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Discussion Starter #1
what is the diffrence and what one should i get? what one is more easily compatable with silencers and so on? i would like to hear all everyone knows before i to buy one.

Thanks
Murlow
 

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Discussion Starter #3
im confused.

It going to be on my ps90.

it comes in two diffrent 1/7
1/9

Which one is better?

I will be shooting a 5.7x28mm
 

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I don't even know why they would offer it in a 1/7... 1/9 will do everything you need. Unless you plan on reloading some 77 gr ammo. I went with the 1/9 and I love it!
 

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cmmg says the 1/7 is for subsonic ammo...guess you need less twist to get the lower load bullet out of the barrel?
 

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1 in 7 is a faster rate of spin than 1 in 9. 1 revolution in 7 inches of barrel length compared to 1 rev in 9 inches of length 1/7 would be faster twist rate than 1/9.

I think the faster twist (1/7) would have more friction so a bit slower fps using same ammo compared to the slower twist (1/9). Maybe thats why its better for supressed?
 

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The slower a bullet is traveling the faster the twist needs to be to get the same number of RPM's for stabilization.
So if you are shooting subsonic ammo, you will need a faster twist for the same bullet length and weight.

Over stabilizing a bullet will only hurt the accuracy on a precision rifle, you won't notice it on a PS90, but under stabilizing as you know will cause keyholes and, if shooting suppressed, baffle or endcap strikes.

I've been lurking on and off for about a year and a half now. I spend most of my time on silencertalk.

I hope my first post was helpful.
 

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I emailed them on this topic and here is what they said:


The original PS90 barrel is 1/9 twist. If you plan on
shooting factory loads, you want to stay with the 1/9.
If, however, you're planning to consistently shoot
subsonic rounds that you're reloaded, you'll want the 1/7.
Linda
 
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