parts needed to convert 16" to 7.5" AR15

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soiled

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i'm new at this ar15 thing (just picked up a S&W mp2)

I want to chnge it to a 7.5 barrel set up

other than... barrel, low pro gas block, gas tube, hand guard. what else is needed?

are there 7.5 barrel kits out there, for a full conversion?

if anyone has a complete parts list, i'd love to be schooled

plus I need more weights? because of the extra gas pressure?

thanks
 
Might be easier to just pick up a complete 7.5" upper, then you have both! NEA is one option there that is reasonably priced.
 
Get a complete upper.

I mean, you would almost be getting all the parts anyway.

Then you can play with it, and put the 16" on for resale....
 
Doing the Build yourself could be pretty fun- I'd also get a new Upper to have both set ups, uppers aren't too expensive..or as said above, Buy a complete w/BCG etc too. I have seen some 7.5" for sale. some were complete rifles, but they said they would just sell the complete upper to me at the time, & for very fair prices. I too just got my first AR recently, it's a 14.5" & seen the good deals on the S&W after I bought it. My Question is if anybody knows. Since it's restricted anywayz, could you say Cut down the barrel on a 16" to 10.5" {or shorter} & thread it/crown etc. properly? Im not that fond of the 16" pencil neck profile/look, but the prices are good. There's no restrictions to do something like that on an AR factory barrel is there?
Great Rifle/Great Deal- I'd like to chop it Just an inch after the front site- :p
S_WII.jpg
 
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No, you cannot just cut down a barrel. That is manufacturing a prohibited device. The barrel has to be manufactured at it's finished length.

Auggie D.
 
Ahh.kk Thanks- I know you can't do it on an 18.5" NR like a factory Shotgun or 10/22 barrel- I just wasn't sure on a Restricted set up already, since that in itself isn't even a regulated device, & would be part of a Restricted set up. Cheerz ... ~
 
I'm gonna assume same caliber?

-Barrel
-Low profile gas block (could reuse the A2 if you want)
-Pistol length gas tube and new roll pin.
-Handguard (nut should be included if different than mil-spec)


If it is over pressured you can get a heavier buffer but try it out first. Muzzle device can be reused. You also want an armorers wrench, a torque wrench and a BEV block or similar. Go/No Go gauges are good to make sure there are no issues with the new barrel spacing. Lithium grease or bearing grease for the barrel nut (no graphite).
 
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If money isn't really important, then for sure build it yourself. However, as many have mentioned, you may be happier to just purchase a second upper at a barrel length you prefer. then you have the ability to quickly swap out the uppers depending on the kind of shooting you want to do.

Also, if you have never shot a shorty before, I highly recommend trying to find someone that has one you can shoot a couple mags out of as they are VERY different shooting from the standard 16" length. It would be a shame for you to do all that work to find out that a shorty AR-15 isn't what you wanted.
 
bruh said:
Also, if you have never shot a shorty before, I highly recommend trying to find someone that has one you can shoot a couple mags out of as they are VERY different shooting from the standard 16" length. It would be a shame for you to do all that work to find out that a shorty AR-15 isn't what you wanted.
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:agree:

Think of a small bomb going off in your face every time you hit the trigger. If you MUST have something that short, a pistol cartridge upper will have a fraction of the blast, as should 300 Blk.
 
SigWig said:
take your time.

can you settle for 11.5"?

http://www.nordicmarksman.com/Colt-CanadaDiemaco-MRR-116-Upper.html




I know it's more then the complete gun. It should keep pretty good resale and cost less over a franken upper should you sell it.

colt-canadadiemaco-mrr-116-upper14881786.jpg
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Hello:

Sorry for the hijack, just a quick question. If one had a Daniels Defence 16" AR would one be able to simply change from a 16" upper to an 11.5" upper (like the one you suggested above) without any other required changes? i.e. I just pop two pins and change uppers? I have read that one can have "timing" issues when switching between different length uppers. Thank you for your time.

Regards,

Chizzy
 
Chizzy said:
Hello:

Sorry for the hijack, just a quick question. If one had a Daniels Defence 16" AR would one be able to simply change from a 16" upper to an 11.5" upper (like the one you suggested above) without any other required changes? i.e. I just pop two pins and change uppers? I have read that one can have "timing" issues when switching between different length uppers. Thank you for your time.

Regards,

Chizzy
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only issue i can think of that you would potentially run into is if your buffer spring is too light/heavy since you would have a different length of gas block. again, that's just a potential issue. i have swapped many different length uppers on to the same lower and did not encounter any problems with timing. that being said, most of my uppers were either mid-length or carbine length gas tubes.

good luck
 
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