12.5" Pistol

[lead chucker]

I think it looks quiet nice, good work! Im sure you will fill us in on how it shoots.

[CrisAnderson27]

I think it looks quiet nice, good work! Im sure you will fill us in on how it shoots.

Thanks!!

I got it out to the range today. First order of business was to set the gas block. So I closed it completely, then turned it out one full turn. Gun jammed with a failure to even shove the bolt back enough to unlock it. 10 minutes of fiddling (and prying the bolt back with a piece of plastic rod) got it cleared. Opened it two more turns just to make sure it didn't happen again. Next time, great ejection, didn't lock on the empty mag. Another turn, same result. Rinse and repeat until the set screw fell out lol. It never did cycle open on the empty mag. So I turned it back in enough to get it to stay (about a turn and a half in on the adjustment screw), and went ahead and put a few rounds through it...thinking I'd go ahead and break things in a bit and maybe get a rough zero. I'd load 2-3 rounds in the mag only. It was starting to get dark on my last mag, and oddly enough, the bolt cycled fully enough to strip a round and chamber it. The next round it didn't lock open though...so it's still not getting enough gas.

The buffer is a 3oz carbine, and the spring is a carbine spring. The bolt is from Anderson Manufacturing, and the carrier is their M16 unit. The gas block is an adjustable unit from BHW. I really don't want to take the handguard apart to screw with the gas block positioning...but that's the only thing I can think wouldn't be allowing enough gas through...meaning the hole being partly covered. Getting it right did wonders for my 20" gun.

I can say this though...once I get it right, this thing's going to be a freaking expensive toy for all the ammo I'm going to go through in it, lol. The first shot surprised me a bit with how it felt...not being shouldered and all. But after that...it was just plain fun. One thing I'll need to learn is to grip it in such a way to keep the muzzle down (I took video of a few shots, and the muzzle lifts noticeably by eye...though it didn't feel excessive in hand).

In other words...I've just got to get used to it, lol.

[CrisAnderson27]

So, I got back out to the range today. I spent some time reading around last night, and it made me realize that the bolt may not have been short cycling at all...but could have actually been passing over the magazine before the follower caught up. I also remembered that I'd skipped from 1 turn out on the gas block, to 3 turns...because I didn't want the bolt to lock up again. So I closed the adjuster, and turned it out two full turns. Gun cycled, and ejected the spent casing, but didn't lock the bolt. I turned the adjuster 1/4 turn in (1.75 turns out), and tried again, same result. Another 1/4 turn in, same result. Next 1/4 turn in (1.25 turns out), and it locked the bolt again, forcing me to pry it open a bit before I could cycle it with the charging handle. Another full turn out, and things went back to normal. After that, I figured I'd see if it would strip the rounds from the mag again. It did...mostly reliably, too. The only issue I was running into was a FTF from the bolt stripping the round and slamming it into the extension below the ramps. Out of almost 50 rounds fired today, it did that four times. Total number of rounds through the gun is right at 80...and I think breaking things in is helping too. The bolt cycles cleanly now (before it felt almost 'gritty' when cycled manually, for want of a better word), which certainly can't be hurting things. I do think I'm going to need to try an H2 buffer to help with the timing...as I'm 90% certain it's not short cycling. This would let me run right at about two turns out without any issues.

Anyway, here's some video of the last rounds I fired of the afternoon. In general, the video makes me think it's over cycling almost for sure, but the second malfunction makes me wonder. The first FTF was the round butting up just below the feed ramp as I mentioned above. The second time, it didn't fully go into battery, so I cleared it (the live round surprised me a bit...you can see it in the video) thinking it was a FTE. Also, please excuse my poor form. I was shooting at one of those square Cabela's self healing 'Ground Pounder' targets (love those, I have something similar for archery), and was shooting rather quickly on purpose, both to try to get on target quickly, and to try to work the gun a bit. Also, I'm still not used to the form factor of the pistol, and shooting something like this unshouldered makes me try to adapt my body positioning in weird ways!

https://www.youtube.com/watch?v=PCeGXQOB9nc

Oddly enough, when I loaded that live round into the magazine and fired it, it locked the bolt back. Go figure!

Also, here's some video of what I was shooting at:

https://www.youtube.com/watch?v=aPYhnIlrLLY

Anyway, if you all see anything in the video that gives you any ideas...please let me know. I'm going to order an H2 buffer this week (if non one I know locally has one to let me borrow). Once that's done, I'll let you all know how it goes .

