16" Barrel Twist Rate

[CCinClovis]

Brand new to reloading and am interested to know if there is an ideal bullet weight for a 16" Grendel barrel with a 1:8.5" twist? Although I've done no scientific testing, I have shot approximately 3000 rounds through it in weights from 100 gr. Berger's to all the way to 130 gr. Swift's and a lot in between. The only round it does not digest well is the Hornady 123 A-Max. The AA 123 A-Max run perfectly as do all of the Precision ammo rounds.
Anyway, just wanting to know if on paper anyway, there is an ideal bullet weight for this barrel?
Thanks for any input.

[LRRPF52]

The only round it does not digest well is the Hornady 123 A-Max. The AA 123 A-Max run perfectly as do all of the Precision ammo rounds.

I'm confused by this statement. Can you explain a little more?

As far as ideal bullet weight, I think one of the selling points with the Grendel is that it handles a lot of different bullet weights well. Sounds like you already know that better than a lot of people with that round count.

I personally find that my diet consists more of 123gr A-MAX than anything else, although I have shot 90gr TNT, 100gr NBT, 120gr SMK, 123gr Scenar, 123gr SST, and 129gr SST a bit.

I think AA uses a tighter twist of 1/7.75" on the carbines to keep the bullet stabilized longer, and 1/9" on the 24" guns.

[CCinClovis]

That was a little vague. The Alexander Arms Lapua 123 A-Max feeds perfectly in my Grendel. Never a malfunction of any kind, and that goes for all other ammo that I've tried, with the exception of the Hornady A-Max. About every 4th or 5th round jams into the lugs of the barrel leaving deep grooves in the round and making it very difficult to extract. At this point, the bolt does not close all the way.
I sent my mags (4 and 10 round Alex-A mags) to Bill A. when this first happened and he gave them all a clean bill of health.
I am 100% convinced that it is the Hornady ammo as I have not had any other malfunction of any kind.
Thanks for taking the time.

[CCinClovis]

I stand corrected on that statement. The AA rounds are 123 Scenars. The Precision Ammo rounds are 123 A-Max bullets in Lapua brass.

[LRRPF52]

So the 123gr Scenars feed fine, but the 123gr A-MAX does not? That's weird. Have you tried factory Hornady 123gr A-MAX box load? That runs 100% so far in my 16" AA Grendel.

[CCinClovis]

So the 123gr Scenars feed fine, but the 123gr A-MAX does not? That's weird. Have you tried factory Hornady 123gr A-MAX box load? That runs 100% so far in my 16" AA Grendel.

That is the case. Just to clarify, AA 123 Scenars are GTG.
Precision 123 A-Max with new Lapua brass are GTG.
Actual Hornady boxed 123 A-Max not GTG. This is the round that has the jamming issue.

[LRRPF52]

What barrel do you have? Who made it?

[CCinClovis]

What barrel do you have? Who made it?

Alexander Arms barrel, I think it is a Shaw.
Maybe Bill A. can chime in. 16" bead blasted stainless w/ a 1:8.5 twist.