Any suggestions for 16" 6.5 Grendel

[Highbrass]

I recently got to try out my 6.5 Grendel that I put together several years ago. I wanted to test it long range but I had several issues. Most of these issues were self inflicted, but I think I have most of them under control. My main issue was a cheap scope mount that would not stay tight. It will be replaced with either an Aero Lightweight or Leupold One Piece mount. My other issue was a Magpul stock that was flexing.
I have the AA 16" 7.5 Twist barrel. My goal was a lightweight short barreled Grendel that I could take to 800Yds (longest range at the place i shoot)
I need to test some handloads and i'm looking for input here also I have some 123 AMX's with 30.5 Gr CFE and some 100 Gr Lapua Scenar's @ 31.5 CFE
My last range trip started off to be a disaster but I was still able to hit steel @400 yds.
My scope might get a swap also. Current optic is an Athalon Argos 6~24
I have an Arken on order and have a Athalon Ares 6-24 that I can swap from another rifle.
I know others have 16" Grendels, what are your suggestions?

 

[plt228]

a 16" Grendel should hit 800 without issues. I've taken my 16" out to 800 with factory ammo, 123 ELD and 123 AG (2400-2450 fps). The scope mount and scope sound like they're part of the problem. What does your rifle group at 100? Mine is only 1.25-1.50" with most factory ammo. My scope is a PST II 3-15 in a Seekins MXM mount.

 

[Highbrass]

I think I want to try the Leupold mount. I have several Aero mounts on other rifles but the Leupold mount looks stout and is competitive on price. I will report back results after I get it in.

 

[TonyTheTiger]

What is the question exactly?

 

[Highbrass]

To the point..I built this rifle the first time on a shoestring budget. There was a several year gap between the rifle assembly and being fired. I used some "budget" parts which have proven problematic. I now wish to atone for my foolish choices, and was looking for some recommendations on parts and loads to make a lightweight short barrel Grendel that will be consistent to 800 yards.

 

[Gustav7]

My buddy’s 16” 6.5G groups around 1-1.5 with factory 123 ELDx at 100 and he’s successfully taken it to 400 with relative ease.

We’re going to start loading for it soon. Gonna try XBR 8208 and CFE.

 

[drewthebrave]

I have an 18" Alexander Arms barrel and it's been great for me. Your 16" barrel should get you out to 800+ yards no problem with good ammo. Your scope is probably just fine for what you're doing, but an upgrade might be worthwhile eventually. I would focus on the mount first and foremost.

If you're "upgrading" your scope mount, I would not recommend an Aero Precision. I had nothing but trouble with one on my lightweight coyote-hunting gun, and the issues went away after I switched to a Warne XSKEL mount. The Aero mounts are not something I would recommend for any "precision" oriented uses. Get a solid mount from Burris, Warne, LaRue, ADM, Bobro, or similar (depending on budget) and accept that it will be a couple ounces heavier than the Aero. Those few ounces of saved weight don't matter if you can't reliably hit where you're aiming. If you really want a lightweight mount, Nightforce makes a quality one that's around $200+.

 

[Highbrass]

I have the Leupold mount coming in this week.

Leupold Mark AR 1-Piece Picatinny-Style Mount Integral 30mm Rings

There are two common issues when mounting scopes to AR-style platforms - getting the right scope height and the eye relief. The Leupold Mark AR family...

www.midwayusa.com

 

[drewthebrave]

I have the Leupold mount coming in this week.

Leupold Mark AR 1-Piece Picatinny-Style Mount Integral 30mm Rings

There are two common issues when mounting scopes to AR-style platforms - getting the right scope height and the eye relief. The Leupold Mark AR family...

www.midwayusa.com

While I haven't used one myself, I have heard that they're quite good. Hopefully that helps you get on target. A quality torque driver will be essential in getting it mounted properly. Be sure to follow the instructions from Leupold, and you'll be all set.

 

[Highbrass]

I have put plenty of bolt guns together and a few gas guns but never any gas guns for long range. This is my one and only Grendel, so exploring fresh territory.

 

[AMG04]

I like the 100-130gr bullets in both a 16 & 20 inch Grendel.

My go to bullets are 108/123 scenars or 123 Hornady BTHPs (cheap) or SSTs. Later used for hunting.

For powder, I've had good luck with AR-COMP, H4895 and CFE 223.

 

[Mad_Charlie]

@O.P. Did you lap the upper receiver and bed the barrel?

 

[Highbrass]

Negative on both counts.
The barrel has a full length handgaurd and makes no contact.
I am afraid I have never heard of lapping the upper reciever. I would be interested in learning about it.

 

[drewthebrave]

Here's a thread discussing the topic. It may be worth the effort if you're looking to extract every last bit of precision from your build.

Upper Receiver Lapping

is there a benefit to doing it? Also, doesn't lapping affect headspace and how do you know wen enough is enough? Are you just looking for a shiny surface all the way around?

www.snipershide.com

 

[LRRPF52]

My first 6.5 Grendel was one I built with an AA 16” barrel/bolt combo back in 2009.

I figured it was a solid 600yd gun at best, but soon learned that I could reach out to 1200yds with on full ISPC sils, which was kind of shocking. That was at 4200ft elevation in the summer though, shooting factory 123gr A-MAX, which has been replaced with ELD-M/Black from Hornady.

I got a bunch of Lilja barrels after that, including 16”, 18”, and 22”.

All my uppers get trued and barrels bedded into the upper for a tight fit.

I shoot the 12” Faxon-barreled Grendel out to 800yds even with 9/10 hits from a good position.

Optics mounts I use:

LaRue x many
NightForce x 1

16” is plenty capable out to 800yds though with the right bullet from an accuracy checklist build.

Accuracy checklist for me starts with a quality, upper end barrel. The Faxon was a group buy pipe I wanted to play with to get an idea of what kinds of velocities I would get. It shoots a little better than MOA from bench, rear bag, suppressed with most ammo so far. I think 120gr Federal OTM was the largest grouping load from it for me so far.

I like a lot of the Aero products, but several guys have had problems with the really lightweight Aero mount with those thin rings snapping.

A Vortex 2.5-10x Viper PST Gen II would be the baseline I would start with for shooting out to 800yds.

It’s a lot of fun since you can manage your sight picture throughout the shot and see your own impacts, even with lightweight rifles.

Enjoy

 

[Highbrass]

The new Leupold mount showed up today. The 5 mounting screws make it Hella stout. Gonna shoot tomorrow

 

[bfoosh006]

With the new setup, and just a thought... make sure you understand how to adjust your parallax.

Sample random video...