Boolit weight and accuracy, a QC question

[TexasAggie06]

Today I sized, gas checked, and powdercoated (twice) about 150 30 caliber rounds for 300BLK. I weighed each Boolit and they all came in between 159.5-161.5g with the vast majority in 160.0-160.9g range. A couple of questions; is that decent? When you QC boolits what's your acceptable variance? At 100 yards would their be a noticeable accuracy variance between boolits that differ by a couple of grains?

[Lagamor]

I get up to 3 grain variance with a small 95 grain mold. The majority will be withen less than a grain. No accuracy variance for me, but it's pistol not rifle.
Seems to me your doing something right.

[stu1ritter]

I was wondering much the same thing. Loading pistol, almost all at min start loads. Has anyone read any published research on this question?

thanks,

Stu

[Hickok]

Tex, I have to say according to your weights you have given, you are doing a great job with your casting.

I believe the standard for being real "picky" about weighing boolits is plus/minus 1 % of the boolit weight. There is a lot of discussion/argument about this, but I have no dog in that fight.

In times past, I got real picky about sorting boolit according to weights, but have now given it up.

I will at times weigh/sort rifle boolits to see what max accuracy I can squeeze out. Mostly I just shoot'em, and if a flyer goes way out of the group.....well that was a bad boolit......shoot again!

[Outpost75]

Weighing bullets which are perfect to visual inspection is mental masturbation.

[bobthenailer]

Trapped air pockets is your biggest problem as well as flat bases ,If your mould is vented correctly the air pockets should be elimated .
When casting after closing the mould blocks tight, tap the hinge pin on the handles to make sure the mould halves are seated all the way , sometimes the two mould halves aren't completely closed causing a dia & weight varaition

[runfiverun]

weight sorting powder coated boolits is gonna give you an aneurism.
is it the boolit or the powder?

I weight sort some of my rifle stuff.
by some I mean stuff I want to go fast and I want the holes in the paper right next to each other.
my pre-64 30-30 shoots good groups for what it is but I doubt 1gr of boolit weight is even gonna be noticeable.
my ruger target/varmint rifle in 223 is another matter.
I expect it to shoot under an inch and I'm getting the little guy's there at 2800 fps so I weight sort into .1gr weight groups.

[44man]

I don't know how you can cast an air pocket! I will send every boolit I have and you can section them. If you find air I will toss you the biggest BBQ ever.
Heat control is more important to make the same weights and I probably would weigh .22 boolits.

[Yodogsandman]

Today I sized, gas checked, and powdercoated (twice) about 150 30 caliber rounds for 300BLK. I weighed each Boolit and they all came in between 159.5-161.5g with the vast majority in 160.0-160.9g range. A couple of questions; is that decent? When you QC boolits what's your acceptable variance? At 100 yards would their be a noticeable accuracy variance between boolits that differ by a couple of grains?

A recently banned member ran a test using the 30 XCB boolit at maybe 2800 FPS and found that by dividing boolits into .1 gr groups and shooting them, a sweet spot was found that spanned about .5 gr. It's posted over on the NOE forum.

That's good casting! Be sure to visually cull boolits before weighing them. For most of us, a +/-1.0 gr difference with a 30 caliber 160 gr rifle boolit will give acceptable results. The smaller the variance, the smaller the groups should be, with all else being equal. So, make a few lots of boolits grouped by different weights and then shoot rounds within each lot together for best groups. You'll figure out what works best in your rifle. As caliber and weight is increased, that +/- difference can be increased a little bit.

[philzilla]

Lots of good info

[stu1ritter]

I was at the range the other day and had some rounds with bullets loaded at .1 gr accuracy (all 151.5 gr) and with the same exact case, primer, powder, a mixed bag as I cast (probably 150.5-152 gr). Granted, it is just a two hand hold with a snub, but I thought it pretty interesting. You may draw your own conclusions. Flyers were self inflicted and called.

Stu