first AR loads acting strange

[goldy1]

I just got finished firing my first 5 rounds with my ar. its got the 24' varmit 1/8 twist barrel. I'm using 75 a-max over 24.2 rl-15 well over mag length for single feed but still not touching the lands. I started out using some other rounds to check my 200 yard zero and got just under a 2" group. so i went to my rounds and after i fired i walked to the target and there was only one bullet hole. I dont know where the rest went, so that means the group opened up to over 8" the one hole looked fine so it looks like they are stable enough. I've never loaded for a gas gun before so I'm not sure what to do from here.
any directions would be really helpful, thanks.

 

[gunsnjeeps]

Re: first AR loads acting strange

Not to be a smart ass but start with a bigger target. Seriously, you could have a 4 round 2 or 3 inch group just off target and the one on paper was a flinch. Especially if you zeroed with a different ammo. Do you have access to a chronograph? I find it easy to copy a round for velocity to get the same performance and reduce inconsistancy when hand loading. The load sounds like a reasonable load. I don't think you have a round that would be that instable.

 

[goldy1]

Re: first AR loads acting strange

The target is a 12" by 12" paper. Im thinking of bringing the target in to 100 and see what it does.

 

[jbailey]

Re: first AR loads acting strange

Load/rifle combo looks good.

(1) load up more rounds at lower charges (start at 23.5, load others at 23.8, 24.1, 24.4)
(2) bigger target
(3) 100yds
(4) chrono
(5) play with seating depth of best group (low for best combo of precision and high/low velocity spread) from this powder charge group.
(6) verify performance of best powder charge group at 300yds

Walk before you run. This will solve problem and you will be out at 600yds drilling <6" groups in no time!

 

[MALLARD]

Re: first AR loads acting strange

12 by 12 is pretty small , get a big one and try again. Some guns have poi/poa shift when you switch ammo , so you might have to re-zero when you switch loads.

 

[goldy1]

Re: first AR loads acting strange

i'll try again at 100, and see how it goes. Guess I'm used to my F-class rifle at 200 it'll do around 1/2" groups, so this ar is all new to me. I've got more loaded up to see what happens sunday.

 

[gunsnjeeps]

Re: first AR loads acting strange

Try either a 200 yard repair center or a 100 yard reduced target. You can print a repair center and put it on a 24 by 24 piece of cardboard. I can't find it right this minute but the 200 yard reduced for 100 repair center is a download PDF.

 

[goldy1]

Re: first AR loads acting strange

I moved the target to 100 and all rounds were on target, but the group was awful around 4" and the brass was covered in carbon. doesnt that usually mean the charge is too light to seal the brass in the chamber? tonight I'll load up some at different powder charges for tommorow.