300BLK SBR

[UWone77]

There was just no comfortable way to shoot it. I could get rounds on target no problem, the first one. The recoil was too much without a stock for any type of follow ups. And then of course I could get up on it and get a nice cheek weld like it was a rifle, but then I had a buffer tube poking my collar bone.

I know what you mean, when I shot my AR pistol regularly, it was pre-KAK Shockwave and Sig Brace.

I think the best shooting style for my personal tastes when shooting an AR pistol is a single point sling and SAS style.

[Aberration79]

I know you're SBR'ing but a Thorsden buffer tube kit or KAK Shockwave would help... I've had no issues with my 12.5" pistol using the Shockwave and can Cheekweld it comfortably and really get on target comfortably..

Edit: Those Gemtech are definitely warm in your pistol.. I'd keep a watchful eye.. youre not too far fron flat primers and swipes...

I have dabbled in reloading and read the manuals. I have never worked a load up that hot. But that was my first thought with them.

[Aberration79]

I know what you mean, when I shot my AR pistol regularly, it was pre-KAK Shockwave and Sig Brace.

I think the best shooting style for my personal tastes when shooting an AR pistol is a single point sling and SAS style.

Forgot the sling on the chair. I got enough ammo and a few people quite interested in the build so I am going to have to give it a try. I guess just pushing out instead of pulling in. And try not to look too tacticool doing it lol. God the laws are so stupid.

[UWone77]

Forgot the sling on the chair. I got enough ammo and a few people quite interested in the build so I am going to have to give it a try. I guess just pushing out instead of pulling in. And try not to look too tacticool doing it lol. God the laws are so stupid.

It's not perfect, and it can get tiring shooting like that, but AR pistols in general are a compromise and only exist because of NFA.

[Soisauss]

It's not perfect, and it can get tiring shooting like that, but AR pistols in general are a compromise and only exist because of NFA.

Only reason I built one and currently treading the NFA waters with the new sub combat pistols ( Anggstadt Arms UDP-9) in mind to build.

[Jerry R]

So here she sits in her initial pistol configuration. I am very pleased so far.

Looking at the build (very nice!) I am curious as to which suppressor you are considering with that barrel length and handguard.

And I definitely agree with Dstrbd -- cratering is a sure sign pressure is up. Unless that load is extremely accurate, you may want to consider dropping the load slightly.

[Aberration79]

Thanks! I am going with Surefire once I get around to it.

All of those loads are 'factory' loads with new brass. I didn't have the time to make some or find some and load them. I have heard nightmares about getting the light and heavies both to cycle, I didn't want to throw reloading into that.

So I need to test out the PDW stock that I have on my 16" 5.56. Buddy has a chrono so I am going to bring it out and get the measurements from some 5.56. And then I will chrono some of this 300.

[Aberration79]

Well my darn stamp finally got approved. Went through the work and got the MVB stock installed and all that. It ended up short stroking frequently on the 147gr FMJ's. So I had to order the Carbine buffer. Though I wondered about getting at the weights and removing some. But now if I run a rifle length upper I got a buffer for the hell of it. I also went with a Surefire 3 prong muzzle adapter as a friend had a Surefire suppressor.

Just today I ran my friends Surefire finally. Running 208gr subs from Armscore. Ran a mag, perfect function. Zero'd at 50 previously with 147gr FMJ, with Magpul BUIS. Was able to hit my buddies man size targets at about 75yds without any adjustments. Didn't do much thorough testing. The clearance to the handguard is about 1/8th inch. But it fits lol. It was a cheaper barrel so I am eyeing replacing it anyways. I'd like maybe 1/4-1/2in more. I love how light this thing is and the ergonomics of it all.

It probably shoots way better than I do. I got the Primary Arms 1-6x 300BLK. I also recently picked up a target stand and a 8" and a couple 4" round plates to shoot at.

All in all I couldn't be happier. Kind of pondering getting some cerakote. We'll see how long it last until something breaks :D

[BoilerUp]

It's not perfect, and it can get tiring shooting like that, but AR pistols in general are a compromise and only exist because of NFA.

...and state laws that don't allow for loaded rifles in or on vehciles, such as in WA.

[Dstrbdmedic167]

Pics or it didn't happen...

Glad to hear you got it straight and it's running well for you.

[Aberration79]

[Joelski]

I know you're SBR'ing but a Thorsden buffer tube kit or KAK Shockwave would help... I've had no issues with my 12.5" pistol using the Shockwave and can Cheekweld it comfortably and really get on target comfortably..

Edit: Those Gemtech are definitely warm in your pistol.. I'd keep a watchful eye.. youre not too far fron flat primers and swipes...

I'm with the OP on shooting. Never interested me to fire it in pistol mode, nor any other AR pistol config; I guess I just have a rifle image thing going on when it comes to AR's.

Flat primers and swipes: 'splain, please. Never heard these terms before. To my knowledge, the 300 is one of the least finicky calibers with respect to gas volume and pressure.

[Jerry R]

Flat primers and swipes: 'splain, please.

I believe "swipe" is defined as:

Primer swipe is caused by the ejector starting to push the case off the breech before the firing pin has fully retracted.

Flat primers would normally be defined as "showing signs of pressure" - that would be pressure higher than normal, something to watch.

If you look at an unfired cartridge, the primer cup has rounded edges.

If you look at a fired case that is "normal" the primer strike is clean and shaped like the firing pin tip. The edges of the primer cup are still visibly round.

A swipe would show a little drag mark of metal at the edge of the firing pin indentation (wish I had a picture for you) - in other words, not a "perfect" indentation.

A flat primer would be where the edges of the primer cup are no longer round - the edge has "flowed" under pressure to square up with the edges of the primer pocket on the case. This may, or may not, be a bad thing depending on the amount of pressure being generated. I generally back off my powder charge if I start to see flattening on the primers.

Another term you may hear is "smudge" or something similar. It would be a smoky stain around the edges of the primer pocket. This is either a really loose primer (not likely) or high pressure. The seal between the primer and primer pocket has been compromised, and flame is leaking back through the primer pocket - definitely not a good thing.

Lastly, "cratering" --- this is where the firing pin indentation looks like a miniature meteor strike - the outer diameter of the indentation has a ring around it where the metal has flowed under heat/pressure.

Most reloaders consider any (or all) of the terms as being indicative of increased pressure - or, if a known "safe" load is being used, some might indicate a potential case failure.

Again, if other definitions are more accurate, please speak up. Hope this helps.

[Dstrbdmedic167]

Jerry answered better that I could have. I was waiting to get to a PC before I responded. Thanks Jerry

[Slippers]

Swipe usually pertains to marks on the rim of the case due to the ejector cutout on the bolt face, such as this:



With an overpressure load, the brass flows into the ejector cutout slightly, and then the bolt face rotates, and leaves the swipe mark.