How much bullet weight deviation is acceptable?

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How much bullet weight deviation is acceptable?

Post by joy2shoot on Sat Aug 13, 2016 6:44 pm

When using .45 cast lead bullets for the 50 yard line, how much deviation in bullet weight is acceptable?
 
Currently, I shoot JHP for the .45 long line.  But I want to try 200 grain cast lead SWC for 50 yards.  I did some internet research and narrowed bullet suppliers to two companies.  I slugged my barrel and ordered 0.453" diameter bullets from each.  One order has come in.  I took one hundred bullets from this order and weighed each one on an electronic scale that has +/- 0.02 grain accuracy.  These are the results.
 
lightest bullet: 200.88
heaviest bullet: 204.38
difference between heaviest and lightest: 3.5 grains
average weight: 203.11
std deviation: 0.75
number of bullets between
    200-200.99: 1
    201-201.99: 6
    202-202.99: 35
    203-203.99: 50
    204-204.99: 8
 
So my question is, is 3.5 grain variation acceptable for the long line?  I really do not want to get into weighting and sorting bullets.
 
Thanks.
Thomas

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Re: How much bullet weight deviation is acceptable?

Post by LenV on Sat Aug 13, 2016 7:34 pm

I just played with my ballistic calculator and had to add some variables for reduced MV on the 205 gr vs 200. Using 700 fps for the 200 and 690 fps for the 205 ( this is probably your max variable) the POI difference between the lightest and heaviest bullets at 50 yds is a whopping .27 inch. If you load hotter then 700 fps that difference drops. I don't think there will be a problem.

Len

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Re: How much bullet weight deviation is acceptable?

Post by sharkdoctor on Sat Aug 13, 2016 7:47 pm

A couple of caveats - difference in weight of a few grains might not be noticable in accuracy unless it represents bullet voids, or comes from a smaller diameter sufficient to affect accuracy.  Best thing is to test them at extremes so you are not worrying about it.

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Re: How much bullet weight deviation is acceptable?

Post by jglenn21 on Sat Aug 13, 2016 8:21 pm

Tony had a good article on this a while back

http://tonybrong.blogspot.com/?view=flipcard#!/2016/03/repost-consistency-product-of-adhearing.html

personally I weigh my cast bullets out into .75 variance lots.. I usually get a couple of lots with enough bullets to be worth while loading for the long line.. the rest go into the 25 yards pile with one that have obvious voids or are really light or heavy from the norm into a practice lot.. if you sort bullets based on visible inspection and weight it will matter. 

YMMV

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Re: How much bullet weight deviation is acceptable?

Post by john bickar on Sat Aug 13, 2016 10:24 pm

It kills me to think how much time I've wasted training over all these years when I should've been weighing bullets.

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Re: How much bullet weight deviation is acceptable?

Post by pistol champ on Sat Aug 13, 2016 10:37 pm

John, training is so over rated. You now know the secret to becoming a HM you just need to invest in a good scale.

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Re: How much bullet weight deviation is acceptable?

Post by robert84010 on Sat Aug 13, 2016 10:58 pm

john bickar wrote:It kills me to think how much time I've wasted training over all these years when I should've been weighing bullets.
I'm sure you will be emailing Mr. Buljung asking why he never told you about this secret!

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Re: How much bullet weight deviation is acceptable?

Post by joy2shoot on Sat Aug 13, 2016 11:22 pm

Len,
 
Thank you for the analysis.  I will be using around 4.0 grains of N310, which should push the bullet around 840 fps.

Thomas

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Re: How much bullet weight deviation is acceptable?

Post by Wobbley on Sun Aug 14, 2016 1:25 am

joy2shoot wrote:When using .45 cast lead bullets for the 50 yard line, how much deviation in bullet weight is acceptable?
 
  I took one hundred bullets from this order and weighed each one on an electronic scale that has +/- 0.02 grain accuracy.  These are the results.
 
lightest bullet: 200.88
heaviest bullet: 204.38
difference between heaviest and lightest: 3.5 grains
average weight: 203.11
std deviation: 0.75
number of bullets between
    200-200.99: 1
    201-201.99: 6
    202-202.99: 35
    203-203.99: 50
    204-204.99: 8
 
So my question is, is 3.5 grain variation acceptable for the long line?  I really do not want to get into weighting and sorting bullets.
 
Thanks.
Thomas
Obviously these are bad bullets.  Real bad.  You ship them to me and I'll accuracy test them for you.  I'll let you know how they work out.  Let me know when you send them. lol!

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Re: How much bullet weight deviation is acceptable?

Post by fc60 on Sun Aug 14, 2016 10:52 am

Greetings,

If you purchase cast bullets in bulk that are already greased and sized, weighing them is a waste of time, in my opinion. Are you checking the bullet weight or the amount of grease?

I still cast my own 45 bullets. I no longer weigh them. I give them a thorough visual inspection with a magnifier. For serious match ammo, I check the as cast bullet diameter with a micrometer to ferret out the ones that did not fill the mould correctly or the mould did not close fully.

Should you decide that casting is not for you, the only way to sort out the bad bullets is to buy them from a vendor that will offer them "as cast". Now you begin to sort out the good from the bad.

