reduced BP loads in 45-70

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  • Last Post 27 March 2021
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Ross Smith posted this 23 February 2021

The mantra for black powder has always been to seat the bullet onto the powder.In a straight wall case like the 45-70, can a bullet be seated all the way down on the powder of say a 30 grain charge? Or, just seat as usual at the case mouth. I have seated the bullet normally in the case with only 30gr FFg, but always wondered if it was dangerous. I'm shooting an original trapdoor.

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Bud Hyett posted this 23 February 2021

The bullet jump will be horrendous, this jump will affect the accuracy. With the taper of the case, can you even get the base down that far without pinching the base and also affecting the accuracy? Compressing the black powder charge for uniform ignition becomes another question. 

The 55 grain charge for the "Carbine" load uses extra wads to close the gap between powder and bullet base. The paradox of the Trapdoor is an oversize bore. Soft alloys that expand are recommended for accuracy. The Carbine load uses a hollow base 405 grain bullet to expand the base and engage the rifling. 

What happens as the bullet slides down the case and then engages the rifling could be interesting.  Seating the bullet down would be an interesting project, but I'd first do this in a modern rifle. A Trapdoor with good bore condition is becoming rare. 

Farm boy from Illinois, living in the magical Pacific Northwest

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RidinLou posted this 23 February 2021

Not even an amateur at BP Cartridge loading, but I would thin one would want an over powder wad, a filler and then seat the bullet.not unlike what is done with percussion revolver, but with the addition of an over powder wad,

One could probably do without the over powder wad IF they made sure there was good compaction with the filler.

The more knowledgeable folks can certainly correct my guestimations.

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Ross Smith posted this 24 February 2021

I've also used wads to fill the gap.

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tlkeizer posted this 07 March 2021

Greetings,

FWIW IMHO when using Black Powder (BP) I use wads in non-405 Hollow Base bullet loads for slightly better accuracy; not enough to make a difference when shooting for "heart of caribou".  The 3 molds I have place the bullet at the top of the BP without wads when seating the bullet to the top ring above the lube bands.  If fact, for over 60 grains powder I slightly compress the BP with the beveling die using 5 grains under the load I am using, then put 5 grains loose on top of the packed powder when not using wads.  If I am using a wad I compress starting at 60 grains, compress all of the load, then put the wad on top as it fills the gap between powder and bullet.  I could go the 5 grains less compressed and 5 grains loose on top route when using a wad, but the extra compression distance compressing by pushing down on the bullet when seating imprints the seating die much more on the bullet itself than I like.  It works either way, but like most of us when there are two ways to do something one way becomes the preferred way.

I am shooting original Springfield Trapdoors, one with the barrel re-lined and one completely original.  My groups are usually around 4 inches at 100 yards, some well under 4 inches and others not so well.  If the group is not under 2 inches at 50 yards I am disappointed and it is usually due to my eyes and not the loads and rifle.  Sometimes I really wish I had a scope for the trapdoors to see how well they shoot without my eye sight variance.  But, that is part of the challenge and keeps me shooting.

For those who have not followed my travels and travails with the 45-70, I have found that the two rifles are like any siblings.  One likes one set of loads and the other a different set.  The complete original likes the lightest bullet with the lightest load, meaning 405 grain Lee Hollow Base bullet over 55 grains FFG.  The re-lined barrel 45-70 prefers the heaviest bullet with the heaviest load, meaning 500 grain flat base bullet over 70 grains FFG.  Guess which one my shoulder prefers.

When it gets a bit warmer I have some loads with wads to shoot, and will post the results.  Warmer, in this case, means over 20 degrees.  Right now as I write this it is well below zero, but did get up to +12 today.  Maybe Wednesday for shooting?

Anybody that wants to come up and shoot 45-70 with me is welcome to do so.  We will manufacture some rounds and go un-load them at the range.

TK 

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Ken Campbell Iowa posted this 07 March 2021

hi TK ... what is the 5 grains you speak of over and under the charge ? ...  

i am hoping to shooit the BPC challenge match of GWarden here, and need all the sly little tricks i can gather ... 

ken,   Black Loads Matter 

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tlkeizer posted this 07 March 2021

Greetings,

Hi Ken.  For a 65 grain load, FFG, I put 60 grains of BP in the case, compress it, and add the last 5 grains of FFG on top, then seat the bullet.  If I am using a wad I put all 65 grains of powder in the case, compress it, then load the wad and bullet on top.  All 3 of the molds have the top ring above the lube channels the same distance from the base of the bullet, so that makes life a bit easier to deal with for me at least.

