New horizontal spread?

[mao0720]

So I went to the range yesterday morning and this morning to do some prep for a 1000yd HP rifle / F-class match this sunday, I am getting a lot of horizontal dispersion that I wasnt getting before. Im not sure if its my hold (I dont feel Like Im changing anything shot to shot), or if my I lost tune with my load. Load is the same as Ive always used since I got the rifle. Lapua 308 Brass, CCI BR-2 primer, 46.7gr LeveRevolution, 155gr SMK Palma load about .010 into the lands. Any help would be appreciated.

 

[22BRGUY]

Since bullet seating depth usually helps horizontal, wonder if you may have gotten some throat erosion that changed the picture somewhat or maybe a different batch of bullets with somewhat different ogive.

 

[mao0720]

Im still working with the same lot of bullets, in fact the same 500ct box. I was a bit worried about the throat erosion hypothesis, I have shot about 600 rnds through the barrel now.

 

[22BRGUY]

Tough call. Could be anything from something loose on the rifle to your form, to a scope issue to the seating depth. Are you inadvertently applying pressure with shoulder or cheek or on the trigger maybe?

 

[mao0720]

I generally have pretty firm shoulder and cheek pressure but I havent seen this much horizontal spread before. Checked all fittings on the rifle and nothing seems loose. Which leaves me back at my load. Gonna try to shoot again tomorrow and see what happens.

 

[37Lincoln1]

Carbon ring?

 

[BradY]

Run a quick seating depth test with rounds another 5 thou and 10 thou further out. If 5 thou solves the problem and 10 is just as good, stay the 10 so you have a little room for barrel erosion up your sleeve.

 

[dkhunt14]

If you are at the same seating depth as when gun was new. My guess is the throat moved with 600 rounds. I always check my seating depth each time I load. I load the first round and steel wool the bullet. I take the fire control out and put shell in gun and close bolt. I then take it out and look for marks on bullet. 10 thous. in gives a nice little mark on bullet. Matt

 

[fdshuster]

A friend recently had the identical problem, uncalled wild shots left and right, points-of-impact not changing after adjusting windage on the scope, etc. The scope ( a well known) is going back to the manufacturer.

A no cost and quick test is to mount a different scope. They do fail, more than I ever believed.

 

[22BRGUY]

I generally have pretty firm shoulder and cheek pressure but I havent seen this much horizontal spread before. Checked all fittings on the rifle and nothing seems loose. Which leaves me back at my load. Gonna try to shoot again tomorrow and see what happens.

When I read this about cheek pressure, I couldn't help but remember that I found out at one time that putting cheek pressure on my stock was throwing bullets to the opposite side of the target. In other words, if my right cheek was applying pressure to the stock, it would throw bullets left. I try now to concentrate on just being a straight back trigger puller....that's all, and avoiding all pressure I can to the rifle that might interfere with it's straight rearward recoil. JMHO

 

[dkhunt14]

Those two answers by 22BRGUY and fdshuster are also things to check. Holds on guns can cause vertical and horizontal issues. That's why for BR I mount my scope real high so there is no contact on stock. Matt

 

[bow shot]

Horizontal has always been me. Drives me nuts. YRMV, of course.

Now that I think of it, ALL my problesm are me, LOL !!

 

[mao0720]

Shot again this am. 5 shots seated at my usual 2.246 CBTO, 5 at 2.250, and 5 at 2.255, all shot at 200yds. For the most part the wide horizontal stringing I had was gone in all 3 groups. Had a little bit of vertical with the 2.246 group, the 2.250 group was the tightest with 4 rounds in .75" and a fifth shot low to open the group to 1.75. The 2.255 group was ok, but not great. All 3 of the groups came in right under 1MOA. Not my best groups ever, but Im thinking the issue is me. Guess I'll see how I fare at 1000yds this weekend.

 

[C. Collins]

wind?

 

[mao0720]

As calm as I could ask for each of the last 3 days.

 

[rminut]

Just wondering how you weekend went at Rattlesnake? I'm guessing the horizontal issues re-emerged with the crazy winds that place is known for!

BTW, what did your 46.7g load chony at?