what can cause........

willie332

A buddy called me and said suddenly, a gun that he had worked up a load for approx several years ago, has started spitting out bullets that are tumbling or yawing. It started out as usual with a perfect 3 shot, 1/2 inch group at 100yds. His 4th shot hit 2 inches off the side and sideways (what I call yawing) Now the gun is spitting about every 3rd or 4th shot out like that. He's shooting 140 gr Accubonds out of a .280 Ruger LSS, which is about 8 years old. Not sure which powder. He is wondering if his barrel is shot out. Only has about 1000 rounds of out it and he does not overcharge his loads. I didnt know what to tell him since ive never had this problem but suggested starting out with deep cleaning of his barrel. Any one know what causes this and what the cure might be? Thanks for your suggestions.

gcs10

Have him check the crown on the barrel. My guess is he has dinged it somehow (or messed it up with a cleaning rod).

XXCross

Sounds to me like hes shooting bullets intended for a 270 from a 7mm gun. Mike some of the bullets and see if any are undersized.

perry shooter

Velocity may be on the edge the speed needed to stabilize this bullet.

gunho1954

check bedding for shiny marks.check bedding screws first

JustC

Bullets hitting a nice group then all of a sudden a sideways impact???? When was the barrel last cleaned?? is the crown, or more importantly the edges of any rifling lands at the muzzle dinged up? How many firings on the cases?? Have they been annealed??

RCrosby

gunho,
Welcome to the forum.
All due respect, though, I don't think bedding could give you the tumbling bullet problem. I'd put my money on the dinged crown or undersized bullets.

XXCross

A dinged Bbl or a very bad job of crowning will result in some very unimpressive shot groups. I have never know dings or bad crowns to be the source of bullets tumbling. (maybe a REALLY BAD crown?)