Grendel Accuracy Issues, Help Wanted.....

[scroder]

Hi,

I am in need of some help with a new to me 6.5 grendel. I purchased this recently from a guy that had built it and put less than 2 boxes of ammo through it (it looked brand new). It came with a no name muzzle brake and has an 18" Odin barrel, bcg, and forend. The seller said it shot 1/2 moa for him with Hornady 123 amax.

I sold the scope it came with, put on a new Bushnell LRTSi in a Larue mount and installed an Odin adjustable gas block on it. I took it out to shoot for the first time today and my 100 yard groups look like a shotgun blast. I shot it suppressed and unsuppressed and with amax and sst ammo. All groups look like crap. I don't know much about AR's as I have always been a bolt guy, so any ideas on how to improve this would be awesome. I have attached a pic with the groups. Zoom in to see my notes.
20170311_131258 2.jpg

[LRRPF52]

Take the suppressor off for starters.

Make sure your LaRue throw levers are on tight, like really tight, to the point that they bind up hard at 45˚.

The scope rings need to be tightened starting from the base, then the top with the LaRue or similar mounts. This is a very common problem I have seen over the years where people skip over the distractions and assemble themselves.

It sounds like it was shooting for the previous owner, then several important things were changed like optics, muzzle devices, mounts, and now it doesn't shoot.

[Rickc]

The QD LT104 mount needs the levers so tight you can barely close them and have to pry them loose

I know. I have one. I have used it on several ARs. In fact i am using it on my grendel. I learned the hard way. I would never use that mount on a precision rifle

That is the first.step i would take in diagnosing you problem

[scroder]

Take the suppressor off for starters.

Make sure your LaRue throw levers are on tight, like really tight, to the point that they bind up hard at 45˚.

The scope rings need to be tightened starting from the base, then the top with the LaRue or similar mounts. This is a very common problem I have seen over the years where people skip over the distractions and assemble themselves.

It sounds like it was shooting for the previous owner, then several important things were changed like optics, muzzle devices, mounts, and now it doesn't shoot.

If you look at my pic and read my post I show where I shoot it without the suppressor and it actually looks worse. I've used quite a few Larue (mostly bipod mounts) over the years but I didn't realize I needed to tighten them that much. I will tighten them up tonight and give it another shot next week and post my findings. I thought it might be something with the adjustable gas block as its my first time using one. Thanks for the insight though.

Dave

[LRRPF52]

The other thing might be because you are used to shooting a bolt gun, where you can free recoil and get away with loose technique.

With lightweight 6.5 Grendel AR15s especially, I personally apply a lot of hard, rearward pressure, trying to make the rifle not jump as much when fired.

There is different technique involved in making them shoot, at least for me.

When I get on a bolt gun, it feels like cheating. Almost like I can't miss.

[scroder]

The other thing might be because you are used to shooting a bolt gun, where you can free recoil and get away with loose technique.

With lightweight 6.5 Grendel AR15s especially, I personally apply a lot of hard, rearward pressure, trying to make the rifle not jump as much when fired.

There is different technique involved in making them shoot, at least for me.

When I get on a bolt gun, it feels like cheating. Almost like I can't miss.

Thanks for the comment. I have another 223 AR with a Steiner military scope that I can nail steel at 400y consistently. I enjoy long range precision shooting with my 6.5 creedmoor bolt action and was hoping to make this an 800y gun between my 223 and creed. My grendel has a geissele trigger so it does feel like cheating! I really hope its the scope mount.

[LR1955]

Hi,

I am in need of some help with a new to me 6.5 grendel. I purchased this recently from a guy that had built it and put less than 2 boxes of ammo through it (it looked brand new). It came with a no name muzzle brake and has an 18" Odin barrel, bcg, and forend. The seller said it shot 1/2 moa for him with Hornady 123 amax.

I sold the scope it came with, put on a new Bushnell LRTSi in a Larue mount and installed an Odin adjustable gas block on it. I took it out to shoot for the first time today and my 100 yard groups look like a shotgun blast. I shot it suppressed and unsuppressed and with amax and sst ammo. All groups look like crap. I don't know much about AR's as I have always been a bolt guy, so any ideas on how to improve this would be awesome. I have attached a pic with the groups. Zoom in to see my notes.

SC:

"The seller said it shot 1/2 moa for him with Hornady 123 amax."

Used to be the seller would say it shot under a minute. Now it is 1/2 minute. Next it will be 1/4 minute.

Before I would go into anything else, I would want to know if the barrel really is an Odin Gunworks. Next how well the barrel was installed. You can have all sorts of problems and a rifle can still shoot better than yours. However, you can't have a bad barrel shoot well, or a barrel that was poorly installed shoot well.

Just out of interest, is the barrel and BCG Odin Gunworks?

LR55

[AZBackcountry]

My vote is the gas block is out of adjustment because your groups changed without the suppressor. I have a JP adjustable block and just watched a YouTube to learn how to adjust it.

[scroder]

SC:

"The seller said it shot 1/2 moa for him with Hornady 123 amax."

Used to be the seller would say it shot under a minute. Now it is 1/2 minute. Next it will be 1/4 minute.

Before I would go into anything else, I would want to know if the barrel really is an Odin Gunworks. Next how well the barrel was installed. You can have all sorts of problems and a rifle can still shoot better than yours. However, you can't have a bad barrel shoot well, or a barrel that was poorly installed shoot well.

Just out of interest, is the barrel and BCG Odin Gunworks?

LR55

Yes, its an Odin works 18" barrel, bcg, and adjustable gas block.

My vote is the gas block is out of adjustment because your groups changed without the suppressor. I have a JP adjustable block and just watched a YouTube to learn how to adjust it.

Without the suppressor it wouldn't cycle the next round so I had to manually do each one. That is normal though as there is a lot more back pressure with the suppressor on and the gas adjustment is lower.