Accuracy challenges, new barrel

[Cowin8579]

Hello gentlemen. I bought one of the 18" green mountain monster barrels and matching bolt. A friend of mine who shoots competitively installed it in a palmetto upper. I believe he installed it correctly.

I work at an indoor range that maxes out at 25 yards. I initially sighted in the grendel with a non parallax adjustable scope and it was challenging with fuzzy crosshairs. Right away the wolf ammo I was using was shooting a rather wide group, but I didn't take that as an issue due to previous experience with wolf.

I used a standard break in process similar to the Army designated marksman method, clean every shot for 5 shots, and then every 3 shots etc. Using Seal 1 and a bore snake.

Then I went to a 100 yard range and setup a lead sled. I then shot federal fusion and hornady black eld. The wind was gusting, it wasn't an ideal shooting day. For me at that time the fusion and hornady black both shot over 3 MOA. Due to the challenges of that range day, I did not take pictures of the groupings which would have been helpful to you.

I switched the upper to a 5.56 that I've hunted with for years, and shot my best sub inch group ever with Gorilla 77 grain SMK. Shot a few more loadings and it performed well.

My friend who installed the barrel (Matt Trout) offered to test it for me. His groups were way better than mine, with the Hornady black getting the closest to 1 inch MOA. He recommended I try more loads, and to try reloading etc. I do not reload.

Do you folks recommend any other premium loadings to try that you would eventually hunt with? I see Barnes and Alexander arms have some very premium rounds, I suspect hornady SST will group like the black, and Sellier and Bellot make an FMJ? Any other recommendations, or should I grab another barrel?

I have been hunting for 20 years, and hoped this new setup would be amazing.

[Bigs28]

Close to 1 moa groups using factory ammo with a barrel at that price point is a win.

[rabiddawg]

I ditched a lead sled because I was having to twist the gun to keep the reticle level. My guns just didn’t fit it very well and groups showed it.

Precision firearms makes premium ammo with a large selection of bullets.

I have been using the 100 gr nosler bt for hunting and target shooting with great results.

If you plan to shoot past 500, I would stick with the 123 class because of the better ballistic coefficient. I may switch to the larger pills when I’m out of the 100.

[A5BLASTER]

Hello gentlemen. I bought one of the 18" green mountain monster barrels and matching bolt. A friend of mine who shoots competitively installed it in a palmetto upper. I believe he installed it correctly.

I work at an indoor range that maxes out at 25 yards. I initially sighted in the grendel with a non parallax adjustable scope and it was challenging with fuzzy crosshairs. Right away the wolf ammo I was using was shooting a rather wide group, but I didn't take that as an issue due to previous experience with wolf.

I used a standard break in process similar to the Army designated marksman method, clean every shot for 5 shots, and then every 3 shots etc. Using Seal 1 and a bore snake.

Then I went to a 100 yard range and setup a lead sled. I then shot federal fusion and hornady black eld. The wind was gusting, it wasn't an ideal shooting day. For me at that time the fusion and hornady black both shot over 3 MOA. Due to the challenges of that range day, I did not take pictures of the groupings which would have been helpful to you.

I switched the upper to a 5.56 that I've hunted with for years, and shot my best sub inch group ever with Gorilla 77 grain SMK. Shot a few more loadings and it performed well.

My friend who installed the barrel (Matt Trout) offered to test it for me. His groups were way better than mine, with the Hornady black getting the closest to 1 inch MOA. He recommended I try more loads, and to try reloading etc. I do not reload.

Do you folks recommend any other premium loadings to try that you would eventually hunt with? I see Barnes and Alexander arms have some very premium rounds, I suspect hornady SST will group like the black, and Sellier and Bellot make an FMJ? Any other recommendations, or should I grab another barrel?

I have been hunting for 20 years, and hoped this new setup would be amazing.

1moa is good with over the counter ammo and a budget barrel.

Your friend shoot that, means you are most of the problem with the 3moa groups you fired.

Do you have a flinch? Did the increased recoil of the grendel compared too 556 feel more noticable?

You could try the AA and PF ammo that's loaded with match type bullets or maybe the federal 130 hybrid load.

I think you just need a lil time with it too get better adjusted and comfortable with the new round is most of the issue.

Could be your technique when holding the rifle needs some work as well.

Your competitive shooter friend should beable to help with a few tips.