Yes, you will need to purchase a bullet greaser. I have several brands and for my Match ammo, I use the Star. I also use a fitted nose punch. No nose first base punch sizing for me.

Cheers,

Dave

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Re: How much bullet weight deviation is acceptable?

Post by dronning on Sun Aug 14, 2016 11:28 am

Check out what Jerry Keefer does for his lead prep.

Canton Perry Prep

- Dave

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Re: How much bullet weight deviation is acceptable?

Post by james r chapman on Sun Aug 14, 2016 11:54 am

Fc60 has it right. If they are lubed you can't weigh them. When casting, your weighing out the bullets with voids. Voids off center can caused wild shots.

Or, do as Jerry did, gas em up to remove the lube.

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Re: How much bullet weight deviation is acceptable?

Post by BE Mike on Sun Aug 14, 2016 3:05 pm

joy2shoot wrote:When using .45 cast lead bullets for the 50 yard line, how much deviation in bullet weight is acceptable?
 
Currently, I shoot JHP for the .45 long line.  But I want to try 200 grain cast lead SWC for 50 yards.  I did some internet research and narrowed bullet suppliers to two companies.  I slugged my barrel and ordered 0.453" diameter bullets from each.  One order has come in.  I took one hundred bullets from this order and weighed each one on an electronic scale that has +/- 0.02 grain accuracy.  These are the results.
 
lightest bullet: 200.88
heaviest bullet: 204.38
difference between heaviest and lightest: 3.5 grains
average weight: 203.11
std deviation: 0.75
number of bullets between
    200-200.99: 1
    201-201.99: 6
    202-202.99: 35
    203-203.99: 50
    204-204.99: 8
 
So my question is, is 3.5 grain variation acceptable for the long line?  I really do not want to get into weighting and sorting bullets.
 
Thanks.
Thomas
What kinds of 50 yard 10 shot groups are you getting from the machine rest with the bullets without weighing them or separating them? If you're getting 10 ring size groups, you are good to go! Usually if the bullets look good, especially the base they are usually good. Certainly don't worry about trying to get those amazing 1" and 1 1/2" groups. Any good bullets should group well within the 10 ring at 25 yards. If your bullets don't group well at the long line, use them for the short line and buy some good 185 gr. JHP and load them just for the long line. You won't have to inspect them or weigh them and they will always group very well out of an accurate pistol. That way, as some have hinted, you can spend more time training and less time worrying and sorting bullets.

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Re: How much bullet weight deviation is acceptable?

Post by joy2shoot on Sun Aug 14, 2016 3:47 pm

Thanks for the input.  These bullets were purchased from a caster.  Therefore, they are already lubed and sized.  I weighed one hundred of them to get an understanding of bullet weight variation and posted my results here with the question if the variation I found matters at 50 yards. Since I just got them, I have not actually shot them yet.  My primary concern was do I need to worry about the weight deviation.  Based on Len's reply, I think the answer is No.
 
I also took one bullet, weighed it (203.94 grains), removed the lube and re-weighed it (203.48).  It does not appear the lube adds significant weight.
 
I do not cast and I really do not want to get into casting and I also do not want to get into weighing, sorting, washing, re-lubing, etc.  I currently shoot 185 gr JHP for the long line but wanted to try lead.  It appears I should stick with JHP or go to a polymer coated lead bullet.  It seems polymer coating would elevate the fine lead residue discussed by Jerry.

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Re: How much bullet weight deviation is acceptable?

Post by james r chapman on Sun Aug 14, 2016 4:32 pm

Well then. Take your heaviest and lightest and remove the lube. Record the weight difference.

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Re: How much bullet weight deviation is acceptable?

Post by dronning on Sun Aug 14, 2016 7:29 pm

Why spend time problem solving what appears to be a non problem.  Are you seeing uncalled flyers then I get it, but if all you really are concerned about is casting voids then buy swaged bullets.

- Dave

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Re: How much bullet weight deviation is acceptable?

Post by joy2shoot on Sun Aug 14, 2016 10:17 pm

Dave,

I am trying to determine if my 50 yd results would be noticeably better with LSWC compared to JHP.  I will find out in a week or two when I am able to go to the range.  Based on slugging my barrel, I need a lead bullet diameter of 0.453".  I was not able to find swaged bullets in that diameter.

Thomas

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Re: How much bullet weight deviation is acceptable?

Post by james r chapman on Sun Aug 14, 2016 10:26 pm

Are you properly measuring it, a 5 groove cannot be measured directly.
Often you can send the slug and the caster can properly match it.

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Re: How much bullet weight deviation is acceptable?

Post by joy2shoot on Mon Aug 15, 2016 8:11 am

James,  I concur.  I actually had Matt Dardas of Dardas Cast Bullets measure my slugs.  --Thomas

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Re: How much bullet weight deviation is acceptable?

Post by james r chapman on Mon Aug 15, 2016 9:51 am

joy2shoot wrote:James,  I concur.  I actually had Matt Dardas of Dardas Cast Bullets measure my slugs.  --Thomas

That would have been my suggestion also.

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