6" Barrel?

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roxy
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6" Barrel?

Post by roxy » Sat Nov 24, 2018 8:19 am

So I have been seeing 6" 300 Blk Barrels out there recently.
It sure would make a compact pistol or SBR!
I have a 7.5" 1:7 twist that shoots both Subs & Sups pretty well.
Would a 6" Barrel be at all practical for either Sups or Subs??
Any of you guys have any experience with a 6 incher? (Barrel that is!)
SBR Gibbz G4 8.5" CMMG 300 Blk 1:7" WASP
Gibbz G4 16" Ballistic Advantage 300 Blk 1:7"
Savage AXIS 16.5" BFG 300 Blk 1:7"
Ruger ARR 16.5" 1:7"
Saker 762
SDN-6

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gds
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Re: 6" Barrel?

Post by gds » Sat Nov 24, 2018 9:19 am

I don't have experience with a 6 inch 300blk barrel. However I do with 7.5 and a 3.75 inch 300blk barrel.

Practically speaking its usefulness will only be limited by what you want to do with it.

If you are wanting to stay with supersonic loads in a short HD/enty weapon, I suggest 9 to 11 inch barrel. You can of course go shorter but at the loss of velocity of course.

If you want to stick with Subsonics, you can go as short as you want if you hand load. The load can then be tailored to your barrel length.

My plinking sub load for the 3.75 inch is a 155gr cast powder coated bullet. But even with a heavy duty 10 inch suppressor it is not very quiet at all. I don't have sound measuring equipment and I have tinnitus really bad but even I can tell it is pushing the sound safety threshold. There is a point of diminishing returns on suppression the shorter the barrel is.

Having said all that, I think 6 inch is close to the perfect length for a subsonic compact gun.
Yes, I am a Baptist, and yes I carry a gun. You might think I carry a gun because I don't trust God. Well you would be wrong. I have complete faith in my Lord. It is mankind I have no trust in

BlogSarge
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Re: 6" Barrel?

Post by BlogSarge » Sat Nov 24, 2018 9:53 am

I built a six inch just to see if it would work.

Yup. It does. Supers are 100% with or without a can, subs are 100% with a can and work most of the time without a can.

Both group well, too.

I thought I chrono’d some loads through it but can’t find any on my laptop, but gds’s reply is spot on.

Bottom line, for a short, compact, maneuverable short range setup it is wonderful.

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dellet
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Re: 6" Barrel?

Post by dellet » Sat Nov 24, 2018 10:25 am

I did not notice enough difference in maneuverability between a 6.5” barrel and an 8” to justify the increase in noise. For me it was more important to be able to shoot without hearing protection inside a building, than not bang the end of the suppressor on something.

I chose to go with a shorter, better suppressor to reduce overall length. The key here tho was handloads. Nothing available off the shelf that I know of would even get me to consider a barrel that short.
300 Blackout, not just for sub-sonics.

withoutremorse42
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Re: 6" Barrel?

Post by withoutremorse42 » Sat Nov 24, 2018 3:03 pm

Three part article series starts with part 1 here
https://loadoutroom.com/50929/ultra-sho ... up-part-1/

I ran 5 different barrels, 4.75"-6.5" for chrono data and accuracy with ~10 different ammo types.

Now that the series is done, I'm keeping the 6.5, which was nearly identical in performance to the 6" and 6.25". Each barrel preferred one type of ammo more, and another less. I like the barnes 110's, so am keeping the barrel that shot best with those
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roxy
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Re: 6" Barrel?

Post by roxy » Sun Nov 25, 2018 12:25 am

Thanks guys!!
SBR Gibbz G4 8.5" CMMG 300 Blk 1:7" WASP
Gibbz G4 16" Ballistic Advantage 300 Blk 1:7"
Savage AXIS 16.5" BFG 300 Blk 1:7"
Ruger ARR 16.5" 1:7"
Saker 762
SDN-6

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