My best friend is a heck of a marksman with a bolt action, but when I built his first grendel ar he had bad group's as well. Takes a certain technique too shot the ar good, more so when you increase the felt recoil over the 22cal.

Hope this helps sir.

[Cowin8579]

I very much appreciate all of your insights and expertise. All of you gave a new angle for sure. To start, the matching bolt and barrel is quite the value. The 6.5 G is extremely popular, and the retail on the bolt alone for a premium barrel is often over 70 dollars.

I used to be a better shooter, a designated marksman in an Army Infantry unit.. and lots of tough shots on moving game animals. I now have bad habits, don't shoot as often, and rush shots as an example. I do indeed go from one excellent group to a poor group when unfocused, but normally can focus on fundamentals and get a good group following a poor group. The difference here is this rifle upper/barrel so far has acted a little differently regarding the shooting characteristics. I grouped averaging an inch with a light weight 270. before shooting the Grendel.

I do need to shoot more frequently at longer distances (time to shoot is exceedingly rare).

Rabbid, that is interesting regarding the lead sled. I was sitting much lower than desired, and there certainly is less room for you to get behind the rifle. I will order some Precision Firearms ammo right now. It would be nice to be able to shoot medium sized game animals farther away (Over 3-400), but at this point that's a fantasy hunting trip in another state.

A5 Blaster, we estimated with how tight his group was at 25 yards that it likely would equate to 1 moa or near moa. As you said, the problem is partially mine, as my friend certainly got closer to the mechanical accuracy of the rifle. In this day of shooting, a bolt action 270. and palmetto 5.56 absolutely killed it with extremely small groups.

Whether it is a flinch, or a shotgun shooting technique.. when it happens it certainly negatively effects rifle accuracy. I certainly do it when shooting in a lazy fashion. I switched to a mission first tactical minimalist buttstock and am having trouble getting used to it. I certainly noticed the hotter 6.5g loads with it.

That is a great idea, I will ask for critical feedback. Sometimes men hold back unless someone asks for it. I will take pictures of the target during the next shooting.

Thank you very much! It helps big time.

[A5BLASTER]

I very much appreciate all of your insights and expertise. All of you gave a new angle for sure. To start, the matching bolt and barrel is quite the value. The 6.5 G is extremely popular, and the retail on the bolt alone for a premium barrel is often over 70 dollars.

I used to be a better shooter, a designated marksman in an Army Infantry unit.. and lots of tough shots on moving game animals. I now have bad habits, don't shoot as often, and rush shots as an example. I do indeed go from one excellent group to a poor group when unfocused, but normally can focus on fundamentals and get a good group following a poor group. The difference here is this rifle upper/barrel so far has acted a little differently regarding the shooting characteristics. I grouped averaging an inch with a light weight 270. before shooting the Grendel.

I do need to shoot more frequently at longer distances (time to shoot is exceedingly rare).

Rabbid, that is interesting regarding the lead sled. I was sitting much lower than desired, and there certainly is less room for you to get behind the rifle. I will order some Precision Firearms ammo right now. It would be nice to be able to shoot medium sized game animals farther away (Over 3-400), but at this point that's a fantasy hunting trip in another state.

A5 Blaster, we estimated with how tight his group was at 25 yards that it likely would equate to 1 moa or near moa. As you said, the problem is partially mine, as my friend certainly got closer to the mechanical accuracy of the rifle. In this day of shooting, a bolt action 270. and palmetto 5.56 absolutely killed it with extremely small groups.

Whether it is a flinch, or a shotgun shooting technique.. when it happens it certainly negatively effects rifle accuracy. I certainly do it when shooting in a lazy fashion. I switched to a mission first tactical minimalist buttstock and am having trouble getting used to it. I certainly noticed the hotter 6.5g loads with it.

That is a great idea, I will ask for critical feedback. Sometimes men hold back unless someone asks for it. I will take pictures of the target during the next shooting.

Thank you very much! It helps big time.

I will give a few more ideas too try.

If the rifle was assembled without lapping the reciver face or bedding the barrel. Then I would tear down and do that.

I also like too bed the gas tube into the gas block and bed the gas block to the barrel with lock tite. Helps remove any lil bit of gas leakage.

I also use adjustable gas and lowmass bcg's, less mass moving around means less movement of the gun.

