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View Full Version : 12.7X44R problem solved



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.

MtGun44
12-15-2008, 11:51 PM
Great results, sounds like that RB really wants to do good
if it gets fed the correct recipe. Not many would have figured
out how to make this work.

What is a refrigerator anti-mold mat? How thick?

Thanks.
Bill

Buckshot
12-16-2008, 03:30 AM
.................I was thinking about getting one of those punkin' slingers as something to fool with. However I woke up and realized I'd have to live to 200 to get a handle on the projects and stuff I already have, that needs to be fooled with! I'm just scared spitless I'll crawl out of bed one morning and realize I dont' have anything to do :-)

...............Buckshot

guninhand
12-16-2008, 11:40 AM
MtGun44,

I got the anti-mold mat in a dollar store, about 24X8 inches area and 0.29 inch thick.
http://i238.photobucket.com/albums/ff170/guninhand_2007/rb3.jpg
Here are the .50 cal wads front and side on alongside a .22 bullit
http://i238.photobucket.com/albums/ff170/guninhand_2007/rb4.jpg

A wad weighs 0.3 grains. By cutting them out with a punch you get a consistant product. I put the powder in a glass vial and the wad on top..... and some of the ball powder, when shaken, got into the air spaces of the wad. I think this is a good thing as according to Charles Dell, ringing of the chamber occurs when the powder is flat-faced to the boolit with an air space inbetween. This way the powder isn't "flat-faced".

Buckshot, I too have a zillion projects, it took me 2 years to solve this problem, the main reason I posted about it is because it's possible the double sizing technique, i.e. manufacturing a heeled boolit from pure lead, might be applicable to a number of the older guns that originally shot heeled boolits. I might try this mext on a Model 71 Mauser sizing .452 then .446.

Regards

Boz330
12-16-2008, 11:44 AM
.................I was thinking about getting one of those punkin' slingers as something to fool with. However I woke up and realized I'd have to live to 200 to get a handle on the projects and stuff I already have, that needs to be fooled with! I'm just scared spitless I'll crawl out of bed one morning and realize I dont' have anything to do :-)

...............Buckshot

Now that would be a problem, unfortunately not one I have at the moment. Like you I have lusted after one of these, but they have gotten hard to find. I got one of the sporterized 8MMs that might get converted to a 40-65 huntin rifle though.
Rick, what I do is ruthlessly cull my safe every couple years and get rid of stuff I haven't shot for a long time and use that $ to get stuff I'm interested in NOW. Besides my safe won't hold everything now anyway. Built my gun & reloading room way too small to get a bigger safe in. Seemed huge when I built it, now I can't turn around in it without jumping straight up in the air.
Right now the economy has put a hurtin on my business, but I'm getting all sorts of gun projects done, finally. Took the poceeds of the last culling and stocked up on primers and powder. Even if some of Obama's wishes don't come true the stuff ain't going to get any cheaper, and I'm only a couple years from fixed income.

Bob