guninhand
12-14-2008, 04:21 PM
So I got this swede rolling block in 12.7X44R, all original and in pretty good shape, manufactured in 1873. Based on web research I got the RCBS 50-450-FN for a boolit and a .510 sizer die. Using modified 348Win brass I was dismayed to find rounds wouldn't chamber. Slugged the throat and found it measured .508 where it was supposed to be .510.
So I went through the rigmarole of trying to set up as a breech seater. After pounding the sized and lubed bullet into the bore found there was a lot of lube being squeezed out and messing up the chamber.
So next I decided to try a hollow base, the Lee .50 cal minie. It proved hopelessly inaccurate with BP and very poor with 777ffg. In the meantime I had bought a .50 sizer to use with the Lee boolit.
So I got the inspiration to use both sizers on the RCBS boolit, lubing and sizing the whole boolit in the .510 first then from base to the crimp groove with the .50.
Results, it worked:-D. Now there is a lot of lube still squeezed out in the second sizing operation, and I make up for this by using a beeswax wad or a CF ventures wad, otherwise there is minor leading in the last 4 or 5 inches of barrel.
Here are results at 100 yards with the open sights, no wind, loading and shooting as fast as I could, 1st boolit at the top and tracking down to last boolit in the white. There was a lot of room taken up in the case so I switched to smokeless. the load is a 480 gr pure lead, soft smokeless lube, CF Ventures wax wad, .060 LDPE wad, 2 pieces of refrigerator anti-mold mat (cut to .50 inch, to keep the powder back towards the primer), and 19.4 grains IMR4227. There was unburnt powder in the barrel. Results are reproducible:drinks:
http://i238.photobucket.com/albums/ff170/guninhand_2007/rb.jpg
Because I'm effectively using a heeled boolit, I've found I can crimp it up by removing the decapping stem from a 50/70 sizing die and sizing the assembled round (assembled first without resizing the brass). Chrono'd at a very pleasant 1020fps.
So I went through the rigmarole of trying to set up as a breech seater. After pounding the sized and lubed bullet into the bore found there was a lot of lube being squeezed out and messing up the chamber.
So next I decided to try a hollow base, the Lee .50 cal minie. It proved hopelessly inaccurate with BP and very poor with 777ffg. In the meantime I had bought a .50 sizer to use with the Lee boolit.
So I got the inspiration to use both sizers on the RCBS boolit, lubing and sizing the whole boolit in the .510 first then from base to the crimp groove with the .50.
Results, it worked:-D. Now there is a lot of lube still squeezed out in the second sizing operation, and I make up for this by using a beeswax wad or a CF ventures wad, otherwise there is minor leading in the last 4 or 5 inches of barrel.
Here are results at 100 yards with the open sights, no wind, loading and shooting as fast as I could, 1st boolit at the top and tracking down to last boolit in the white. There was a lot of room taken up in the case so I switched to smokeless. the load is a 480 gr pure lead, soft smokeless lube, CF Ventures wax wad, .060 LDPE wad, 2 pieces of refrigerator anti-mold mat (cut to .50 inch, to keep the powder back towards the primer), and 19.4 grains IMR4227. There was unburnt powder in the barrel. Results are reproducible:drinks:
http://i238.photobucket.com/albums/ff170/guninhand_2007/rb.jpg
Because I'm effectively using a heeled boolit, I've found I can crimp it up by removing the decapping stem from a 50/70 sizing die and sizing the assembled round (assembled first without resizing the brass). Chrono'd at a very pleasant 1020fps.