I'm using a Lee 405 gr 45-70 bullet mold.. I am using the tumble lube and it is a plane base design. Shooting as cast.. I loaded my first batch of bullets with 4198 at the starting charge, in the book.. rifle is a Marlin guide gun.. My question is.. is it worth resizing these bullets in a sizing die.. i shot these at about 75 yards got about 4MOA with very limited rest (was not very steady).. I'm just looking at plinking load mostly.. B2B

Check your barrel for leading. If you did not get excessive leading or high pressure signs, you should be ok. I shoot the majority of my cast bullets unsized. Invest in a pair of calipers to measure your bullets. Check ebay, I have picked up several good calibers for about $20.

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A truely successful life is mostly based on how well you handle PLAN B.

I use the digital calipers that Harbor Freight has on sale. I shoot that bullet as well as many others in my 1895. If you tumble lube, why not buy one of the Lee sizer die sets, they work. My Lee sizer that was .457, I took it out to 459, the bullets engage the rifling better in my 1895.

Jerry

I was thinking about using a lee sizing die lube kit but I didn't know if it was needed for sure, I did have some leading in my barrel but the tumble lube does not fill the lube groove's very well like a luber sizer does..and it was very minor..leading.. B2B

Often you get less leading firing as-cast because sizing corrupts the surface of the bullet which has a softening effect that migrates over time. However, if the as-cast bullets are too big, you usually get some swaging that can be uneven, introducing wobble to the flight path that reduces accuracy. The question will be what diameter your barrel grooves actually are and what diameter the bullet actually is? A lot of us with lever guns find that a cast bullet about 0.002" over groove diameter is near peak accuracy. Even half a thousandth can make a difference if you get to tuning this. So, you need to slug the bore with a pure lead slug and measure the bullet to be sure.

You also need to slug the length of the bore. This means running an oily patch down the bore and pushing a soft lead slug all the way through it to feel for constrictions. They are not uncommon under dovetails for sights and magazines. They are ruinous to lead bullet accuracy, and need to be removed by firelapping or by hand lapping to get best lead bullet accuracy. Smoothing the bore that way will also greatly reduce whatever metal fouling you still get.

Typically, I haven't really found calipers are adequate for this task. They've gotten better over time, but occasionally you find a set that are off by as much as 0.002" and 0.001" error is not uncommon. The fact the digital ones now often resolve half a thousandth doesn't mean their absolute accuracy is that high. You can compare a slug and a bullet directly that way to find their diameter difference is correct, but if you need the absolute number for ordering a sizing die, you may not wind up with the right die. The best thing for measuring slugs and bullets is something that will resolve ten thousandths. That means using an OD thimble micrometer with a 0.0001" vernier scale. There is one on sale at Enco for $14 that should be adequate to the task.

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Nick

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"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

Uncle Nick is right. I am not a machinist so I said calibers when I should have said Micrometers. Check ebay as there are a lot of them for sale at reasonable prices.

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A truely successful life is mostly based on how well you handle PLAN B.

You would be better off unsized in a Marlin, they tend to run large on the bore.

Unsized is what he has now, and it isn't shooting for him. Hence the need to do some slugging and measuring.

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Nick

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"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

Don't forget that it might not be a bullet problem alone. He is using a starting charge of 4198, which might not be performing that well. Also, his alloy could affect his accuracy, especially with a starting charge (hard bullet, slighlty undersized, low pressure, no obturation). None of those would be solved by sizing the bullet. Also, we don't know how well cast the bullets are, and if the bases are perfect.
As a side note, a friend looked for my advice on some .30-30 bullets he had cast, because he was having poor accuracy. He brought in a bag, and I rejected 9 out of 10 due to poor bases or other gross casting errors.
Perhaps a couple of pictures of the cast bullets would help us to help him?
Perhaps a different powder, or an increase in powder to see if it makes a difference.

