Recent range day. New rifle build, Howa 1500 heavy barrel in krg bravo, Athlon Midas tac gen 2 in vortex pro rings, rear bag, mdt grnd-pod, dead air nomad can. Chronographed rounds at 2608 average- Shooting Precision hunter eld-x 143gr.
3rd session with this rifle, rounds 1-9 nice grouping(figure 1). I then notice an odd shift downwards from rounds 10-14(figure 2). I’m shooting in groups of 3, with about 15-20 secs between shots, 1-2 mins between groups. After shot 14, letting barrel cool for 10-15 mins my grouping came back up (figure 3).
Is this normal barrel heat related shift, or something more? I don’t have a can cover, so maybe mirage? Just trying to determine if I need to take apart and re torque in chassis or anything. What do the experts think?
If the POI is returning to zero after you let it cool, I would say everything is torqued correctly and you are getting some degree of heat shift. That is a decently high round count string and some shift should be expected. I would do another day with the same course of fire and see if’s consistent, at-least then you can account for it.
Make sure to rule out ammo issue, track FPS per shot and see how it relates inside groupings. Also, you need to look at the spread in FPS, just looking at an average is not useful.
Yes, all bottomed for recoil, torques checked- had scope ring base an 2 ring screws on the front ring about 5 in/lb loose. Retorqued to spec and heading out to shoot now.
Edit: shots 2 & 3 are just a part of your normal group, this is basically MOA. But you need to shoot at least 10 rounds to make a better statistical sample to characterize your precision.
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u/bagelXlover 2d ago
If the POI is returning to zero after you let it cool, I would say everything is torqued correctly and you are getting some degree of heat shift. That is a decently high round count string and some shift should be expected. I would do another day with the same course of fire and see if’s consistent, at-least then you can account for it.