Dalyoke
01-17-2012, 08:39 PM
Hello!
Looking for a sanity check and/or useful suggestions re breech seating nitro powder loads.
I have a situation where cast bullets that will definitely seal bore result in loaded cartridges that cannot be seated in chamber because of resulting case neck being larger than chamber neck. However these same bullets will fit nicely in the neck and up against ramped start of rifling. This seems like a situation where breech seating, with mouth of case snugly up against base of bullet, would give good results. Case mouth would logically be sealed with fiber wad, flush with end of case and base of bullet.
This is a rifle that I use nitro powder and cast bullet loads with, getting decent but perhaps not smallest groups this rifle is capable of. Cases would have been previously fireformed in this rifle but not resized, and, if needed, case mouths chamfered and/or shorted to give snug fit of case and bullet in chamber. In effect, this geometry would be same as seating cast bullet out so that it was engraved slightly by bullet.
Reaming chamber neck slightly is not an option because I want to keep bore with original dimensions.
Loads would be used in metallic silhouette matches, where shooter has 2,5 minutes to fire 5 shoots offhand.
Selection of powders could include 2400, IMR4350, Reloader 7, IMR 4198, IMR 4895. The cast CG bullets weigh slightly over 200 grains, sized 0,329 and are soft. They may have been lubed with liquid Alox. Case is 8X58Rimmed Danish and rifle is Swedish roller converted in 1892 and in excellent, new, condition. Bore is 0,325 groove-to-groove on both ends. Velocities sought are 1300 fps minimum and 1700 fps max for silhouettes.
Thanks,
Dalyoke
Looking for a sanity check and/or useful suggestions re breech seating nitro powder loads.
I have a situation where cast bullets that will definitely seal bore result in loaded cartridges that cannot be seated in chamber because of resulting case neck being larger than chamber neck. However these same bullets will fit nicely in the neck and up against ramped start of rifling. This seems like a situation where breech seating, with mouth of case snugly up against base of bullet, would give good results. Case mouth would logically be sealed with fiber wad, flush with end of case and base of bullet.
This is a rifle that I use nitro powder and cast bullet loads with, getting decent but perhaps not smallest groups this rifle is capable of. Cases would have been previously fireformed in this rifle but not resized, and, if needed, case mouths chamfered and/or shorted to give snug fit of case and bullet in chamber. In effect, this geometry would be same as seating cast bullet out so that it was engraved slightly by bullet.
Reaming chamber neck slightly is not an option because I want to keep bore with original dimensions.
Loads would be used in metallic silhouette matches, where shooter has 2,5 minutes to fire 5 shoots offhand.
Selection of powders could include 2400, IMR4350, Reloader 7, IMR 4198, IMR 4895. The cast CG bullets weigh slightly over 200 grains, sized 0,329 and are soft. They may have been lubed with liquid Alox. Case is 8X58Rimmed Danish and rifle is Swedish roller converted in 1892 and in excellent, new, condition. Bore is 0,325 groove-to-groove on both ends. Velocities sought are 1300 fps minimum and 1700 fps max for silhouettes.
Thanks,
Dalyoke