Also if useing a free float handguard that is of a non indexing design. Depending on the thickness of the barrel, I would start my torque levels low and work up at 5 pounds changes till you see the effect.

If you have a muzzle device on the barrel take it off throw the crush washer, peel washer in the trash can and get a accuwasher set from precision armament and reinstall it with the accuwasher that allows it too be timed properly with lil to no torque.

The barrel nut and muzzle device torque is called balanced torque theory you can Google it to learn more.

Doing these things should help balance it out and improve your groupings.

[Cowin8579]

Those are great ideas and insights! I did major research and found some quality videos of older gunsmiths/builders discussing barrel tuning, and common weak points for accuracy.

The receiver was absolutely not lapped. I also learned quite a bit about testing torque setting for accuracy and found that to be amazing. My buddy just "put her on". No leakage/gas issues but not refined. I found a nerdy gun smith with very high end equipment. I also found some videos of him performing work and he seems like the right guy to take this apart and do a proper install. I will get the accuwasher etc, that sounds incredible. I use an adjustable gas block, but couldn't find a low mass bcg during the time I was rushing to finish the build. That makes perfect sense.

I am currently using a midwest lightweight free float handguard.

Even though I didn't start this thread with pictures... Once we reshoot the upper I will post pictures to show the final result. I bought 130 dollars of premium ammo from the above sources, and then decided it was foolish to shoot it without a better installation and then refining the torque.

Thank you for the education!

[Rosecrans1]

Late to the thread but in my experience, many cheaper barrels need 200, 300 or more rounds through them before you start seeing tighter groups. Ditch the lead sled! Sand bag off a sturdy bench and choose more ideal weather conditions to shoot if you can. And don't get down on yourself after shooting factory ammo. The 123gr ELD-M Blacks seem to be the best factory ammo for most barrels from the start. You may find another offering that the barrel likes but more rounds/cleaning and working off sand bags should show what that gun can do. If you see your groups tighten, go back to the rounds that didn't shoot well and you may be surprised at the results.

[VASCAR2]

I have been reading about the 6.5 Grendel for many years and purchased my first 6.5 Grendel in 2009 or 2010. At that time the accuracy was typically good and most members believed the 6.5 Grendel to be an inherently accurate cartridge. Only in the last couple of years have there been frequent post regarding poor accuracy.

Early on the 6.5 Grendel barrels were only available from a very few sources who tended to produce quality products. Alexander Arms, Les Baer, Precision Firearms, Sabre Defense, Shilen, Satern. J&T Distributing/Double Star (Shaw barrel blanks) were on the cheaper side compared to the other manufacturers. Lothar Walther, Black Whole Weaponry and Model 1 Sales sold variant chambers (6.5 CSS, 264 LBC 6.5 Sporter) but accuracy was consistently good.

In the last couple of years since the 6.5 Grendel has become more common, numerous companies have started manufacturing some very inexpensive barrels with inconsistent quality control. We now see more complaints of poor accuracy.

Stick with quality barrels and your likely to see excellent to good consistent accuracy. I think the quality standard for low priced rack grade barrels has declined with the current very low priced barrels. Back in 2010 it was hard to find a 6.5 Grendel barrel for $250. It was not uncommon to spend $400-$500 for a quality 6.5 Grendel barrel with significant wait times. Today is a buyers market but quality still cost more, especially with barrels and optics.

[grayfox]

One other comment since you are looking at hunting ammo, esp any off the shelf loads. The Hornady Custom 123sst load is pretty finicky as to which barrels it likes, so I would avoid that box for now. 123 Eld in Hdy Black is a pretty good COTS standard, there are some 120 and 130 OTM's from Federal AE I believe, that many recommend. Also the Federal AE 90tnt, for varmints and hogs.

Being more of a bolt-guy myself, I have taken to putting a MB on the ends of my ARs, using a jam nut and some blue loktite so you don't need to over-torque the barrel or action. A good quality and yet economical MB is the VG6 6.5 gamma, usually runs 50-70 bucks. Use either the accuwasher system or a jam nut to time it yourself, it is easy. No crush washers!! This MB reduces recoil and muzzle jump significantly, but will make a louder report to the shooter/bystanders (all MB's do this). It is worth it to help my shooting.

O, and hunting-wise, you will want to look at the PF and AA offerings... but if the hdy Blacks shoot for you they are good for up to medium size game, at grendel MVs they expand fine in those targets.