without a problem. If I put a new Stag upper on my old Colt SP1, I would have to get a front hinge adapter pin (like $3) to make the different hole sizes match up. And yes, it works fine. The biggest differnece is many times the upper and lower color will not match with different companies.

Txs

cpermd is correct

Bushmaster fire control group parts (trigger, hammer, disconnector) will only interchange with SP1 and earlier Colt semi-autos. With the idea of preventing people from converting their AR rifles to full-auto Colt increased the diameter of their semi-auto FCG pins from .155" to .170". All other AR manufacturers continue to use the milspec diameter pins.

Bushmaster also uses a milspec size .250" pivot pin but on some Colt semi-autos these are .315". Adapters to remedy this problem are readily available and inexpensive.

On rifles equipped with a collapsible buttstock the receiver extension or buffer tube diameter is also different between Colt and many aftermarket types, including Bushmaster. The Colt tubes are actual milspec diameter.

All other parts are interchangeable.

Rosie

Thanks guys.