I may have found my dream AR upper: 6.5 Grendel/Adj. Gas Piston

[melensdad]

I've got a spare premium quality Alexander Arms lower receiver that is just screaming to be built up over the winter. Probably with a MagPul UBS buttstock and an AR-Gold trigger group. But the upper has been the thing holding me back.

Alexander Arms is now producing a MONOLITHIC upper which uses the Adams Arms gas pistol system. This thing looks like it should fit the bill for a new 16" rifle build. The gas piston system is adjustable so it can be used with a silencer, light bullets, heavy bullets, fast bullets and sub-sonic bullets.

 

[dom1104]

I dont drink the piston gun coolaid, but wow that thing looks nice.

 

[geronimojoe85]

Can you get "Grendel worthy" accuracy out of a piston gun?

 

[sgreen3]

Man that thing looks sweet!

 

[dagibson1507]

Adams arms kits aren't fully adjustable. Full, reduced and off are your only settings. Plus pistons don't have any advantage if your running supressed. Think the money would be better spent on a fail zero coating and an adjustable block. Your also going to have the extra moving mass of the piston fighting you on precision shots. Although with a shorter 16" barrel I don't think you'd be doing many. Out of a 16 barrel I think super sonic 300 blackout would be a better choice.

 

[Aszerigan]

That thing is beautiful.

 

[dom1104]

That thing is beautiful.

Frankly, the best thing I have discovered from this thread, is on Azerigans sig line.

"Firearms transfers - $20"

That, is a bargain. Phone call incoming.

Thanks OP.

 

[melensdad]

Can you get "Grendel worthy" accuracy out of a piston gun?

For a tactical sized gun, extreme accuracy is not the goal. I've got a long heavy barrel Grendel for that purpose, this would be more of a fun, HD, tractor, gun but with the punch of a Grendel (granted the short barrel will compromise some of the punch, but its still going to blow away the 5.56 in terms of bullet energy)

As for piston, I just want to have one. Seems like putting on a piston is always a compromise in accuracy, so putting it on a short barrel gun that is not used for long range shooting seems like a sane compromise.

Adams arms kits aren't fully adjustable. Full, reduced and off are your only settings... Out of a 16 barrel I think super sonic 300 blackout would be a better choice.

I don't need a bunch of settings, 3 are plenty good, just like the FN SCAR.

I already have a couple thousand rounds of 6.5 Grendel on hand and 2 other Grendel rifles. I see no need for the 300 AAC Blackout given the other guns I've already got. Sure its great for subsonic supression but won't bring any other real ballistic goodness to what I have and other guns can be surpressed just as easily by downloading the powder and uploading the bullet weight.

That thing is beautiful.

Yup. AR sexy goodness right there

 

[dagibson1507]

For a tactical sized gun, extreme accuracy is not the goal. I've got a long heavy barrel Grendel for that purpose, this would be more of a fun, HD, tractor, gun but with the punch of a Grendel (granted the short barrel will compromise some of the punch, but its still going to blow away the 5.56 in terms of bullet energy)

What punch?, out of a 16" barrel its equal to 300 blackout and you will only get about a 30% gain over 5.56. http://www.alexanderarms.com/grendel_ballistics.pdf .

Of course your also giving up 4-5 extra rounds, a propieatary bolt thats also weaker as they mill out a standard 5.56 to accept the bigger cartridge, your stuck with steel mags and wont cycle sub-sonic rounds. The only advantage I can see for you is you already have several thousand rounds.

 

[melensdad]

What punch?, out of a 16" barrel its equal to 300 blackout and you will only get about a 30% gain over 5.56. http://www.alexanderarms.com/grendel_ballistics.pdf .

Of course your also giving up 4 extra rounds, a propieatary bolt thats also weaker as they mill out a standard 5.56 to accept the bigger cartridge, and wont cycle sub-sonic rounds. The only advantage I can see for you is you already have several thousand rounds.

Yes. I know well the Grendel ballistics. And you just proved my point. Out of a 16" barrel the 300 AAC Blackout offers no real advantage. And out of a 16" barrel, the Grendel will kick butt over a 5.56 (30% is pretty significant).

I've already got a 19" Grendel and a 24" Grendel. I've already got loading dies for the Grendel. And I've already got a couple thousand rounds of Grendel. You are trying to talk me into a round that, out of a 16" gun that you admit is no better than the Grendel, that I would have to buy new loading dies for, that I would have to inventory in addition to what I already have. That seems like a pretty foolish use of resources when it provides essentially no advantage.

As for the claims of the weak bolt, that pretty bogus. Yes, some folks have tried to use 7.62x39 bolts and broken those, but the Alexander Arms 6.5 bolts have a long track record of working and having a very very low failure rate.

And given up "4 rounds" in a magazine . . . oh please get a life. Sure I can load "only" load 26 to 27 rounds (varies by magazine brand) in a "30 round" AR magazine and that might be an issue if I was in a war, but I'm not. I'm overlooking bean and corn fields. The biggest threat I have are coyotes and raccoons.

