7mm RUM a-max problem

[docp]

I went shooting today and decided to check my zero on a Remington 700 w/ 1-9 twist Pac-Nor 3 groove. My load is 85 gr. of Reloader 25, Fed match primer, 162 A-max bullet .020 off the lands. Conditions were: Overcast with temps in the low 50's w/ 92% humidity.
First group 10 MOA high and 3" @ 100 yds.. This from last fall's 200 yard zero and 3/4 MOA or better groups.
Adjusted zero 8 MOA down and shot 3 more. 3" plus.

Started another group. 1st shot 6 MOA low. #2 OFF the target altogether! #3 was 2 FEET right and 1 foot low. Bullet tore a jagged hole in the paper.

This barrel has less than 100 rds. down the tube.
Bore scope shows excellent interior. Lands in great shape. Throat is fine. crown is fine. I can find nothing wrong with the rifle. Mark 4 seems to track fine. all bolts and screws torqued on scope and action.

Could this bullet be coming apart, because that is how it is acting. I find that hard to believe, so if anyone has thoughts, I'd like to hear them.
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[jeffro]

I would check your scope. Sounds like you have a scope issue. Guns dont change that much even with different loads.

 

[Pdvdh]

Bullet tore a jagged hole in the paper.

Could this bullet be coming apart, because that is how it is acting. I find that hard to believe, so if anyone has thoughts, I'd like to hear them.
`

That jagged hole in the paper is a telltale sign the bullet is coming apart or not stabilizing properly.

 

[kiwi3006]

Do a search on here for 3-groove barrels. I know Kirby posted up about problems he was having with 3-groove barrels tearing up bullets with thin jackets.
You might have to try the 175 sierra match king, it should hold up better.

Stu.

 

[docp]

Thanks for the input. I will look into 3-groove barrels. 175 Matchkings on the way.

 

[ahuntnfool]

Hi all,
I am new to the LRH forums, but have read alot of useful info in these threads.
I am with jeffro on the check your scope out.
I just had a Winchester model 70 in 270 wsm with a Leupold 4-12x40 on it that did exactly what your gun is doing,and I also have a Remington model 700 sps in 300 wsm with a Burris fullfield 2 on it in 3-9x40 and it was doing the same thing.
I took both scopes off and sent them in to the manufactures and when I got them back and put them back on..... well sub moa @ 100 yards with both guns.

 

[Iron Worker]

I bet your scopes are just fine. Its the thin jacketed bullets they're being ripped in the 3 grove bbl.Try a thicker skinned bullet