Springfield trapdoor. 45-70

I'm fairly new to reloading, had the equipment and materials for years, and now that I'm retired I finally have time. So glad I purchased everything long ago while prices were reasonable.
I've successfully reloaded for my .50-70 Navy trapdoor, but I'm havng an issue with my .45-70 reloads.
I purchased some loaded rounds and they work fine, so I bought some cast lubed bullets and also made some of my own cast bullets. The cast bullets are .459 diameter, and I am unable to chamber these rounds. The overall length of the finished cartridge is the same, but the bullet diameter seems too large. I measured the bullet diameter of the loaded rounds that I purchased and they mic out at .451.
I can't seem to find any cast bullets of that diameter. Any help on that
Would be appreciated.
Also, is there any way that I can use a resizer die to salvage the .459 bullets that I purchased and the ones that I cast?
I slugged my barrel and it comes out at .451-.452.

My trapdoor shoots a 461 bullet. My 45 acp shoots a 452. What is the weight of the 451 bullets?

The cast bullets I purchased are 500 grn RN. I don't have my moulds here, but they are the same weight only with a FP.
The loaded rounds I purchased are 405 grn.,but they say .458" on the box. But when I mic the bullet just at the top of the brass it measures .451. These are from Buffalo Arms Co.

I think your bullet is probably hanging up on the nose diameter. It needs to be smaller then the bore diameter. See if the bullet nose will go in the muzzle freely. The chamber on those rifles were not throated.

I did notice that the cast bullets I bought and made myself are round nose. The loaded rounds I bought have more of an angled nose.
Wondering if I seat the bullet deeper if that would solve my problem? I sure don't want to bulge the barrel, or worse.
Thanks for your input on this. I'm a little cautious, especially with these old antique long guns which I absolutely love.

I agree with kootne. Depending on how your throat was cut, you may have to seat the round nose bullet more deeply into the case. My Sharps won’t chamber a Lee 500 RNFP seated to the front driving band but my buddy’s High Wall has no problem. I think I’d re-slug the barrel. Your bore is probably 0.451” but your groove diameter is going to be right around 0.459”

The bore of your trapdoor is most likely .450". The groove diameter is most likely between .460" and .462". The nose of the 500 grain bullet is too large for the bore. Use fairly soft lead so the bullets can bump up to seal the rifling or shoot a larger diameter bullet. I shoot a .462" diameter bullet in mine cast in 25/1 lead/tin. It shoots well.

I did try seating the 500 grn bullet a little deeper, and I can now chamber a round. Next step is to test fire a few rounds.
Thanks to everyone for their help, I greatly appreciate it!

63 grains under the 500 gr Lee bullet is best load for me. I’ve got a single round hole with 4 rounds and one slightly out at 100 on sandbags. Good luck

Would enjoy seeing images of the Navy 50-70. Not a fan of the small bore trapdoor myself.

Kevin