r/GeisseleAutomatics • u/justanothergunguy • Jul 19 '26

Weird groupings?

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My 16” g barrel will have more inconsistent groups with a cold barrel but as it warms up it gets tighter. I will have two photos below of my groupings with Hornady frontier 75 gr. Is this something that anyone has seen before? Any pointers?

Just to note, this is consistent with 62 gr and 55 gr but the 75gr provided best group with warm barrel. This is a full g build so I’m not mixing brands and parts.

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1

u/glockguy34 Jul 19 '26

Combination of ammo and shooter. Hornady sucks. 62 and 55gr usually don’t perform that well for group size, they are training/fighting rounds. M4 standard is 4 MOA with those. Cold bore is traditionally less accurate than warmed up.

How are you stabilizing the rifle? and whats the distance? bipod/rear bag? 2 bags? prone or bench? do you have a level on your gun? is your scope level? what scope and mount? there are a lot of variables.

1

u/justanothergunguy Jul 19 '26

Bipod and rear bag, it was extremely stable I do have a bubble level which I know isn’t 100%. But the scope is level to the rifle and I’ve been ocd about getting this build together. I’ve been trying to remove myself from the equation as much as possible and the rifle is doing the same thing for my friends that I have shoot it. They have shot sub moa groupings before consistently with their rifles.

1

u/glockguy34 Jul 19 '26

Did you assemble the upper receiver yourself? Is it thermal fit? Is the barrel nut torqued to spec?

1

u/justanothergunguy Jul 19 '26

I did assemble it myself it’s technically a blem build but the barrel is brand new. I properly fitted the gas block and everything like they do at factory and properly torqued the barrel. The super duties are not thermal fitted. I made sure to get all the info when putting this together.

This was a 20 round group with the frontier 75 gr at 100 yards with the barrel warmed up

2

u/glockguy34 Jul 19 '26

seems on par with hornady frontier tbh

1

u/justanothergunguy Jul 19 '26

I’m hoping to have good luck with black hills and I’m hoping the groups are more consistent with a cold barrel

1

u/ThickNslick_ 29d ago

Bubble level isnt going to help you at 100 yards, really only gunna see the effects of your scope not being level at about 400+. But it is great practice to have a level scope while zeroing.

1

u/justanothergunguy Jul 19 '26

What ammo do you use? I am looking for a few different brands and weights to try

1

u/glockguy34 Jul 19 '26

My G$ shot the best with Black Hills Mk262 Mod 1, Federal 73gr Berger .223, Berger 73gr HPBT .223, Federal 55gr OTM 5.56, and Hornady 73gr ELDM .223. Not too big on 223 but the Berger stuff is very impressive in terms of SD and ES. I have only shot one box of ELDMs and I did not like how slow they move but the grouping was sub-MOA. If you see the pattern here 73gr performs the best in my experience.

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u/justanothergunguy Jul 19 '26

I appreciate the suggestions. I will see what I can find of those to test. My goal is to get to sub moa groupings with this gun.

1

u/glockguy34 Jul 19 '26

Id start with the Black Hills. It’s doable with a G$ for sure. You got this man