PDA

View Full Version : CB Design for Rifles



insanelupus
02-12-2008, 11:22 AM
I'm fixing to get into the reloading buisness after about 15 years of reloading jacketed bullets. I'm starting to see some of the advantages (and disadvantages) of both cast and jacketed bullets and have a wonderful mentor in an older Uncle who has considerable experience and knowledge in such things.

One thing he and I discussed and I'd like to get the board members opinion on, is bullet designs for rifles. From what I've seen of various wound channels from revolver bullets, the wide flat meplat seems to cause the most damage (limiting the requirement for expansion in big bores where the bullet hardness can help determine penetration). Additionally, I understand that the longer noses on bullets (with slightly smaller meplats) are much more efficient at long distance shooting.

With rifle bullets I have to wonder at the designs which basically seem to be a flat nose, round nose, and spire point type design with the ogive farther forward (Loverrin? designs SP?). It seems to me that while the round noses and spire designs would make for perhaps a more accurate bullet, that they would lack some of the "shocking power" that I've seen referred to in magazines and books of yore, compared to the flat nose design. I also see where there is an advantage to the round nose and spire points in the difference between the ogive and the end of the bullet as far as seating depths and how much "jump" there would be into the lands of the barrel. I would think a flat nose design has the possibility to make the entry into the lands slightly askew, compared to the round nose and spire points, due to the fact they are already in the barrel and can help guide the bullet in.

I am primarily getting into casting bullets for hunting uses. I see where I can have much more control over the design of the bullet, the hardness of the bullet, etc. I also plan to use gas checks on most all of my rifle rounds and the first calibers I plan to cast up are for .32 Winchester Special, .45-70 Gov't., and later on my 35's (.35 Remington, .35 Whelen, and someday a .35 WCF). All of these calibers I think are prime candidates for cast bullets and can be held around the 1800-2100 fps mark (maybe not quite that fast for .45-70 in my High Wall to cut recoil perhaps 1600-1900 fps). These are the calibers I hunt with the most in jacketed bullets and I want the experience of casting bullets and delving into this art.

I'm simply curious as to what most board members find the most useful as far as bullet design and if anyone has any comparitive data for similar loads where the major difference is bullet design and how it works on animals. Species of interest will mostly be deer, bear and elk, with the possibility of moose. Thank you.

mroliver77
02-13-2008, 01:34 AM
Veral Smiths book has a lot of information on boolit designs and terminal performance. For such a small thing it is very informative.
http://www.lbtmoulds.com/books.shtml

Also Paco Kelly's articles has quite a bit o notes and observations on killing power, expansion and downrange performance.
http://www.leverguns.com/articles/Default.htm

There is so much info here too but can be a bear searching for it. Bruce B is doing some research on spire pointed hard cast boolits with a soft lead nose and posting results on this forum.
I have little comparison experience but have done some killin with flat nosed rifle boolits. Flat nosed boolits are every bit as accurate as spire point but loose downrange energy much faster. In my hunting shots are all under 200 yds with most 100 or less so wide meplat boolits are the ticket. In the .30 I just love the 311440. At 1800-1900fps it gives 1"+ wound channels without expansion. I would like this design in a heavier weight( and a 115 -130gr too) for larger game. The sharp cornered meplat cast boolits turn into round nose very quickly(unless they are very hard) inside of game and still do lots of damage. I dont see why a blunt round nose design would not work very well. I have an LBT spire point 18ogr that I am set up tpo pour soft noses the next casting session and will do some wet newsprint testing with when it warms up.
J