As for cycling Sub-Sonic . . . that claim is bunk. I know people who have proven your claim wrong. But for what it is worth, I don't know of any SBR 6.5 Grendels that cycle sub-sonic.

 

[dagibson1507]

Yes. I know well the Grendel ballistics. And you just proved my point. Out of a 16" barrel the 300 AAC Blackout offers no real advantage. And out of a 16" barrel, the Grendel will kick butt over a 5.56 (30% is pretty significant). Agreed no advantage ballistically.

I've already got a 19" Grendel and a 24" Grendel. I've already got loading dies for the Grendel. And I've already got a couple thousand rounds of Grendel. You are trying to talk me into a round that, out of a 16" gun that you admit is no better than the Grendel, that I would have to buy new loading dies for, that I would have to inventory in addition to what I already have. That seems like a pretty foolish use of resources when it provides essentially no advantage.

Your spending 1600$ on an upper but the 30$ dies are whats tripping you up? A loaded noveske blackout upper would run you $1300. Your going to be buying bullets and powder regardless. Brass is ridiculously cheap compared to grendel and loaded ammunition is cheaper if you arent shooting wolf, which is about the same if you are. Ive not extensively priced 6.5 bullets but they seem to be about the same price, just a little harder to find. If you cant find 308 bullets on the other hand, something is wrong.

As for the claims of the weak bolt, that pretty bogus. Yes, some folks have tried to use 7.62x39 bolts and broken those, but the Alexander Arms 6.5 bolts have a long track record of working and having a very very low failure rate.

Broken bolt/great customer service - AR15.COM Popped up in the first listings on google. Not knocking their customer service, for yours as a plinker wouldnt be much of a worry.



And given up "4 rounds" in a magazine . . . oh please get a life. Sure I can load "only" load 26 to 27 rounds (varies by magazine brand) in a "30 round" AR magazine and that might be an issue if I was in a war, but I'm not. I'm overlooking bean and corn fields. The biggest threat I have are coyotes and raccoons.

I dont know what a life has to do with it. Discredit an advantage blackout has if you will. If offered the choice of 4-5 more rounds of grendel im sure you wouldnt say no because "I'm overlooking bean and corn fields. The biggest threat I have are coyotes and raccoons." The lack of polymer mags especially pmags was a big turnoff for me.

As for cycling Sub-Sonic . . . that claim is bunk. I know people who have proven your claim wrong. But for what it is worth, I don't know of any SBR 6.5 Grendels that cycle sub-sonic.

Imagine they cycle with a suppressor, maybe a reduced power buffer spring and light weight, which would hinder super sonic rounds. You said you wanted to shoot them all which you wouldnt be able to easily on one lower.

Dont get me wrong Im wanting to build a grendel rifle too. Just weighed out all the options and thought the blackout was better for a shorter ranged gun. Was trying to point out the shortcomings I discovered while making the decision on which to build first. Maybe we could get together some day and shoot the each others. Would be nice to sample both worlds side by side.

 

[melensdad]

Ok with the 300/Noveske I don't get the monolithic upper, which I covet.

And I don't get any better ballistics.

And I don't get a piston upper, which I would like to have, if only to try.

What I do get is to increase my inventory/investment for ammo. I also do get to increase my time at the reloading bench.

Assuming I keep 500 to 1000 rounds on hand, I've now spent all the 'savings' on a set of loading dies and ammo that can only be used in 1 gun, and that gun's upper lacks the features I was looking to attain. Further that ammo has very limited use, and is basically relegated to short/moderate range paper punching. As I've got many other AR choices in the safes, the 300 would not be called upon to take out a coyote, it would likely be out of practical range. It would not be called upon to shoot a deer out back (with a depredation tag) because an 18" Grendel or a 458 Socom simply are better choices.

Honestly I see no point (for me) in getting one. You've thread jacked the thread, very successfully.

The 300 AAC Blackout is something I didn't see the point of when it first arrived on the scene. I've now changed my mind, after learning it is pretty much just a SAAMI legitimized 300 Whisper. So fine, that makes sense to those who want that. I look at it sort of like I look at the old Winchester 30-30; good, but not for me. But if you want a 30-30 then go buy one. Thats about what the 300 AAC Blackout really is. Can't fault the 30-30. Its a great short range deer round, but there are plenty that are as good and more flexible.

Oh sure, with a 300 AAC Blackout I could kill zombies with it when the SHTF and I have to backpack my way across the apocolyptic wastelands of Illinois while I bug out to my luddite style cabin in the foothills of the Cascade mountain range. . .

 

[John Galt]

I'm waiting for Krebs to come out with his 6.5 Grendel on an AK platform. Rumored to have a Sig upper with a Shilen barrel. SWEET!

 

[Zoub]

I'm waiting for Krebs to come out with his 6.5 Grendel on an AK platform. Rumored to have a Sig upper with a Shilen barrel. SWEET!

I am waiting for Melen to do this project so we can see how it goes.

 

[melensdad]

I am waiting for Melen to do this project so we can see how it goes.

Well I posted the Krebs videos a while back, I'm still waiting for Krebs