7.5" vs 10.5" AR pistol

[BillM]

I picked up a PSA 7.5" in a trade. It would loosen your fillings and give
you a headache. The blast/concussion was brutal. I put a Krinkov
flash can on it, which pushes most of the blast forward. Much better.
I may re-barrel it to 10.5-12, might make it a bit more friendly.

 

[Sekiro]

10.3/10.5 is the lowest i'd go with an AR.

 

[Kruel J]

I'll take more maneuverability over a slight ballistics increase. Meaning I'd take 10.5 over something longer. As stated above, these aren't for distance shooting and at 100 yards or so I think a 10.5 offers a good balance of size and performance.

For me, the ONLY reason to build an AR pistol is to have something easy to carry with capacity and ballistics advantage over other traditional pistols in pistol cartridges. Again, 10.5 for the win for me.

 

[Member 34319]

Then again like most, you take off 4-6 inches of barrel, only to add 6-8" of suppressor!

 

[deerbandit]

I'm looking to build an AR pistol. Can't decide whether to go with a PSA blemish 10.5" upper or a CBC blemish 7.5" . They are about the same price, I've heard that 7.5 is louder but is it that much of a difference? Any other considerations?

Louder and they will blind you. I shot my buddies with a 7 or 7.5 and it was deafening and blinding for me. I went with the 10.5 and it's not as bad. I enjoy shooting mine, his not so much.

 

[TTSX]

I'll be Mr different guy and say my 7.5 isn't that loud, the concussion isn't that bad and the fireballs aren't that big. Mine wears the standard A2 and I'd compare the experience to a 16" with a 3 port brake, except a whole lot smaller. I don't care that it's going to wear itself out faster, or really about the ballistics. It's a ton of fun and that was the point.

 

[The Courier]

Go with a 7.5" it's lighter, more maneuverable, doubles as a flash bang, clears out rifle bays quickly, and well just looks cool.
Plus by my calculations you only lose 22.58% vs a 16" and are above the 2200fps minimum.

 

[kmk1012]

My 7.5" is freaking loud! I wanted the shortest possible configuration and machined a FSB to be TIG welded onto the top of a three port brake. It is just a toy at this point, like something when you're out in the woods with a bunch of friends you grab and do a mag dump when no one is looking. It definitely gets everyone's attention. I've tried to use it at my range that has a roof overhead and it's unbearable unless ear pro is doubled up. If I were to do it again I'd go the 10.5" route. Now, my 8.5" 300blk is just right, especially when running suppressed!

 

[GrayGoose]

Go with a 7.5" it... clears out rifle bays quickly...

You just talked me into one.

 

[Diamondback]

As for ballistics, worth noting that Tier One guys with good ammo and good optics have gotten confirmed kills with Mk 18's out to 300-400yd. 7.5 you might as well switch to either .300BLK or a pistol caliber.

 

[orygun]

Mine's 11.5. I'd not go 7.5 with 223/5.56. if I was to do 7.5", it would be a PCC.

 

[mkwerx]

I have an 11.5 and it handles nicely, shoots smoothly, and with the flash can vs a brake, it doesn't make people at the indoor range hate me as much. I took the wife to the range a couple weeks ago, and while we were still uncasing guns - dude in the bay two lanes over started popping off with his muzzle-brake equipped AR pistol... I jumped outta my damn skin and almost smacked my head on the seperator because of the concussion and boom. It was pretty damn startling. Dude a couple lanes over had a .44 Mag smith & Wesson, not nearly as nasty as the AR w/ the brake.

 

[Member 3687]

I have 7in, 7.5, 10.5 and 11,5in guns and if you want reliability with most ammo go with the 10.3 or 10.5 or longer. The 7 in with a little playing will run most ammo but you need to run the extra O-ring on the extractor and usually a H3 buffer minimum to make them work well then fine tune from there.

The 7 in has a bird cage flash hider that does not hide the flash at all and the 7.5 has a KAK flash can to push the noise, flash and sound somewhat forward so its tolerable to shoot. Also, the velocity drops so bad it is worthless past 100yards for anything except JUST PURE FUN!

If you have other ARs then get one as when my friends come over it is the one, they want to shoot the most as it is a BAD A$$ looking movie type gun that most will never have or get to shoot as life will not allow them to spend the money on toys. It is worthless yet the most fun.

Just my opinion.

 

[2A2Dend]

They all get the job done.
Choose accordingly.

 

[clanhanson]

They all get the job done.
Choose accordingly.

If by job done you mean fire a projectile, you're right. If by accelerate the projectile to a velocity that will allow proper breakup of the round, then that's a different discussion. Ideally you'd have at least 16 inches, and a nice bullpup like the X95 avoids the tax stamp/brace conundrum and allows for full ballistic performance. Anything less than 10.5" in an AR is a waste of powder.

 

[Certaindeaf]

If by job done you mean fire a projectile, you're right. If by accelerate the projectile to a velocity that will allow proper breakup of the round, then that's a different discussion. Ideally you'd have at least 16 inches, and a nice bullpup like the X95 avoids the tax stamp/brace conundrum and allows for full ballistic performance. Anything less than 10.5" in an AR is a waste of powder.

What size is your keyboard?

 

[clanhanson]

What size is your keyboard?

The giant size with huge letters. It takes up about five feet of desk space. Typing is like playing Whackamole

 

[2A2Dend]

If by job done you mean fire a projectile, you're right. If by accelerate the projectile to a velocity that will allow proper breakup of the round, then that's a different discussion. Ideally you'd have at least 16 inches, and a nice bullpup like the X95 avoids the tax stamp/brace conundrum and allows for full ballistic performance. Anything less than 10.5" in an AR is a waste of powder.

For those of you who did not comprehend anything in the previous posts...,
Re-iterated for better understanding.

Choose accordingly.

 

[osprey]

I built a 7.5" upper for a guy and he loves it and it's spectacular fire balls. Not my cup of tea but to each their own. I have settled on 11.5" as the sweet spot for performance and wieldability. It is pretty dang accurate out to 200 with just irons or a red dot. I may have to change the three prong flash hider though as it controls flash very well but you can feel the ring in your fillings when you shoot it. Sounds like a damn tuning fork.

 

[dinky450]

7.5in is way too short IMO. I did build one and ended up parting it our for a 10.5in. it just wasnt fun to shoot and every loud even with a fortis muzzle brake and blast shield still hurt your face. i couldnt imagine shooting that indoors or being surrounded walls of the sort. My 10.5 i did a adjustable gas block, captured buffer spring, and lighted BCG it shoots very flat and all around better decision in my book. you can shoot lighter bullet weight to maintain velocity to keep it effective but not by much.