11.5" Carbine vs. 12.5" Mid-length Unsuppressed

[titsonritz]

I'm trying to make up my mind which setup to go with. Assuming equal quality components and running primarily unsuppressed which would you go with and why?

[JediGuy]

It seems like the 12.5” is not as developed a system. People used to say that about 14.5” midlength, too, of course.

I’m curious about BRT’s possibly EXC for a 12.5” barrel.

[Clint]

This could be solved with an unconventional combination.

A 12.75" barrel would be compatible with 10.75" and 12.0" hand guards.

The EXC gas system would be Optimal for un-suppressed use with this barrel length.

I’ve actually put a lot of thought into this over the years. I think the reason has to do with the legacy handguard lengths.

The 12.3 and 12.5 barrels exist in a nether region between 11.5 and 13.5, despite being an awesome barrel length that is compact, but compromises very little in velocity.
Most handguards suitable for the 12.5” barrels are really made for 11.5” guns, but they work just fine. I’ve got one in a KAC 10.75 URX4 and another in a SLR 11.7.

It seems like the 12.5” is not as developed a system. People used to say that about 14.5” midlength, too, of course.

I’m curious about BRT’s possibly EXC for a 12.5” barrel.

[Clint]

We're going to step up and solve this.

We put together a test mule with a 12.7" EXC barrel ported for mixed suppressed use, as that seems to be the ideal use case for for a 12.x

Initial testing is very promising and it runs like we expect it to.

I’m curious about BRT’s possibly EXC for a 12.5” barrel.

[Ironman8]

We're going to step up and solve this.

We put together a test mule with a 12.7" EXC barrel ported for mixed suppressed use, as that seems to be the ideal use case for for a 12.x

Initial testing is very promising and it runs like we expect it to.

Do you have a glossary of terms or list of definitions for the acronyms for your products?

What gas length would you use with the 12.7”?

Also when do you think it would be available?

[JediGuy]

Don’t want to speak for Clint, but I think I know the answer to your question...

“EXC” = Extended Carbine
More than CAR(bine), less than MID(length)

“EXT” = Extended
More than Midlength, less than Intermediate

The EXT was designed for 16” barrels. The EXC was designed for suppressed-only 11.5” barrels (? on actual design origin). Earlier this year or so, maybe in this thread, Clint mentioned that the EXC gas length was ideal for an unsuppressed 13” barrel with .5” leeway on either side.

[Clint]

Correct on all counts.

Don’t want to speak for Clint, but I think I know the answer to your question...

“EXC” = Extended Carbine
More than CAR(bine), less than MID(length)

“EXT” = Extended
More than Midlength, less than Intermediate

The EXT was designed for 16” barrels. The EXC was designed for suppressed-only 11.5” barrels (? on actual design origin). Earlier this year or so, maybe in this thread, Clint mentioned that the EXC gas length was ideal for an unsuppressed 13” barrel with .5” leeway on either side.

[docsherm]

I'm trying to make up my mind which setup to go with. Assuming equal quality components and running primarily unsuppressed which would you go with and why?

12.5 any day.

[mack7.62]

12.5 carbine gas. IIRC from Colt M4 testing the optimal barrel length for carbine gas was 13", the reason for going 14.5 was for bayonet mounting.

[Five_Point_Five_Six]

I voted 11.5" carbine gas because that's what I have experience with. I've never owned a 12.5" mid length.

I have an over gassed 16" PSA mid length CHF barrel that is just sitting in a box, I'm thinking of chopping it to 12.5" and seeing if it will still run reliably with that blown out PSA gas port.