How I slugged a .45-70 without a 'mold'.

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How I slugged a .45-70 without a 'mold'.

Post by walstr » Mon Dec 29, 2014 8:57 pm


Last year I desired a 45-70-405 mold with a defined crimp groove, for my 2003 vintage Marlin 1895GS. I saw nothing on the 'commercial' market that tripped my trigger. It was then necessary to obtain a chamber & breach impression to see what I actually have to receive some future magic boolit. I cannot afford those exotic low melting temperature alloys & didn't feel I could trust their dimensional stability, after some articles I read, so, after a few calculations I:

-- obtained some SWW's [stick on wheel weights] which are reported to be 99% [or so] pure lead, a propane torch, a small aluminum
funnel, needle nose pliers, 3/8" dia. rod, 3/8" dia. rod or dowel @ barrel length, hammer, helper/3rd hand & an empty rifle case
-- drilled a few 1/2" dia. holes, about 3/4" deep in a scrap 2x4,
-- drill or fashion a 5/8" dia. hole to hold the rifle case,
-- wrap aluminum foil around a 27/64" drill shank & fashion a "cup" about 3/7' deep,
-- place your new aluminum cup into the 1/2" dia. hole & gently enlarge it with a 15/32" drill shank,
-- melt lead into these "slug" molds,
-- heat the rifle case's top half to a red heat & cool with water/wet rag [this annealed case will better form to your chamber],
-- melt lead into your case, stopping 1/4" from full,
-- force one of your suitable lead slugs into the case & taper its front,
-- place your barrel muzzle down into an old boot [a cushion],
-- place this "chamber slug assy." into receiver & with the steel [wrapped in tape] or brass rod, hammer down onto the case, thus forcing
the slug into "battery" until you can close the breach,
-- now open the action, & tap the "chamber slug assy." from muzzle, into the receiver,
-- measure diameters [micrometer or dial caliper], dutifully record & gently wrap this valuable "tool" for safe keeping.

The result was not perfect, but did yield sufficient areas for good data taking.

Looking back at all these steps now, I'm surprised I accomplished this arduous task. Truth? It was fun to figure it out & help myself to obtain a needed piece of information. Since then, I've read where some use a bore dia. + slug & pound it in from the muzzle. That seems to me as not a great idea, stressing the bolt, etc.

Best regards & play safe,


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Re: How I slugged a .45-70 without a 'mold'.

Post by mtngun » Tue Dec 30, 2014 10:38 am

Well done. Thanks for sharing.

I always have done it by pounding from the muzzle. Use a brass rod, or if you must use a steel rod, give it several wraps of tape in several spots to keep the steel from touching the surface of the barrel.

It is not necessary to have a perfectly fitting bullet to make the impression. Drop a too-small bullet in from the muzzle and pound it to fit. Or smack the bullet with a hammer to bump it up to a close fit.

Having tried both methods, I now favor the upset slug method over cerrosafe, at least for rifles. Sometimes the cerrosafe method works well, but othertimes stuff goes wrong -- either it spills into the action where it is difficult to clean up, or else it gets stuck in the chamber and has to be melted out. Then there is the problem of guessing the true diameter based on the cerrosafe diameter.

Cerrosafe perhaps makes more sense for measuring revolver chambers. If it gets stuck in a revolver chamber, it's easy enough to pound out or melt out by putting the cylinder in a boiling pot of water. But there are other ways to measure a revolver chamber -- pound a soft slug or a fishing sinker through to determine the throat diameter -- bear in mind that the resulting slug may be about 0.0005" smaller than the true throat diameter. To measure how far out you can seat a full diameter bullet, drop a slightly oversize bullet in base first. Pin gages also work well for that purpose.

If you need a bore riding bullet, measuring the bore diameter precisely can be difficult no matter which method you use, plus the bore is often eroded near the throat. Ultimately there is no substitute for trial and error with a real bullet. :(

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