bullet weight variation

[tomf52]

What is the acceptable weight variation for a 105 grain (Lee) bullet coming out of the mold? Mine average 109 grains, not 105, and vary in weight by about one grain in either direction. Thanks for any help with this.

[crowbeaner]

4 grains over weight usually doesn't make that much difference unless you are in the max. load category. 1 grain over or under is quite good, actually: it's less than 1 percent variation between cavities and pours. I'd be happy with what you are making and cast up a big batch. CB.

[montana_charlie]

If your bullets are 109 instead of 105, I don't see that as a problem at all.
If you get a two-grain spread over an entire casting session, there is probably nothing to worry about there, either.
Of course, if your session only produced three bullets, that would be more significant than a session that results in 200 bullets.

I don't actually care how much any bullet weighs because I sort by appearance.
Rounded corners and imperfections like nicks, pits, and wrinkles are places where lead is missing, so that explains (to my satisfaction) why a bullet might weigh light.

All that look good...are good, in my estimation.
But I will then segregate them to be fired into particular groups on the target if group size is going to be important. I don't care what they weigh, just so all of them are the same (plus or minus one tenth).

I loaded up some 45/90 yesterday using matched bullets because I am in load development on a particular bullet design. Just for grins I weighed the loaded rounds.

Every cartridge in each set of five weighed the same (plus or minus two tenths) as the other four in the same set. That covers bullet, powder, case and (even) primers.
To me, those seemed like exceptionally well-matched cartridges...but I don't intend to make it a habit to weigh them like that.
CM

[Ricochet]

Dimensional variations in the mould can add a few grains, but mostly it's variations in alloy density from the standard the manufacturer used for the prototype bullet. My bullets are often quite a bit heavier than specified. My Lee 430-255-F bullets, for example, weigh around 273 grains in the first big batch I cast from soft scrap lead.

[Ohio Rusty]

I kinda expect the same as you TomF .... If a company says the bullet is 105 grains, then it should be 105, not 4 grains over .... I've never found a weight difference between straight WW's and 20 to 1. If the Doctor said that we were having one baby, and we were over and ended up with 4 ...I would consider that a problem. Maybe a better example would be you bought a sizer that is supposed to size bullets at .430, and it actually makes them .434. It's only 4 off, but most reloaders would scream if a sizer was off '4'. I would like to know what lead allow the company used in the original weight measurement and how they arrived at that figure. I have a mould that doesn't match the advertised weight.
Ohio Rusty

[Dale53]

There is a great deal of weight variance depending on the alloy. Lyman traditionally uses Lyman #2 bullet metal for a standard. I have heard that Lee uses 10/1 lead/tin while others use Linotype.

Having a bullet weigh 4.0 grs more than advertised weight is NOT a problem. I do like bullets from a batch to weigh close to the same as their brothers. I consider pistol bullets should be + or - .5 grs. I consider large BPCR bullets should be = or - .6 grs. My schuetzen bullets are held to + or - .2grs. I weigh my Schuetzen bullets but I do NOT weigh my pistol bullets. The accuracy expectations are considerably more for the schuetzen bullets.

Dale53

[Onlymenotu]

I kinda expect the same as you TomF .... If a company says the bullet is 105 grains, then it should be 105, not 4 grains over .... I've never found a weight difference between straight WW's and 20 to 1. If the Doctor said that we were having one baby, and we were over and ended up with 4 ...I would consider that a problem. Maybe a better example would be you bought a sizer that is supposed to size bullets at .430, and it actually makes them .434. It's only 4 off, but most reloaders would scream if a sizer was off '4'. I would like to know what lead allow the company used in the original weight measurement and how they arrived at that figure. I have a mould that doesn't match the advertised weight.
Ohio Rusty


that being said isn't unreasonable to say it's exacly going to weight xxx... even if they told you the alloy mix....they would have to say run the mix at exactly xxx degress ( then you would run in to different methods of calabrating the heat one person/manf using this method and the next person/manf using something else) and hold exacly this mutch pressure on the mold-mould handles to make sure they are closed properly..... don't get the mold-mould over xxx amount of degress.... there are just to many varables to say this mold-mould will throw a boolit of this exact weight.... no 2people cast the exact same way to beable to control those types of varables

[Bass Ackward]

Well, were your jacketed bullets always spot on over the years? Bet you didn't weigh those did ya? Assumed that you got what the package said. Up until some point in the 80s, bullets could be all over the place too, even outta the same box.

