I've been trying to find a way to seat bullets closer to the rifling in my .308 Remington 700 5R, since the poly tipped hunting bullets I've tried do not shoot as well as the match bullets and the biggest difference I can find in the bullets is that the hunting bullets have longer noses due to the poly tip, and secant ogives, resulting in a longer "jump" to the rifling when seated to mag length.
 
The bullet I *want* to use is the 180gr Nosler Accubond. But the jump to the rifling when loaded to max OAL that will fit in the magazine is about .170" That's a lot.
 
The length of the poly tip is, ironically, .170". So you can guess what I was thinking.
 
I grabbed the tip with pliers and tried to pull it off/out. No go. It just smashes. Then I decided to try to cut it off with a box cutter. THAT WORKED! And was easy to make "even" on the tip. Some rubbing on a piece of sand paper laying flat on the table made it nice and even with the jacket.
 
A meplat trimmer from Sinclair *might* be in my future, depending on how this works out.
 
Now I can load right up to the rifling if I want.
 
My only question is what will the effect be on BC by increasing the surface area of the tip from .045" to a meplat of .145"? My SWAG is that it will reduce BC by about .050 from looking at similar bullet designs. So BC will likely drop from "about .500" to "about .450"
 
I strongly suspect the on-game performance will be the same, or more likely better.

This is going to be an interesting question, I also have no idea what the answer is going to be.

I've got a BC estimator (whoodathunkit?). If you give me good measures for meplat diameter, bullet length, and boat-tail length, the calculaor should give you a ballpark figure for the THEORETICAL decrease in BC. Personally, I suspect that short of 500 yds, it will be indistiguishable from other sources of "error" in PoI.
 
Paul

Meplat - .145"
OAL - 1.210"
Boat tail length - .10"
Base diameter - .265"
 
Unmodified would be the same except that:
 
Meplat - .045" (rounded tip)
OAL - 1.380"
 
Nosler says .507 BC in unmodified form.

OK, I'm home now, so here is what this calculator says the difference would be.
 
Note the yellow-highlighted cells.
 
There's about a 40% (.5 down to .3) loss. I'm not sure this is real, but this calculator has been fairly accurate in the past. One problem with it, is that it has no way to account for the "longness" of a plastic-tipped bullet. Therefore, it applies the specific gravity figure to the whole calculated volume as if the bullet were of uniform construction. HOWEVER, don't discount its figures because of that. Note that it predicts VERY close numbers for the unmodified bullet.
 
Paul

In the grand scheme of things.......insignificant. Regards, Rick.

Thank you Paul!

I would suspect your calculations aren't far from the truth.