Load workup help

[KimberPB]

Ok I went to the range today to test some different loads for my 16" AR15 topped with an EOTech. In the past when working load workups I'll see the groups shrink then open back up. Then I can take the tightest group and tweak it from there. Today I was shooting 55gr FMJ Hornady, PMC brass, Tac powder, and CCI primers. Loaded up as followed:

1. 23.0 grains
2. 23.5 grains
3. 24.0 grains
4. 24.5 grains

Well, this time all the groups shot the same size. About 1.5". I don't have a chrono yet so I didn't load up to max (25.3) but this is the first time I've had all loads shot the same size groups. Anyone have any ideas? By the way I hand weighed each powder charge and bullet (each 55.0 gr)

 

[festus]

I load a lot of .308/7.62NATO

Ok I went to the range today to test some different loads for my 16" AR15 topped with an EOTech. In the past when working load workups I'll see the groups shrink then open back up. Then I can take the tightest group and tweak it from there. Today I was shooting 55gr FMJ Hornady, PMC brass, Tac powder, and CCI primers. Loaded up as followed:

1. 23.0 grains
2. 23.5 grains
3. 24.0 grains
4. 24.5 grains

Well, this time all the groups shot the same size. About 1.5". I don't have a chrono yet so I didn't load up to max (25.3) but this is the first time I've had all loads shot the same size groups. Anyone have any ideas? By the way I hand weighed each powder charge and bullet (each 55.0 gr)

I have never had that happen either. Your best bet would be to chrono the rounds and see what Velocities you are cooking up. As soon as you reach Mi-spec velocity...STOP!:23:

If the groups aren't moving in check your rifle for copper fouling. I think you may need to clean between strings to get the most out of her and plan on the first shot being a fouling shot.

My brother-in-law has a Bushy M-4 that holds a 2 inch group with 55 grain factory ammo. You may be at your sweet spot already.

When you do change a component or a dimension check before changing any thing else.:bulb_r:

 

[KimberPB]

I have never had that happen either. Your best bet would be to chrono the rounds and see what Velocities you are cooking up. As soon as you reach Mi-spec velocity...STOP!:23:

If the groups aren't moving in check your rifle for copper fouling. I think you may need to clean between strings to get the most out of her and plan on the first shot being a fouling shot.

My brother-in-law has a Bushy M-4 that holds a 2 inch group with 55 grain factory ammo. You may be at your sweet spot already.

When you do change a component or a dimension check before changing any thing else.:bulb_r:

Thanks Festus.

I ran a patch through the rifle before I headed to the range just to clean out anything that may have found its way in there. I also shot 3 round with the same component as the load workups. Just to warm up the barrel. Then shot the workups. I think I'm going to invest in a chrono when my $600 from the Gov comes in. Then maybe try it again. The groups were not bad it was just the first time my groups were all so close.

 

[DrDavidM]

They all sound good to me. I, too, have been wanting to get a chrono. Midwayusa has some that are very reasonably priced and have good reviews on them.

 

[festus]

You may have stumbled across one of those rare loads

What I wouldn't give for that kind of consistency in a combat load! 2" =headshots at 400 yards on a regular basis.:vampire:

 

[Red Hat]

My best load for 223 is 55 gn FMJBT with 25.5 gn of BL-C(2). I haven't run it through my chrono yet to see the velocity. It should be around 3100 fps.

 

[KimberPB]

Thanks for the comments guys. I did look over my groups again last night. I noticed that the first 3 groups all grouped in a circular pattern. You could measure from any two opposite holes and get about the same distance. The last group grouped 3 shots really tight, 1/2 in, then about an inch and a half directly above that group were 2 more shot almost touching. I may have bumped the rifle changing the point of aim just slightly. In any case the barrel may just like hotter loads. I'm going to get a chrono and try up to max and see it that shrinks the groups some more. But less than 2 inches with a carbine is more then fine for me.

Thanks Red Hat I'll have to try that powder and see how it shots. How clean does that powder shot?

 

[Red Hat]

It's basically the same as military powder. BL-C(2) burns very clean.

 

[KimberPB]

It's basically the same as military powder. BL-C(2) burns very clean.

Sweet. Thanks for the info Red Hat.