point of impact differences

[blackpowderbill]

I hope this is the right board for this question
When I shoot my M1903MkI with M1 ball it is zeroed dead on at 100 yards, when I shoot a cast bullet load through it (any that I have tried so far) it groups 10 to 24 inches high.  I have the same problem with my 2A Ishopore. I can not lower my sights enough to put it on the paper when shooting cast loads. Is this normal when shooting cast bullets ?

[Grumulkin]

I presume you've loaded your cast bullet loads at a lower velocity than the ball cartridges to avoid leading.  The rifle barrel has more time to rise with recoil whilst the bullet is traveling down the barrel; hence the shooting higher.  The solution would be to increase the velocity.

[LaOtto222]

Yep - a lighter cast bullet MIGHT work too.

[blackpowderbill]

Thanks. My 06 load is a 173 gr WW with Gascheck over a charge of Unique with an estimated velocity of 1700 fps.
My .308 load is the same bullet with an estimated velocity of 1600 fps.