Killing power of smaller meplat LFN

[paulschweik]

Hi Veral,

First, I'd like to say thanks for your book that shares so much knowledge.  And for your great molds.  I've got 2, and they're the best molds I've used in 40 years of casting.

I'm building a new rifle to shoot cast.  It's based on a Ruger #3 action.  I plan to use a LFN and want to use the bullets hardened (water dropped wheel weights) as I am sold on the performance of these hard, non-expanding flat nose bullets.

I'd like as much velocity as is practical, to flatten trajectory, but I understand that for a given meplat diameter there is a DV limit to the velocity I should drive them.  I know that the large caliber LFNs are very effective.  I am wondering how much I can increase velocity by decreasing the caliber and meplat diameter, and still have a good effective bullet on game?  Here's a table on caliber/meplat dia for LFN/velocity for a DV of 125:

CALIBER   LFN MEPLAT DIA   FPS FOR A DV OF 125
458         .328                    1524
416         .286                    1748
375         .245                    2041
357         .227                    2203

Can I get as good an effect on game with a heavy 35 cal LFN at 2200 FPS as I would with a 45 cal LFN at 1500-1600?  Or is there a size at which the hard flat point bullet effectiveness drops off?  What would you suggest as the smallest caliber for hardened LFNs that will still be very effective on deer, boar and elk?

Thanks,

Paul
 

[Veral]

  If DV is the same, caliber isn't important.  In other words, for the flattest trajectory choose the fastest in your list.  To keep the DV high at longer ranges, choose a cartridge that will move a fairly heavy bullet at the needed velocity.

  For hand gun use, which I consider 100 yards for good shooters, and out to 200 for very experianced, don't worry about velocity loss at longer ranges.  The bullet will kill clean.

  For rifle use, where ranges may be out to 400 yards and more, heavy bullets are important.  Be informed that 2200 fis about the max impact velocity for water dropped wheel weight bullets.  Any faster and large bones will break them up some.  Of coarse, a muzzle velocity of 2200 will be down considerable at 50 yards and more, so you can wind them up so that optimum 2200 fps with the 35 cal is being obtained at whatever range you expect will be "normal close range".  I bracketed that because there is no such thing except in our imagination.  Plan on it being 50 yards and an animal will step from behind a tree at 10 yards!  If so.  Pop him, the bullet won't fail, it will just make a bit more messy wound than at longer ranges.

  I told you caliber isn't the factor.  Well.  It is to some degree but you don't have to think about it for most uses, except for extremes.  Example.  Suppose one were using a 50 caliber full wadcutter and tissure spray( DV) was capable of cutting a 3/4 inch wound.  In other words, very low impact velocity and a DV of perhaps as low as 30, because the wounding only has to go 1/4 inch larger than the huge meplat.  DV is actually a rough measure of wounding in excess of meplat diameter.  So, to match that wound with a 35 caliber LFN DV would have to be perhaps 80.  Read that till you understand it, then forget it when you do your figguring.  It is fact that few will incounter.   

  The DV formula given in my book is a bit long.  A short one that gives the same answer is Meplat diameter in thousandths times velocity divided by 4.  If you want to play with velocitiies for a specific bullet, punch meplat devided by 4 into your calculater and store the result in memory.  Then try the number with several velocities.  You'll get your numbers fast this way..