How much clearance past the rail is needed for 51T brake?

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hokie2000
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How much clearance past the rail is needed for 51T brake?

Post by hokie2000 »

Hi, I have a Daniel Defense MK18 upper with the 10.3 barrel and MK18 RIS II rail and I wanted to find out if anyone knows if that will allow enough clearance for the 51T brake and the 762-SD to fit on there.

Edit: added some pics for reference:

Image

Image

Image



Thanks!
Last edited by hokie2000 on Thu Sep 22, 2011 7:07 am, edited 1 time in total.
oneinseven
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Re: How much clearance past the rail is needed for 51T brake

Post by oneinseven »

I also would like to know this. I've got a sdn-6 pending approval. It will go on a mk18 clone with colt 10.3 barrel. I too have the brake. I was thinking if it is close maybe a few more shims could be added behind the brake.
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Re: How much clearance past the rail is needed for 51T brake

Post by Kramer »

A close up pic of the muzzle area would work better.
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J Krammes
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Re: How much clearance past the rail is needed for 51T brake

Post by J Krammes »

My M4-2000 goes ~.125" past the rear most area of the mount. I would guess the 7.62 series of suppressors should be the same. So if you have at least .125" from the sholder of the threading to the front of the forend you should be fine.

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bayonet14
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Re: How much clearance past the rail is needed for 51T brake

Post by bayonet14 »

viewtopic.php?f=86&t=68520&p=660653#p660653

Take a look here at my set up w/a 51T mount and M42K suppressor installed - you have .21" of clearance and that with a 10.5" barrel.....with a 10.3" barrel and same rail you AAC suppressor will secure to the 51T mount but you WILL have contact with the rail...

my 2cents
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JasonM
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Re: How much clearance past the rail is needed for 51T brake

Post by JasonM »

it most likely will not fit with the Brake mount. You'd need a 10.5" bbl.

Likewise it might just fit with a BLACKOUT Flash Hider because the hider has the extra length at the back. The early runs of BRAKEOUTs had a flush back like the brakes, but the newer runs have an extended rear that is like the hiders, so they would probably work as well.
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hokie2000
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Re: How much clearance past the rail is needed for 51T brake

Post by hokie2000 »

Thanks for the information! I checked last night and it looks like there will not be enough room. So now I'm torn between putting a new barrel on it or ditching the upper all together and going with something else.
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Re: How much clearance past the rail is needed for 51T brake

Post by Kramer »

When I bought my two LWRC uppers I did not buy the M6A2 just because the can would hit the rails.
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Re: How much clearance past the rail is needed for 51T brake

Post by bayonet14 »

The early runs of BRAKEOUTs had a flush back like the brakes, but the newer runs have an extended rear that is like the hiders, so they would probably work as well.[/quote]


Hey Jason thats good to know - has AAC change the ability to shim all the AAC Brake/Brakeout mounts - or are they more like the flash hiders that you just Rockset and index as you tighten to spec?
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JasonM
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Re: How much clearance past the rail is needed for 51T brake

Post by JasonM »

bayonet14 wrote:
JasonM wrote:The early runs of BRAKEOUTs had a flush back like the brakes, but the newer runs have an extended rear that is like the hiders, so they would probably work as well.

Hey Jason thats good to know - has AAC change the ability to shim all the AAC Brake/Brakeout mounts - or are they more like the flash hiders that you just Rockset and index as you tighten to spec?

The Muzzle Brakes are the same- flat/flush back that you shim in place.

The newer BRAKEOUTs have an extended rear (like the flash hiders), but they still need to be timed with shims. This extension was added so that they could be easily pinned on 14.5 bbls.

The flash hiders are the same- torque in place with rocksett, no shims.
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lawman1380
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Re: How much clearance past the rail is needed for 51T brake

Post by lawman1380 »

I am running into the same issue. Is there anything I can do, or am I farked.
Image
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continuity
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Re: How much clearance past the rail is needed for 51T brake

Post by continuity »

All I will say ... Dr. Dremel. Works every time........ all the time.

