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View Full Version : Matching a bullet to your gun. (bullet design)



texaswoodworker
08-09-2014, 05:42 AM
I have an old Type 99 Arisaka with a pretty oversized bore. I was getting pretty bad results with pulled .311 bullets, and now I know why. My bore is .316...

So this gun is a perfect candidate for cast. I need a mold that drops .317-.318 bullets, so I've decided that I eventually want to have a custom one made by mountain molds. The only problem is, I don't know exactly what makes for a good cast bullet when it comes to designing one. I was wondering if anyone had any suggestions for how I could figure out exactly what would shoot best.

I don't know what the optimum front band diameter or length is, or how much bore ride length I need, or really anything like that. I just know the diameter I want, and what weight I want (was thinking 170gr). I'm going to do a chamber cast as soon as I can get some Cerrosafe, so I'll at least know my throat diameter and my max OAL.

leftiye
08-09-2014, 06:04 AM
I think one needs a swami turban to do that? Look at threads on other rifle cartridges as per what works well in those guns for purposes similar to yours, adapt those designs to your caliber. Cast your chamber before ordering. I'd guess a flat nose of weight close to the military bullet, with or without bore riding nose (your preference)and length to reach the rifling when seated to the base of the case neck, gas check if you want velocity, one or two grooves.

milkman
08-09-2014, 06:47 AM
Texas
Check out the 30 XCB thread in Special Projects starting with post 408. Very good discussion of boolit fit in the chamber and lube grooves. The guys posting are all good folks and don't mind answering questions, even from dummies like myself.
Milkman

texaswoodworker
08-09-2014, 09:18 AM
Thanks for the tips guys. :)

runfiverun
08-09-2014, 11:17 AM
there is also a sticky on doing a pound slug of your throat started by good steel [one word]
and another thread in the mold section started by him on a lever guns throat.
it takes a few pages for the pictures and discussion to turn to static and mechanical fit which is where the real magic lays.
but there is some good tips there on what you are looking for also.

Larry Gibson
08-09-2014, 02:19 PM
Take a good look at the NOE 316299. Cast of COWWs + 2% tin or Lyman #2 alloy the bullets should drop out at .317 .318.

Larry Gibson

Paul Tummers
08-10-2014, 09:08 AM
You also can send a mail to Mountain molds and explain what you have and use their enormous experience in this and follow their suggestion, did that once and never have had any regrets.