AA Entry upper and 6.5 American Gunner Ammo

[justified]

I finally got my Grendel where I want, except I’m still waiting on my can. I have the AA Entry Upper with 20” barrel, Rock River lower with fixed stock and Geisselle SSA-E trigger. The scope is a Leupold 4.5 x 14. This rifle is more accurate than I am and a blast to shoot.

I tried the American Gunner Grendel ammo in it yesterday. The group below is at 200 yards off a bench. The flier was called. Average velocity was 2509 fps with a SD of 23.84 and a 64 fps spread. At 200 yds the AG and 123 SST ammo shoot to the same point of aim. It is also lethal for groundhogs.

Unfortunately, this ammo does not like to extract from my rifle. The bullet lodges in the rifling when I try to manually eject a loaded round. Time to run it through my seating die to set it back a little.

I also chrono’d the other ammo I had on hand:
100 Wolf steel case ammo averaged 2757
123 AA Scenar ammo averaged 2697
123 Hornady SST averaged 2600 with an S/D of 17.58

[BluntForceTrauma]

By design, the first angle of the SAAMI throat can just "kiss" the ogive of certain rounds when chambered. This is part of the accuracy equation for the SAAMI design, as you are finding out. Maybe trying shooting it a bit to see if things settle in before going thru the hassle of reseating rounds?

[murfvol]

Thanks for the report and chrono data. Do you happen to have temperature and elevation info too?

[justified]

It is interesting that only American Gunner ammo hangs up and will not eject. AA, Hornady SST and Wolf loaded rounds would all eject just fine.

[justified]

Temp was 90 darn hot degrees and about 800 feet

[worthen86ford]

AG and hornady black jam in my lands. Giggidy. Sst and wolf dont either. My rifle has a 16” AA lite barrel. Ejects just fine cold but after a string of fire it wont eject by hand. I think the chamber shrinks down on the lands as the chamber cools where as it just seats the bullet a little when the chamber is already cold.

[biodsl]

123 AA Scenar ammo averaged 2697

That is screaming fast out of a 20 incher! Not temperature stable I'd assume.

[VASCAR2]

I think Overwatch barrels are 24”, my guess a typo.

[LRRPF52]

If you're jamming the lands, pressures can spike on you.

That 123gr Scenar speed is pretty fast for a 20".

What do your case heads look like?

[justified]

I'll chrono again when I can get to the range.

I double checked the barrel length, it is 20". This is the upper that is on the rifle:https://www.shopalexanderarms.com/Uppers...eiver.html

Here's the brass: AA, American Gunner, and Hornady SST on the right.

[VASCAR2]

My mistake justified, you mentioned AA Entry in your description and I thought it looked like the Overwatch which is a 24” barrel. I need to read the post again before commenting. The velocity is pretty high and in the same velocity range I see with 24” barrels. Sorry for any confusion.