It will mostly depend on what length bullet that you want to shoot.

A very successful combo is the Paul Jones, 1.290 long bullet in a 11.5 - 12 twist

1.17 - 1.20 long, 14 twist 

1.11 - 1.17 long, 15 twist

1.1 and less, 16 twist

All the above will shoot well with a good barrel and a good fitting bullet, breach seated. Many other things are required but, that will get you on the path.

The first combo may have a edge.

Frank

I appreciate all the info, gents, but I guess I'm a bit dense, being a newbie at the Schuetzen game.

I'm miissing the point of Ken and Dave's posts and the proposed bet.  I get that bullet length and twist rate have to be balanced for optimal accuracy.  What's a BRC barrel?

Paul

I like the Geoffrey/Kolbe medthod of calulating SG. It also includes the center of gravity It uses the nose length and meplat dia. to do that) in the calulation and also, gives calulations for subsonic proformance:

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This is the results for the Paul Jones, 1.170 Spitzer that I have, it gives a min. of 1.5+ SG @ 1100+ fps for it and I have shot it my 15 twist Douglas, 32/40 with excellent results.

As a side note, Spitzers take less twist to stabilize (not by a large amount) than flat nose bullets.

Frank

Your welcome, Bob.

This is the results from my 1.11 long, Ron Long mold in a 16 twist Douglas barrel.

.862 was the small group of the 5 targets.

Gentleman

I have seen the letters SG stated several times. What does it stands for, and what is involved to arrive to that figure?

ron

Dave,
Both formulas, only predict stability and not accuracy but, the Geoffry/Kolbe prediction also includes CG, where the Miller doesn't. CG is very important in aerodynamic preformance as that is how gravity works against the bullet and the aircraft wing (a bullet is a completely round wing).

The Miller doesn't deal with the transonic stability either. The buffeting that occures in transonic flight needs a faster twist to remain point on.

Until I discovered the Miller program, I used my own formula for minimum stability with accuracy,  by modifing the Greenhill to a constant of 175, that matched my results of the 1.11 long RL bullet with a 16 twist. That worked for me for about 15 years before I discovered the Miller program. 

After finding the Geoffry/Kolbe program, about 5 years ago, I have abandoned the Miller, in favor of it. I think it gives better rel life predictions and deals with the sub and transonic areas.

Frank

The reason that I use these predictors of stabilization, that I've used over the years is, that I like to know what's going on and try to maximize as many things as possible. it's the same reason that I bought the bullet program and QL. They haven't made me a better shooter, I'm still not up to Dave's level but, it does help me build and trouble shoot my equipment. I've never been one to just shoot what everyone else does. That's why I shot the 32/35 back in the 80's and 90's, my 33 ELCO Max and the 30/30 Wesson. I really like trying new things and working the bugs out.

I'm not a over spinner, overspinning works and could even have a edge but, one of my first mentors was Ron Long and he was a proponent of the bullet "sleeping" when it went through the target and I've always followed that concept, too. So, I have to be careful in matching the bullet to barrel twist.

It's not a big deal, anyone should be able to put a competive barrel and bullet together by watching what the successful shooters use but, I like to try things I think are interesting and work with them.

Frank