Need Help with casting for .45-70 Trapdoor Carbine please

[paulsnapp]

I recently purchased a Lee single cavity mold 459-405-HB to cast a 405 grain hollow base bullet for my Springfield .45-70 Trapdoor Carbine. I cast a hundred bullets using a RotoMetals 20:1 alloy at 725 degrees F and they came out looking pretty good. But, I weighed them and they were consistent at 388 grains. I tried the tech at Lee and they said I needed to cast at 800 degrees. I tried again and it did increase to 390 grains. I called Lee again and asked why I could not get 405 grains as they advertised. They said their molds were based on a 10:1 alloy and since I was using a harder alloy my bullets would weigh lighter. I tried to explain to him that I was using a 20:1 alloy which is not harder than 10:1 and by their logic my bullets should weigh more than 405. I also told him their 10:1 alloy has a hardness of about 11 and the 20:1 alloy I am using has a hardness of about 10. He still says I am using a harder alloy and will not get the advertised 405 grains unless I use a 10:1 alloy. Can someone here please help me understand what I am missing???? I think the Lee tech does not understand alloy hardness. Also, anyone else used this Lee mold and how to get to 405 grains? Heat higher than 800 degrees? Thanks for any help!!

[rancher1913]

don't worry so much about weight. as long as they all weigh close to the same, load and shoot. if your recipe calls for the 405 grain boolit, back off the charge a little and see what it does.

[Kraschenbirn]

If you've got (or can obtain without too much trouble) some pure lead, try 25-1 or 30-1. Dunno where Lee's so-called "tech" learned his metallurgy, but tin (Sn) is considerably lighter than lead (Pb). The higher the percentage of tin, the lower the weight for a given volume. Also, finished weight can (will) vary from mold to mold; I've had two-cavity molds from Lyman and RCBS that varied as much as 1.5 gr. (a little over 1%) between cavities. FWIW, my own Lee 405HB drops just a touch over 400 gr. from 25-1.

Bill

[country gent]

just manufacturing tolerences on length or the hollow base plug could make that much difference. Sometimes preheating the mould to temp and casting hard and fast helps. The hollow based pin may be the issue being at max size for length and dia. A 458 dia bullet cut on the short side of tolerences may be part of the problem also.


If weights are consistant and fill out good I would try them as cast and see how they do. On a 405 grn bullet 10-15 grns wont make a lot of difference in reality.

[JimB..]

Maybe a dumb question, but won’t running hotter reduce the amount of melt that fits in the mold? Said another way, won’t the bullet shrink more as it cools the hotter it starts? Might get better fill out to offset some or all of this.

I know that it probably isn’t significant, just curious.

[roharmon]

Adding a little pure lead will increase the weigh

[Harter66]

I had a 405 HB I poured pure , 408 I think . I wasn't keeping really solid track as it was a trial of the bullet and it didn't work out for me .

The base plug is most likely the bug in the weights . If they are scaled for tin/lead it's probably closer to 1:40 than 1:10 .

[GhostHawk]

Don't sweat the small stuff! They'll shoot, and that is all that matters.

[WHITETAIL]

I would shoot them and see.
Be more concerned about size.:cbpour:

[Freightman]

My 405 HB cast at 394+ - dont worry they still hit what I shoot at. [smilie=l:

[chutesnreloads]

My 405HB drops at 401 grains with 1 lb. Lino to 8lbs. pure with enough tin mixed in to equal the antimony

[GoodOlBoy]

have
you
tried
shooting
them?

Everybody is worried about bullet weight... You should be doing handstands and cartwheels that it is an eerily consistent weight. Try shooting the darned things and see what kind of grouping you get. Nothing you shoot; paper, critter, etc; is going to look back at you and laugh because it wasn't 405 grains.

my 2 cents - guy who also owns a lee 405 HB mold that doesn't drop at 405 grains but is consistent and DANGED accurate....

God Bless, and One Love

GoodOlBoy

[mehavey]

Same mould, 30:1, 800° --> 398gr
Don't sweat it.

[Echo]

Don't sweat the small stuff! They'll shoot, and that is all that matters.
Big PLUS ONE!

[gpidaho]

I have Harter66's old 45 cal HB mould. My Henry 45-70 loves that bullet. I don't think I've ever bothered to check what the castings weigh. Gp

[modified5]

I have the Lee 457-405 rnfp mold and with 50/50 soww/coww it casts about 420 grains.
I weighed them just to see how consistent the mold was.
If I can get them to shoot, I don’t care about the weight.

[KCSO]

Sized and lubed mine run just under 400 grains. They shoot good though.

[Joe S]

I quit keeping track of my 45-70 reloads when I hit 20,000, and a good many were loaded for the trapdoor. I see no reason why a slight deviance in weight would be a problem. I have quite a few 45-70 molds and I don't think ANY ever cast 405 grains, even though 405 is the listed weight.
If you want to maximize your accuracy, weight and sort them by weight so that each box that you shoot has bullets of the same weight.
Unless you are shooting in competitions, a variance of a few grains wont be noticeable, especially for offhand shooting.

You probably already know this, but if not: You can expect a trapdoor to have a groove diameter over .457. Groove diameters of .459-.461 are common. One thing about Lee molds is that they usually are very good about dropping bullets at the standard diameter. If you have not already done so, slug your bore and get a mold that drops a bullet equal in diameter to the groove diameter of your rifle or 1-2 thousandths over. Accurate molds can provide a mold to your specifications for under $100, (double cavity).

The trapdoor is a great rifle, all of mine have been very accurate and very reliable.(Way more reliable than a Sharps).
I hope this information is helpful to you.
Joe S