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View Full Version : AR Pistol 7" or 10.5"


ripcurlksm
08-19-2014, 10:37 AM
AR Pistol 7" or 10.5"

SDM44
08-19-2014, 10:38 AM
http://www.calguns.net/calgunforum/showthread.php?t=968916

tacticalcity
08-19-2014, 10:43 AM
Depends on caliber. 7" is great if running 9mm. 10.5" is statistically more reliable if running 5.56mm. Also...get the correct weight buffer regardless of barrel length. Will make all the difference with regards to reliability.

That said, an AR pistol is mostly a toy. So get what ya like. I dig the looks of the shorty AR pistols a lot. In a perfect world, get both.

Fenr1r
08-19-2014, 10:55 AM
I'm going 7" with a KX3 and a 9" hand guard. 10" + muzzle device length is too long for a pistol for me unless we ever can SBR it.

tacticalcity
08-19-2014, 11:07 AM
Cool!

THEJAPINO
08-19-2014, 11:09 AM
There should be an option for "both" in the poll.

bohoki
08-19-2014, 11:16 AM
i got the 7.5 cause i wanted it small but the 10 lets you use carbine handguards

SNCaliber
08-19-2014, 11:19 AM
yup 7.5 for 9mm, 10.5" for 556/223

k1dude
08-19-2014, 11:35 AM
Since .223 sucks out of both lengths, go shorter simply because it looks cooler. If we were talking about .300 Blackout, I would say 10.5" because there are real performance benefits to the longer length.

phase1
08-19-2014, 11:47 AM
If just for fun 7.5 in 556, otherwise 10.5 & up... If 9mm, 762, or 300blk 7.5 will work

RobertMW
08-19-2014, 12:28 PM
Basically, do you want the fireball maker, or the really big fireball maker?

Josh3239
08-19-2014, 12:51 PM
10.5 offers more advantages, 7.5 has the cool factor.

zcktomcat
08-19-2014, 5:55 PM
Ballistics wise out of a 10.5" barrel a .223 remington will be exiting the muzzle at a velocity of about 2600 fps. A 7.5" barrel will give you muzzle velocities of only 2300 fps. Fackler found that the M193 55 grain round will only reliably fragment at an impact velocity of 2500 fps. Being that the fragmentation is a large part of the wounding mechanism for the rifle that is something to keep in mind if you plan on using the gun for defensive purposes. That being said either barrel length will be deafeningly loud even in an open field and will almost definitely result permanent hearing damage. This makes either choice poor for defensive purposes. If you're getting the gun just to have a good time at the range, as I did, I personally went for a 7.5". The shorter barrel will give the gun better balance, it will weigh a lot less, and big fireballs are just fun.
My main suggestion with either choice is get a good break that redirects the concussion forward (IE noveske KX3 "pig brake) and not a muzzle break that reduces recoil by redirecting the gasses to the side. It will be the difference between everyone at the range wanting to check out your cool piece and everyone hating you guts.

Edit: Also keep in mind most any short barreled rifle caliber gun will take some experimentation to get it to run reliably. Be prepared to test different ammo, buffer weights, and other small parts to get it running well.

bohoki
08-20-2014, 6:20 PM
here is my dinky caution turn down your volume cause this is a loud bastage

http://vid43.photobucket.com/albums/e366/bohoki/V08-20-14_1329_zpsfff180d2.mp4

blam its hot

TacRak
08-20-2014, 6:30 PM
You cant go wrong with either one

saki302
08-21-2014, 2:42 PM
Go with 10.5 over 7.5 + kx3. The KX3 on the short barrel makes it heavier than the 10.5, and pretty much just as long.

You shouldn't need a KX3 to make the 10.5 run if they made it right.

-Dave

michiganboy
08-21-2014, 3:30 PM
Built mine bufferless using arak21 upper that was 12.5 inch, still shorter then a 10.5 with buffer but with more barrel for longer range accuracy.

Jimi Jah
08-22-2014, 7:19 AM
7.5". It's a pistol. 10" or 11" is a SBR.

TacticalChihuahua
08-22-2014, 8:10 AM
If u want a gun purely for novelty get a 7.5. If it's in 5.56 the round will be below the fragmentation threshold before it even leaves the muzzle. So basically you're shooting a glorified .22 hole puncher. It's also utilizing a pistol length buffer tube instead of carbine and they are known to be finicky.

If you want a functional gun that offers good terminal ballistics and that will be reliable then get the 11.5. That's why BCM created the 11.5. More dwell time and more reliable.

desertjosh
08-22-2014, 8:19 AM
I went 7.5 and haven't regretted it in the least. It's been flawless so far as well.