[lead chucker]

Hey Chris nice shooting! Few things here, first what mags are you using? You shouldnt be under gassed at all, my gas block is just barley open and runs hard even though its suppressed. I do use a H2 buffer in my SBRs or a JP silent capture spring with tungsten weight and the heavy spring. I would check the alignment of the block and then clean and re-oil the BCG and cycle it by hand 100 times to smooth it out some. Also check the gas key on the carrier, make sure is not loose or leaking. My 12" runs like a champ and without the adjustable gas block would be way over gassed.

Second thing, not sure what brand of pistol buffer tube you using but looks a little short in the video. My just be the angle but looks short, should be same length as a carbine buffer tube. Before I SBRed a lower I used Phase 5 pistol tubes, yes we all have heard your not suppose to shoulder them with the Sig Brace! But do what you need to do! If the action isnt getting a steady positive place to stop and let the buffer cycle correctly that could be part of the problem, kinda like weak wristing a pistol so to speak. Anyway, looks good and let us know how it goes!

[CrisAnderson27]

Hey there!

I'm using mags from Alexander Arms. I know they are supposed to be high quality, but the followers seem very loose. In addition, it is difficult to remove the rounds by hand. I have Pmags and hexmags for my 5.56 rifle, and I can slip the rounds out smoothly with average hand pressure (pushing them out like my hand is the bolt). These AA mags, the rounds feel like they're being mechanically held in. The process of pushing them out requires a ton of force comparably, and has a number of tactile mechanical 'stops' that I'm not quite sure what the source is. I've considered adjusting the lips of the retaining flaps upwards to see if that helps...but haven't messed with it yet. I have yet to check the gas block...though I plan on getting that done before shooting again (probably this afternoon). Still need to order the H2 buffer, too lol.

On the buffer tube, it's from a company called 'Guntec'. It's supposedly very good quality, though the price is definitely a bargain. I have a number of friends running them (on 5.56 builds of course), and they highly recommended them. I just took a look at the Phase 5 ( http://phase5wsi.com/ar-15-complete-...-assembly.html ) to see how long it was, and it says 7.4" OAL, which is the same as mine (measured from the buffer retention detent to the butt). Mil spec seems to be 7.25"...which is probably the inside tube length for both units.

All in all...I love the gun, and it seems to be getting better as I shoot it. I'm also still sure it's not 'right' though, and I'm not the type to settle until it is!

[lead chucker]

Iv never had a problem with AA mags, iv got some ASC mags that can be problematic. But I use 20 round Pmags with 4 or 5 rounds in it, work snd feeds ok. The Elander mags from AA work good also. Check your gas block and cycle it some, let it brake in, should be ok. If you take the gas block off, measure the port diameter just to make sure its not undersized.

[CrisAnderson27]

I think it was the block position. There is a dimple in this barrel, and the seat marks from the set screw were clocked off of it forward and to the left. I realigned the hole visibly, tightened the front screw, then tightened the screw into the dimple. This time the witness marks were perfect. Sooo...here's to hoping that helps lol. I finally ordered my buffer yesterday, as no one I knew had a spare. I'm hoping to get out by Wednesday to test.

[CrisAnderson27]

Soooo! My H2 buffer came in today. 45 seconds to change it out and I was headed to the range lol.

Unfortunately though...it seemed to make no reliable difference. I closed the block all the way, opened it one full turn...and began tuning on 1 round per shot. Got all the way out to 5 turns with no difference...so I closed it off again, and began tuning from closed, 1/4 turn open at a time. First 1/4 turn from closed, the case didn't eject. This happened for the next two adjustments to 3/4 turn out, at which point it ejected...but didn't lock open. From there, it was the same as before. The only difference is that 'sometimes' it would lock open...but not consistently. Out of 50 rounds of testing, it only locked open 5x...and at no time would it repeat on the next shot.

So I'm back to square one. H2 buffer didn't make any appreciable change. I oiled the piss out of it before leaving too...and have cycled it easily 150x by hand...plus the 150 or so rounds I've put through it total.

I'm wondering if my phone will take a high enough quality slow frame video to see what the bolt is doing.

Any thoughts you guys have would be appreciated!

[CrisAnderson27]

Talked to BHW today. They said that they've been seeing a problem with gas tubes being machined improperly, and covering part of the gas hole in the block. Took my rig apart and it did cover a very small part of it...but even then what was left is easily 2x or better the size of the gas orifice in the barrel lol. Regardless, I cleaned it up some. You can barely see it here:


Needless to say, while I don't like it not lining up, I'm sure the 1/8" hole that's left isn't the problem.


But I cleaned it up anyhow.

