Bayonet for M1A

[ArmyJerry]

Where do I find a bayonet that fits the M1A?

Also one for a RRA M4?

[Chipperman]

You should be able to get one at ebay, Gunbroker, most gun shops, Sarco, etc

[Tucker 1371]

I think the M9 bayonet should fit either. Expect to pay $80-150.

[ATW525]

For the M1A, google the M6 Bayonet. They're not hard to find.

The M7, M9 and M10 bayonets should all fit on an AR-15 pattern rifle assuming the barrel extends the proper length past the bayonet lug. Bayonets will work on a rifle length gas system with a 20" barrel, a mid-length gas system with a 16" barrel and a carbine length gas system with a 14.5" barrel.

[Winchester_73]

I think the M9 bayonet should fit either. Expect to pay $80-150.

This is not correct. Here is the bayonet evolution since WWII:

M4 - M1 carbine
M5 - M1 garand
M6 - M14 / M1A
M7 - M16 and its cousins

You need a M6 for the M1A and I personally would buy a M7 instead of a M9. M7s were what our boys had in Vietnam. M6s were in Korea and Vietnam. M9s are a lot because they're the most modern but they're not worth it. A M6 should cost 20 to 30 and a M7 the same. I myself am partial to the historic bayonets.