You'll be alright Tom, are they loaded yet? Are they loaded yet? Are they loaded yet? :grin:

[44man]

My Lyman .45 booit is supposed to weigh 325 gr's but comes out 347 gr's with almost a no. 2 alloy. It's OK, I use the same load I do with a 320 gr and it shoots tiny, tiny groups, sometimes all five shots touching at 50 yd's. Would I gripe to Lyman? No way, I might get a new mold that won't shoot.
I spent years weighing my BPCR boolits, never made me shoot any better! :mrgreen:

[tomf52]

Thank you all for your replies and most helpful input. These 105's are cast from straight WW's and I take no exceptional pains when casting and knock out many bullets per hour with the Lee six banger. I was just getting some fliers that may well have been nothing more than me but weighed a few bullets out of curiiosity and found the results I stated. Will now try some sort of more steady rest with my handgun to see if it shows any change. Appearance wise the bullets come out of the mold looking pretty good. Thanks again for the help.

[Ohio Rusty]

I have found that some flyers can be caused by an air bubble or void in the bullet. These happen when it cools right after you pour it. You can actually watch the lead being sucked down into the bullet when it goes from molten to hard. I pour with a ladle and I try to make sure there is a puddle of lead on top of the sprue hole to prevent that void problem in the bullet.
Ohio Rusty

[felix]

OR, for your next experiment, take a "perfect" boolit and then sand it down all around very gently. You will see air bubbles, however small. The boolit will not shoot straight unless all of these micro-bubbles are extremely uniform throughout the center line, even at 100 yards or less. The actual weight of the boolit makes little difference at a reasonable distance, say up to 300 or slightly more yards at 2400 fps or less. The reason we weigh BR boolits (not custom BR bullets) is to hopefully find the out of balance boolits without having to spin them. I would strongly consider purchasing a balancing machine for the purpose should one be invented for a realistic price (fat chance of that on both accounts). So, it actually makes no difference if the boolit is made by a gentle pour of a fast and furious pour by any means, as long as the distribution of the inclusions within the boolit are uniform in distribution about the center line. ... felix

[Leftoverdj]

It's the alloy, as others have said. If the four grains bothers you, cast with linotype. That'll get the weight down.

Exactitude is unreasonable. There are hundreds of thousands of us casting with about anything that will melt, and we are not all going to get the same results. Manufacturers need some tolerances, too. The difference in cost between machining to plus or minus a thou and machining to plus or minus a tenth of a thou is enormous. They do a pretty good job, considering.

[Sundogg1911]

I find that I usually cast lighter bullets that what the mould says. I use a good bit of Linotype which is lighter than lead. (but much harder) Each mould company has their own "standard" alloy that they use. Most companys also use a different alloy, so if you cast exactly what a Lyman mould says it should weigh with Lyman #2 alloy, and then switch to a Magma mould. It may be different. It is much more important to have consistant weights than exactly what the mould says it will throw.

[montana_charlie]

If a company says the bullet is 105 grains, then it should be 105, not 4 grains over ....
There will be slight variations in almost anything that is mass produced. If you need an exact weight (and diameter) when using a particular alloy...you need a custom-made mould.
CM

[testhop]

relax and try them if you get a big spread in your group then weigh the slugs to plus or minus
1 or 2 gr.or some outher guide line you set
but take in to acount you are useing 6 cavty mouldand you have to give up perfactoion
for speed now one way is to keep each hole seapert and weigh each
boolit t see what each one weights sort them out by hole or wt.
anouther way is to use a single cavty mould ( i know thats the hard way but it
keeps things simple)



tom