New bullet

[Distant Thunder]

I think if you keep the nose on the short side of things that you can stretch the OAL a bit and still be pretty well stabilized in the 19-twist and especially if you don't shoot it too far from the 19. It would be very well stabilized in the 17-twist and would shoot as far as you would want. Exactly what length you could get away with I'm not sure but I think that it could be estimated fairly easily.

If the nose length was adjusted to be say 40% of the OAL and still maintain that original looking profile the length might be stretched to 1.350" or maybe even 1.400" and have good stability out to 600 yards in a 19-twist. The problem is that molds are not cheap and trial and error can get expensive very quickly.

When I developed my 18-twist 2-D .40 caliber PP bullet I kept the nose a bit on the short side and a bit on the fat side and that worked out very well. I had an old nose pour adjustable mold that was originally made with a longish tapered nose that I used as a Guinea pig. It never really shot well as made so I machined it to have a shorter nose without the taper and also converted it to 2-D. Once I had a good idea of what length I could stabilize in my 18-twist and what length of base diameter worked best for the long freebore in that rifle I went ahead and cut a new mold at a fixed length and used my developed dimensions, diameters and lengths, from the adjustable mold.

Unfortunately I no longer have the access to the machines that I did back then. I still think I could come up with the design and length that would work in my 17 twist using molds I have with a minimum of machining and testing to get good results.

That same process could be used to develop a bullet that would work in both a 19 and 17-twist.

You give up some BC in designing a bullet this way, but an accurate bullet with a lower BC is not the worst thing in the world. You just have to turn the knobs a little more and shoot enough to know how much to turn them.

It would be an interesting experiment to see how well my little .40 caliber ppb shoots in a 16-twist rifle. I may have to talk to Arnie and see if he would be able to run some of those through his 16-twist rifle and see how they do. I'm guessing they would shoot very well and even might surprise us with how far they would shoot well.