Maven
07-01-2013, 09:30 AM
If you read these pages, you know several of us, e.g., Ben, HarryMPope (sic), et al., have been experimenting with plain base CB's or those [cast from molds] which have been converted to plain base. Needless to say, to avoid bore leading while maintaining accuracy, the powder charge is light, and the recoil practically nonexistent. The other day I retested the Saeco #315 CB (truncated cone nose wi. meplat, tapered Loverin style body, gas check) that's a tack driver in my .30-06 with GC's, but reformed into a plain based CB via a Hanned bump die*, which essentially removes the GC shank and leaves a perfectly flat base. It will also "salvage" CB's with minor imperfections, i.e., those you don't want to waste a GC on. Once reformed, I ran them through a .312" sizing die and lubed them in a normal fashion. The results are attached in a PDF file below. (My camera is being a bit balky this AM.) If the PDF opens for you, you will notice a 10-shot group, with the last shot a flyer (my fault) and #7 a bit out of group (my fault as well as I was fending off mosquitos)**. Those results are typical of the bumped/reconfigured #315 and are repeatable.
The particulars: The rifle is a Win. Westerner glass bedded and wearing a Tasco Mag. IV 4 x 16 scope. Rem. 30-06 brass fired 6x, but FL resized and flared via a Lyman M-die. The powder was 8.7-8.8grs. of Unique thrown from a Lyman Accumeasure (rotor #10s), while the primers were CCI #334's (ca. 1997). Btw, what leading there was was minor, easily wiping out with 2 Hoppes #9 soaked patches. The accuracy of the now plain based #315 is more than worth the extra effort to reform it.
*When I first started casting for the '06, I purchased 2 molds, a Lee C309-180R & a Lyman #311291, bore riders, which didn't ride the bore. I later read about Ed Wosika's bumping/reforming die (in "The Fouling Shot"?) and after much CB fitting as per Ed's detailed instructions, ordered one. Prior to using the Hanned die, the best I could do with either gas checked CB was ~2moa. After using the die, which bumps the nose to .302" and the body to .3105", accuracy improved greatly: 1 moa if I paid attention. Btw, the die flattens the GC and has a nose/ejector punch that allows you to form a small meplat on the CB. So flattened, the noses cut a nice, clean hole in the target. Lastly, the die gives remarkably uniform results when you use it consistently.
**The target is 3" x 3"
The particulars: The rifle is a Win. Westerner glass bedded and wearing a Tasco Mag. IV 4 x 16 scope. Rem. 30-06 brass fired 6x, but FL resized and flared via a Lyman M-die. The powder was 8.7-8.8grs. of Unique thrown from a Lyman Accumeasure (rotor #10s), while the primers were CCI #334's (ca. 1997). Btw, what leading there was was minor, easily wiping out with 2 Hoppes #9 soaked patches. The accuracy of the now plain based #315 is more than worth the extra effort to reform it.
*When I first started casting for the '06, I purchased 2 molds, a Lee C309-180R & a Lyman #311291, bore riders, which didn't ride the bore. I later read about Ed Wosika's bumping/reforming die (in "The Fouling Shot"?) and after much CB fitting as per Ed's detailed instructions, ordered one. Prior to using the Hanned die, the best I could do with either gas checked CB was ~2moa. After using the die, which bumps the nose to .302" and the body to .3105", accuracy improved greatly: 1 moa if I paid attention. Btw, the die flattens the GC and has a nose/ejector punch that allows you to form a small meplat on the CB. So flattened, the noses cut a nice, clean hole in the target. Lastly, the die gives remarkably uniform results when you use it consistently.
**The target is 3" x 3"