Author Topic: up date on 240gr cast .308 (Read 1116 times)

Billy Marr · « **on:** December 20, 2002, 11:42:12 AM »

:-) after about 6 hours boy my eyes and hands hurt. I have made an equvilant cast bullet to the 240gr Sierra. Now the Sierra sports a .619 bearing seruface. this is good with a strong jacket and core bond. Now with a cast bullet you do not have that is is all core.
What I have done is make a shorter version in oal ie the Sierra is 1.6 inches while mine is 1.117 inches long. But my bearing surface is .897 inches thus .278 longer than the Sierra. This was meassured by pushing a bullet in to my TC barrell in 30BR. My barrel measures .295 lands and .304 groves. This cuases the bullet to seat deeper in my cases but I will find out if accuracy is afected tommorow when I go to the range. The nice thing is that I have a throat reamer just waiting to be profiled to this bullet. If all goes well.
Now here comes the intresting part this was done to a Lee 200gr mould that with my alloy comes out at 195 the finished bullet with the modification comes out at 204grs. I will be expirimenting with some slightly different desings on the basic bullet here in the next few weeks hopefully I can come up with a cheaper way to make them as a single cavity mould will drive cost up.
More with in the next few days

Billy Marr · « **Reply #1 on:** December 22, 2002, 10:33:08 AM »

well the new bullet performed flawless it shot plain great 1 inch group at 100 yards. I will defintely make a cast iron mould for this one.

hammerhead357 · « **Reply #2 on:** December 22, 2002, 03:35:30 PM »

Ok Billy can we see a picture of the bullet? Who is making your cast iron moulds, if I may be so rude to ask? Wes

Billy Marr · « **Reply #3 on:** December 23, 2002, 03:34:56 AM »

I am not trying to duplicate the Sierras BC just its bearing surface. So that I have a bullet that will stablize in faster twist barrels.

Cat Whisperer · « **Reply #4 on:** December 23, 2002, 03:44:26 AM »

Quote from: Billy Marr

well the new bullet performed flawless it shot plain great 1 inch group at 100 yards. I will defintely make a cast iron mould for this one.

Billy -
(Following up on Alladin's comment re: rate of twist) how did it stabilize? I.e.: any signs of tipping?

Also, I'd love to know how you aligned the mould to recut it. You must have some good techniques.

Thanks,

Billy Marr · « **Reply #5 on:** December 23, 2002, 10:33:00 AM »

Well here is the link to the shooting cornerwww.bbtcastbulletsales.com/theshootingcorner there you will find a picture of the new bullet.

The bullet showed no sign of tipping when going through the target.

As for how I cut the mould I use my fingers to apply the pressure when cutting it. I use a dremel for part of the operation then make a casting and lapit to where I want it.

I will be recuting a mould block from Lyman some time soon I just have some orders to fill and catch up on some other things tis week. We were rained out to day so the son and I will do testing on Thursday.