Sorting by weight

[madsenshooter]

First time I've done this, hope it's worth the hassle. The Cast Bullet Association benchrest regional match is coming up next month, and I want to be ready. I cast a few (139 after visual culling) of the Eagan MX3-30Gs from a mould Bernie Rowles of Old West cut using my cherry. I had to go back in with the cherry and straighten out what he messed up for me. I had to make the bands wider, the lube grooves shallower, in order to get it closer to right, so the bullets weigh closer to 208.4gr vs Eagans figure of 190gr cast in lino. I thought I was doing pretty good keeping the temperature of the melt and mold constant, but there was a 1gr difference between the lightest and heaviest ranging from 208-209, with the majority of them being between 208 and 208.6gr. Only 20 heavier than that. I think it'll be worth the effort, I had four of them the other day that I shot at 1625fps out of a cutoff Krag and they fell into a .475" group at 100yds!

[HARRYMPOPE]

When i was shooting a lot of CBA heavy and production matches i would cast lots of 300 and weigh the first 50 against the last 50.if i noticed a large weight variation i would check each 50 lot group i segregated them into.Sort of like shooting them in order cast like Pope and those guys did.I assumed the center batches were the best and used those.I couldn't tell a difference but i weighed bullets for the big matches to make me feel better.

Good luck at the regionals.Are you shooting Hunter Class?

HMP

[madsenshooter]

Shooting the modified military with a scoped Krag Harry. I like the CBA rules in that class, allows you to use sporterized rifles, though I have several originals. I noticed you posted a pic of the Eagan catalog page for the 30US. I don't know about that 2000fps, oh I can get the 30G up there, but with a 1/10 twist its best accuracy is 1600fps. Maybe when Eagan said 1/12 minimum twist he meant 1/12 or slower. I've been looking for someone to cut some molds with the 30G and 30US cherries I have, gotta be brass, and they have to have a centering vise.

[HARRYMPOPE]

I have to get the eagan catalog scanned and posted I just keep forgetting it when i go to dads house.I have the 30 US and sold the 30g they're both nice bullets.Good luck at the match.I shot plainbase in the 30-06 at the 2010 Military Nationals.I actually did well at 200 yards with my 1.145 long spitzer PB @ 1175 fps.

HMP

[madsenshooter]

I'm glad I did sort this lot. I set the OAL by using the heaviest, set them to go hard into the rifling. Today I got out to shoot the ones that were on the ends of the range, both the lights and heavies, quite a difference in diameter between them, and thus a difference in rifling engagement. The light ones went right in with little resistance, the heavies took some torque on the bolt handle to get it closed. Trapped air seems to be a problem with these molds, a few of my rejects looked like a banana as there was an air pocket on one side. Those ought to fly well.

[HARRYMPOPE]

Shoot the ones with voids.I had a couple i found recently and marked and shot them.They were out of the groups about 2".far better than i thought they would be.So now when get that wild 5" out shot i dont automatically blame a void.The voids were both in the middle band of a 3 band 30 caliber bullet and about 3-8g in missing weight.I have never found a void in a ladle cast bullet only bottom pour.They are there i bet though.

HMP

[noylj]

I would not expect any difference on-target of a 1-2 grain weight variation.
If you are doing long-distance shooting, then the difference in drop and ballistic arc will have an effect.
Get an exterior ballistics program and plot a 198gn bullet vs a 205gn bullet and see if you can determine any difference at just 100 yards.
Heck, wrinkles on the nose of the bullet and the first couple of driving bands has no real effect as long as the bullet base is full and square.
Take your bullets and try the high weight, low weight, center weight, and mixed weight and determine what the targets tell you and let us know.

[Cap'n Morgan]

Your weight variation is only 0.5% Wish I was that consistent in my casting!

Now, I'm theorizing here, but if the bullets were cast from a completely closed mold with a tight fitting sprue plate, you should cull the lightweights only as they would be the ones with voids and poorly filled edges. If the mold isn't completely closed, however, perhaps due to a speck of lead between the blocks, a gap of only .0005 will increase the weight of a 30 cal bullet in the 200 grain range at least a grain. Never the less, the heavier bullets should still be more "perfect" than the lighter ones.

[madsenshooter]

I shot the lot in a match today. the results were dismal. Could be I overlubed them. I got excited about this bullet because I had four that I shot out of my cut off Krag that went .475". They were lubed by double dipping in thinned LLA. What I shot today I lubed by dipping in molten C-Red, bringing the bullets up to the same temp of course, then letting them sit in the old electric skillet to drain down some before taking them out to cool. They were all over the target at 100yd, and not even on the target at 200! I shot so many sighters I ran out of ammo 10 rounds shy of the full match. Too much of a good thing perhaps. I noticed the benchresters clean their barrels about every ten rounds, maybe that would have helped. The bullet, being tapered, seems to be better suited to something with a shorter throat than the Krag, with the old cut off I only had about 1/8" of bullet in the case. I appreciate the input gentlemen, I seem to be one of those guys that learns the hard way.