45/70 cast bullets

[Frank46]

Got to thinking today and was wondering about the nose or land riding portion of a cast bullet for the 45/70. Lets take the lyman 485 grain gas checked bullet for example. We all know that we have to size the groove section to about .002 over the nominal groove diameter of the barrel. But what about the nose section which in theory is supposed to ride on the tops of the lands. Has anyone done any research regarding this?. Reason I ask this is I was suspecting that the nose section of the bullet could be made larger in diameter to better ride the lands. I was looking at pics of some paper patched bullets that had been recovered and they showed rifling marks further along the entire bullet rather than the groove sized diameter of the bullet. Now I realize the paper patched bullets are more of a straight cylinder that the above mentioned bullet I used as an example. So if this makes sense any comments and or knowledge anyone wishes to share would be greatly appreciated. Thanks,Frank

[44man]

It can get tricky with the 45-70 since many molds are too small, so many at .457". In theory the nose should be bore size. Harder to find. Makes for a straighter start.
It is not easy to get a mold exact, made one for my 30-30 and I have to size the nose in a separate step. The bore on my Marlin is .301". Darn nose came out .302".

[Litl Red 3991]

...........Reason I ask this is I was suspecting that the nose section of the bullet could be made larger in diameter to better ride the lands.

I was looking at pics of some paper patched bullets that had been recovered and they showed rifling marks further along the entire bullet rather than the groove sized diameter of the bullet.

Those PP bullets may or may not have been cast larger in the nose than the bore dimension of the rifle, but could just have easily slumped on obturation. Since there aren't too many commercially available PP on the market, good chance they were home made and soft enough to have fitted the nose to the grooves on firing. Unless the picture taker explained, it's not a good bet either way.


But what about the nose section which in theory is supposed to ride on the tops of the lands. Has anyone done any research regarding this?.

Yes, there has been research into this from almost the very beginning. And it's still going on for sure.

If you look at any of the custom mould mfgs that cater to the big guns, you'll see plenty of their output is for just what you're wondering about.

[country gent]

Bore riding noses are a big plus and some rifles perform well with them. Sulg your bore and see what bore and groove dia actually is. Then measure several bullets as cast and see how the dimensions match up to your barrels. Driving section should be ,002 or so larger nose can be .000 - -.002 and still obtrate to work depending on alloy. I havent recovered any bullets yet they turn to dust when hitting the steel shillouettes. Ideally is the bore ride portion is size for size. ANy over bore size can make loading into the rifle hard. A indersized mould can be lapped to be exactly what you want. Coat bullet with very fine lapping compund and work by hand back and forth rotation the full dia of the bullet. If just the base or nose need "adjustment" only apply lapping compound to that area. remember .001 removed metal is .002 on dia here. Some shoot a driving section as big as they can load in a fired case regaurdless of groove dia. I normally size to .459 amd noses are on bore riders are just a light snug fit at the muzzle when testing.

[44man]

Slump to fit has always been there but it needs controlled. A Minie' ball too small will slump off center. Get it wrong and the skirt would balloon at muzzle exit.
The Lee 459-500-3R proved a failure with BPCR shooters from off center slump.
Maybe the best boolit ever is the 500 Gov't boolit from long ago. They knew more long ago then they get credit for.
Rapine made the best for BP with a choice of diameters for each boolit to fit your gun. Ray was a great guy but retired. He would talk my ear off and offered to sell me his business, Darn, wish I could have afforded it. He knew more about BP boolits then anyone I know.
I learned from the best, the Kindigs, Bill Large and more.
I took a Minie' ball from missing a 4x4 board at 50 yards to hitting a gong at 200 meters.
You will have a hard time telling me about slump from any gun.

[dh2]

I think the boar riding and dropping .460 is why I am getting along with an NOE460-405 in my marlin. I have no idea why Lee makes there 45 cal. rifle molds drop .457

[Frank46]

Thanks for all your input. I have 4 45 cal rifle molds and every one casts undersized. Only the lyman 486 grain gas checked bullet comes close at .459 on the groove dimension. I shot some out of my ruger #1 and groups were not anything to write home about. Since some of these rifles have constrictions where the barrel band/sling swivel and right at the front sight as mine has. I slugged the throat and that comes out at .459. maybe it's time to re-slug the barrel again. Frank

[JimP.]

SAECO 883 mold drops a 500 gr roundnosed bullet that is a two diameter bullet. it is a copy of the govt bullet loaded in the 1884 military 45-70 cartridge using 70 grs of black powder. i cast them and love how well they shoot using 25 grs of AA5744.

[Frank46]

Think I still have a couple of the 486 grain gas checked boolits in or around here somewhere. I recently got a set of pin guages and will try again. And thanks to all. Frank