Author Topic: cast bullet sizing (Read 735 times)

hiram · « **on:** November 23, 2003, 01:09:25 PM »

I have a win94 in 30-30. grooove diameter is .309 so I size to .310.
I am using the lyman 31141. It drops from the mold from .313---.317, depending where I rotate the bullet for the micrometer. Is sizing to .310 excessive for a cast of .313--.317? I am not that happy with accuracy--50 yds--about 2" with 14.5 of IMR 4227. Any comments or help? Any recommendations for the 311291--I have that mold also. Thanks

Cat Whisperer · « **Reply #1 on:** November 23, 2003, 03:06:32 PM »

Have you tried some without sizing - lube only?

The Cast Bullet Kid · « **Reply #2 on:** November 23, 2003, 04:35:29 PM »

Hi
The boffins suggest that sizing off anymore than about 3 thou. is determental to accuracy.
.317 down to .310 is not a good look.

richp41 · « **Reply #3 on:** November 24, 2003, 12:27:50 PM »

Try sizing incrementally not in one big jump. Sizing dies are also a factor. I have sized bullets down from .337" to .325" and still maintained excellent accuracy. I did this sizing in 2 nearly equal steps in newer Lyman sizing dies. .003" reductions are not at all detrimental in new tapered dies.

Aladin · « **Reply #4 on:** November 24, 2003, 12:46:00 PM »

" It drops from the mold from .313---.317, depending where I rotate the bullet for the micrometer".

This out of round casting is the problem. Your mold likely isn't closing all the way-- some metal buildup somewhere or a pin not set right. There's other flaws to be sure.

Your also assuming a 308 bore which is just that-- an assumption. Most 30's run oversized from what I've measured. Sizing a cast bullet most often is just a recreational pursuit--- not helping the loading in any way. Only real consideration in loading a cast bullet is the loaded neck dia and making sure it has enough clearance once it's chambered. And some push that limit too, which is an advanced technique. You might find a throat sometimes that's very tight and won't accept bullets oversized too, so matching that dia if you want the bullet near the leade requires sizing to that throat dia.

waksupi · « **Reply #5 on:** November 26, 2003, 05:49:38 PM »

Aladin is rubbing the right magic lantern. Check out that mold. If it IS out of round that far, I would lap it until it was concentric. That way, when you size a bullet, the deformation will be more consistant. As it is, if the bullet is that oblong, it must be pushed quite out of balance by the time you chamber it to shoot, by running it through the sizer. It may go down range, but it ain't going to the bullseye!

Cat Whisperer · « **Reply #6 on:** November 27, 2003, 02:50:43 AM »

TCBK -
If, perhaps, it's not out of round; i.e.: your .313-.317 measurements were not on the SAME band, but on different bands then the boolet may be normal. (There are a number of designs that are larger at the bottom than at the top or middle.)

It may be that there is deforming going on when sizing. There are some that will lightly size AND LUBE and then do a more rigorous sizing. That way the lube fills the grooves and tends to be incompressable, providing a more uniform result.

Sheriff Bart · « **Reply #7 on:** November 28, 2003, 02:29:00 PM »

I size 314 to 310 with no problem, but I size in two stages. I would give it a try and see how they shoot.