Colt HBAR 16" cut to 11.5" without opening up the gas port?

[Five_Point_Five_Six]

There's a local guy selling an 11.5" Colt HBAR complete upper that was cut down from 16". It's 1:9 twist and he said he did not change the gas port size. He says it runs reliably and has no problems with stabilization with many different 55 and 62 grain loads. Does this seem plausible? I've only ran barrels in factory configurations with the exceptions of AK's which don't give a shit about barrel length.

[MistWolf]

I suppose it depends on the gas port size. Modern 16" Colt barrels run a .0625" gas port. I have one 11.5" barrel with a .063" BRT Micro Port and it will run 5.56 spec ammo unsuppressed.

At the end of the day, it depends how much he wants for the barrel. Quality made new 11.5" barrels can be found for reasonable prices using good gas port sizes. I'm also of the opinion that short AR barrels should be 1:7 or at the most, 1:8 twist. Slower velocities equals lower RPMs.

[Clint]

The port seems a little small for unsuppressed use, but would be almost perfect for a dedicated suppressed upper.

The twist rate might be limiting too.

If you can pick it up for a song, great, but there are many good alternatives available these days.

[MegademiC]

Unless its like $100, Id pass.
Is it really colt? Who cut it down? Twist rate is a potential issue.

With current barrel prices and offerings, I would go with a brand new known quantity.

[Five_Point_Five_Six]

I'm gonna pass. He has a receipt from a local gunsmith for the cut, crown and threading service totaling $150. He's asking $300 obo but it's not worth the headache to me even if he takes less.

[JoshNC]

I'm gonna pass. He has a receipt from a local gunsmith for the cut, crown and threading service totaling $150. He's asking $300 obo but it's not worth the headache to me even if he takes less.

Ha, nope. You can get brand new factory Colt HBAR FBI 11.5” 1/7 twist barrels for that or less.

[scooter22]

Ha, nope. You can get brand new factory Colt HBAR FBI 11.5” 1/7 twist barrels for that or less.

What’s the GP on the FBI barrels ?


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[Clint]

they've been measured at 069

What’s the GP on the FBI barrels ?

[Five_Point_Five_Six]

Ha, nope. You can get brand new factory Colt HBAR FBI 11.5” 1/7 twist barrels for that or less.

This is a complete upper, bcg, charging handle etc, not just a barrel.

[MQ105]

This is a complete upper, bcg, charging handle etc, not just a barrel.

That's different than just the barrel, assuming you are looking for a complete upper. If you can test fire the upper and check thread concentricity it may be worth it. I still prefer 1/8 or 1/7 twist, though.