Like mah nutcase neighbor says... "Don't worry about the pristine looks. It's all about making it work".
What amount of a man is composed of his own collection of experiences... and the conclusions that those experiences have allowed him to "know" for certain as "Truth"? :Ick
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Re: How much clearance past the rail is needed for 51T brake

Post by Ryo »

lawman1380 wrote:I am running into the same issue. Is there anything I can do, or am I farked.
Image
Have a machinist make a collar for you so you can push it out a bit more? Just make sure it's squared and double check by looking down the barrel to make sure you don't have any potential baffle strikes. Just an idea..
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Re: How much clearance past the rail is needed for 51T brake

Post by J Krammes »

Ryo wrote: Have a machinist make a collar for you so you can push it out a bit more? Just make sure it's squared and double check by looking down the barrel to make sure you don't have any potential baffle strikes. Just an idea..

NO WAY... He would loose about .25" of threading. The ONLY two options are cut existing forend or get a new one. Even with that, it looks like it will hit the regulator knob. (AA kit?) Like I said in my post, the can will come past the back end of the mount ~ 1/8". From the pic it does not look like there is enough room. Going to an 11.5" barrel will fix everything.

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JasonM
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Re: How much clearance past the rail is needed for 51T brake

Post by JasonM »

lawman1380 wrote:I am running into the same issue. Is there anything I can do, or am I farked.
Image
Have a machinist cut off the front of the rail. refinish it and enjoy.
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Re: How much clearance past the rail is needed for 51T brake

Post by jcsparky »

Jason
I like your Engineering Solutions... :mrgreen:

Not sure I'd want a 10.3 suppressed, maybe a 12.5
give it a lil room to breathe..
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este
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Re: How much clearance past the rail is needed for 51T brake

Post by este »

jcsparky wrote:Jason
I like your Engineering Solutions... :mrgreen:

Not sure I'd want a 10.3 suppressed, maybe a 12.5
give it a lil room to breathe..
I agree with cutting the rail, it's the fastest solution. Although a new barrel would probably cost as much as the rail. So either way.

+1 on the 12.5. I'd grab another gun if I had to shoot a 10.5 unsuppressed ever. 10.3 is cool, and I trust that Colt did the correct work to the buffer, spring, chamber, gas port, carrier and bolt to make everything work 100%, on a clone you're just bolting parts on imo. I would expect most 10.3 guns out there to be way overgassed. I firmly believe there is a functional difference in Colt v Clone.

I'm a big fan of 12.5. Then again, I also sold my Mk18 rail because it was too heavy/bulky. So this thread really isn't for me ;)
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Re: How much clearance past the rail is needed for 51T brake

Post by bigdog2003_99 »

JasonM wrote:it most likely will not fit with the Brake mount. You'd need a 10.5" bbl.

Likewise it might just fit with a BLACKOUT Flash Hider because the hider has the extra length at the back. The early runs of BRAKEOUTs had a flush back like the brakes, but the newer runs have an extended rear that is like the hiders, so they would probably work as well.
Jason is correct, if you use a blackout/breakout will barely fit. if you use a muzzle brake it wont fit since the can screws behind the rear of the mount. the wrench slots on the blackout give you the extra clearance needed for the suppressor to fit with the mk18 rails

if my only spare blackout mount wasnt rocksetted on to my acr i'd give you a better pic on the mk18

Image

btw mine is a dd 10.3" upper too
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Re: How much clearance past the rail is needed for 51T brake

Post by alanjreid »

I know this first hand that with the DDMK18 if you use a AAC 51T flash hider and a AAC M4-2000 it will work 100% theres about enough room to slide a piece of notebook paper through with the suppressor all the way bottomed out on the mount. If you would like i can send pictures of it.
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Re: How much clearance past the rail is needed for 51T brake

Post by karn »

alanjreid wrote:I know this first hand that with the DDMK18 if you use a AAC 51T flash hider and a AAC M4-2000 it will work 100% theres about enough room to slide a piece of notebook paper through with the suppressor all the way bottomed out on the mount. If you would like i can send pictures of it.
Could you please post your pictures here? I've been looking into this for my next project and would like to see some close ups before I start emptying my checking account. It would be much appreciated!
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Re: How much clearance past the rail is needed for 51T brake

Post by cpatterson86 »

karn wrote:
alanjreid wrote:I know this first hand that with the DDMK18 if you use a AAC 51T flash hider and a AAC M4-2000 it will work 100% theres about enough room to slide a piece of notebook paper through with the suppressor all the way bottomed out on the mount. If you would like i can send pictures of it.
Could you please post your pictures here? I've been looking into this for my next project and would like to see some close ups before I start emptying my checking account. It would be much appreciated!
Standard 51T flash hider.
Image
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