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Discussion Starter · #1 ·
Does anyone know of any 1/9 twist barrels in stock anywhere?

I've had a backorder CMMG directly for over a month now and got notification today that it could be another month before new ones are available.
 

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I have. Brett is making me a custom barrel as we speak. Should be ready by End of week, then we are off to the suppressor store :twisted:
 

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Discussion Starter · #5 ·
thanks guys. i was looking at gunbroker prior to posting yesterday and saw a 1/7 twist for auction only. after a closer look today there are some 1/9s available although one is overpriced.

i'll keep that link in mind too shipwreck.

/edit - www.trosusa.com is working again
 

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Just wondering what the chief difference is putting a 1:9 barrel on instead of a 1:7? I understand the 1:7 is a faster twist, but wouldn't you want that since you're loosing the extra length? Or is it the other way around?

Pondering doing an SBR conversion on my PS90 and saw this, so thought to ask.

Gregg
 

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I don't know how far the bullet "skids" down the barrel before it's spin matches the 1:9 or 1:7 twist, but I'll bet it ain't far if at all.

The twist would be chosen to get the most accuarcy from a given bullet weight without spinning it into self destruction wouldn't it?
 

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Texas Armadillo said:
I don't know how far the bullet "skids" down the barrel before it's spin matches the 1:9 or 1:7 twist, but I'll bet it ain't far if at all.

The twist would be chosen to get the most accuarcy from a given bullet weight without spinning it into self destruction wouldn't it?
Yeah, one would think, but when dealing with a 10.3 barrel, does it really matter? And if it does, any ideas what the limitations would be on bullet weights for each? While most just go to the store and buy factory, I reload more for mine, so would be pretty important to know in considering a barrel for my conversion.

Gregg
 

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Discussion Starter · #9 ·
i have read in other threads on here that 1/9 is ideal for factory rounds. wikipedia says the p90 also uses a 1/9 twist.

the 1/7 is ideal for heavier reloads. i already have my form4 in for a suppressor so i ordered one of each.
 

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Wound wise, the less a bullet spins the more unstable it is when it hits.

I remember seeing the wound tracks of the orignal M16 that used 1 in 14 twist. WOW. One VC got hit in the Right superior hip area and part of the bullet exited just to the left of his right scapula. It was pretty gruesome.

Back to the point, the service wanted to increase the accuracy and the UN wanted a more humain round, what ever that means. The barrels went to 1 in 12 then 1 in 9 and now 1 in 7. The 1 in 7 makes the round very stable but you loose what makes the small caliber so deadly. Frequently a 5.56 fired from this 1 in 7 barrel pass straight through the target.

To me a 1 in 9 would be a better choice for a short barreled PS90.
 

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Wound wise, the less a bullet spins the more unstable it is when it hits.

I remember seeing the wound tracks of the orignal M16 that used 1 in 14 twist. WOW. One VC got hit in the Right superior hip area and part of the bullet exited just to the left of his right scapula. It was pretty gruesome.

Back to the point, the service wanted to increase the accuracy and the UN wanted a more humain round, what ever that means. The barrels went to 1 in 12 then 1 in 9 and now 1 in 7. The 1 in 7 makes the round very stable but you loose what makes the small caliber so deadly. Frequently a 5.56 fired from this 1 in 7 barrel pass straight through the target.

To me a 1 in 9 would be a better choice for a short barreled PS90.
I remember the talk of the first test in Nam but the reason I heard for the faster twist to 1/12 was that 1/14 was too unstable in cold weather regions do to the denser air. The rest is history and have heard report of the 1/7 passing through targets with little disruption.

I know its a logistics nightmare but for the M16 to rise back up to its former glory the military needs to change the uppers for the proper enviroment. So for warm desert conditions go back to the 1/12 twist with 55gr projectiles and I bet we will hear less stories of insurgents needing multiple shots to put down
 

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When I first joined the Navy I had the good fortune to work for two prior vietnam vet Navy surgeons and one Nam vet that was a E.R. MO. They taught how to care/treat high velocity missle wounds. All of them said the orignal M16 was a much more deadly weapon with the 1 in 14 twist and the then 1 in 9 twist. The one thing I will never forget them all talking about was the issue of how the energy release was one of the most imprortant issues.

They said if a bullet is traveling say 2500 fps when it hits a target and it passes through the target now exited at 700 fps the amount of tissue distroyed is much less than a bullet traeling the same 2500 fps yahs and tumbles and releases all its energy into the target. Most that were shot in what would be thought as none vital areas wound die 4-6 days later because the energy release had disrupted/distroyed tissue 8 to 10 inches following the wound track.
 

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I must be near the top of the list for drifting threads... but didn't the man find his barrel? :-D
 

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Discussion Starter · #15 ·
I must be near the top of the list for drifting threads... but didn't the man find his barrel? :-D
Indeed I did! I picked up a 1/7 twist (now installed, yay :)) for sub sonic rounds mostly and the 1/9 will get here whenever. Can't wait to get my can!

/1 edit, quote fix. Shipwreck is busy enough already...
 
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