Duane Mellenbruch
posted this
31 January 2013
onondaga wrote: I disagree with the theory of knurling bullets and believe the knurling makes a pathway for gas jetting. To believe that lube in knurling will stop gas jetting seems folly to me.
I think this is an interesting approach and worth trying. I realize that the method does leave a likelihood that gas cutting could occur, but that could be eliminated by either the PVC wads or the CFventure soft gas checks. This might work better than expected if a soft alloy is used because the Knurling will center the bullet in the bore, and hot gas pressure might be sufficient, with the wad, to form a better seal than knurling alone.
There may be an optimal size that minimizes gas jetting and some may get them to perform well, but I think you would be better off to start with a chamber casting and get your bullets sized to slide fit into your chamber throat with as large diameter bullet that will load. A simple tumble lube with 45:45:10 would be excellent and well proven with the 45-70 and bullets that fit.
This is more of an enthusiastic approach of shooting what ya got, rather than not shooting at all. Heck, I have even gone so far as to paper patch a few pistol bullets just to see what kind of difference it would make on the diameter. But, not having a 45-70 to try it with, I tossed those attempts back into the casting pot.
250 gr is very much underweight for the 45-70 to shoot well also. Lee 405 gr .457 plain base or hollow base .459 un-sized and tumble lubed would be a much better selection; either one of them generally drop .460-.461” in #2 alloy.
If you want a heavy weight, huge ballistic co-efficient (.443) plain base for the 45-70 the Lee 459-500-3R spire is difficult to beat at all for paper punching and $20.00 for the mold. Lee also has a FNGC 500 grainer too,same price. The one hollow base mold is a little more.
Pea weight 250 grain bullets from a 45-70 rarely get even 2-3 MOA accuracy. The cartridge and rifles for it is designed for ~ 400+ gr bullets."Under weight” bullets serve just fine in other calibers. Especially for plinking and fun shooting. Remember, the CBA nature and purpose: “stimulating and encouraging experiments in casting and handloading cast bullets that will improve the design, accuracy and effectiveness of the ammunition and increase the satisfaction and enjoyment of shooters.
I say go for it and let us all know if it works and how much fun you have finding out if it works or not. Duane
