So I’m getting ready to start building out one of my Glock based AR lowers. I cannot remember what the recommended weight for the buffer should be. Any suggestions? Additionally, I have a random PSA buffer with an orange plastic end cap to it, is there a weight marking anywhere on the buffer, or does the color indicate the weight?
Usually orange is used for 9mm. As to weight, it’s probably 5.6oz or close to it. Is it a regular looking carbine buffer or is it extended (the head will be really thick). If it is a regular looking buffer, you may need a buffer spacer (a few companies make and sell) or some folks use quarters. I buy nylon spacers at Lowes. These help prevent bolt overtravel which can break your bolt catch.
1 Like
That could be the H2 buffer that PSA sells? Can you weigh it and measure the overall length?
I don’t have a small enough scale to weigh it. It is 3 1/4 inches long top to tip. The head on it is a touch thicker than the standand buffer in my 5.56.
1 Like
That is their 9mm buffer.
That seems too short? How much clearance do you have from the bolt catch when you manually cycle it? This is what I’m running in mine for reference:
I can’t tell you clearance, as I haven’t started the build yet. It was a spare buffer in my gun safe separate and apart from my other build parts.
I probably need a small digital scale.
Pulled my .40 AR open and the buffer on it is the same length as the one in the safe. It has a white tip on it. It feels heavier than the orange tipped one pictured above. Also opened my 5.56. Sam length on the buffer, but feels like half or less than half of the weight of orange tip. Perhaps I have the right weight, but need spacers?
You have an extended one with the bigger head on it. He doesn’t, and may either need the buffer spacer, use quarters, or a nylon spacer.
Went back and weighed the buffer (wife bought a kitchen scale). 5.539 ounces.
1 Like
That’s a good weight for a 9mm buffer but you may need to add some quarters or get the spacer
Has anyone used the spring buffer that PSA offers in their AR9? If so which p/n? And what thoughts if any on improvement versus the standard buffer setup?
Why buffer spacer or quarters ? I have seen this comment before… Would you please explains ?
Because the bcg of a 9mm is not the same dimensions as a regular bcg. Therefore, the bcg will move farther to the rear. Moving farther to the rear, combined with more weight, can lead to the bolt returning with more force. This can lead to bolt bounce and can (and actually does) break the bolt catch. The spacer and quarters prevent the bcg from traveling as far back to the rear, which prevents it from gaining more momentum.
2 Likes
The 9mm AR bolt is 3/4" shorter than a 5.56mm bolt, but uses the same receiver and buffer tube, so you should use a buffer that’s 3/4" longer than a normal carbine buffer to make up the length difference. Otherwise, the bolt gets a running start at the bolt catch and will eventually break it. Carbine buffers are 3.25". Extended 9mm buffers are 4".
The buffer should also have internal sliding weights to help prevent bolt bounce. Solid buffers are obsolete and have been for decades.
Last, the buffer+bolt total weight should be around 22oz -24oz. This seems to be optimal for most 9mm blowback builds. Subtract the bolt weight from 22 to get a good buffer weight for the build.
You can find a buffer selector for 9mm blowback AR’s here. The buffers are all the correct 4" length for 9mm and have deadblow weights inside.
9 Likes
@Blowback9 welcome aboard sir! glad to have you!
2 Likes
Thank you! I didn’t even know PSA had a forum until recently. Love your products - great value for the money. (still trying to figure out your system - hit the wrong button 
)
4 Likes
Am currently in the process of changing to an extended buffer and a standard carbine spring. Have been running the normal 9mm buffer with a spacer and the 308/9mm spring and broke the release.
no problem. glad to have you here… we love friends who are fans of fire arms and all to do with them… Yeah we love PSA as well, although unfortunately none of us Moderators/admins are employees. We all are actually volunteers and fans and friends of the owners/management of PSA. That said, we do not have customer service here either, but we do have PSA employee’s on here who can and do help out here to help any customers or problems that may arise on the retail and product side.
its ok about trying to figure things out here… every forum is a little bit different. Anyways, ive rambled on long enough… so agian, Welcome, Glad to have you !
1 Like
I have the PX-9 lower with an 8” PSA upper. It runs fine with the 5.5oz buffer that it was shipped with. I was thinking of trying the PSA custom AR9 9mm 8oz buffer to reduce some of the recoil. Has anybody tried this or have any recommendations on another way to reduce recoil? Thanks.