Was this a bad Idea?

[SpringOWeiler]

As an owner of 18 rifles (only 1 mosin) and 3 handguns I've been really obsessed with my 1895 Marlin 45-70 guide Gun as of late.
I decided why not try out the traditional load.
So I stuck 70 grains of Pyrodex in a case behind a 405gr bullet. When I poured the powder in I was a little shocked by how much it filled it; (1/4") from mouth. But being the "BOLD" re loader I am i seated the bullet on and seated it too the crimping groove. Goly that is alot of compression; but i didn't feel any abnormal resistance getting it that far down. I calculated it out too about 33% compression.
Is this normal for using black powder? FFG fyi

[Barnacle Brad]

Sounds reasonable. Lee sells a powder compression die which avoids distorting the bullet when seating...

[TimSr]

Thats why the cartridge was made so large. Look at typical muzzleloader charges.


I will caution about one thing I learned from doing similar with 45LC loads . Pyrodex is very corrosive, and makes a filthy mess in your gun. The only way I would do it again is to try one of the other, non corrsive black powder equivilents like Triple 7 or Black MZ

I'm sure you already know, but a reminder to others who may not, black powder equivilents are measured by volume, and not by weight. 70 grains of Pyrodex on the scales will be a lot different than 70 grains out of a power measure, so you must measure it, and NOT weight it.

[g.willikers]

Don't forget that Black Powder and the substitutes cannot have an air gap between powder and bullet.
That's why the recommended powder load filled the case.
There's one advantage to the muzzle loading rifle.
No matter how much or little powder is put down the barrel, the bullet is always right on top of it, with no dangerous air gap.
Not so with BP cartridges.
Care is needed.
If a light load is desired with the BP cartridge, filler must be used to eliminate the air gap.

[Salmoneye]

I thought Pyrodex was a substitute by Volume, and not by weight?

ADDING:

I see TimSR beat me...

[HiBC]

Spring,frankly I have only use true Black Powder,not the subs.

The cartridges were designed to be full,lightly compressed.

I suggest,at least for BP,you not worry about the scales.

Want to use your crimp groove? Good.Measure bullet base to crimp groove.I have made a nice adj brass gage,a depth gage case mouth to powder.You could make one of hardwood for one load,one bullet.About .437,or .440,maybe a larger dia/shoulder to stop on the case mouth.Drop tube your powder.

Make your gage to set up a moderate amount of compression.A sixteenth inch is not wrong.You just want to tamp enough to ensure zero air gap.What is best?A mystery of BPCR loading.

Now,you may want to weigh that charge.It might be useful to make a measure,but volume trumps weight.

I question 30% compression as a good idea.

[FrankenMauser]

I thought Pyrodex was a substitute by Volume, and not by weight?

That is assuming that it is measured at all.

I've known quite a few people that did the old "mountain man pour" - just tip the powderhorn up and stop when it 'feels right'...

Some of them, later on, discovered that they were dumping as much as 130 grains of 2F or 3F behind .54 and .58 caliber round balls.

Even people that do measure can make dangerous mistakes.
One of my brothers misread the owners manual of one of his first .54 cal muzzlestuffers and shot it with 120-135 gr of 2F or Pyrodex behind round balls, Hornady 425 gr 'Great Plains' bullets, and 750 gr 'buffalo bullets', for about three years.... before discovering that the barrel was rated for just 100 gr FFg with a round ball and no more than 90 gr FFg with conicals. "So that's why the recoil was so bad..."

[SpringOWeiler]

I measured it by volume.
I got a little confused on the compression and I may have over estimated.
This was my formula

Internal Case Height 1.95"
70gr Pyrdoex (BYVOLUME) 1.75"
Open space = .2"

Bullet Length 1.03"
Distance to crimp grove .6"

1.75"/(1.75"-(.6"-.2)) = 1.296 Which roughly equals 30% compression of original volume.
Is that formula wrong?

I only made 2 because it was more of an enthusiastic curiosity.

[Crankylove]

One of my brothers misread the owners manual of one of his first .54 cal muzzlestuffers and shot it with 120-135 gr of 2F or Pyrodex behind round balls, Hornady 425 gr 'Great Plains' bullets, and 750 gr 'buffalo bullets', for about three years.... before discovering that the barrel was rated for just 100 gr FFg with a round ball and no more than 90 gr FFg with conicals. "So that's why the recoil was so bad..."

He was pretty wide-eyed when he discovered that mistake.

Not that I would recommend it, but, that load was very accurate.

[hartcreek]

My current load for my Thompson Center Hawkin 1/66 is 140 grains/volume of FFG under a roundball. The PO shot it with that and I worked up to that gives best accuracy and under a round ball is quite mild.

[Barnacle Brad]

Curious why you are stuck on a compression ratio. Where did you get the idea you could do a one for one pyrodex for bp substitution? I have never used pyrodex, so presumed you were using published load data. My bad!

So get your bullet puller out and pull those loads apart. Then do your home work. You will either find load data or a conversion indicating how much pyrodex to use in place of bp. Or as HiBc suggests, make a gauge and fill the case to where the bullet will seat to the bottom of the top driving band with a little compression. That is unless pyrodex has a limitation such as triple seven on how much it can be safely compressed.

Gauges...

I have made guages with the bullets I am using by mounting the bullet in my drill press and taking down the diameter with a file, making sure to only remove material from below the top driving band. Red nail polish identifies it as a gauge after machining.

[45_auto]

Hodgdon (manufacturer of Pyrodex) seems to think that you ought to load Pyrodex by volume. In other words, fill up the case with light compression just like black powder.

Just as a side note, you're MUCH better off going to the manufacturer for loading info rather than asking a bunch of unknown, unqualified internet yahoos. I've copied part of the page below, but you really should read and understand the whole thing.

https://www.hodgdon.com/loading.html

All charges of Triple Seven or Pyrodex should be measured by VOLUME not weight....

Pyrodex works best in straight walled cases, but it will work satisfactorily in bottle necked cartridges as long as our warnings are observed.

WARNING: Never allow an air space in any cartridge loaded with Pyrodex. The loading density must be 100% by light compression. 100% loading density may be accomplished in two ways:

The case is filled with powder to a level that will provide light compression of the powder (1/16" to 1/8") when the bullet is seated. Bottle necked cases must be loaded in this manner.

In straight walled cases, filler wads may be used to reduce the powder charge. This is done by inserting card or Polyethylene wads between the base of the bullet and the powder. Wads should be sized to the internal diameter of the cartridge case. The loader must be careful to insure that there are no void spaces in the assembled cartridge. NEVER use any other type of filler material. Be careful as loads are reduced. At some point, the bullet will fail to exit the bore.

[Dragonflydf]

I use triple 7, filling the case to the bottom of a seated 405gr bullet. I use that load in my 1873 and 1886 Trapdoors.

[Colorado Redneck]

https://www.hodgdon.com/PDF/muzzlelo...?CHECKBOX_1=on

Hodgdon load data shows 60 gr. of Triple 7 for the 405 gr. bullet in 45-70. For the most part it looks as though Triple 7 and Pyrodex is interchangeable. Good advice above---pull the bullets and use the load data if you can find it.

[SpringOWeiler]

I'll take your guys advice and pull the bullets. And try again.

[catgunguy]

Brad mentioned a lee die for compressing powder. I can't seem to find it. Does any one know of a die for that purpose?
Thanks and I hope I am not hijacking the thread.