What is an acceptable boolit weight variance for accuracy?

[Grmps]

What is an acceptable boolit weight variance for accuracy less than 100yrds

IN A:
100 Grn boolit? pistol 1200 - 1600

200 Grn boolit 30 cal 2200+

250 Grn boolit? .44 pistol / rifle

500 grn boolit? -- 45-70 rifle subsonic/sonic 100-200 yds

I'm loading a bunch of 45-70 for a friend and would like to know how tight to cul
l the boolits. are we talking .01 or .005 or .001?

[tazman]

This may sound like a stupid question, but rifle or pistol?
And how far?

[leadhead 500]

A lot depends on the velocity,Distance, and the kind of accuracy you are wanting

[dragon813gt]

In general the lighter the bullet the less acceptable weight variation. Only you can determine what's acceptable.

[Grmps]

I'm loading a bunch of 405, 485 gc & 500 grn 45-70 for a friend and would like to know how tight to cull
the boolits. are we talking .01 - (.500 to .510) or .005 - (.500 to .505) or .001? - (.499 to 500)?

[leadhead 500]

In my opinion if you can keep the ones for the 45-70 to with a half of a grain they will do just fine

[RedlegEd]

Hi. Based on what you said in your OP (100-200 yds) for the .45-70, as long as it's not bullseye or benchrest competition shooting, I'd say +/- 1% (0.01) should be fine. So for a 500 gr bullet, you could go as light as 495 gr to as heavy as 505 gr. If your friend find that's too much, drop to +/- 0.5% (0.005)=(497.5 gr - 502.5 gr.) I'd use the same for the 405 gr and 485 gr as well. Ed

[1Hawkeye]

For sorting 45-70 bullets I sort them to the nearest grain. Example I use an Arsenal 4 cavity mold .460 dia 330 gr bullet. If the bullet weight is 330.0 to 330.9 that would be a 330 gr, a 329.0 to 329.9 would be a 329 gr, a 331.0 to 331.9 would be a 331 gr ect ect . I used to sort them by the nearest half grain but I really couldn't see a difference on the target. In Mike Venturino's book Shooting Buffalo Rifles of the Old West he said he sorts them to the nearest tenth of a grain but he is also talking about using those black powder loads for long range competition. I gave it a try weighing them that way but soon adopted what I'm doing now.

[country gent]

+/- As to weight the standard allowed deviation was 1% of weight average. Some hold closer weight variations as a normal thing. One other way is to sort into batches. On you 100 grn bullet sort into 98-99 grns 100-101 grns, and then 102-103 grns and load each group together. This makes more of a casting session useable.
As to size the bullets ran thru a sizer and lubricator die should be very close to the same size and not enough to be an issue.
I would sort for visual defects first then weight if necessary. Depending on requirements required. If sorting to a given weight 1% +/- should be fine for most uses. 1% is a pretty broad range in reality even your 100 grn bullet that transfers to +/- 1 grn. On the 500 grn its +/- 5 grns. On a 50 grn bullet its only .5 grns +/- so bullet weight may playa role here also in what you want to sort to. I normally cast heavy bullets 360-550 grns and for a given session I'm usually within .5-.7 grns on weight. for the run of a given bullet after sorting visual defects out.
One thing to do when you have time is load a test group of full weight range extreme and a test group and a test group of weighed exact same weight and shoot see how big a difference it makes in your firearms. You may be surprised at how little difference weight makes. Weight not voids or visual defects.

[RedlegEd]

Very well said. Ed

[Grmps]

I don't own a 45-70 so can't test them -- therefore the question.

You are wondering what I'm doing with the molds :) I acquired them in a deal last year.

I appreciate your answers and explanations.

[country gent]

That's even better, it can be a blind test. give him 10 rounds each way numbered load 1 and load 2 ( He dosnt know the difference only you do) and have him fire them on 2 clean targets and label them as to load number.

On my bullets I sort for visual defects while sorting the different bullets into containers. Pan lube and shoot them. I shoot these bullets in the 1150-1200 fps range and out to 500yds. I'm loading over black powder also. I believe the visual imperfections are more degrading to accuracy than a small weight variation is.

I would recommend to cast the best looking bullet you can. Use the technique that works the best for you. and work from there. For me ladle casting these big long bullets works better.

I ladle cast my bullets. I don't pour for a sprue but pour a ladle full of lead into the sprue hole letting the excess run back into the pot. This keeps the srue and bullet molten longer allowing for better fill and better off gassing. Watch the sprue you will see it solidify then a "frost" come over it. Give it a couple seconds more and cut the sprue. Drop on a layer of towels. I cast with 2 moulds at a time 2 cavity Normally brass moulds from Old West moulds. My 550 grn is 1.4+' long so its a long bullet and the ladle gets the lead in while its still molten, the over pour helps keep it there longer.

[scottfire1957]

Well, when you consider one grain is one 7 thousandths of a pound, 5 or 10 grains I don't worry about.

I do not shoot precision.

