Some questions for everyone

[C4iGrant]

Been interested in building some AR's in this cartridge and had some questions if you don't mind.

1. What barrel length allows all of the powder to burn?

2. What is considered the optimal barrel length in an AR platform?

3. If one is using 200gr-220gr bullets, what is the best twist rate to use?

4. What size Suppressor seems to work the best? 9mm? 308?


Thanks for the help guys.


C4

[pug]

The first question can start a big time discussion. It is more of a percentage of burn thing rather than total burn. The majority of powder is burnt in the first few inches of barrel and a 10" is throwing them out about 1500 fps. Take it up to 16" and you get about 1800 fps or somewhere there abouts. The longer you go the less gain/inch you get and at some point it isn't worth it but you would still be getting some increase probably even at 26" or more. I like the carbines so 16" gets my vote and mostly 150s and 180s go down my barrels and the 1:8 works well for them. As far as suppressor performance you want the bore only slightly larger than bullet diameter so the 308 designed suppressor would be the best although there is something to be said for a well built 9 mil can even if it is louder. You of course would not want to shoot a supersonic 308 through a 9mm pistol can because the baffle stack usually can't take the beating.

[C4iGrant]

The first question can start a big time discussion. It is more of a percentage of burn thing rather than total burn. The majority of powder is burnt in the first few inches of barrel and a 10" is throwing them out about 1500 fps. Take it up to 16" and you get about 1800 fps or somewhere there abouts. The longer you go the less gain/inch you get and at some point it isn't worth it but you would still be getting some increase probably even at 26" or more. I like the carbines so 16" gets my vote and mostly 150s and 180s go down my barrels and the 1:8 works well for them. As far as suppressor performance you want the bore only slightly larger than bullet diameter so the 308 designed suppressor would be the best although there is something to be said for a well built 9 mil can even if it is louder. You of course would not want to shoot a supersonic 308 through a 9mm pistol can because the baffle stack usually can't take the beating.

Thanks for the info. I have decided to go with the Noveske 10.5 barrel (as I am already a dealer for them) in a 1/8 twist. I have also ordered an AAC 308 can for it.

Let the fun begin!


C4

[TheWizardOfOdd]

Thanks for the info. I have decided to go with the Noveske 10.5 barrel (as I am already a dealer for them) in a 1/8 twist. I have also ordered an AAC 308 can for it.

Let the fun begin!


C4


Do you have 10.5" Noveske 300 Whisper barrels in stock?

[dflicker]

Grant, Mike Brown of Jet Suppressors makes a small can specifically for the 300W. 5.5x1.75". Do you have a source of subsonic ammo, or will you be loading your own?

I'll get that LWRC upper (5.56x10.5") to you in a few weeks. Will call when I have it in hand. I will also have a 6.8SPC (10.5") available if you would like to check it out.

David

[RWBlue]

Grant I am glad to see you here. I bought stuff from you in the past. You will love the Noveske barrel. 10.5 is good for subsonic and supersonic.

Once I got my act put together, it really began to shine.

If you want to do supersonic, you will need a regulated gas tube or gas port. I went with the gas port.

According to Gemtech, for subsonic a 9mm suppressor will do, but you need a 308 can for supersonic loads. I went with the HVT 308 can.

I have purchased suff from you in the past. You are now somewhat local to me. Give me a yell if you want to see one that is together.

[m21black]

1. What barrel length allows all of the powder to burn?
I don't know but prefer a 16.25" barrel for suppressor use.
2. What is considered the optimal barrel length in an AR platform?
16.25"
3. If one is using 200gr-220gr bullets, what is the best twist rate to use?
I'd pass on the smaller bullets and use the 240 SMK's... in the subsonic world the only way you can gain energy is with heavier bullets not to mention that the 240 grain bullet has a better BC.
4. What size Suppressor seems to work the best? 9mm? 308?
I have a AAC Cyclone that works great on everything from the 300 Whisper to the 300 Win mag.