Change 9mm AR15 buffer for use with suppressor?

[Bret]

Interesting. My 9mm Colt carbine that I bought new about 15 years ago has a buffer that looks exactly like the RRA you pictured. Is your Colt a newer model? Searching Colt 9mm buffers show the design to be just like I have.

That's interesting. I bought the Colt SBR about a year ago.

[Bret]

Interesting. My 9mm Colt carbine that I bought new about 15 years ago has a buffer that looks exactly like the RRA you pictured. Is your Colt a newer model? Searching Colt 9mm buffers show the design to be just like I have.

I bought the Colt 9mm SBR right at a year ago. I just checked the buffer that came in a Tiger Stripe finished Colt 9mm receiver set that I bought last June. It's the same.

[Smokin338]

Running multiple AR-9 setups suppressed... I would go with a dedicated 9mm 7.5-8 oz buffer and 308 spring. With your current setup I would still put in a 308 buffer spring and $1.50 in quarters to act as a buffer stop in the buffer tube... your going to need it !

[Bret]

I shot my RRA 9mm SBR today. I started with 100rds of Speer Lawman 147gr TMJ. It ejected about 10 feet to my right with and without the suppressor. There was definitely not a noticeable difference in the ejection distance. I then attempted to shoot some CCI Blaser aluminum case 147gr FMJ. The rifle would fire, but would not eject the spent cases. They'd just end up getting smashed by the bolt right outside of the chamber. After five failures in a row, I gave up on this ammunition in this rifle. Just for a sanity check, I put 25rds more of the Speer Lawman 147gr TMJ through the rifle. It again functioned 100%. Given the short ejection distance, I think that I'm going to leave well enough alone. Thanks everyone for your help. Perhaps I was just overthinking things.

[6mmAR15]

I shot my RRA 9mm SBR today. I started with 100rds of Speer Lawman 147gr TMJ. It ejected about 10 feet to my right with and without the suppressor. There was definitely not a noticeable difference in the ejection distance. I then attempted to shoot some CCI Blaser aluminum case 147gr FMJ. The rifle would fire, but would not eject the spent cases. They'd just end up getting smashed by the bolt right outside of the chamber. After five failures in a row, I gave up on this ammunition in this rifle. Just for a sanity check, I put 25rds more of the Speer Lawman 147gr TMJ through the rifle. It again functioned 100%. Given the short ejection distance, I think that I'm going to leave well enough alone. Thanks everyone for your help. Perhaps I was just overthinking things.

Every thing Ive ever read about aluminum case ammo in blow back carbines is to stay away from using it...…..I have no experience in either of my AR 9's and with that said, I have seen numerous posts about not using aluminum case ammo and problems associated with it.....

[Bret]

Well then I can confirm what you read.