I would add another item to the sound advice that has thus far been posted. With plain base, generally you will get reasonable results around 1200fps with basic techniques and equipment. This of course will occur with some alloying of your lead.

Refer to the last few editions of the Lyman Reloading Manual. Starting loads with Unique. Use filler as recommended. You could use soft toy filler or basic light foam cut into strips or wads. You must keep the powder on the primer to get consistent ignition. If laying loose there is a greater surface area exposed to the primer flash.You will get irregular burning and pressure curves. In some cases hazardous peak pressure curves. The filler wad is ONLY to retain the powder in the base of the case.

Gradually work from the fast burning powder (Unique) and others to where you get your desired result. Do not be seduced by velocity. You have projectile mass in a relatively short range practical off the shoulder hunting rifle.
This will put game down and be great to practice on targets with. Personal experience has been favourable with Unique and lower velocity loads.

Thanks for the info on this bullet.. this was my first batch of bullets I have cast with this bullet mold.. so I think it is too soon to tell if it is a bad load bullet combo/ yet.. My bullets were not perfect, that is a known, and the alloy was an unknown mix of lead so I'm not sure how hard it was.. etc... I used to cast bullets a lot years ago, but I have not done it in a while so I have to get back into it.. The starting load was just to sight the gun really.. I had not expected great accuracy out of this first load.. so have some work to do to dial it in.. and I will continue.. Thnaks again B2B

B2B I am shooting a Marlin 1895CB mild load in it is 405 and 25gr of AA5744 ...around 1200fps and cast at 20-1......sized .459

I cast 405gr bullets using linotype with lee mold dipped them while hot in javelina bullet lube,didn't size them used sr4759 in my navy arms octagon barreled remington rolling block,never had any leading problems.

When I am using my Ranch Dog bullets in my 45-70 Marlin, they are sized in a Lee sizer to .460 and are extremely good for hunting.

It isn't the bore is over sized, it is the microgroove rifling that likes the larger diameter bullets.

Jerry

I think the first thing I would do is take a look at your crimping......I had the same issue with that same bullet...And I found if I lighten the crimp that it shot pretty good......Another thing I found is that for a pinking load,I used Uniqe powder..It was like 14 to 16 grains is all..I was really surprised at the accuracy...at 100 yards I had bullet hoes touching each other...Get yourself a good steady rest as well...Good luck and let us know what you have found out..John

My marlin 45-70 guide gun does not have the micro grove rifling. i think marlin changed that over awhile back.. I'm going to do a bit more casting with the combo before I get serious about sizing and such.. I'd rather use a gas check but that is not an option with the lee 405 mold.. and it adds a bit more money to the price of the bullet as gas check have gotten to be very expensive these days.. B2B

Micro-grooved rifle barrels often need larger diameter bullets because the bores are larger. My understanding that it is a result of the micro-groove manufacturing process. Once the bullet fills the bore there is no need for the bullet to be any larger. We tend to use slightly larger than bore diameter bullets to help fill the throat, and to cover any discrepancies in bullet diameters and loading procedure. Micro-grooves do not need extra large bullets once you hit bore diameter.

The manufacturers can make the bores any size they want. If they can make a .310" bore, they can surely make a .309" bore, or a .308" bore, or a .307" bore, etc.

Slightly oversized bores do reduce pressures a tad. Also, don't forget that tooling wears out over the production run. There are tolerances for everything.

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MikeG

For three of my 45/70's the LEE 457X405 shot into sub one inch at 75 yards, but my original 1895 45/90 Marlin needed the LEE 459X408 hollow base. Then i found that one of my older 45/70's had a rusted barrel and the 459X408 cured its accuracy problem.

B2B,

I cast that bullet, size it .458 in my Lyman sizer and have great results with it in my M1884 Rifles and IMR4198 powder. I cast my bullets out of OLD wheelweights with a dash of tin and drop all bullets from the mould into a bucket of cold water. No leading, just great accuracy. Hope this helps.

Webley