HELP NEEDED QUICKLY

[FullCurlHunter]

Was at the range last weekend testing some new loads in my .300 WBY Mag, Weatherby Mk V Ultra Lightweight.

Last week I was 2.5 inches high at 100 and about 4 inches low at 300 yards.

Yesterday my goal was to get dead on at 300 yards. I started at 100 yards, crystal clear skies, no breeze cool weather (45 degrees). I was shooting .5" groups and I raised the point of impact up to 3.25 inches at 100 yards. I proceeded to clean the barrel with a jag, patch and sweets 7.62 followed by a brush with sweets follwed by a jag and patches until perfectly clean patches were coming out of the end of the barrel.

I moved to 300 yards expecting to hit around dead on. My first shot was 6 inches high and 6 inches to the right. First thought was it was a flyer so I fired off a few more where I could not see any bullet holes through my 4.5-14x44mm Zeiss Conquest. I figured all 5 shorts were in the black circle and I just could not make them out.

I went down range to discover that one of the 6 bullets that I had shot after the flyer had hit the paper on the very upper edge of the target. I was using a big piece of paper...3'x2' with a target centered in the middle. I went back and was disgusted beacuse something happend from the time I cleaned my rifle and went from 100 (where it was shooting like a dream) to 300 where I was hitting over a foot high.) At this point I should mention that I am reloading and they were made with every bit of attention to details in regards to every variable including measuring powder charge 3 times.

At this point I moved my scope down 2 clicks where I started to hit around 7 inches high from bullseye but the group was about 8 inches (which I am used to shootig 2" groups with ease at 300 yards).

At this point I took off my bipod and anchored into a sandbag, checked to see if the scope mounts were tight...they were all very tight except for 2 screws out of the four in the rear mount that were tight but could be torqued further...I dont think it was loose enough to be moving around. They are Talley one piece alluminum rings where the base is attached to the rings and bolts directly to the receiver.) I moved the scope down 8 clicks and shot 3 about 6 inches low and 5 inches right. I moved the scope to the left about 2 clicks and up 4 clicks and shot a 3 inch 5 shot group dead on, moved to 200 yards and shot a 4 shot group 4 inches high with a groupig of about 1 inch...it was shooting well again....for now anyways

I am curious as to your thoughts as to what happend from 100 yards to 300 yards. All I did was clean it and I have done this many of times during an outing at the range and it has never affected its shooting. I did not bump the scope in any way so there were not issues there. The barrel was not hot either as I fire one shot ever 4-5 minutes to control this inthe featherweight barrel.

What are your thoughts everyone!? I am heading out west in two weeks and need to get this figured out, last thing I need is to have a monster buck and miss or worse yet wound it and end my hunt.

Thanks!

Dan

 

[257Tony]

I don't see anything obvious. Do you need to clean the barrel that often? I know some guns need it, but mine seem to shoot just fine for at least 40 or so rounds between cleanings.

 

[mtmuley]

Same lot of powder in your handloads? You stated that you were testing new loads. What was new? Bullet, powder, seating depth? Something changed from the load you had good groups with to the bad groups. mtmuley

 

[huntindude]

I had a rifle with a VX-III Leupold do a trick like that to me a few years ago and it turned out to be the adjusments in the scope. it sounds like you have a history of accuracy with the rifle, most people have a 3" group at 100 yards and expect a nice group at 300, not going to happen.

You probably know it but how you hold the gun makes a big difference on point of impact, more than most people know. all scopes have parallax no matter what quality or how you adjust them.

With the changes you have I would look to the bigger things like scopes, mounts,parallax and not to sound like a wise guy but yourself, I have days I just don't shoot good. I've learned to try it again later and have fixed some guns that way. every issue with a rifle that has a good history of accuracy has a solution and you'll figure it out, good luck.

 

[RELH]

Dude gave you good infro. I would suspect the scope based on the information you supplied. I have seen top end scopes shoot loose internally, and do what you stated. My Father-in-law had a Leupold scope go sour on his 300 Weatherby and would not hold a pattern until it was replaced by Leupold. If not enought time, I would look at taking a different rifle for your hunt or different scope and you can do further testing when you have the time. One reason I have more rifles then I need.
RELH

 

[Pre64]

I've had similar problems. When you return to 100 yards do the groups return to original POI??

If so, you might try shooting groups at progressively longer ranges to see how they hold up. Say 150, 200, 250.

good luck