338 lapua mag accuracy problem

[kaseyfied]

Ok fellow long range shooter it's question time.. I have a custom lapua mag that is having some accuracy issues down range. At 200 it's a .675 inch 3shot group.. At 500 it's a 1.72 inch 5 shot group.. And now at 800 it's about a 8-9 inch 5 shot group. I use a bushing die lapua brass 300 grain Berger bullets. I anneal all my brass every 3 firings. 215 m primers and h1000. I have the same lots of bullets.. Primers and powder.. I was getting 2.25 inch 5 shot groups a month ago with the same load.. Any help would be great my friends thanks

[Broz]

Paralax?

Mirage?

Fouled bore?

[Joe King]

or the wind took you school

[kaseyfied]

no wind that would effect my bullet like that.. i clean my bore after every day out.. and I always shoot 2 fouler shots before I start shooting for group size.. it just doesnt make any sense to m whats going on.. weird..

[Greyfox]

This is a long shot. I once had a fatigued erector spring in a scope that caused accuracy problems when dialing at the longer ranges. As elevation is increased, the spring tension is lessened. A fatigued spring woukd apply very little pressure and possiblly allow movement of the tube. Very rare, but ruling out shooter error, and conditions, the fact that your shorter range groups are tight, and the components are identical, that leaves the scope. Easy to rule out by swapping the scope.

[kaseyfied]

i have a brand newblue diamond scope I just mounted a month or so ago in this rifle.. I would hope ths is not causing this.. i guess it could be though cus ya my groups are pretty dang tite up to 500 yrds.. i know this is a lng ways but just a chip shot for a lapua mag

[kaseyfied]

but at the same time.. this is the same scope that was on the rifle when it shot 4 shots into a 2.32 inch group at 800.. so I am at a loss for words I guess.. only thing I can think of is my primers extrude passed the case head now.. I uniform my primer pockets but non of them seat far enough in now.. they all extrude past the case head.. would this maybe cause something??

kasey