no idea what happened

[hydehunter]

I have a Cooper model 21 6.5-284 that shoots Berger 140 grain bullets into bug holes and is sighted on steel out to 500 yards.today I decided to try Nosler RDF 130 grain bullets, so I loaded a few up to see how they group and see what velocity I can get.went outside to my bench and took the first shot at 100 yards on a white paper target 24"x30" and guess what I could not put one bullet on target but was happy with the velocity. now since I put the gun in the safe last Sept. it has not been touched and the barrel is not touching wood all screws on the gun are still tight and the gun room stays at 53 degrees and the safe with golden rod stays at 50 degrees humidity anyone ever run into this? as soon as the weather changes I will check the bore sight and start from scratch and figure out what happened. sorry for the long post. note gun has never been dropped

 

[Golovkin]

shooting off the same rest?

 

[cohunt]

check your scope?

 

[jibnast]

Did you make sure you reset your turrets from your last trip and they still aren't set up for 500.

 

[hydehunter]

yes turrets were reset before I shot the first bullet, been using the same front and rear for years, checked scope rings and bases both torqued down. weird. well if no more severe thunder storms tomorrow I will bore scope and start fresh

 

[WildBillG]

Try again with your Berger load. Bullet change shouldn't change that much but you never know.

 

[ATH]

Not much to diagnose until you figure out if it is grouping and if so where. It could be many many things. Try your former load and get a bigger target, or move it closer.

You could be just off the paper, have a scope issue, or one time I saw a guy leave hit gun in a soft case for an extended time and ruin the barrel and finally we shot it at 50 FEET and realized it was keyholing.

 

[MagnumManiac]

This is not necessarily unusual.
I have had similat changing from heavy to light and back again.
I have a few switch barrel rifles that will not hit paper in the same barrel after being sighted with one bullet and then switching to another in the SAME weight.
Barrel harmonics can and do change POI quite dramatically.

Cheers.

 

[hydehunter]

today I set up a target at 50 yards and went back to my normal load to see what would happen.140 berger this is the last load I shot at 200-300 and 400 yards incase I decided to use it instead of my 6mm for deer. first shot was 10 inches left, tried another to see if it was me and it want in the same hole, so I guess I will have to re-zero my load and go from there. WEIRD!

 

[huntsman22]

scope puked?

 

[James L Holzhauer]

poop happens. Something moved your scope. You could have proved this by firing the same bullet you had zeroed before. I bet it wouldnt shoot to zero.

 

[JC Lepley]

I have a Cooper model 21 6.5-284 that shoots Berger 140 grain bullets into bug holes and is sighted on steel out to 500 yards.today I decided to try Nosler RDF 130 grain bullets, so I loaded a few up to see how they group and see what velocity I can get.went outside to my bench and took the first shot at 100 yards on a white paper target 24"x30" and guess what I could not put one bullet on target but was happy with the velocity. now since I put the gun in the safe last Sept. it has not been touched and the barrel is not touching wood all screws on the gun are still tight and the gun room stays at 53 degrees and the safe with golden rod stays at 50 degrees humidity anyone ever run into this? as soon as the weather changes I will check the bore sight and start from scratch and figure out what happened. sorry for the long post. note gun has never been dropped

Measure CBTO to lands contact and try .010 off lands or less.

 

[hydehunter]

the 140 berger is my normal bullet in fact before putting it up last fall I shot 3 shot groups on steel at 200-300 and 400 yards and every thing was good to go

 

[JustMe2]

I had a similar thing happen on my 300WM and discovered one of my 4 Picatiny base screws had sheared. Pulled scope rings and base off, used screw extractor to get remaining screw out, replaced all base screws, everything back to normal. Also had a scope "Bell" come loose once that did the same POI shift. You said you checked scope torque, did you check base torque?