M4A1 Barrel 14.5”?

**5.56Geo** · 02-02-20, 14:50

What is the better option to bring a 14.5” M4A1 barrel to legal length, an ADCO KAC spacer or an extended A2 Birdcage flash hider? Can any one post a close up picture of the ADCO spacer installed? What route did you take. Thanks- Geo

**JediGuy** · 02-02-20, 15:04

Not what you’re asking, but you did ask what route I took...

1. SBR - no pinning
2. 16” barrels - no pinning

That’s the route I took, in order.

**Diamondback** · 02-02-20, 15:22

Or talk to John Thomas at Retro Arms Works--he does shim-pin-and-weld jobs too, and parks the shim to match your barrel. Once Shark Arms and I have everything ready to ship on my Colt contract-overrun M4 upper, it's being shipped to him for the compliance work.

**MikhailBarracuda91** · 02-02-20, 15:45

Originally Posted by Diamondback

Or talk to John Thomas at Retro Arms Works--he does shim-pin-and-weld jobs too, and parks the shim to match your barrel. Once Shark Arms and I have everything ready to ship on my Colt contract-overrun M4 upper, it's being shipped to him for the compliance work.

How'd you get a contract overrun upper? Did it include everything? Or was it just a barreled reciever

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**Diamondback** · 02-02-20, 15:49

Originally Posted by MikhailBarracuda91

How'd you get a contract overrun upper? Did it include everything? Or was it just a barreled reciever

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I *think* it was an overrun, might just be surplus, but it includes RAS and Matech BUIS. Scroll down to where it says "Colt M4S 14.5" at https://sharkarms.com/ -- the normal is a complete ready-to-pin-onto-pistol/SBR-lower-and-fire URG, but I'm having them delete the BCG and CH since I already have those for this build.

**omegajb** · 02-02-20, 16:15

You could pin a muzzle device or put it on a pistol lower with a SBA brace.

I used a 3 prong flash hider, it makes it long enough to be legal and I do like the size compared to a 16" with a muzzle device.

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**Gatorgrizz27** · 02-02-20, 16:59

I’d go with the extended flash hider if an A2 is what you want, it’s only $15 more than the spacer. Unless you live in a state where cans are banned, I’d just run a Dead Air Flash Hider, it will be long enough and other cans have QD mounts that fit it. Their new key micro brake also “just” makes 16”, and I didn’t find the noise/blast to be noticeable compared to a bare muzzle, I’m assuming due to only being 2 ports and having a .38 diameter bore. It did make a difference in recoil though. Granted I haven’t shot it indoors with somebody next to me and no ear pro.

https://www.capitolarmory.com/dead-a...110-da111.html

**MikhailBarracuda91** · 02-02-20, 17:04

Originally Posted by Diamondback

I *think* it was an overrun, might just be surplus, but it includes RAS and Matech BUIS. Scroll down to where it says "Colt M4S 14.5" at https://sharkarms.com/ -- the normal is a complete ready-to-pin-onto-pistol/SBR-lower-and-fire URG, but I'm having them delete the BCG and CH since I already have those for this build.

Wow how didn't I know about this site. I just bought a BCM bcg. I have no regrets but I spent almost the same and had I known this existed I might have gone another route with my rifle I have on the way

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**phixion** · 02-02-20, 19:04

Originally Posted by Diamondback

I *think* it was an overrun, might just be surplus, but it includes RAS and Matech BUIS. Scroll down to where it says "Colt M4S 14.5" at https://sharkarms.com/ -- the normal is a complete ready-to-pin-onto-pistol/SBR-lower-and-fire URG, but I'm having them delete the BCG and CH since I already have those for this build.

How much did that end up being -- upper less BCG and CH?