Improved Stability Formula for Plastic Tipped Bullets

[Michael Courtney]

Should the second quote read "The effect of a plastic tip or an empty space in the tip of a bullet is to increase stability relative to a constant density bullet of the same dimensions."?

Right. Good catch. I've edited the original to correct the mistake. Thanks.

 

[DocB]

Late... but tagging in. This is some really good stuff!

DocB

 

[cowboy]

Late... but tagging in. This is some really good stuff!

DocB

E
I'm right with you Doc. Never have shot plastic tip bullets before but I can see that is about to change.

Been hesitant to try the new ELD-X bullets just because the info coming out says I need a 1-9" twist barrel for their lighter .284 pill but this shows they should stabilize with my 1-10" twist.

I wonder if Hornady is just being a little extra conservative with their twist recommendations.

Carry on - I'm late but paying attention and appreciate this older thread being brought back up.

 

[KYpatriot]

Missed this before, enjoy ths kind if stuff. Thanks for reposting it, and investigating the tip effect on stability.

Good times to be a long range shooter!

 

[Pdvdh]

Bryan Litz once posted on this Forum that he wasn't confident in the science behind the stability formulas that account for bullets tipped with less dense materials. His post was in response to my post referencing a stability formula provided in Patagonia Ballistic's ColdBore 1.0 ballistic software that accounted for plastic tipped bullets. But I got the sense he didn't feel comfortable with the science supporting the formula in a broader sense. For what it's worth. . . .

I do believe that less weight in the tip of bullets does reduce the barrel twist rate required for bullet stability, compared to bullets with lead all the way out to the bullet tip. Bryan may also. Bryan didn't go into a detailed explanation on his concerns, and I didn't pursue it. Mostly because I got the sense he wasn't interested in diving into a detailed post.

 

[KYpatriot]

Phorwath one takeaway that I think most current shooters, and scientific study, would agree with is that our tradition sense of what "normal" twist should be ought to be tweaked a kittle in favor of tighter twist. Now that all the major bullet manufacturers are producing bullets with incredible BC, factory twists probably should adjust down, and it seems there is little downside to having a little tighter twist when ordering custom barrels unless you have velocities in excess of 3400 or so, after all we arent talking 100 yard benchrest.

 

[elkaholic]

Phorwath one takeaway that I think most current shooters, and scientific study, would agree with is that our tradition sense of what "normal" twist should be ought to be tweaked a kittle in favor of tighter twist. Now that all the major bullet manufacturers are producing bullets with incredible BC, factory twists probably should adjust down, and it seems there is little downside to having a little tighter twist when ordering custom barrels unless you have velocities in excess of 3400 or so, after all we arent talking 100 yard benchrest.

I go back to my original comment earlier in the thread. While I do not understand everything that causes all the various changes, I do understand that when you add a heavier tip of identical shape in an otherwise identical bullet, accuracy goes south in every instance that I have done it. I am not sure if more twist would correct this or not, but it seems to upset the balance in one way or another. This may or may not be true with all shapes and sizes of bullets, but it held true in the 190-240 grain bullets that I shot in my 30 cal. with 10 twist........Rich

 

[cowboy]

Phorwath one takeaway that I think most current shooters, and scientific study, would agree with is that our tradition sense of what "normal" twist should be ought to be tweaked a kittle in favor of tighter twist. Now that all the major bullet manufacturers are producing bullets with incredible BC, factory twists probably should adjust down, and it seems there is little downside to having a little tighter twist when ordering custom barrels unless you have velocities in excess of 3400 or so, after all we arent talking 100 yard benchrest.

KYpatriot: This is exactly what my thoughts have been for quite a while, I think you are dead nutz on and I would hope that the rifle manufacturers would finally acknowlege where the industry needs to gravitate to.

 

[elkaholic]

I go back to my original comment earlier in the thread. While I do not understand everything that causes all the various changes, I do understand that when you add a heavier tip of identical shape in an otherwise identical bullet, accuracy goes south in every instance that I have done it. I am not sure if more twist would correct this or not, but it seems to upset the balance in one way or another. This may or may not be true with all shapes and sizes of bullets, but it held true in the 190-240 grain bullets that I shot in my 30 cal. with 10 twist........Rich

This was meant to be a reply and not a quote of Patriots comment. Having said that, I agree with what he said......Rich