I have an 1867 danish rolling block. I thought it was chambered in 45-70 but to get a lee 459-500-3r to touch the rifling it’s barely up to the first grease groove. Could it be a 45-90 or just have a really long throat? It doesn’t give great accuracy with them seated to normal 45-70 oal. Could I load it long like that to just plink with it or is that too much air space in the case?

It won't give good accuracy with that bullet no matter where it's seated.
Best to do a chamber cast and see just what you're dealing with.

You also might want to check the barrel twist.

Years ago, Winfield Arms sold those as 45/70's. It is a different case, and a metric bore. Close, but no cigar. Check Cartridges of the World for specs.

Originally 11.7x56R. I just fireform 45-70 brass and use a .460 " cast bullet and black, works fine. Buffalo Arms carries the bullets.

Does it chamber 45-90 brass?

Thanks Craigster. I don’t have any 45-90 brass to try in it Bugger.

The Lee bullet has failed since it was found it will slump. The best bullet was the Rapine 500 gr Gov't at .460" but Ray retired long ago. I have the Lee mold and it will rot before I use it again.

Why don't you have Lee re-grind the mould to your specs?

I didn’t know they did that. Thanks

By the time you have that lee bullet reground, assuming they don't screw it up, you'll have the a good bit of money tied up in a set of aluminum blocks that are to soft to last long , and handles that are to flimsy to cast that big of bullet to start with. Better off to just go with a proven bullet like the Lyman Postel, or the RCBS 820284 or the Saeco 645.

I gotta kinda go with Ranch on that one. All my best moulds were made of cast iron {Lyman} and will outlast me.

Nose profile is wrong so it will slump. Too pointy. I put the mold on my table cheap along with a block of expensive lube touted by a shooter in gun rags. Forget but even a free sign left the stuff untouched, Shippensburg PA. Mike Ventorino and SPG. Stuff fouled the last 10" of my barrel so bad a patch would not go through. I could not give the stuff away. One of our shooters won the nationals every year. I met Kermit Hoke and he sends me an E mail every day, some days 20. I have a Browning BPCR to sell and no luck yet. Make offer. Paid $1400 and it is not made anymore. Perfect condition with sights and the Kermit adjustable iris. Change the peep in a second.

There's a fella on Historic Shooting forum by the name of Old Jim, that may be interested in that rifle.

My experience: I got one of those rifles going. The rifles were modified, as I understand it, to accept a 45-70 case by the importer-mainly in the area of the rim. . You will find that using 45-70 brass the 11.7x56R is larger in diameter.. I used Starline brass with no problem. You will have some swelling of the case. My C&H dies worked very well. Now here is the rub. I had slugged the bore. At one time there was a gentlemen who would accurately measure slugs from three groove barrels. He would keep slugs as payment. The groove diameter was .464. What to do? Running in circles with hair afire was not the answer. The Lee 400 gr. hollow base bullet worked great. I ran my in the last session using BP.. First up, I would try the Lee mold. My bullets were handlubed with SPG (no problem in this rifle or my four other BP rifles). The bullets were used as cast from unalloyed lead.. No wad was used as the bullet is a hollow base. The Lee bullet was made for TD Springfield's but will work very well in Danish RB's. I'd also look at the custom makers who can alter a mold without having to mortgage the ranch. The rifles imported here had been mostly modified for the longer 56mm case. My rifle had a excellent bore. Gave the rifle to a friend who had a RB fetish. I made up some loads with smokeless using Lee Tumble Lube and AAC 5744 using standard 45-70 loading data for low pressure actions. Yes, I know RB's are strong actions blah, blah. Take care and be safe. .

Lee Bullet won't fit? You recon that might be a bore riding bullet is a greatly over-sized bore? Also, what I was sharing was on a rifle that had not been further altered for another cartridge like 45-90. I think you will find these rifles did have a long throat, Don't cuss Lee. This generation of molds is vastly superior to those we grew up on.