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Posted: 3/14/2023 10:47:47 AM EDT
6" Faxon 1-5 300BO Barrel.

Gas Journal is 1.03" long

Superlative Arms clamp on .75" gas block is 1" long, but the length doesn't include the adjustment mechanism.

direct threading a dead air sandman ti.

I'd really like to run an adjustable gas block behind this. who makes a decent one that will fit in that space?
Link Posted: 3/14/2023 11:38:33 AM EDT
[Last Edit: flcracker] [#1]
Thread spacer? 🤔
Link Posted: 3/14/2023 3:38:46 PM EDT
[#2]
Yes, use a thread spacer to get that muzzle device away from the gas block?

https://www.brownells.com/gun-parts/rifle-parts/rifle-muzzle-devices/adapter-12x28-thread-spacer/
Link Posted: 3/15/2023 2:57:01 PM EDT
[#3]
that thread spacer would mean that the direct thread suppressor would barely be half threaded on.
Link Posted: 3/15/2023 3:24:15 PM EDT
[Last Edit: KalmanPhilter] [#4]
Three or four threads is typically full design strength for fastener applications.  Certainly no issue holding typical 20-35 ft-lbs torque and plenty of contact area for Rocksett if used. The bigger issues with spacers are fit/diameter and parallel faces.

I doubt you’ll need adjustable gas with that short of dwell even with that huge gas port.
Link Posted: 3/15/2023 4:10:52 PM EDT
[#5]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By KalmanPhilter:
Three or four threads is typically full design strength for fastener applications.  Certainly no issue holding typical 20-35 ft-lbs torque and plenty of contact area for Rocksett if used. The bigger issues with spacers are fit/diameter and parallel faces.

I doubt you’ll need adjustable gas with that short of dwell even with that huge gas port.
View Quote


I think you might be right. I'm probably going to try it without the adjustable gas block first, then I'll back up and punt if I need to.

Thanks.
Link Posted: 3/15/2023 6:23:43 PM EDT
[#6]
you can also use a BRT gas tube spec'd for your build instead of using a adjustable gas block if you find your gun is too gassy.
Link Posted: 3/16/2023 2:23:29 PM EDT
[#7]
The only issue with short threads is that threads will be exposed and get crud in them.

Not an issue if this is a dedicated setup, but if that can is used on other hosts that use the full threads it can become an issue.
Link Posted: 4/11/2023 1:46:12 PM EDT
[#8]
I just did the exact same thing. Ordered a 6in faxon barrel then felt like a dumbass when I realized there isn't enough room for superlative gas block.
I'm gonna see how it runs with a fixed gas block and maybe buy a bootleg adjustable bcg if it's over gassed.
Link Posted: 5/9/2023 4:35:24 PM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By zpduff:
I just did the exact same thing. Ordered a 6in faxon barrel then felt like a dumbass when I realized there isn't enough room for superlative gas block.
I'm gonna see how it runs with a fixed gas block and maybe buy a bootleg adjustable bcg if it's over gassed.
View Quote


bumping for....

I just put a regular gas block on.

gun cycles, ejects spent brass, strips off new cartridge, bang, repeat.
ejection around 3:30 - 4:00 pattern

the rifle will not lock back on last round.

magazine?

standard carbine spring. standard carbine buff (I have removed every weight out of it. just ended up being a bit more violent recoil)
Link Posted: 10/28/2023 10:07:51 PM EDT
[#10]
I finally had a chance to get back out with this build and do some diagnosis.

for my little experiment, i had three brands, two different bullet weight of 300BLK supers as well as 1 brand, 2 different bullet weights of subsonics.

Rifle cycles, strips and chambers next round, then locks on empty with all three supers with the can on or off.

It will not strip or chamber next round and will not lock back on any of the subsonics with the can on.

standard buffer and spring. so looks like I'm checking the gas port diameter and drilling it out.

Is there an optimal size for pistol length gas?

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