AR Lower Question

[nickster]

I have a very nice Rock River lower with the original A2 buttstock. Quite a few years ago I had dabbled with a carbine upper. The upper is gone and I can't remember if I swapped the recoil parts back to a rifle mode. Here's a picture of what was in the A2. It had a spacer in it that says use with carbine buffer and spring. I have no other buffer and spring so I'm asking the smart people here to verify if this is a rifle or carbine buffer and spring. Looks to me like they're both rifle. Am I correct? I picked up a nice upper with a 16" barrel and about an 8" gas tube and want to mate it to this lower with the A2 butt.

Steve

 

[LVLAaron]

Looks like a rifle buffer for sure. You won't hurt anything running it. I have rifle buffers in carbine length uppers... Lots of ways to configure it. Run it and see how it feeds. Does it lock back on last round, ejects correctly, etc.

 

[joshb]

Ok. Good to know

 

[nickster]

I remember when I tried the carbine upper with the rifle buffer and spring without the spacer, it operated but it slammed back and forth as I recall. It didn't sound good. I can't remember if I tried it with the carbine spacer or not thats why I'm asking. If it's not the correct parts I might as well get the carbine buffer and spring and do it right.

 

[Twdmar]

Why don't you buy the correct spring and save yourself some headaches? A spring is probably 5 bucks. Carbine and rifle buffer setups, if the spring and buffer is sized to tube correctly, will have no bearing on what upper you use.

 

[joshb]

What happens when you put a 16” barreled upper on a pistol braced lower that had a 7 inch barrel on it?

 

[LVLAaron]

I remember when I tried the carbine upper with the rifle buffer and spring without the spacer, it operated but it slammed back and forth as I recall. It didn't sound good. I can't remember if I tried it with the carbine spacer or not thats why I'm asking. If it's not the correct parts I might as well get the carbine buffer and spring and do it right.

If it's a carbine spring, you for sure need the spacer, or it will for sure slap around in there.

 

[LVLAaron]

What happens when you put a 16” barreled upper on a pistol braced lower that had a 7 inch barrel on it?

Depends... Probably nothing spectacular. If the lower was tuned correctly for the short barrel, it'll probably slam the bolt back pretty hard because of the extra dwell time.

 

[nickster]

Since I don't have the right buffer I'm going to my LGS and buy the buffer and spring tomorrow. Thanks for your help.