Vertical Stringing

[mec1]

Hey Guys,

You may have seen some previous posts from me about my new AR build in .204. Well now everything is working great and I've found a load that groups around 3/4". The only thing that I have noticed is that when the barrel heats up, it starts to string shots vertically. Shooting from a cold, clean barrel, the groups are round or horizontal, but as it heats up, they turn to straight vertical lines and open up to about 1.5". The handguard is freefloated, but is there anything else you AR guys can think of that might cause this stringing? Any help would be great. Thanks!

[bow shot]

Well for me, recoil control is always a tough thing to perfect. I understand what you are saying (heat tends to vertical), BUT in MY case, I have found that If I shoot for a while, I tend to string one way of the other based on my form, or hold, or whatever you call it. Drives me nuts . I can actually force a VERY tigh vertical or horizontal string (I think I actually posted pics of that here, 300 yard groups). Getting BOTH out has been the problem for me.

I have it down quite well with my .204 Savage VLP, but am having a nasty time with it with my .204 RRA (normal A2 stock)

I'm not saying that your soultion is there... just keep it in mind before you start psycho-analyzing your laod.

[bow shot]

I should have said earlier, that verical can equate to variation in powder charge (or bullet seating depth). That's where a lot of folks start looking first. I know that .1gr makes a diference in my loads, and in a certian range, .2" charge variation change means 1" change @ 300y. Hope that helps!

[bow shot]

...funny I should mention that... I just last night bumped into reason to suspect that my scale has (or I have) an accuracy issue.. some of my charges, though they are different weights, read identical on my beam scale

News at 11 if I figure this out ... I just stared a thread on this. I think I cruze the forums on my lunch break, lol!!

[bow shot]

The scale accuracy issue was in my method. I needed to be more consistent in how I was placing the pan, starting the beam motion, etc.