New Build Grendel 20" barrel

[Cjflyer]

Hello everyone, thanks for letting me join the Grendel group. I am in the process of my first Grendel build. I have an Aero Precision upper and lower with a Ballistic Advantage 20 inch rifle length precision barrel. I plan on running the low profile ODIN works adjustable gas block as part of the setup. I would prefer not to but, I am afraid that if I'm having any cycling issues this may give me some additional adjustments.

The gun is primarily for paper and being setup to go 600 yards. I'm going to use box Hornady 123 gr ammo for right now but eventually planning on hand loading in the future.

Question #1

Looking at the Luth-AR MBA-3 adjustable stock for this build. Im hoping to get the rifle gas system to work with the adjustable stock buffer tube. Anything different for this stock other than a mil spec M4 buffer tube carbine setup? H2 carbine buffer seems to be something that is talked about often to smooth out any issues. Is this in my best interest for this build? If this is a huge issue I'll probably go with the MBA-1 rifle stock but would like the versatility.

Question #2

Do I need to to real have an adjustable gas block of this build? I would like to save some money for optics if at all possible!

Thanks for everyones help and opinion.

Jim

[rabiddawg]

I have two Precision Firearms built 20” barreled guns. Neither have adjustable gas blocks

Welcome aboard

[Kswhitetails]

Welcome aboard.

The missing piece here is your port size. From my understanding, if you’re in the .08-.094 range on RLGS, an adjustable GB is superfluous. It should function fine with a standard carbine buffer spring and tube, the AGB comes in handy more for suppression. Especially if you intended to run with the windows open and closed, alternating often.

As far as your stock, it is really up to you. Grendel does well as designed, to function within the rather “standard” AR di system profiles. I’m running three on the carbine buffer. My first build I happened to go with an adjustable from ODIN, but found it to function flawlessly wide open, and never needed to adjust it. My thought since then has been “why”?

If you are worried about it, get the adjustable. Like you say, it will allow you a few more options “just in case”. However, unless you anticipate changing the system on the repeated basis, as in shooting with and without a suppressor or other such modification, it will likely turn out to be unnecessary. All of this assumes that you want quart size is within spec.

[Cjflyer]

Welcome aboard.

The missing piece here is your port size. From my understanding, if you’re in the .08-.094 range on RLGS, an adjustable GB is superfluous. It should function fine with a standard carbine buffer spring and tube, the AGB comes in handy more for suppression. Especially if you intended to run with the windows open and closed, alternating often.

As far as your stock, it is really up to you. Grendel does well as designed, to function within the rather “standard” AR di system profiles. I’m running three on the carbine buffer. My first build I happened to go with an adjustable from ODIN, but found it to function flawlessly wide open, and never needed to adjust it. My thought since then has been “why”?

If you are worried about it, get the adjustable. Like you say, it will allow you a few more options “just in case”. However, unless you anticipate changing the system on the repeated basis, as in shooting with and without a suppressor or other such modification, it will likely turn out to be unnecessary. All of this assumes that you want quart size is within spec.

Yes the digital micrometer says .092 for the gas port width of the hole. Thanks for your input as I think I'm on the right path. My daughter is getting into this so having an adjustable stock seems to be the correct path.

Jim

[Popeye212]

I have the same barrel and expect no problems with the standard gas block. I have researched, and as far as what I have read and the phone calls it is a non-issue. In fact was told not to waste my money on an expensive gas block. If you are going to suppress you will need the adjustable gas block.

[Cjflyer]

I have the same barrel and expect no problems with the standard gas block. I have researched, and as far as what I have read and the phone calls it is a non-issue. In fact was told not to waste my money on an expensive gas block. If you are going to suppress you will need the adjustable gas block.

Not planning on it being suppressed. Thank you for the information. I hope the barrel is as good as it looks!!??

Jim

[grayfox]

An adjustable gas block is only about $40 extra (dependign on the model you choose), but from what's been reported on here, the RLGS doesn't need it so it's an extra you can dispense with. Rifle length gas pressure has dropped down more than the carbine or mid-length (obviously!) by the time it hits the port.
As far as carbine vs rifle length butt stocks, I have 2 on carbine systems and one with the rifle length stock... for that one I just inserted the rifle-carbine spacer and continued with carbine length springs and wts. I'm using the Kaw or Spikes T2, along with the JP centerless springs, again, all carbine length. So they all work perfectly with these setups. My 18" is on the rifle length stock setup... I don't have a 20" AR system.

[Bevo]

I have an Aero Precision upper and lower with a Ballistic Advantage 20 inch rifle length precision barrel.

I have this same upper and barrel. No problems on a carbine buffer tube, runs perfectly. Recently switched to an H2 buffer, but have only fired it once since then. Cycled with no issues. The hog liked it too.

[Popeye212]

Not planning on it being suppressed. Thank you for the information. I hope the barrel is as good as it looks!!??

Jim

One thing I did l leave out I used a CLAMP ON gas block the barrel is not predimpled for the set screws will use the supplied gas block on something else. We will find out as soon as I get the scope on her. Named her Frosty had to freeze the barrel to get the BA barrel in the AP upper. She is TIGHT.

[Cjflyer]

Thanks for the reply’s guys. I look forward to this project being finished up soon. Happy firing.

Jim

[1Shot]

I really like this stock. Go to joeboboutdoors.com and look up the Adaptive Tactical Stock it is only $35.00 and is of better quality than the Magpul MO. I agree with others if you will not be suppressing you don't need the adjustable gas block. Also a heads up on the Hornady ammo. If you will be shooting the 123 SST don't blow a gasket if it shoots 1 1/2" to 2 1/2" groups thinking your rifle will not shoot accurately. I have two different rifles and neither of them will shoot this stuff better than 1 1/2" in one and around 3" in the other. Same rifles will shoot handloads great. The Hornady 123 SST ammo is the only factory ammo I have shot and that was just to get the cases to reload.

[Cjflyer]

Thanks for the heads up. I truly hope I'm sub MOA by summers end. I wish we could get spring started here in the Midwest.

[Cjflyer]

Finally got the rifle put together and couldn’t wait for the weather. Had to go indoors to get it done. Very happy with the results with the Hornady Black Ammo. At 50 yards I’m getting groups between .257 and .433 the second time out. I have about a 100 rounds through the gun and couldn’t be happier. The gun likes the 123 ELD round better than the SST Hornady.

Having an issue on failure to feed when I put in a new magazine. It just doesn’t chamber the round when I close the bolt. Next out I’ll bring a different magazine. It’s an E-Lander 17 rounder. The spring is pretty stiff and am hoping it will break in.

Jim

[Cjflyer]

I would post some target photos but my photobucket is now a monthly subscription, what’s that all about lol! Been forever since I used it.

Jim

[Popeye212]

I would post some target photos but my photobucket is now a monthly subscription, what’s that all about lol! Been forever since I used it.

Jim

I use an app called Share To Resize. Resize them with a different file name save and upload from the Basic Uploader. Hope this helps.