[MT Gianni]

A sc older Ideal 225438 mold recently dropped 100 bullets. 99 of those were within 0.3 grains and one was out .6 gr. I culled it.

[DHDeal]

Since you mentioned accuracy, go for that ideal on your culls/keepers. Like at least one other stated, I cull any imperfections visually and then I'll weigh them and then sort by the weight. Since you don't own the rifle for the bullets and obviously want to produce a fine finished product, I'd only let the best leave my shop. There's the pride attached to it don't you know...

I usually can keep my weight variation into less than a grain as long as I stay at the pot paying attention to the temperature and casting cadence. Any that fall outside of my set limit either goes back into the pot or I save them and remelt them later when I cast using that particular alloy. I ladle cast only.

I'm referring to a Paul Jones, Brooks, BACO, and Old West molds casting long heavy bullets for BPCTR here. When I shoot these rifles, I'll take them to the 600 yard line and if I have a flier, it's probably not the quality of the bullet.

[Harter66]

I ladle cast . I ran a 458193 single for 125 pours . I tossed about 10 straight away for cold defects and 10-15 more for being out of the weigh lot . At the end I had 97 bullets of 416.7-417.4 I'm never going to complain about a run like that .
I ran the same 125 pours in a brass M-P 462-420 Bras 2 cavity , 1 HB , 1 PB .
I culled about the same number times 2 of cold and had a boring +-.2 gr at 380 gr and 414 .

I weighed a bunch from a 3 cavity NOE 461-543 @ 459-535 and they fell into basically the same groove with about a 1.5 gr core window which came out to within 7 bullets in a total of 150 of being .5 gr between cavities . In a bullet that heavy held to the practical speeds of the 45-70 (yes I know a #1 will be hot on the heels of a 458) that's plenty close enough .

I think the biggest weight change was at the start of the pouring session and at the end when the pot and mould was under prime temp and at the end when it was over .

I would also add that the NOE at 3x535 will suck a pot dry in short order and the RCBS ladle isn't quite enough if you make a little fumble between pot and mould .

[popper]

An interesting test. Weigh for your 'bell curve', then re-weigh each. See how much variation you get. Results will be interesting for you. I just cull bad bases & wrinkles.

[DocSavage]

My 45/70 bullets are usually within 1% +/- so for my 500 gr 495-505 grs.

[robg]

My 308 load is 18 gr of 2400 with all my boolits 150/160/180 grgc using the same point of aim at 100 yards they all shoot within a 4 inch group ,each load individually shoots into 1-2 inch group .I only found this out when I was too lazy to change a target.

[bigcountry022885]

I will sort buy weight untill I find where I produce the most within 1/2 grain and I will keep just the ones that meet that spec but I have a PID control and a mold temp gauge so out of a full pot I might throw 1/3 back keep your bullet alloys consistent and your lead temp and mold temp consistent will keep your bullet weight relatively close


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[wv109323]

I think there are other factors that affect accuracy more than just bullet weight. One is the fit of the boolit to the bore and the second is a sharp flat base of the bullet.
I recently cast several 200 gn.SWC for my Bullseye pistol. I visually culled the ones with wrinkles and not fully formed. I then selected 10 of the worst looking bullets I could find in the remaining pile. I loaded and Ransom rested those boolits versus a group from a commercial caster. Both groups ended up at 3 X 2 1/4" for 10 shots at 50 yards. One group was 3" horizontally and the other was 3" vertical. They would have been scored a 100-6X and 100 with 7X.
My thoughts are if it looks good shoot it.

[popper]

for a given session I'm usually within .5-.7 grns on weight. Doubt it. I did ~ 50 168gr rifle, put in bell curve, then REMEASURED. about 1/2 were in different slots. Tried again. Same results. Electronic scale. You need a VERY good scale to measure that + a good air shield above it. A guy across the cube from me was working on an automated medical scale (very high precision) but measurements were not accurate. Had to put an air shield over the measurement instrument to prevent air current from messing it up. Customer was not happy with slow process time. Anything over 1% should show up visually or by dimensional change after a week or so. Larry, Tim & I went around about this a while back. Pb doesn't change density so wt. diff. is a void or dim. difference (Tim DID find a void in one!). Then once you size them, all bets are off. For the 45-70, don't bother. No flaming anyone, just pointing that scale repeatability isn't good enough and for heavy boolits it makes no practical difference. Best I've done with the AR10 is 0.6x0.6 @ 100, nothing weighed or trickled & several times fired brass. I'm not that good a shot to do better.

[Grmps]

I like this, multiple answers WITH explanations.

[Grmps]

Interesting question.
1% is the acceptable variance in weight.
.500 grain boolit = .005 difference is acceptable soo,
if .500 to .505 is acceptable/ shoots the same
and .500 to .495 is acceptable/ shoots the same
would it not stand to reason that .495 to .505 would shoot the same if you base the load on a .500 grain boolit?

Yes, sometimes I tend to overthink things.