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Discussion Starter #1
Hey guys I had a problem that came up when in the process of putting togther my sbr build. I originally wanted a dd mk18 upper. However, after speaking to a few people I am wondering whether I should go for the dd mk18 which has a 10.3" barrel, or buy a 10.5" mk18 upper buy another manufacturer. I guess the question is, can I reliably suppress a 10.3" barrel? I have a YHM phantom LT on a form 4 to mount onto the sbr. Anybody have any hands on with this setup or a similar set up?
 

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An email from YHM I received they will not warranty their suppressors for anything shorter than 11" for 5.56 and 12" for 7.62. With that said though I know some that have used shorter barrels in both calibers. The concerns are blast from the shorter barrels wearing the baffles prematurely and the bullets not stabilizing and causing baffle strikes.
 

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It depends on the suppressor (both manufacturer and model).

I recommend the AAC line, especially if you want a 10" barrel.

AAC's M4-2000™

or if you want a multi-caliber silencer (recommended), the 762-SDN-6™

Both are warrantied for a 10" barrel on 5.56mm
 

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Discussion Starter #6
Does 0.7" really make that big of a difference in stabilizing the bullet? Not sayin I would, but how the heck would they find out if the length of the barrel I used on the can was less than 11"?
 

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Does 0.7" really make that big of a difference in stabilizing the bullet? Not sayin I would, but how the heck would they find out if the length of the barrel I used on the can was less than 11"?
Mostly when you try to get it repaired under warranty as they ask bout the host platform. For SBR lengths "longer" is generally better as it gives more time for the powder to burn out and the gas to escape. Less blowback, less heat/debris in chamber, stabler ROF, etc.
 

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I have been shooting my SDN-762 regularly for a few years (think: tens of thousands of rounds) through my 5.56 BR (7.5" barrel) and have had ZERO issues. I hope this helps you make a decision.
 

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10.3 vs 10.5 makes no difference. I would bet if you put the same Flash Hider on both they wind up the same length. Twist rates and bullet weight are whats important at 10". And it looks like you're going to be shooting 5.56 out of a 30cal suppressor so I wouldn't worry in the least. Surefire makes a "SBR" suppressor. All they did was make OD of the baffles larger.
 

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I have been shooting my SDN-762 regularly for a few years (think: tens of thousands of rounds) through my 5.56 BR (7.5" barrel) and have had ZERO issues. I hope this helps you make a decision.
Using a 30 cal can rated for 300Win mag will hold up better than a 5.56 can. If you care getting a 30 cal can I would not worry about it. Just remember a 30 cal can is long and heavier than a 5.56 can.
 

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I have been shooting my SDN-762 regularly for a few years (think: tens of thousands of rounds) through my 5.56 BR (7.5" barrel) and have had ZERO issues. I hope this helps you make a decision.
That's a lot of cleaning ( gun cleaning ) right there... I'll tell you !
 

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Discussion Starter #14
That's a lot of cleaning ( gun cleaning ) right there... I'll tell you !
Appreciate all the help guys. So, just to be clear I should be fine suppressing a 10.3" barrel with a .30 cal can?
 

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Appreciate all the help guys. So, just to be clear I should be fine suppressing a 10.3" barrel with a .30 cal can?
Absolutely fine. The reason they want 10.5 inches on 5.56 cans is to make sure the bullet has enough spin to stabilize it. If you REALLY want to make sure and it's always a extremely good idea when testing new ammo or barrels or Flash Hiders....anything to change the way the bullet is effected. Shoot a five round group and make sure all the bullets punched a hole correctly through a paper target...ie no key holes. If it's good then attach suppressor, line up some beer bottles on a log and, remove ear muffs for maximum fun.

The one thing I would recommend is using good FMJ ammo anytime you use a suppressor. Also inspect ammo before inserting it in the mag. I've seen some super mass produced ammo where the bullet was not seated properly.
 
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Is 5.56 ear safe through the SDN? I have the SDN but I haven't installed a mount on any of my 556 ARs

Sent from my KFJWI using Tapatalk HD
 

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I shot it outdoors without ear protection. It's not bad on my 10.5" SBR. Indoors, I probably would at least use ear plugs. Even outdoors, I will use ear plugs. Can't be too safe.

Now, 30blk subsonic out of my SDN6 is quiet.

I was shooting my .45ACP indoors without ear protection and it was fine.
 

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Slightly OT, but I have a DD Mk18 and waiting on my SDN. With the latest AAC Blackout flash hider (w/ the wrench flats), my SDN locked up right at the rail; I was probably GTG, butI used the thickest shim in an AAC shim kit to give the SDN about 1-2mm of clearance for peace of mind. On a similar note, I also had to use an AAC flash hider tool to install the Blackout because the wrench flats tucked into the rail.

Anyway, that is something to consider if you plan on going this route. I don't know if the AAC M4-2000 will have the same clearance issue.
 
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