Buffer weight for a 12.5 inch?

[diving dave]

Hi guys, yes I searched the forums but got several different answers, so here goes..... Just built my first SBR, using a BCM 12.5 upper. Currently using a Spikes lower with their buffer. I'm guessing I should replace that with a heavier buffer....H2 perhaps? So far it seems to shoot fine, both with my can and un suppressed...Suggestions? thanks much!

[R0CKETMAN]

BCM 11.5 H2 suppressed and unsuppressed

[Col_Crocs]

I second the H2 if you're looking to just drop in a new buffer. I upped to an A5H3 on my Noveske 12.5 and it's really softened things up. Not sure what the port size is on it though.

[Jwknutson17]

While an H2 will run like a top and have no issues, I would go with an H3 on a 12.5.

[Benito]

While an H2 will run like a top and have no issues, I would go with an H3 on a 12.5.

I actually have an HeavyBuffers.com XH Carbine Buffer (8.5 oz) in my Noveske 12.5. It runs fine even when just shooting American Eagle .223.
I had it left over from an over-gassed DD, and was curious how it would work. So far so good.

[Col_Crocs]

^^ Off topic but what circa is this your barrel and did you by any chance get to measure the port?

[Benito]

^^ Off topic but what circa is this your barrel and did you by any chance get to measure the port?

I did not measure the port. I bought it earlier this year, so I am guessing it was manufactured recently.

[Hwikek]

You said your rifle is functional as of now, correct? If so are looking to try and tune the gun?

[tom12.7]

I've messed with many flavors of 12.5" 5.56 carbine gas systems, they can be some of my preferred shorter 5.56 barrels to run.
I really like a dedicated ported 12.5" 5.56 carbine gas systems properly ported for the range for the A5H2 with the LMT enhanced carrier, with a standard type carrier closely behind in favor, with only a small change in range of porting.
With that dedicated porting range, the system can run well in a wide span of use. Lower pressure ammo can run very well with a lower mass A5H1 buffer. Suppressors, depending on attribute can run well with more mass buffers up to the A5H4.
Setting the 12.5" carbine gas system in that manner can satisfy many user needs, with an easy means to change function to suit users better by only simple buffer swaps to best fit their use. The system in that form has an easy way to have a wide usage, without using an extreme mass difference in buffer weight at either end of the spectrum as a baseline in function for use.
If it runs best with an A5H0, or an A5H4 without a can with 5.56 pressure, what are your options in span of operation without issues when you look at the many variables?

[Iraqgunz]

My 12.5" Kino uses the A5H4 with a Sprinco spring and LMT enhanced carrier.