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Casting for 45/70

5812 Views 19 Replies 8 Participants Last post by  slk
I just called Uberti and asked what the bore diameter was on the 1874 Sharps Down Under model in 45/70. I was told it was .450........I thought 45/70 was supose to be .458.. Am I mistaken or do you guys think it very well could be what they stated??????If it is so I will really have to resize my bullet castings.

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The bore (diameter across the lands) is .450". The groove diameter is .458". And those are just the ideal numbers for conventional rifling in .45-70. You need to slug the bore with a pure lead slug and use an OD thimble micrometer with ten thousandths resolution to measure these two for yourself to know it for certain. When you have the real groove impression OD you can choose the sizing die to size your cast bullets 0.001" to 0.002" larger. Thus, if your bore is dead on (not all that uncommon these days), your cast bullets will be sized 0.459" to 0.460".
I have been told that no question is a stupid question so here goes. What is the procedure to slug a barrel??? Do you mean incert a slug of very soft lead and push it through with something or actually shoot the bullet into something and retreive it???
you want to start with an oversized soft lead slug (probably at least .460") and drive that through the barrel.
If you shoot and catch, it is likely to change the dimensions while being slowed down. The only exception might be really soft snow, but that has it own challenges in finding enough soft snow without any icy base, or ground, or anything else to damage the bullet.
I cast my WW alloy bullets for sizing to .459 and my softer lead alloy bullets to .460. I use gas checks on both of them.

In my Marlin 1895 in 45/70, I cast bullet from a design done by Ranch Dog, which he is out of business.

Ok I think I understand now.

I have been looking at the molds, and for 45/70 they offer one with a hollow bottom and flat bottom. What is the significant difference for this as far as reloading goes. Do you have to use different components or not??
I use the same brass amd primers, The powder depends on the load for that bullet

Uberti sent me a note stating that the grove diameter of their 45/70 Sharps Down Under was .456. If this is so what size mold do I need to get for casting bullets.

Now that being said I thought most 45/70 's were .458-.459 for a groove diameter. Does this mean that I will have to be choosy as to what factory loads I buy???

I will do a slug test to make sure.
Lead bullets won't mind 0.002" over, if they chamber. Find a mold that drops around that much large, and you have the option of sizing down a thousandth or two, whatever the rifle likes.

Factory loads should be mild and trouble-free.
I am starting to get extreamly confused as to what to use to cast my 500gr 45/70 bullets!!!

I don't know if I am making this hard on myself or not.

Some people say straight wheel weights will work just fine.

Some say like Lyman 9lbs wheel weights and 1 lb 50/50 plumbers solder

Then some say heat treating is a must

Does anyone here have a simple solution to casting. I guess this is the $64 dollar question that everyone asks. I need help, but please keep it simple. I am going to try to duplicate the 1200 to 1400+FPS as the BP loads with a 500gr bullet. I will be using reloader7 with 30 gr to start.

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Wheel weights should be fine at velocities of under 1800 fps or so, which is where those big heavies will likely be. Use a mold for gas check bullets if you are worried about fouling or intend to shoot them hot? You can heat treat wheel weights if you want to try that out, but I don't believe you'll find it necessary.

Lee makes a reloading press mounting sizing die in .457" if you don't want to buy a lubrisizer tool? Just use their tumble lube, run the bullets through and lube them again.

If you have ongoing issues with fouling, look into firelapping the bore. Also, you can look into paper patching bullets, though that requires a narrower bullet or a lot of sizing down.
Ok I just cast some 500gr bullets. About 20 of them to experiment with. They look nice and appear to be of similar hardness as a factory lead bullet. I measured them. The base of the bullet ranges from .458 to .462. When I say the base the very last ring at the bottom. They all measured about .458 from that point up till the tip which is round nose. I am thinking I need to size these????? .462 would be hard to start in the case, and deform it.
I agree with unclenick. Wheelweights are just fine for the velocity you are looking for. I load the Lyman postell bullet and AA5744 in a Pedersoli Sharps. Velocity is 1250fps with groups that hover around 1in. ,provided I do my part. As to sizing,I size to .459 with a bore dia. of .457. Hope this info helps.
Ok guys I just weighed the bullets I cast with wheel weights only. They are coming out @ 510- 512 gr...Is this common for the Lyman mold 457125.

