What do we really know about the transonic zone?

[Distant Thunder]

I like to patch .001 to ,002" over my finished base diameter and then size the patched bullet to the finished base diameter. With my .40-65 the chamber was cut specifically for R-P brass and it has a loooong freebore. The mold was cut to patch to .411 and is then sized after patching to .409 which is a slip fit in the brass and the freebore. The result is a rifle that can shoot under 1 moa at 220 yards and very well out to 600 yards. And that's with me on the trigger!

Patching to less that case or groove diameter also works, but the bullet has to bump up to the case ID and or freebore diameter before it moves forward. I just like to skip that bump up. Either way works well if everything else is in line. Heck I'm amazed how well straight bore diameter bullets shoot and they bump up even more!

[Don McDowell]

Lots of ways to skin a cat, for sure.

[Distant Thunder]

These drawings are two of the bullets we've been talking about and it is interesting comparing them dimensionally.

It's interesting that the Postell is 1.437" long. That happens to be a length I have found works very well in an 18-twist barrel. The undersize nose I mentioned is in part the result of the taper but it starts at .443". That's .007" under the bore size of todays .45 caliber barrels and then tapers to .010" undersize. I'm guessing this would want to bump up to bore size when fired. That is an invite to nose slumping. Not exactly a bore riding design!

The original Sharp LR paper patch drawing is from Brent Danielson's website. I believe Brent had this drawing made from an original bullet. The 1.500" length would be too long for an 18-twist. A 16-twist would be better. This design like the Metford actually had a short nose length, around 38%. The patch would go up over the slight taper just before the ogive starts. I'm guessing the taper allowed for a fairly tight fit to the bore without having the leading edge of the patch catching and folding back. The Metford had a similar tapered section. the paper would have had to be fairly thin, thinner than our 9# today, in order to fit a .450" bore.

This design at about 1.440" long would be excellent in an 18-twist. I hope to eventually tests this design in my .44-77.