When I am loading a 55 grain load, I bevel the case before I load the powder.  Otherwise, I bevel the case after I put the powder in as the beveling plug does the compression.  I have my die set so it barely bevels the case while compressing the powder down as far as I desire.  A serendipity situation. 

What I have noticed while shooting is that the 500 grain bullet being considerably longer than the other two will have the cartridge harder to seat after a few rounds, so I need to brush the barrel to insure the cartridge seats easy after the first three or four rounds.  But then again, I find my groups are better by brushing after every shot when using BP.  For those wondering, I use Goex FFG and SPG lube when shooting BP.  For those not wondering, I still use the same.

  I cut up old t-shirts for cleaning patches, and after the second round use a spit patch followed by a dry patch, two patches, for every subsequent round.  Hey, I'm no longer in geometry class so have to use the spit wads someplace, ya' know.  Sometimes I will brush the bore with just the brush first; if you do that keep the action up-side down so the loose charcoal will drop out of the chambering area, a good idea whether you use a brush first, or spit patch first.

Good luck with the BPC challenge.

TK

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Reeferman posted this 20 March 2021

Curious of why you would put 5 grains on top of the compressed powder?

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rmrix posted this 21 March 2021

The mantra for black powder has always been to seat the bullet onto the powder.In a straight wall case like the 45-70, can a bullet be seated all the way down on the powder of say a 30 grain charge? Or, just seat as usual at the case mouth. I have seated the bullet normally in the case with only 30gr FFg, but always wondered if it was dangerous. I'm shooting an original trapdoor.

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rmrix posted this 21 March 2021

In reading your question, I am not sure there was an answer. I could be wrong.

30 grains under a bullet seated in the normal way is how the arsenal put out short range practice ammo (405grn bullet) in the 1800's for Springfield rifles.  In some loading's, using the 145 grn "button" density is even less. Lots of air space. I have the mold and built ammo to give it a try.  You hear all kinds of wisdom about not even a tiny air space under the bullet can be had without catastrophic results. 

The subject of cartridge powder to airspace ratio must not be the same as short starting a ML or even a few inches of air space in a ML. The difference is above my pay grade.

The BP era ammo factories made up unknown amounts (hundreds of thousands or more) of gallery loads for indoor shooting for Ballard's and Stevens rifles using less then 50% density BP loads. They were accurate apparently too.   Nothing in the writings even suggests people were blowing up rifles.   

??????

I don't know what to tell you, but my opinion is you are on safe ground.  (and you know about opinions)

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tlkeizer posted this 22 March 2021

Greetings,

Reeferman, I put the 5 grains of powder on top of the compressed powder to make sure I take up space between the powder and the bullet.  I started doing this when I was first shooting the 45-70'sbased on the "everybody knows you have to seat the bullet on top of the black powder with no airspace" mantra.  Since I started I still do it as I have had moderate success loading it that way.  I personally like to have the powder up to the bullet, and this way I do not deform the bullet nearly as much when seating it.  When I seat on top of 60-75 grains without compression of powder first, my bullet gets deformed somewhat.   Next time I load up some 45-70 with BP I will try to remember to load some in various ways so you can see the difference on bullet tip deformation.  

Using the expander die for compression, if I have less compression I do not get neck expansion for bullet seating.  If I expand the neck more, I compress powder more creating more space between the powder and seated bullet.  My expansion die adjusted as is just compresses the BP to where the bullets bases seat to, a serendipity situation for me.  I tried dropping powder, but this is a lot more consistent and a whole lot less messy with  no air particles to create a hazard in years to come.  Quicker too, and the cases need to be expanded so why not do both in one action?

TK

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Reeferman posted this 22 March 2021

Ok I figured there was a logical answer. I’ve always used a compression die and have it calculated now to where there is slight contact with base of bullet and no bullet deformation.I only load blackpowder in my 1873 trapdoor so don’t have that much experience in it. 

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Ross Smith posted this 27 March 2021

Well I shot the 30gr ffG loads today. 20 were seated as normal with no wads and 20 were pushed down on the powder. No problems, light recoil.  The 20 loaded with the bullet pushed down into the case were very snug but useable. So I won't do that again. It also deformed the meplat to squish them in like that. Thanks for the opinions.

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