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Originally posted by RIP:
Oops! I reset the poll while adding the bullet weight and velocities to the question ...

Try to vote again, .366torque, please.

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Originally posted by Gerard:
, in short, here is my thinking. The twist should be 1:12". .... Doing a 1:10" twist will do little to enhance the HV and FN and seriously hamper the design of a usable SP, given the case capacity.

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Originally posted by Gerard:
Ron,
I will send e-mail over the weekend with more detail but, in short, here is my thinking. The twist should be 1:12". This will make possible an HV in the 330/340gr weight range that will deliver good terminal ballistics from muzzle to 500yds (SF 1.5). It will also result in an FN in the same weight class with a SF of more than 2.5 for similar or better linearity as the 380gr 416 Rigby and 270gr .375 H&H. Here is the cherry on top: An SP of 340gr or so with a BC of 0.700 plus will deliver supersonic flight to silly distances. Doing a 1:10" twist will do little to enhance the HV and FN and seriously hamper the design of a usable SP, given the case capacity. Could be a real do all rifle and load development would be a snap.

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I do tend to wish they would all turn out to the same weight in HV, FN, and SP,

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Originally posted by Gerard:
Bullet weight is unimportant. Given the application, bullet length is important. All three styles should be the same weight so loads will be pretty similar but point of impact, no chance. The first 100 yds will be close but after that there is no way that three bullets going at similar speeds but with BCs spanning 0.200 to 0.700 will follow the same path.

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Originally posted by Gerard:
Ok, basic work up is done for 1:12" twist. Bullets are .395"/.387" and all three, HV, FN and SP weigh 340gr. Subject to confirmation by field testing, the HV will start expanding from an impact speed of 1200fps and will be completely expanded by an impact speed of 1500 to 1600fps. Weight retention up to 2500fps or so should be pretty close to 100%. Over that it will start losing petals depending on the medium encountered and petal loss should be complete at around 2700fps. The remaining cylinder front with boat tail rear end will be almost indestructible and will be better than 80% retention. BC is a calculated 0.610 and should be good for spitting distance to 400/500m depending on MV. The bullet will be snoring loudly (sound asleep) from the muzzle.

The FN is good for major calamities up to 120/130m. Any action that feeds one caliber RN bullets will feed the FN as well. It has a stability factor well above 2.5 and even severely angled shots (high angle of incidence) will result in good transition and linear penetration. It will be interesting to see if a Cape Buff can be perforated lengthwise.

The SP is 1.89" in length with an ogive length a hair over 1". Calculated BC is over 0.700. It will not be stable through the transonic range so you must hit before it drops below 1200fps.

Drawings will be done in the coming week and prototypes will be run 27/28/29 December.