Stuid question...But..

[wyomingblizzard]

I got to ask it any way. I am just starting load work up with berger 250 grn otm in a 340 wetherby. I dont have load data for berger, so I started at the low end for 250 barnes. The rifle is zeroed at 100 yards with 210barnes ttsx. The first group with the bergers was almost 12" high. WHY? I would have expected a heavier, slower bullet to shot slightly lowwer not 12" higher. What am I missing here?gun) Thanks

 

[Bullet bumper]

Not sure what is happening but maybe you are not controlling the extra recoil and it's lifting the rig up. At only 100 yards traveled it can't be caused by better drag coefficient . Are you sure the bullet is going slower than the 210 Barnes ?
Maybe the 210 Barnes is underloaded .

 

[wyomingblizzard]

No noticable diff in recoil no extra muzzle jump. Only had time to try the lowest 2 test groups, both in the 2700 fps range. The 210s are 3200 by my cheep chrony. By the way both groups were very bad, 4".

 

[barnesuser28]

Did your gun fall or did the scope get bumbed hard since you sighted it in with the Barnes?

 

[wyomingblizzard]

No gun or scope failure, I shot a group with the 210s to verify the zero was still the same. The berger test load were pretty light. To get the barnes to shoot good I have to push them hard.

 

[Bullet bumper]

Maybe the different bullet is exiting the muzzle at a different point in the barrel vibration cycle . 4" groups does not sound good .

 

[Gunpoor]

As was stated by Bullet thumper, it is mostly barrel harmonics. Sometimes different brand, style or weight bullets shoot to near same POI and sometimes they aren't even close. What matters is group size and velocity. I shoot only one load in a rifle until I want to try something different, and then start from scratch and find a decent load and shoot that one exclusively.

 

[Goofycat]

Any differences in bullet-seating depths? Ogive differences? Coeffient differences? Start with one variable, then check. If that doesn't work, add in another variable. Don't try to adjust all the variables at one time because you will never be able to tell which variable was the culprit. It none of your changes work, have a knowledgeable friend do some reloads for the rifle. Maybe it's something simple that you merely overlooked.

 

[Goofycat]

I just ran across this article that gets into meplat and in ballistic coefficient differences that might explain why the Bergers shot lower than the Barnes'. Also, have you checked the bullet diameters? I never have, but I have not had the problem you described. I don't know if bullet diameters vary to any great degree between manufacturers, but if so, it is just another variable that needs to be checked out.

http://www.6mmbr.com/bulletpointer.html

 

[Daveinjax]

Apple and orange bullets. Completely different harmonics , bc , cross section density.