Seating bullet deeper in a .45-70 Trapdoor load

[ruddy]

I was trying to load some flat point 405 grain bullets in once fired Remington brass, and I discovered that the rounds would not chamber in either my 1888 Trapdoor Springfield or my Marlin 1895SS, because the bullet was hitting the rifling. The bullets were crimped at the crimping groove, the overall length was slightly under the maximum (2.530" - max is 2.550") and the cases were slightly under the trim-to length.

I've loaded some similar 350 gr. bullets that work just fine at the same overall length. The ogive of the 405 gr. bullet is just too blunt to chamber. If I seat the bullets about 1/10" deeper, the round will chamber in both rifles. This means, of course, that I'd be crimping into the bullet above the groove and the case capacity would be reduced. I was planning to use a starting load of 26 gr. of A5744 powder, but I'm concerned about reducing that to allow for the deeper bullet seating. What do you all think?

[Chill Wills]

Is the offending bullet a cast bullet - Don't want to assume too much?
Which one? Normally cast bullets with crimp grooves are set up to work well in standard chambers that conform to SAAMI - that said the bullet would not have a very large full diameter band in front of the crimp groove.

Time to measure the bullet. Do you have a micrometer?
How large and long is this front band?
and, what is the diameter of the nose?

The answer to these questions will start the conversation.
Can you measure these and post them?

[KenH]

Take an empty case, sized so there is a very small amount of neck tension on the bullet. chamber this round and push in so it's fully chambered, with breach closed. Now extract round and check seating depth. That should give you a bullet that's seated so the bullet is touching rifling and a good starting point to determine how much you wish to move bullet from rifling. I wouldn't worry about that tad extra seating depth - 26 grains of Accurate 5744 is barely over half case anyway.

Now, let's hear from the experts - is that Lee's .457-405-F mould?

Ken H>

[ruddy]

Chill,

It's a 45R 405 gr. FP .459 cast bullet from AArdvark Enterprises Cast Bullets. It has one grease groove and one crimping groove. The dimensions are: length - .985, front band just above the crimping groove - .459 diameter & .184 height before ogive, nose length from crimping groove - .437, width of flat point - .323. It actually looks similar to the cast 240 gr FP bullets I load for my .44 Special.

Ken,

That's what I did to determine that I need to seat the bullet 1/10" deeper.

[Chill Wills]

ruddy 10-4 on that.
If I understand correctly, that is an unusually long full diameter band ahead of the crimp groove. Almost 2/10 of an inch.

Springfield chambers are often generous BUT not in throat length - they are short with rifling starting with a taper at the case mouth. You might try what KenH recommends, (see above) if you do that you likely will see the bullet pushed in past the crimp but snug with the start of the rifling.
I agree with Ken, it will only be a little and it will be next to no difference in pressure or velocity - plus; being a singleshot, OAL will not mater IF it is correct for your rifle. You really do not need a crimp in this load.

Over all, I think it should shoot well. Have fun.

[ruddy]

Thanks a lot. That's what I was hoping to hear. I'll load some up and try them out! :-D