While I had it apart, I also blended and polished my feed ramps. While I was out this last time, I had two rounds jam up, and they literally locked right into the feed ramp (left side was the only one that would jam). The rounds were literally wedged into the little step that was there. I (of course), took a few pictures:


This picture doesn't really show how bad it was...but for it to stop a round completely (particularly as slippery as the 6.5 lol), you can guess it was pretty bad.


And after. Not too bad for my first time I think. The little dark spots are actually low spots...not steps. Either way it cycled a full mag by hand as fast as I could cycle it (before it would jam if I tried to cycle them too quickly)...so it did the job I think!

Anyway, I'm hoping to make it back out to do some more testing tomorrow or the next day. I'll TRY to bring my chronograph along this time lol. I know I keep saying that!...but it'll get done eventually.

[din]

Why does your upper have fur?

[CrisAnderson27]

Why does your upper have fur?

Lol, because I'd used q-tips to clean up some of the lubrication in there before I started...and they shed. When it was done it got a full bath and oiling before reasaembly.

[CrisAnderson27]

Well, apparently that little bit of overhang was the entire problem. Took the gun out today to do some chrono shots (and test the gas system of course), and it locked open on the empty mag at 2 turns out. I added half a turn and left it there. Worked flawlessly from then on. I put a full magazine in, and didn't have a single failure to cycle, either. SUPER happy with how the gun is running now! I put a bipod on it as well so I could dial in the scope (yes, a bipod on a pistol lol...hopefully that's not illegal as I was ONLY USING IT FOR SIGHTING IN THE GUN), and ended up with about 2moa accuracy. I'm figuring the poorish accuracy is a combination of me and the Wolf 100g ammo, rather than any issue with the gun. Velocity was lower than I expected from all the reading I've done, running from 2,380fps to 2,440fps over 10 or so shots. From the few short barrel threads I've seen for Grendels...I was expecting more consistently closer to 2500fps. Again though...I'm sure Wolf ammo isn't exactly premium lol. I need to pick up more Hornady SST and see how it runs that.

Anyway, here's a short video of a handful of shots. Still getting used to the no shouldering thing with this gun.

https://youtu.be/lyeiPn3i5UE

All in all I'm super pleased. Couldn't ask for more to be honest. Now I just need to grow into it .

[VASCAR2]

I chronographed Wolf 100 grain FMJ out of my 16" 6.5 Grendel with a Magneto Speed chronograph average speed was 2507 FPS. The shorter you go down from 16" generally the more loss in FPS compared to going to longer length barrels.

Just for comparison here are some averages of other factory loads out of my 16" barrel.

PPU 110 grain FMJ avg 2510 FPS

PPU 120 grain BTHP avg 2392 FPS

Hornady 123 Grain A-Max avg 2419 FPS

Hornady 123 grain SST avg 2430 FPS

Wolf 100 grain FMJ avg 2507 FPS, Max 2528 FPS, Min 2486 FPS extreme spread 42 FPS.

The Wolf 100 grain FMJ chronograph average out of an 18" Brownell's barrel was 2571 FPS. Your velocity out of a 12.5" barrel seem pretty good seeing how my 16" only produced 2507 FPS.

[CrisAnderson27]

I chronographed Wolf 100 grain FMJ out of my 16" 6.5 Grendel with a Magneto Speed chronograph average speed was 2507 FPS. The shorter you go down from 16" generally the more loss in FPS compared to going to longer length barrels.

Just for comparison here are some averages of other factory loads out of my 16" barrel.

PPU 110 grain FMJ avg 2510 FPS

PPU 120 grain BTHP avg 2392 FPS

Hornady 123 Grain A-Max avg 2419 FPS

Hornady 123 grain SST avg 2430 FPS

Wolf 100 grain FMJ avg 2507 FPS, Max 2528 FPS, Min 2486 FPS extreme spread 42 FPS.

The Wolf 100 grain FMJ chronograph average out of an 18" Brownell's barrel was 2571 FPS. Your velocity out of a 12.5" barrel seem pretty good seeing how my 16" only produced 2507 FPS.

That makes me curious what my 20" gun will do. I'm building a 10.5" 5.56 next week...so when I take it out to sight it in I'll see about bringing a box of 123g SST, and the Wolf 100g to see what they both do out of the short and long gun.

On the speeds for the 12.5"...it does look like it's doing better than it should be, rather than worse. Black Hole Weaponry told me that it likely would. They use a 3r rifling that supposedly improves accuracy and velocity both.

[VASCAR2]

My Shilen 20" 6.5 Grendel averaged 2511 FPS with 123 grain factory SST ammo. The BHW Polyogonal barrels usually show a little higher velocity. I figure your 20" BHW will give about 2525-2550 FPS with 123 grain SST.