Thread: Black powder load for the 45-70-500 Trapdoor Springfield

Retrieved: 08/14/2016
Last Post: 07/28/2016

I had been loading 65gr of 2F behind a 500gr bullet until recently when I read book 'Loading Cartridges for the original 45/70 Springfield rifle and carbine. As a result I acquired a 5' drop tube managed to fit 70 grains of 2F with room remaining at the top of the case. To completely seat the bullet I would have to compress the powder 3/16" to 1/4". Whilst the book explains how to compress the powder (.5") and further mentions how the two arsenals of the time also compressed the powder in the service 45/70 cartridges he states not to use any of his compressed load due to pressure.

After all that I was wondering if anyone had any knowledge in this area -compressed loads?

2Bits
02-22-2016

Yes I certainly do sir! Sometime around the area of 1963 give or take, a person that I knew just started to get into reloading. He purchased a little handloader from LEE CO. it was very cheap and easy to use. Well, his father owned a Kentucky rifle (originally built by hand in Kentucky) and his brother owned a muzzle loader too. However, the rifle he was loading for at the time, was a 6.5 Japanese Arisaka.

Well, it seems as though he figured out that compressing loads made the rifle shoot better groups etc. He did "NOT" pay attention to pressure signs, like a sticky bolt and brass been shaven from the case head. This thing he was doing mind you, I had warned him against during a phone conversation. I got a call back 2 days later, as he had blown up a rifle that he was loading for at the time. His face got marked up some as well as his trigger hand. He has never reloaded a pistol or rifle since that day.

robinhood
02-22-2016

I've as a rule compressed all my BPCR loads using a compression die whether using black powder or Pyrodex . Paul Matthews, in his book,"Shooting the Black Powder Cartridge Rifle "suggests that black powder should not be compressed more than 0.1" otherwise it fractures the kernals and the burn is not uniform. Pyrodex however, he states can be compressed to @ 5/16". I usually compress Pyrodex @1/4", with my bullet simply sitting on a felt wad. I have applied his 'rules ' to both types of powders and have happy with the results.

54 flinter
03-07-2016

I've been loading the 45 70 for a while 15 years and I only compress my load of 1 driving ban and I use a 30000 fiber wad and I use 70 grains of Pyrodex P and all my rifles I have to trap doors I have a Remington Lee rifle and a iab sharp.

alfajim
05-02-2016

Bob, I also have Spence's book and having read it multiple times carefully it does state that compressing 2F at 70 grs is absolutely necessary to fully seat the 500 gr gov bullet. It will require maybe .5 to .6 of compression using a compression plug in a spare expander die and then seat the bullet just pass the first driving band and then crimp with a spare seating crimping die with seating plug removed. You also need to use a special expander plug to expand the case to .458 and deep enough to allow the bullet to seat fully.

All the dies and special plugs are available from Track of the Wolf.

To light this tightly compressed powder it needs a large rifle magnum primer with the flash hole drilled out.

Most of the trapdoor shooters do it this way to achieve the accuracy of old.

I am just now setting up to do my reloads for my trapdoor, of which I am still building from parts. Got really lucky and picked up some almost like new parts, barrel, receiver, lock plate assy, trigger assy, off Ebay for less than $400.00 including a shortened stock. Bore is like new lands and grooves very distingtive and edges very sharp. Anxious to get it done to go shoot it.

Dollar Bill
05-02-2016

Agree. There's no way to get 70 grains in without compressing it. As a standard practice, I load all my BP cartridges so there is about 1/4" to 3/8" compression. I get better accuracy and avoids the issue of developing air space if you're bouncing around on a horse for a day or 2, shaking the cartridges and ending up with a loose powder charge.

My heavy 45-70 BPCR loads, with a 525 or 530 grain bullet, light off just fine with CCI BR2s. There's even guys successfully using pistol primers at long range BPCR shoots but because the pistol primers are a little shorter then LR, most guys are staying with standard LR.

qdup1
07-28-2016

Can't figure out how to start a new thread so I need to quote this one. This is my first time on shooters forum and my first time trying to reload black powder cases. I have loaded four 45-70 black powder cases for use in a reproduction Sharps, using 2f KiK in Star Line brass, throwing a 525 Grain cast bullet. By volume I can get 70 Gr of powder in the case easy enough using a 24" drop tube. The charge weighs in at 67 Gr. I am using a .060 wad over powder. In order to compress the powder to the crimp ring on the bullet, I would have to compress the powder about 0.4". I had a super hard time trying to compress the powder down far enough. Seemed un-naturally hard. So after that I wanted to see what all that compression did to the powder, so I literally had to dig the powder out with a thin sharp stick. Some of the powder looked like 4f and it was almost a plug in some respects. After all this I believe I should lower the powder volume to say 60 or so grains by volume in order to have less compression on the powder. Would this charge be enough to throw a 525 gr. bullet accurately. And what other if any problems/issues would I face using a lighter powder charge. It seems that with all the compression the powder would would not burn uniformly or maybe it could cause problems with accuracy. This is very confusing to a beginner like myself. I want to do it correctly, even though I know there will be more experimenting with different powders, loads, etc. down the road. Any eduacted opinions or answers to my confusion would be greatly appreciated. Thanks.

LilysDad
07-28-2016

I believe if it was me, posts #2&3 answer the question very well.

To add my own question, if a person wants more powder in the cartridge, why not use a 45-90 and not have to compress it?

MikeG
07-28-2016

I think I would start with say, 0.1" or so of compression, shoot them, and then evaluate if I wanted more, or less. Drop tube is fine also.

Bottom line, you will have to find out what your rifle 'likes' and forget "so many grains by volume" as there is no such thing as "grains by volume." Grains are mass, volume is the 3-dimensional space the powder occupies

Different powders will have different bulk density, so there will never be a universal "grain by volume" conversion. What is marked on a particular powder scoop or measuring device, is just someone's opinion/experience with some particular powder.

Play around a little and find out what works in your rifle. It will tell you, I bet....

qdup1
07-28-2016

Thank you. I will forget the volume concerns and focus on weight. I have already found out that 2f KiK and 3f KiK fill the case differently when going by volume and going from brand to brand of black powder would probably yield differences in volume measurements too. I am just a little concerned about compressing the powder so tightly that the grains of 2f turn into a finer powder. Maybe I shouldn't worry so much about that and just shoot the rifle like you say and that will tell me more then just reading about it on every forum I find. I think I will just keep confusing myself doing that and learn very little.

MikeG
07-28-2016

I'm not sure I'd shoot loads with that much compression, either, but... there may well be more experienced folk that can be more specific.