Can i use RRA 9mm flattop upper receiver with an olympic arms upper ,is there anything i sould know before i change receivers

Please clarify, are you talking about switching around barrels or lower receivers or what?

Im sorry i have a olympic arms 9mm upper and want to change the upper receiver to the RRA  9mm upper receiver Thanks

Just sell the entire Olympic and replace with a new RRA. Nothing in the upper or mag system is interchangeable. You MAY need a new hammer and or buffer and spring to run the 9mm RRA.

So what your saying is i cant swap upper receivers

Quoted: So what your saying is i cant swap upper receivers

You can put either one on the same lower. But no parts in the upper will work with each otehr, except for handguards and stuff. What have you got, and Oly lower? I had my 9mm on an Oly lower. Worked fine, with stock hammer and buffer.

Ok maybe your not understanding me all i want to do is change the upper receiver itself not the complete upper and still use all the olympic parts but have a different receiver for looks Thanks

Quoted: Ok maybe your not understanding me all i want to do is change the upper receiver itself not the complete upper and still use all the olympic parts but have a different receiver for looks Thanks

No-go. A guy asked that same question a few days ago, and apparently there is no way to mate the different operating systems and barrels.

What is so different with the stripped upper reciever between the olympic and the rra?

Quoted: What is so different with the stripped upper reciever between the olympic and the rra?

Olympic uses an ordinary receiverm RRA is not cut for a gas system, has a different ejection port too. The problem has something to do with the bolt locking up tight, and that not being compatible. You could possibly have something custom made.

Quoted: Quoted: What is so different with the stripped upper reciever between the olympic and the rra? Olympic uses an ordinary receiverm RRA is not cut for a gas system, has a different ejection port too. The problem has something to do with the bolt locking up tight, and that not being compatible. You could possibly have something custom made.

Olympic uses a gas system? RRA 9mm uppers have the same ejection port as a 5.56 upper, just has the 9mm case deflector and shortened port door cover. They can be removed and a "normal" port door can be installed. If the RRA 9mm receiver was cut for a gas tube it could be used for a 5.56 upper if the "normal" port door was installed. The RRA 9mm upper is sans forward assist and case defelector and of course not cut for a gas tube.


RRA 9mm upper with "normal" port door

MGP,
 I have had an Oly 9 for a  few years, so I am familiar with them. I have
purchased a stripped flattop upper to do this, as well. The Oly uppers have
the ejector in the upper rec'r. No one else does this. You will need to have the
holes drilled in the proper location to install this ejector in your flat top
upper. Any decent gunsmilth should be able to do this for you. Someone
here on the boards did it himself. Either way, use your current upper as
a guide.
 Another thing you could do... Dalphon basically buys Oly stuff & resells
it. They have a thicker/heavier duty ejector that they install in their uppers.
I think they will retro existing Oly's to this ejector. They might install one
in your new upper for a fee, if you ask. My standard Oly ejector has been
100%, so I never had this done. I hope this helps. Let me know if you
need more help.

Johnny C!

Dalphon went tits up. They just stanped their name on OAI parts anyway.

No, oly doesn't have a gas system.

Thanks guys