Rolling block out at the range under 1"!!!!

[flintyboom]

Sometimes it just works out. Last week I was so damn frustrated with this rifle. It's an original Norwegian/Swedish roller in 12.7x44R. It was keyholing most of the bullets, and shooting about 6" at 100 yds. I was shooting 60 grains fg with a .06 poly wad with the 450 grain Lee bullet. My thought was to up the powder charge and put less wad under the bullet to obturate it more. I used a .03 poly wad over 70, 67.5, 65, and 62.5 gr of Swiss 1.5 fg. It needed quite a bit of compression for the heavier charges, but it seems like 65 grains is gonna be the magic load. At 100 yds I put 4 out of 5 shots in .86" with one that I pulled opening the group to 3 1/4"

I need to try it at 200 and 300 yds, but this is looking very promising.

 

[dan belisle]

Nice. I have one of those in 50-70, fun to shoot. - dan

 

[Valiant]

Maybe if your bullet is undersized. This would cause key holes. Cast softer bullets. More lead . Maybe with softer bullets the Black powder will bump up the softer bullets more to catch rifling better.
If your flyer opens your group then that is the size of your group

 

[jamesharrison]

Are you using a powder compression die, compressing the charge with your bullets in the seating die, or using a long drop tube?

By using a long drop tube, you won't be crushing the powder kernels.

 

[flintyboom]

I was casting with 20-1 lead/tin alloy. I could try 30-1 or maybe pure lead, but I was worried about leading the bore. I'm using a drop tube and compression die for the powder.

 

[Valiant]

I was casting with 20-1 lead/tin alloy. I could try 30-1 or maybe pure lead, but I was worried about leading the bore. I'm using a drop tube and compression die for the powder.

With wheelweights and undersized bullets you can get more leading than with softer bullets and black powder. I don't know why except maybe the softer bullets bump up and fit the barrel better?
I'm not familiar with your cartridge that you are shooting but my guess is undersize bullets would cause the key hole.
I'm shooting basically straight lead in alot of calipers just because I'm to cheap to by tin. With spg lube and black powder velocities I don't have leading problems.
I don't bother with drop tubes anymore.
I'm not sure if a card wad would effect bullet bump or not?