Short Stroking by powder? HELP NEEDED

[peyton00]

Hello group,
I am new here looking for help. I have a new 6.5 upper for my AR, new BCG and Mags. Everything was going great shooting factory Hornaday Black 123gr ELD 150 rounds. I then switched to my hand loads, 123gr Sierra Match. Used H322 24gr and RE10x 24gr of powder. Both started short stroking bad. I checked all dimensions, and everything is spot on. Neck tension was .003. COAL was 2.26 as stated in Sierra loading manual. I then went right back to factory ammo and no issues; all this was in the same day. Other info on hand load; CCI small rifle primer, Hornaday brass that was shot through this upper one time, I did a full length resize on the brass. Before I start chasing my tail in the wrong direction, I think the powder burned to fast to run the bolt, and these powders are for bolt action rifles. Any help would be greatly appreciated, and maybe tell me what powder and loads with this bullet that has worked for any on you.
Thank you very much

[bj139]

Do you have an 18" barrel with rifle length gas?
I have a Ballistic Advantage barrel with this configuration and it has mostly failed to cycle.
With starting loads there may not be enough pressure. LRRPF52 mentioned elsewhere to drill the port larger.
I have not shot my barrel enough to try the drilling. 18" should really have mid length gas to get more gas back into the action.

[peyton00]

Yes it is an 18" Bear Creek....Wonder why factory ammo runs perfect, just my hand loads failing. I have shot over 250 rounds of factory ammo, not one hiccup, but hand loads failed first mag in.

[Drillboss]

Who installed the gas block? It could be partially covering the port.

Your loads are less than max according to Sierra's data, although the RE10x load isn't that much low. Disclaimer: I haven't used either of these powders.

I did a build and misplaced the gas block (didn't read the directions all the way through) and had FTE's on lower power hand loads while factory ran fine.

[bj139]

I looked on the BCA site and all the 18" Grendel uppers have a midlength gas port so it must be simply lower power reloads.
Try upping your reloads to the middle of the range. You are at starting loads with H322 from the Hodgdon site.
Keep the bolt and receiver well lubed while it is breaking in. I use Rem oil spray.

[VASCAR2]

What buffer and buffer spring are you using, rifle length or carbine length buffer tube. If BCA barrel probably a mid length gas system so are you using a fixed gas block or adjustable gas block?

[LRRPF52]

24.0gr of H322 is a starting load per Hodgdon's data under a 123gr SMK.

Work the load up using Hodgdon's data as your reference (contained in the Grendel Handbooks as well).

Work up over a chrono in .3gr increments. 26.6C gr is the max listed by Hodgdon's under the 123gr SMK.

Your action will start to cycle with bolt hold-open once you get a little more above 24.0gr, I suspect.

Be very careful with RL10X. I would not use RL10X under a 123gr, or even a 100gr in Grendel. It's best left for 90-95gr cup/core bullets in my opinion.

[bj139]

With starting loads you should notice less recoil than factory loads.
I use this as a guide when I start loading higher powder loads.
If you notice one that is MUCH stouter than before, stop and analyze your situation.
The recoil should not feel more than factory loads.