December 05, 2022, 04:28 AM
DusterNon Piston 516
I have come across an upper receiver marked 'Sig Sauer 516'. Barrel is stainless and marked '.223 Wylde 1:7 SS USA'. Handguard is 10". Has no gas piston assembly but has a gas block and tube installed. So did Sig ever make or convert 516's to Non Piston or was this done by person or persons unknown?
December 05, 2022, 05:34 AM
2AdefenderSounds like a Bubba build. I don’t think SIG ever made a non-piston 516.
December 05, 2022, 06:58 AM
12131^^^ Yup.
For the AR-style SIGs, the 516 family is piston driven, and the M400 family is DGI.
December 20, 2022, 05:25 PM
PGTI have several 516 uppers....not all are marked 516. It's conceivable that Sig had some extras sitting around and built them as M400's instead.
December 21, 2022, 10:05 AM
2AdefenderThe rifle Duster described had a .223 Wylde chamber. SIG produced .556 NATO barrels. It’s a Bubba build.