New Upper Range Report--Issues

[walker2713]

I've got several AR format rifles, but haven't had a Grendel until I bought an upper from PSA recently. I mated it with a Colt lower that has a Timney trigger, and took it to the range today. I left the Magnetospeed at home this morning, planning to just focus on breaking the rifle in and shooting for groups.

I'd bought a box of Hornady Black 123gr factory ammo, and reloaded 25 rounds with unfired Hornady brass. The reloads were 95gr Vmax, Rem 7 1/2 primers, and 30.8 to 31.6 grains of H335.

At a 100 yards, groups were lousy....only really decent one was 31.6gr and that was a shade over an inch.

The real issue was that it wouldn't cycle my reloads...but the factory rounds were fine.

Maybe it's a buffer or gas block issue, but I'm stumped about why it handles the Black 123's going around 2500 fps, and not my reloads which were certainly moving at least a couple hundred fps faster?

Your input appreciated.

George

[grizzman]

The speed of the bullet isn't nearly as important of a factor as the speed at which the powder burns.

If the factory ammo works, then I suggest you try a different powder. A Google search should yield a ton of info on recommended powders for the Grendel.

[walker2713]

The speed of the bullet isn't nearly as important of a factor as the speed at which the powder burns.

If the factory ammo works, then I suggest you try a different powder. A Google search should yield a ton of info on recommended powders for the Grendel.

Thanks....though I'm guessing it's more to do with the buffer or gas block.

H335 is a highly recommended powder to the Grendel, but I've got lots of powders and just loaded up 25 with Ramshot's X-Terminator. I'll also make sure I bring the chrono along the next time.

George

[everready73]

No idea on the bullets, but I the grendal uppers PSA sales come with adjustable gas blocks. Did you know this and adjust the gas at all?

[walker2713]

No idea on the bullets, but I the grendal uppers PSA sales come with adjustable gas blocks. Did you know this and adjust the gas at all?

Not yet....I suspected it was that or the buffer....will do that next since that seems to be the default answer to my problem. Thanks.

[MegademiC]

Try more factory rounds.
What is the recommend min for a 95gr bullet and that piwder?

[grizzman]

By thinking the gas block was at fault, I thought you meant that it could be installed incorrectly.

If it's adjustable, then that's the easiest place to start. If you open it up far enough to work with the handloads, it'll likely be overgassed with factory loads (if it's undergassed with handloads, and not so far overgassed that the bolt is outrunning the mag), but you should be able to find a setting that works with both.

I also agree that testing with more than one factory offering is wise.

[ebh]

Maybe you should know and/or share your custom loads, custom load recipes (including the source of your recipes) and your firearm equipment and firearm capabilities when asking questions.

Given your lack of knowledge and/or sharing of that knowledge, all you are getting is speculation on what the problem might, or MIGHT NOT, be (both on the part of others, and FRANKLY THE PART OF YOURSELF).

...

ebh

[walker2713]

Maybe you should know and/or share your custom loads, custom load recipes (including the source of your recipes) and your firearm equipment and firearm capabilities when asking questions.

Given your lack of knowledge and/or sharing of that knowledge, all you are getting is speculation on what the problem might, or MIGHT NOT, be (both on the part of others, and FRANKLY THE PART OF YOURSELF).

...

ebh

never mind

[walker2713]

By thinking the gas block was at fault, I thought you meant that it could be installed incorrectly.

If it's adjustable, then that's the easiest place to start. If you open it up far enough to work with the handloads, it'll likely be overgassed with factory loads (if it's undergassed with handloads, and not so far overgassed that the bolt is outrunning the mag), but you should be able to find a setting that works with both.

I also agree that testing with more than one factory offering is wise.

I took off the handguard and opened the gas block up one turn....problem solved.

Thanks for the helpful feedback.

George

[everready73]

So the issue is fixed by opening the gas block a click? I was assuming that would be it and happy you figured it out.

What kind of accuracy are you getting?