That's not much error. It can be changed by your alloy and casting temperature. I think of most molds as having a range, for that reason.
slk i don't tkink RL-7 is going to be a good choice the load you mantion 30 gr Rl-7 and 500 gr #457125 only generates about 11,000 psi not enough to obturate [expand the base] to seal the bore and most likely will lead the bore, mix your ww w/ 2% tin to help fill out the mold and bullets should be approx 12 bhn for a 12 bhn bullet you need a load that generates between 17,000 and 27,000 psi try 28gr AAC-5744 for 1,183 fps and 17,400 psi as a min to a max of 33gr for 1,397 fps and 26,100 psi and anywhear inbetween. if this powder is not convenient repost with something that is and i will see what amount to use for the proper pressure. if you do use RL-7 a load of 40gr will be needed to make enough pressure to seal the bore and prevent leading this load will make 17,100psi and 1,600 fps, Try here for a ton of good info. Los Angeles Silhouette Club good luck skandic
also my saeco #18 405gr mold drops ww+2% tin slugs at 415gr this is typical of ww lead they also will be a little smaller than pure lead
I just picked up a little booklet on reloading the 45/70. Under the Lyman bullets made in the 457125 mold 500gr it says they used 1/2 gr polyester fiber wad, 5/8" square X 1/4" thick over the powder.

I am starting out with 30 gr of reloader 7

Anyone here ever use the polyester fiber they are talking about and are you supose to use it

Slk: Your 510-512 grain weights are not unreasonable. Lyman moulds are made to throw the designated weight using a #2 alloy, which you can look up in any lyman cast bullet manual. Most casters don't have access to or don't make the effort to have access to the exact ingredients to get the perfect weight bullets. The Lyman 405 gr mould throws anywhere from 405-418 gr depending upon the alloy or with pure lead. I've cast bullets for my vintage Winchester and modern Marlin .45-70's and 90's for over 30yrs and have in that time used about every form of scrap lead under the sun-- fishing net weights, wheel weights, wine bottle wraps, battery lead, you name it, much of it alloyed with babbit material containing lead, tin, antimony, and sometimes nickel or copper. They all go out the barrel with devastating effect and have killed bears, moose, deer, and caribou. Wait 25 days after casting to size your cast bullets; they'll be about done shrinking by then. Size them too soon and they'll shrink more and rattle down the bore and print all over the paper. At low velocities there's no real need to hard cast for the .45-70. Pure lead bullets actually work better on game as they expand more. Even pure lead bullets will go clean through both shoulders of a large moose at 100yds, or even 200 yds. I've seen it in my hunting. When you slug a barrel make sure to use pure lead and lube it v. lightly by hand. Drive it through with a wooden dowel or brass or aluminum welding rod. Wood works very well. Make sure to mic your sized bullets to make sure the sizer is on.... they don't all size to what they say they will. SPG lube from Buffalo Arms is supposed to be the best for the big cast bullets in the big old guns according to a friend who knows far more than I ever will about the subject. Lube can make a huge difference in accuracy I'm told. I use IMR3031 for all my .45-70, 90 loading. Cast or jacketed bullets.
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Ok guys i just got back from the range.I shot my 500gr 45/70's with 30 gr of reloader 7 and I crimped the load. It was a pleasure to shoot and I had very good acuracy at 100 yrds. Round holes went through the paper target. I was able to find the cast bullet and they held up just fine with the front half bent over I presume when it hit the gravel berm. I did not have much, if any leading in the barrel.

I think I will load up to 34/35 gr and see how it does. The guy at Allient told me 34 to 35gr's should be a pretty good load. I also used regular large rifle primers. Allient suggested i use magnum primers but I ellected not to, and the rounds worked just fine.

Thank all of you for your input. It truly was a big help

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