Details? Are you saying that bottom pic is a bullet from a 7.5" barrel that only penetrated 4"? That's crazy! The pic further up in the thread showed one that went a lot deeper. Using a bullet energy calculator online it looks like a 7.5" 5.56mm should have more energy than a 45acp, with the bullet being smaller and more areodynamic, I'd think it would get a lot more penetration.

What type of accuracy do you guys get from these 7-8 inch barrels?  Post up some 100 yards groups!

Don't think Ive ever shot for groups.
Will have to take some next range trip. With an AimPoint I was getting around 4" groups at 100 with 55gr

I may put a scope on mine just for shits and giggles and try groups

No the bottom picture show the gelantin calibration. That is a bb fired at 600fps into 40° gelatin.


The bullets that are mushroomed are the 45gr TSXs with a muzzle velocity of about 2550fps,  they went in about 13". About 650 ft lb energy at the muzzle 460ft lbs energy at 100yds.

The one on the top that didn't expand are 50gr TSXs going 2400fps, they went all the way through.....if I recall, 18" of gelatin.

The very top 2 are the 50gr TSX fired through my 18" at 3175fps , they fully expanded obviously.

The 45gr TSX load through the 18" was 3350fps, too fast, they shed all of their petals.

Was just thinking about that. Would be the 1st time I would have bagged a "pistol" as well

I like 5.56 in a shorter barrel.  While the shorter barrel does not optimize the round it does make for a fun range toy.  I mainly go to an indoor range for everyday shooting as I like in a pretty populated area and outdoor ranges are a bit of a drive.  

I currently run 5.56 in a 10.5 that's awaiting a Form 1.

I also a run a 300BLK in a 7.5 also awaiting a Form 1 with an AAC SDN762.  

I have an unattached 8 inch 5.56 upper but I rarely run it due to the fact that it's so loud indoors.  I would maybe run a 7.5 as a truck gun for personal defense and I agree with your choice on the KAK.  If you're not looking to touch targets outside of 150m ish then have all the fun in the world and the possibilities with your 7.5 are plentiful.  Just watch out for people next to you on the range as it can get a bit loud.

Best of luck!

Here's two of my pistols

For groups ,just using a red dot non magnified scope, I was impressed with the accuracy of my pistol. I cant remember the group size. Will check it the next time I have it out.

I'll second this. I had a 7.5" I built when the 1994 AWB sunset (we threw a sunset build party). The kit was from Model 1 sales and ran flawlessly even on registered lowers. Talk about muzzle blast! The biggest problem was the bolt cracked right where the cam pin goes through. I did manage to get some fragmentation in a watermelon at somewhere between 25-50 yards with some cheap Russian ammo (although no one believes me).

I now have a 7.5" pistol in 7.62x39mm as that round doesn't lose as much velocity per inch of barrel removed. The round also doesn't depend so much on velocity for terminal performance. The 7.62x39mm pistol runs every bit as well as the 5.56mm one as long as you stick to CProducts mags and do the barrel extension modification.

Note the hole to the left on my bag 

Can't remember what I got with it, seems like 3"@100 with plinking ammo.




Minute of man at 100 kneeling.

I have a 7.5" pistol that I built with an Andro Corp upper @ 1:7, and a Thordsen cheekrest/saddle.  I figured if I was going to make a saddled pistol, I might as well go as short as possible, 'cause why the heck not - any longer than as short as possible seems like p*ssing in the wind to me.  I was also looking forward to a devastating muzzle blast with a 3' diameter fireball, which would've been cool.
Oddly, I didn't notice any significant blast, and there is literally NO fireball, even at dusk - which I have to admit was disappointing.  OTOH, the pistol is surprisingly accurate and seems to be gassed perfect, depositing empties in a neat pile 6' away at 4:00.  I have it equipped with a cheapo Chinese holograph sight from ebay, which also works surprisingly well (better than the cheapo Chinese aimpoint that I had on there first - lasted exactly 8 rounds).  It's really fun to shoot, hits what I aim at, and did a fine job dispatching a homicidal porcupine with a single shot at ~40 yrds that was terrorizing my property last summer.

Personally, I think all those that poo-poo 7"ers are those that get their information from the internet, and have never actually shot one.  Mine runs like a Swiss watch.

I've shot a 7.5" 5.56 and own an 8" 300blk. Supersonic 300blk has a lot less muzzle blast and concussion from my experience.

Interesting.  This week we can shoulder our braces, according to the Trump BATFE.  With a folding brace, looks like you could get down to approx 16", same as a folded SUB-2000.  And with a 7.5" bbl, you're still over the 2100 fps permanent cavity velocity with certain ammo.  Be a nice placeholder until the folding bbl upper makes it to market.

Here is a target I shot yesterday at 100yds using a primary arms red dot and old man eyes. This is pretty much what my pistol can do with this set up. The r d dot covers almost a third of the target at this range and I'm sure it would do better than this if I had a scope on it.

I punched the numbers in a ballistic calculator and 55gr SP and 62gr Fusion don't hit the floor of their expansion threshold until 150 yards and have more energy than a +P+ 9mm at the muzzle.

Doesn't sound like a range toy to me.

You throw a cookie cutter on it. It's gon be loud but you'll be happy

wrong thread.

Bump

Shot some 77gr AYSM through my 7.5" PWS mod 1 upper today. With a Trijicon 1-4 scope, I was grouping five shots at 2.25"
Best I can do with it. This ammo was grouping just under an inch from my Mod 2 14.5" pinned carbine

Damn that's not bad at all. Is that PWS a piston? If so does it run pretty clean?

I kinda want one piston gun

It is a piston.
After nearly thirty years of shooting DI carbines, I love these PWS piston guns!
Dare I say it, but the best of the AR mated with the piston system of an AK.

I have this upper, a new PWS Mk 114 Mod 2, but a Mk116 upper for it as well.
Going to be losing my Mk116 Mod 1 shortly.

They all run darn clean. A great deal cleaner than DI guns do. Suppressed, they run about the same, but the piston chamber stays cooler.

Interesting, man I wish I would've bought an Adams Arms rifle blem for $500 at Buds when I saw them.

I have enough DI might be cool to try out

I was always interested in piston uppers. I bought the PWD Diablo to run as a 7.5" pistol.
Loved it so much I've gotten more.