12.7 group buy Faxon gas block troubles

[Kswhitetails]

HAHA will do. But the proof is on the wall, not the weapon. The weapon is merely getting older. Did I fail to mention that this is my truck gun build? Hmmmm. Seems like it's aware of it's finish requirements even before being completed!

[grayfox]

Well, grandkiddies, that boar was SO MEAN AND UGLY.... you cried so hard as a baby when you saw him.... that I had to get rid of him....
hahahahahahahahahaha!!!!!!!!!!!!!!

[grayfox]

Well, I finally got it all together to take out for a test run. Shooting was very good excpet for the appearance of several scratches. I'll post pictures later. I'm using a Vortex Strikefire II red dot right now to try out the whole RD scenario, with my eyes, etc...

24 rounds so far downrange... 15 then an attempt at polishing the chamber, then 9 more. Firing and extracting/ejecting is 100% so far. Mixture of Federal AE 90's, Hdy 123 Black, Hdy 123sst factory, and some 90-TNT's I loaded at 31.2 of H335.
The 90 AE's I've got ~3/4" at 25 yds, the 123 eldm's and 123 sst's are tight but a bit side to side, again at 25 yds. All with the red dot, set t lowest brightness.
Boy the H335 has a lot of flash!!!

But smooth shooting so far. Just the scratches.

The big question I have now is, what is the best description of the role and shooter-expectation for a "truck gun"? Has this been laid out somewhere as to role, targets, distances, expectations on accuracy? I will say that this lil GRRRR shoots really nicely off of a bench rest, haven't tried it in the field yet.

[BluntForceTrauma]

GF, good to hear after all your tribulation.

As far as scratches, I'd focus your attention on the extension teeth more so than the chamber; seems this batch has extra-sharp edges and is scratching brass.

[VASCAR2]

Grayfox my criteria is to be able to use what I brung, if that is a AR-15 pistol in 6.5 Grendel I’d have to do some testing. In full disclosure I’ve only ever shot a Kel-Tec PLR-16 and an AK pistol plus SBR AR’s. I’d be interested in your results using your 12.7” 6.5 Grendel.


Test I would preform is shooting at silhouettes at 7, 15, 25 and 50 yards off hand. I used the PLR-16 with a sling to help stabalize by pushing forward. I would be intersted in your results compared to using a handgun(9, 40, 45). At 50 yards and further a prone position aids with handguns and I’m curious how effectively you can use your 12.7” 6.5 Grendel from prone with no bipod.

Shooting steel silhouettes with your 12.7” 6.5 Grendel should prove effective further than typical pistol caliber handguns. Using a high capacity mag in an AR-15 pistol planted on the ground it would be intersting to see if you could hit steel targets to 200+ yards using a red dot sight.

When I think of using a 12.7” 6.5 Grendel pistol for hunting I envision very close off hand shots, improvised support/rest or shooting from a stand/blind with a supported rest. I never tried shooting a pistol AR-15 with shooting sticks or tripod, is it even practical in a hunting situation?

Maybe forum members with more practical AR-15 pistols experience will chime in.

[Kswhitetails]

Well, I for one am a happy camper with mine. Just got back from some off hand 100 yards on an 8" plate. After dialing in the 1-4 PST gen 1, 10/10 at 100 standing. Just after eating 2 burgers fresh from the grill. Bad idea, I haven't seen belly-table like that since I was in HS doing two a days... Anyway, belly was so full it was uncomfortable to stand still, especially holding my breath.

Here's the kicker, we backed up to 230 today, the absolute farthest we can go at this location, and prone on 1x went 4/5 holding at the center top of the 8" circle. Hit at the inch just below center plate.

At 4x, 230 was easy, so we put on the can. Suddenly things got fun. Dialed two MOA up, and rang center-plate when holding center-top and we both went 100% till the mags were empty. With the suppressor, the steel really rings. It rings without, but with the absence of muzzle blast, well it was fun.

Checked zero at 100, and it looks like there should be about a 1moa point of impact drop when adding the can. No stringing, and the barrel seems like a shooter. I go hopefully tomorrow or Sunday to get some solid groups with some bags or prone. Will report those on my build thread.

I don't have ANY doubt that I can hit what I want to, out to whatever distance I want to run within reasonable velocities. I was originally thinking a heavier bullet for the short barrel, but the velocity within 300 is getting more and more attractive. I am still eyeballing 129 ABLRs and am sourcing a large buy of those. The 129 SSTs appeared to blow away the 123s. The Black runs well, but I need a good rest to know better. My 120SMK loads all seem to like whatever I run them in. For this little stubby Grendel, That is my absolute target bullet to beat so far.

I chose Grendel for my truck gun specifically because I wasn't giving up much at all by shortening the barrel. Ballistic wise, you should be fine doing whatever you want. If you can hit what your'e aiming at, then finish line crossed right?

