Thinking about an SBR...

[MikeDVB]

I wouldn't have known to try and put multiple calibers on it - but I appreciate the information in the event that I happened across information that told me to do it that way... I now know not to.

 

[MikeDVB]

I've been looking at parts. The suppressor I'd like to get is 8.5" long and if I put that on an 11.5" barrel I'll end up somewhere around 20" so about 4" longer than my current non-suppressed non-SBR.

I've read that 11.5" is about as short as you want to go for an SBR that will be reliable but that was for an unsuppressed rifle... I'm not sure how the suppressor will change the dynamics [i.e. if a 10.5" with a suppressor would run fine, where 10.5" without may not for example].

 

[CountryBoy19]

I've been looking at parts. The suppressor I'd like to get is 8.5" long and if I put that on an 11.5" barrel I'll end up somewhere around 20" so about 4" longer than my current non-suppressed non-SBR.

I've read that 11.5" is about as short as you want to go for an SBR that will be reliable but that was for an unsuppressed rifle... I'm not sure how the suppressor will change the dynamics [i.e. if a 10.5" with a suppressor would run fine, where 10.5" without may not for example].

Suppressor will increase back-pressure and make it more reliable. The thing you have to start to worry about though is damage to the suppressor. Many manufacturers won't warranty cans on super short barrels. Each manufacturer has their own policy, just make sure you know the minimum they will warranty the can at.

 

[rvb]

I've been looking at parts. The suppressor I'd like to get is 8.5" long and if I put that on an 11.5" barrel I'll end up somewhere around 20" so about 4" longer than my current non-suppressed non-SBR.

that's a long can. I have a .308 can on order and it's only 7.6". If length is a big concern you should look around. M4-2k is 6.6", for instance. surefire's are around 6".

10.5" or 11.5" barrel + a SF can would get you to to about the length of your 16" carbine + muzzle device...

(sounds like you aren't considering muzzle device... a 16" barrel will be 17-18" long depending on what you have screwed on the end, so if you go SBR to 11.5" barrel plus 8" for the can [they overlap at least .5"] you're only adding an inch or two over your current 16", not 4")

-rvb

 

[rvb]

Suppressor will increase back-pressure and make it more reliable. The thing you have to start to worry about though is damage to the suppressor. Many manufacturers won't warranty cans on super short barrels. Each manufacturer has their own policy, just make sure you know the minimum they will warranty the can at.

One way to go shorter is to go with a bigger caliber can. AAC, for instance, will waranty their .308 can down to something like 7.5" w/ 5.56.

-rvb

 

[MikeDVB]

I had a long drawn-out response... But seems my computer decided to eat it rather than post it .

Short version: I didn't think about the length of the muzzle device and the overlap. I believe the one I'm looking at is long due to it being user-serviceable.

I'll look at my other options, I wasn't aware you would still get decent suppression if you used a larger caliber can - I thought the tighter the seal around the bullet the more effective the can would be?

 

[rvb]

I had a long drawn-out response... But seems my computer decided to eat it rather than post it .

Short version: I didn't think about the length of the muzzle device and the overlap. I believe the one I'm looking at is long due to it being user-serviceable.

I'll look at my other options, I wasn't aware you would still get decent suppression if you used a larger caliber can - I thought the tighter the seal around the bullet the more effective the can would be?

Well, there is no "seal." The larger the hole the faster gas can jet, so the larger hole means less reduction in sound. I can't quickly find the data on-line, but I know I read tests somewhere showing it was on the order of 1-2db difference between most 5.56 cans and shooting 5.56 through a .308 equivalent (it's never apples to apples though, but I was comparing an AAC M4-2k to an SDN-6, for instance. Some of what you give up in bore size you gain in having more volume in the silencer...)

I opted for a .308 can.... gave up a smidge of sound reduction and length but gained a ton of versatility.

well, that's the plan anyway.... I ordered the thing in January. waiting on it to show up to the dealer so I can start my paperwork.

-rvb