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up date on 240gr cast .308

1280 Views 5 Replies 3 Participants Last post by  Billy Marr
:) 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
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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.
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.
Well here is the link to the shooting 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.
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