Bullet weights/bell curves

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  • Last Post 19 April 2008
KenK posted this 05 April 2008

Any thoughts on why the curve is so one sided?

Hopefully I will have time to test some tommorow to see what it does to my groups.

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billwnr posted this 05 April 2008

Don't know...but a half grain range on bullets isn't bad.  If you shoot them in order of increasing weight I don't think you'll notice any difference at all and probably not any difference even if shot in random order.

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CB posted this 05 April 2008

Looks typical to me Ken. I usually end up with the same type a curve. If you would increase your sample to at least 100 or 200 CBs, I think it would bell out more. With a curve like that, I'd combine the 50.7gr, 50.8gr, and 50.9gr, even with your 22 CBs. That would only be about a .3 average of a 1% variation................Dan

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RicinYakima posted this 05 April 2008

This is normal for my distribution also. I've have been told, but haven't tested, the theory that it is from failure to close the mould with the same pressure on your grip or a small piece of debris between the mould faces. If you have a good micrometer, you may try measuring the heavier ones and see if that are bigger by a few ten thousandths.

Ric

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KenK posted this 05 April 2008

RicinYakima wrote: This is normal for my distribution also. I've have been told, but haven't tested, the theory that it is from failure to close the mould with the same pressure on your grip or a small piece of debris between the mould faces. If you have a good micrometer, you may try measuring the heavier ones and see if that are bigger by a few ten thousandths.

Ric I could get behind that theory.  I wish I had thought of it on my own.

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KenK posted this 19 April 2008

I cast a small batch of bullets out of 25-1 alloy yesterday and weighed them.

This distribution makes me wonder if I am seeing the difference in the two cavities.

I need to get some electronic scales, I don' t have the patience to weigh a big sample with my beam scales.

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sundog posted this 19 April 2008

Ken, the first thing I thought of when I saw your pic is that it must be a 2-cav mould.  Distrubution looks okay to me.

Electronic scale is the way to go.  I've had one for several years, and it sure makes weighing a lot faster.

Kinda curious..., why do y'all weigh your bullets.  I know exactly why I do mine -- it eliminates flyers by culling the lightweights.

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jhalcott posted this 19 April 2008

  I think this is excellent results. I do NOT normally weigh each bullet,except for target work. I HAVE on occassion ,weighed some high dollar BENCH REST bullets. The results mirrored the ones you have here.

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CB posted this 19 April 2008

Yep, looks good to me.

Yep, looks like a 2 cavity mould. Yer doin' just fine. Mine are just the same and I don't know how I'd improve it any. You could put an index mark in the cavities to separate the cavities by visual............Dan

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KenK posted this 19 April 2008

I shot these two groups this afternoon at 50 yards.  I started with a clean barrel for each group.  The target on the left was the 52.2 grain bullets and the target on the right was one or two of each from lightest to heaviest.  The overall group is the same for both targets but that 9 out of 10 shot group is fairly compelling. 

In the nature of alibis, the flier in the left target was the first shot for “score", the next nine went into the group.  Maybe I need to shoot two foulers, or learn to shoot. : )

It was a little windy to be really convinced but I absolutely proved to myself that this 25-1 alloy is going to shoot better than any of the four harder, antimonial, alloys I've tried.

I'm going to get this thing shooting yet!

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CB posted this 19 April 2008

What load were you using and any idea of the velocity?

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KenK posted this 19 April 2008

The load is 5 1/2 grains of 2400. I have no idea about the velocity, I plan to get my chronograph out now that my busy time at work is about done.

 I think I have about three different threads about this project, I should have put it all together.  The rifle is a Ruger No. 1 in 218 Bee, the mould is a plain base NEI.

This rifle will put Sierra Matchkings into 1” at 100 yards as long as I care to sit there and shoot.  Several five shot groups under 1/2".

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