Barrel Question

[KnotRight]

Not questioning anything about a pistol brace or SBR but do have a question about the barrel on one of those platforms.
I have an 8.5-inch 223 barrel of a build and have it zeroed at 50 and 200 yards. I know that I am under the desired length for a DI driven 223 but with a can on the end, it seems to be accurate out to 200 yards. The can is about 6" long.
The question that I have, would you change out that barrel to a 10.5" barrel that seems to be the minimum length for a pistol or SBR. With the can on the gun and adjustable gas block it runs fine.

 

[Catfish]

For shooting paper or steel? no. I wound't mess with success.
Are you doing anything where a couple hundred ft/s terminal velocity might make a difference?

 

[Cole_McD]

If this is a defensive carbine and you don't mind the length, I'd consider an 11.5 over 10.5. 10.5 is fine, but 11.5 allows for significantly more dwell time (40%) which means you don't need as obnoxious of a gas port size to ensure reliable function. That reduction in gas port size gets you a less gassy gun, and decreases your bcg velocity which means less wear and tear on your internal components.

I do think the velocity you're probably getting from most ammo out of an 8.5" barreled 5.56 is probably not suitable for defensive use outside of a few very niche loadings.

 

[KnotRight]

If this is a defensive carbine and you don't mind the length, I'd consider an 11.5 over 10.5. 10.5 is fine, but 11.5 allows for significantly more dwell time (40%) which means you don't need as obnoxious of a gas port size to ensure reliable function. That reduction in gas port size gets you a less gassy gun, and decreases your bcg velocity which means less wear and tear on your internal components.

I do think the velocity you're probably getting from most ammo out of an 8.5" barreled 5.56 is probably not suitable for defensive use outside of a few very niche loadings.

Cole_mcD, I got the gun to run good when the can is on it by adjusting the gas block for it with the can. Without the can, there is not enough gas to cycle the bolt. Being a gun that is used for HD, maybe a truck gun or hitting steel plates, I am questioning what I am losing with targets less than 50 yards away with the 2-to-3-inch shorter barrel? The loads that I am shooting are usually loaded with CFE223 and in a 18" barrel, they should be traveling around 3,100 Ft/Sec.

 

[Cole_McD]

It would be interesting to see some Chrono numbers on it. 5.56 is so incredibly velocity dependant, there's a good chance that without a very specific projectile selection you won't be getting very good terminal performance.

The rule of thumb Ive always heard is that 10.5 is the minimum because beyond 50 yards or so, you won't get fragmentation of the round and the gel testing I've seen generally support this rule. Any rifle cartridge can still mess up your day in a heartbeat, but at those seriously reduced velocities you will have "less" performance.