Ar buffer question

[backtrail540]

I have done many searches and still haven't found an exact answer to my question.

I am doing a 20" build, and it will have a rifle length gas system. I will be running a UBR, therefore I will need a carbine buffer. Now my question is which weight buffer to use?

As far as I can tell from my reading, the heaviest buffers(h3,9mm) are used for sbrs,pistols,etc with carbine gas systems. These slow down the cyclic rate and help lessen felt recoil/muzzle rise.

For middies many seem to prefer the midweight buffers(h1,h2,some even prefer the standard carbine buffer), they don't seem to have as high of pressure and therefore don't require the extra weight to help them with recoil etc...

So following that trend, I assume that with the rifle length system being the lower pressure of the three that I could run the standard carbine buffer, or a h1 and be fine?

Also, if I run a heavier buffer on a rifle length will I most likely run into short stroking or would any buffer most likely function? I would guess that I probably couldn't run to light of a buffer with the full length system, so no overgassing would occur? I know that the gas port size can also have affect on all of this so it most likely differs from manufacturer, but I am speaking generally.

I'm making alot of assumptions, so please correct me where needed. There seems to be all kinds of info on the carbine length systems but not so much available on the rifle length system with the carbine length stock. Pretty much they say you can run it but leave it at that.

 

[mvician]

The rifle buffer weighs 5.1oz, spring rate is different. I'd try a H2 to start with. Lighter will always work, It is all trial and error to see what the heaviest buffer your rifle will run reliably with the weakest ammo you plan to run.

 

[abnk]

I would go with a standard carbine buffer.

 

[backtrail540]

The rifle buffer weighs 5.1oz, spring rate is different. I'd try a H2 to start with. Lighter will always work, It is all trial and error to see what the heaviest buffer your rifle will run reliably with the weakest ammo you plan to run.

Thanks Mike, it's going to be my chatterbox build So am I correct on my understanding or am I off somewhere?

 

[mvician]

Lighter will always work, There are no set rules as to what buffer and spring combo will work in any given rifle.

From what I've read the H2 and standard carbine spring rate is a close match to the rifle buffer/rifle spring rate.

I went through a few changes on my ChatterBox build. BCM midlength barrel. Started with the standard carbine buffer and spring. It worked but was still cycling to fast. Wouldn't lock the bolt back, I'm running the Phase 5 EBRv2. Bolt would close before the follower would trip the hold open. This was with PMags, Wolf, and XM193 ammo. Only locked back on a GI mag with Wolf.

Next I tried a H buffer...same thing. Next I tried the H buffer with a "blue" spring from Tactical Springs. Getting better, Wolf in a GI mag or PMag now locked back on empty, 5.56 ammo of different manufacturers still too hot.
Next step I ordered the Palmetto branded version of the Spikes ST2 buffer.
Getting closer but still not 100% lock back on empty with 5.56, Wolf still working in both types of mags. So last step before I ditched the Phase 5 I ordered the "red" heavy duty spring from Tactical Springs. Bingo

5.56 locked back in GI and Pmags and even the Wolf still had enough oomph to cycle and lock back on empty.

So it's not an exact science as to say yes setup A is going to work. It's all trial and error. I'm sure if I took the EBR off that a lighter buffer or spring would have worked, but with the extra weight of it I needed to slow the cycling rate down. It runs smooth as silk right now

 

[backtrail540]

Lighter will always work, There are no set rules as to what buffer and spring combo will work in any given rifle.

From what I've read the H2 and standard carbine spring rate is a close match to the rifle buffer/rifle spring rate.

I went through a few changes on my ChatterBox build. BCM midlength barrel. Started with the standard carbine buffer and spring. It worked but was still cycling to fast. Wouldn't lock the bolt back, I'm running the Phase 5 EBRv2. Bolt would close before the follower would trip the hold open. This was with PMags, Wolf, and XM193 ammo. Only locked back on a GI mag with Wolf.

Next I tried a H buffer...same thing. Next I tried the H buffer with a "blue" spring from Tactical Springs. Getting better, Wolf in a GI mag or PMag now locked back on empty, 5.56 ammo of different manufacturers still too hot.
Next step I ordered the Palmetto branded version of the Spikes ST2 buffer.
Getting closer but still not 100% lock back on empty with 5.56, Wolf still working in both types of mags. So last step before I ditched the Phase 5 I ordered the "red" heavy duty spring from Tactical Springs. Bingo

5.56 locked back in GI and Pmags and even the Wolf still had enough oomph to cycle and lock back on empty.

So it's not an exact science as to say yes setup A is going to work. It's all trial and error. I'm sure if I took the EBR off that a lighter buffer or spring would have worked, but with the extra weight of it I needed to slow the cycling rate down. It runs smooth as silk right now

Cool, I guess I can look forward to some "research and development" Thanks for the help as always.

 

[Litlratt]

I've ran a standard length gas system with a CAR buffer and spring for 15+ years without issue. The buffer tube is CAR length.