Effects of cutting a barrel
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Do you have a rifle length gas system?
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You will definitely have cycling problems. Your best bet would be to get the 16". If you do get the 20" cut to 16", you have to get the gas port closed and re-drilled at the Mid or Carbine length. To me, it sin't worth it.
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This must be specific to 6.8 right?paulosantos said:
I did this to my 5.56, opened the port slightly on my drill press and it is good to go.
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From my understanding all gas systems require a certain amount of dwell time of the bullet remaining in the barrel for proper back pressure on the gas system. I would guess that by opening the port on your 5.56 you overgassed your system and that is what is allowing it to work.Renegade360 said:
This is from Springfield Armory on the SOCOM II "The SOCOM II action is identical to the M14, using a gas piston and rotating bolt, except that a muzzle brake has been added. It sounds easy to shorten a rifle, but just lopping off the end of the barrel reduces gas pressure and affects functioning, so the muzzle brake, which also acts as a pressure chamber, was added to ensure proper cycling." [/color]
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Yes, specific to the 6.8SPC.Renegade360 said:
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Harrison tested that and he said it also didn't work well.zoomie said:
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Paul already answered correctly, the faster powders used in the 6.8 combined with a larger bore area makes the pressure curve very short. An 18" 308 with a rifle gas barely works, a 18" .223 with a rifle gas works better because it uses the same powders as 308 but much smaller bore area.zoomie said:
The 6.8 is a no go.
I am thinking about using mid gas on 20" barrels with a smaller gas port to see if it gives better accuracy due to the smaller port. During the pressure trace test last year there was a large dip as the bullet past the port. I am thinking if we can go to a smaller port we will have less pressure disturbance but longer dwell possibly giving better accuracy while still functioning.
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Good to know the 6.8 won't function in the same way as the 5.56.Equalizer_2 said:
As a side note, it's possible on the 5.56 by opening the gas port from .102" to .109" using a 7/64ths bit. So it is just a slight increase in gas port size. Also, a fouled gas port will cause short stroking with this setup, so keeping the port clean is an absolute must. I have used this set up in multi day tactical courses with no cleaning just running wet with clp and had no issues using Rem UMC 55gr ammo. Wolf has issues when dirty, but Umc and other better quality ammo runs fine at the same range session.
Interesed to hear more on Constructors work with port placement/sizes on the 6.8.
When you get over .100 it tends to have a noticeable negative effect on accuracy.
6.8 pressure curve even with the same powders like H335 is noticeably shorter and pressures can be 2-5K lower at the port depending on the powder bullet combo and port location.
The larger the port the more effect it has on the size of the pressure drop behind the bullet as it passes.
The STAG 7 has also has other mods to the gas system to help with cycling reliability. There are other things that can be done to aid cycling when you cut duration by shorting the barrel length after the gas port. I need to do some testing to confirm how it well it works and the total effect.
Cutting a 20 to 16 with a rifle gas port will give you a singe shot rifle.
6.8 pressure curve even with the same powders like H335 is noticeably shorter and pressures can be 2-5K lower at the port depending on the powder bullet combo and port location.
The larger the port the more effect it has on the size of the pressure drop behind the bullet as it passes.
The STAG 7 has also has other mods to the gas system to help with cycling reliability. There are other things that can be done to aid cycling when you cut duration by shorting the barrel length after the gas port. I need to do some testing to confirm how it well it works and the total effect.
Cutting a 20 to 16 with a rifle gas port will give you a singe shot rifle.
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along these same lines..
I have one of Construtors 18" stainless DMR 1/11 barrels and have thought about cutting it back to 16 just to lighten it up a little...
it has a midlength gas system
see any problems with doing this and what type of crown is ideal?
would it be much louder?
more muzzle flash?
I use h322 powder
I have one of Construtors 18" stainless DMR 1/11 barrels and have thought about cutting it back to 16 just to lighten it up a little...
it has a midlength gas system
see any problems with doing this and what type of crown is ideal?
would it be much louder?
more muzzle flash?
I use h322 powder
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That would work fine. I don't know what the profie is, but you may also want to conside making it .740" under the handguard to lighten it up even more.ccoker said:
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ccoker said:
:shock: :?Couldn't you sell it and then get a Xtreme barrel?
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