So in a 1-28 barrel using both .429 and .452 bullets, what length bullet should group the best???

nchawkeye

Since you are looking for length using a 1:28 twist...

L= 150*D2/TR

L= 150*(.429*.429)/28
L= 150*1840/28
L= 27.606/28
L=.985

So the estimated Length of bullet should be very near 1" long

L=150*D2/TR
L=150*(.452*.452)/28
L=150*.0192/28
L=28.815/28
L=1.029

So with the 452 bullet you are one again looking for a bullet close to 1" long

Do that help you any??? But again remember these are estimations...

Need to make a point here. The formula gives maximum length for stabilization you can stretch it some by increasing the velocity. For instance 400 feet over the 1800 will stabilize a bullet that is a .1 of an inch over length.
But in the other direction there is a lot more give it takes quit a bit more to over stabilize. for instance a 230gr 45 caliber bullet is going to be considerably over stabilized in a 1-28 twist but about right in a 1-38 twist but it can be made to shoot well by reducing the load. with all that understood I will give you the max lengths for some calibers for 1-28 and 1-48.
For 1-28 twist
caliber length in inches[max for 1800 FPS]
.400 .85
.429 .97
.450 1.00
.500 1.3
For 1-48
.45 .63
.500 .78
Was this what you were looking for nchawkeye?

Yep, that's what I was wanting, thanks guys!!!

My Knight Disc groups the Barnes MZ 300gr and the 250 SST very well...Both are longer bullets...

It doesn't like the .452 XTP 250gr or 300gr...Both are shorter than an inch, probably aren't 3/4 inch...

That's why I'm thinking the .429 300gr XTP will do well...It's not an inch long but it's close...