I chuckle now when I think about whether or not I'd like to have a 5.56 pistol. You just lose so much performance because the weight of the bullets is already so light. Any significant drop in velocity drastically hamstrings it in comparison to the Grendel.

If I had my druthers, I'd love a 300BLK sub upper to shoot suppressed for a HD platform, and the Grendel pistol for a woods/truck gun. I guess I'm half way there.

[grayfox]

BFT and Vascar, thanks. I took my 16-er out this evening to shoot it (it was feeling neglected!) but also to compare any scratches on it to the brass from my 12.7 (what do I call the 12.7? Junior? Shorty? LOL)
I'm still looking at the scratches and I'll focus mor on the teeth, you may have something there... my 16er gives some scratches around the shoulder break but not as bad as the 12.7... I think the 12.7 scratches are somewhat better now than before, 'course maybe that's via getting some edges of the teeth rounded by round count... idk.
But tomorrow I'll look more at the toothies... I have some narrow fine tooth files that I could touch them up with...

As an index point, which ext teeth cause the vampire bites on the neck? At the 4-5 oClock position? (6 = centered between the feed ramps).

Vascar, appreciate the feedback, to tell the truth I haven't shot prone for quite a while (back issues). I've been trying it so far with a red dot off of a rest. But I don't think the RD is going to work with my eyes. I can get about 0.7-1.0" at 25 yds with the RD... I'd want to be more accurate at that range, esp off of a rest!
The good news is that 3 factory ammo's seem to be "not too bad" with this rig, I'll reload of course but I like to have 1 or 2 factory loads I could use in a pinch. Hornady Black, 123sst and Federal 90 AE's.

I'm going to put a 2-7x on it (I have one on hand) and see how that does, I think that should work better for me. My eyes aren't what they used to be.
7 lb with the 2-7 on it, 6.5 lb when the RD was there.
Handguns (9mm/45) I've only used in the 7-10 yd range so far. Kind of a nub in that category!

[Sticks]

There is a detailed thread that I can not remember. Troubleshooting section? Found the offending lugs, and method. Chamber could used some polish as well.

[dpete]

If I had my druthers, I'd love a 300BLK sub upper to shoot suppressed for a HD platform, and the Grendel pistol for a woods/truck gun. I guess I'm half way there.

KS I thought the same as you do about subs until I read about how much subsonics overpenetrate. I even have an 8" barreled 300 BLK with a suppressor mounted to use. What changed my mind was this thread on the BLK forum:
http://www.300blktalk.com/forum/viewtopi...2&start=10
The link is the second page of the thread and the first two posts and the fourth are by three of the most experienced and knowledgeable guys on there.

[Les]

I still have an alignment issue but gas block sliding on isn't one of them, I bought another SLR AGB clamp on.

[Klem]

KS I thought the same as you do about subs until I read about how much subsonics overpenetrate. I even have an 8" barreled 300 BLK with a suppressor mounted to use. What changed my mind was this thread on the BLK forum:
http://www.300blktalk.com/forum/viewtopi...2&start=10
The link is the second page of the thread and the first two posts and the fourth are by three of the most experienced and knowledgeable guys on there.

dpete, I thought your handle sounded familiar. Back in 2012/13 I was active on the Blackout forum too until moving on to bigger and better things...

Regarding overpenetration of subs, I could not agree more. Having hunted roos (kangaroos) using different subs from a suppressor I can vouch for them being not much more potent than a bow. None of the few dedicated subsonic bullets have worked on flesh like their websites claimed. This includes the 220SN by Outlaw State and 220 HP by Blackout Bullets. None of the heavy bullets designed for supersonic did anything more than laser-beam through flesh. Only one, the 220SMK seems to tumble through the target. There is an audible 'zing' out the other side of the animal as the bullet heads off into the distance taking precious energy with it.

If you look at the internal ballistics of both a Grendel and Blackout subsonic on Quickload it is only 2/3 the available peak pressure. In other words you are deliberately handicapping the calibre to make it subsonic. You will be turning your Grendel into an accurate 9mm round (120-160gns at 1,020fps is equivalent to 9mm). With less diameter than a 9mm its crush trail will be smaller, there is no familiar kinetic shock, and the bullet will laser beam through flesh with no expansion from any made-for-supersonic bullet you try.

Given the drop of subs you are also limited to shooting 50-100metres, which requires you to stalk up to the target.

Here's a thread I posted in 2013 on the subject after the end of a hunt. Apologies for the deleted photos, they are long gone but basically showed entry and exit holes with exit holes being no bigger than entry.
http://www.300blktalk.com/forum/viewtopi...45&t=86384

Every now and then I head back to that forum to see if any new dedicated sub bullets have come out. Suppressed subsonic is my only interest in Blackout as its supersonic is a poor cousin of the 223, and the Grendel is a 223 on steroids.