Need Reduced BP loads for 38-55

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r.j.medals2

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... I have an 1881 Marlin in 38-55 and am looking to fix up some reduced Black powder loads . I have reloaded many other cartridges with nitro powders but never BP , I have some Goex Ffg and Fffg . Any advice on how to do this and what is required , fillers , technique etc. ? Cheers
 
In theory, the 38-55 case should hold 55 grs of BP, but I've never been able to put more than 50 grs thru a 30" drop tube. Keep in mind that there are 2 case lengths available for the 38-55: 2.085" and 2.125". This is the protocol I use to arrive at a charge for my 38-55's (2), 40-60 Maynard and my 40-70 Sharps Straight. I fill a case to the top using the drop tube to determine case capacity. You can omit this step, I do it out of curiosity! For the 38-55, it's 50 grs. Take an empty case and the bullet you want to use, lay the case on your bench, then lay the bullet beside it to the crimp groove and mark the case at the base of the bullet. Now, fill the case to the mark plus 1/8". Add a milk card wad, usually .020" over the powder and using a compression die, compress the charge to the mark on the bullet. Approx .145". Seat the bullet and apply a slight taper crimp to the case, just enough to remove the flare and add a little neck tension. To my knowledge, no one makes a taper crimp die for the 38-55, so I bought a spare sizer die, removed the de-capping stem and use it as a taper crimp die. I use Starline 2.125" cases, and segregate the brass for smokeless powder and black powder use. For the first loading with BP, I prep the cases normally: Full length size, bell expand, prime and load. For all successive loads, no re-sizing, I seat the bullet by hand and apply the taper crimp to provide neck tension. If you're using a hard cast bullet, you can accomplish the compression while seating the bullet, because it's only .145" of compression but if you're using a soft lead bullet, then a compression die is a must!
I'm sure other BP shooters will chime in with their own loading protocol.
 
Thank-you Oldrodder for this info. I read online that a fellow was using 40-45 gr of Goex FFg for reduced loads , any thoughts ? Also if there is less powder do you fill the case with corn meal or some such filler ? I want to try a safe lower pressure load to start with in this old 1881 [mfg 1886] Marlin.
 
You could always try Fg if you want less pressure. If the rifle is in good shape then I wouldn't hesitate to try a full load of Goex FFg. The 38-55 with black powder is pretty low pressure. Nothing at all like a modern smokeless cartridge.

With that said, if you want to use less powder I'd definitely use a filler to remove air space under the bullet. Felt wads are good for this. Any place that sells muzzle loader stuff should be able to get you some. Or you can punch your own if you get a 38 cal wad cutter. Cork is also a decent filler.

Chris.
 
r.j.medals2 said:
Thank-you Oldrodder for this info. I read online that a fellow was using 40-45 gr of Goex FFg for reduced loads , any thoughts ? Also if there is less powder do you fill the case with corn meal or some such filler ? I want to try a safe lower pressure load to start with in this old 1881 [mfg 1886] Marlin.
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If you're going to reduce the charge then you must use a filler of sorts. I use a dense, closed cell foam and a 3/8" (.375") punch to make the wads. I don't think you will see much difference between 45 grs and 50 grs of BP, keeping in mind that BP is only 40% as efficient as smokeless. When loading with BP, it is essential that no air space remains between the powder charge and the projectile. BP requires 100% loading density.
 
Decide what bullet you're using and then build the recipe from that. As was said earlier: there can be no void areas in a loaded BP cartridge, you need fillers if powder doesn't fill the case to the base of the seated bullet.

I would simplify the process by adjusting the charge to fill the case about a 1/4" higher than the bullet would seat, this will likely be +/- 45gr range. That way you will have a lightly compressed load, and there is no messing with fillers. You likely aren't going to get much over 1100-1200 fps whatever bullet you use, and that's about the minimum velocity you want anyway so no need to reduce farther. Easy-peasy.
 
I've only occasionally seen pressures for black powder loads so data is pretty scarce, but I would expect it to be somewhere around 15,000 psi or so based on what I remember.

Chris.
 
fiddler said:
What are the pressure ratings to expect from BP in 38-55?
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38-55 WCF has a SAAMI standard maximum pressure rating of 30K CUP, which is about 35000 psi. I expect the original commercial 38-55 BP cartridges would have been loaded to about 25-30k psi range, using 50-55 gr of 2F BP with a 255gr lead bullet.

It would be difficult to accidentally over pressure the 38-55 with BP but it could be done with a very heavy bullet and a fine granulation black powder. Stick to bullets under 300gr and use 2f BP and case capacity will run out before catastrophic pressures can be achieved.

Quickload doesn't calculate pressure for BP loads but it will estimate velocity for a given load. Here are some velocity estimates using a 255 gr lead bullet with various charge weights of 2F Goex BP in 22" barrel:
50gr = 1285 fps
45gr = 1228 fps
40gr = 1168 fps

The original 38-55 factory BP 38-55 cartridges moved a 255gr bullet at just over 1300 fps.

There is enough information in the above to make some estimates on pressures.
 
To be honest I can see ever getting anywhere near 25-30k psi in the 38-55. I've seen pressure data for the 50-140 loaded with 140gr of black powder and it was close to 30 kcup. Hodgdon did load testing so they could make smokeless loads of similar pressure. The Lyman Cast Bullet Handbook #3 has BP pressure data. I got rid of mine some time ago and I don't remember any of the normal BP cartridges getting much past 20k, most loads were well under that.

Chris.
 
If we're being honest, I don't know that the actual pressure matters so long as it doesn't exceed safe levels for the firearm it will be used in.

The original BP cartridge was a 255gr bullet at just over 1300 fps and that's the maximum I would aim for in a 1881 marlin rifle. There is some leeway to reduce that load but use fillers as needed to fill up the case.

Starting in the early 1900s ammo companies started selling 38-55 cartridges that were hitting 1700fps using smokeless powders. I would avoid using those loads in a marlin 1881.
 
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jethunter said:
38-55 WCF has a SAAMI standard maximum pressure rating of 30K CUP, which is about 35000 psi. I expect the original commercial 38-55 BP cartridges would have been loaded to about 25-30k psi range, using 50-55 gr of 2F BP with a 255gr lead bullet.

It would be difficult to accidentally over pressure the 38-55 with BP but it could be done with a very heavy bullet and a fine granulation black powder. Stick to bullets under 300gr and use 2f BP and case capacity will run out before catastrophic pressures can be achieved.

Quickload doesn't calculate pressure for BP loads but it will estimate velocity for a given load. Here are some velocity estimates using a 255 gr lead bullet with various charge weights of 2F Goex BP in 22" barrel:
50gr = 1285 fps
45gr = 1228 fps
40gr = 1168 fps

The original 38-55 factory BP 38-55 cartridges moved a 255gr bullet at just over 1300 fps.

There is enough information in the above to make some estimates on pressures.
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Its an interesting comparison. BP is just slightly more pressure at max loads than for modern powder, and not really any major difference in velocity with 255gr bullets.
 
fiddler said:
Its an interesting comparison. BP is just slightly more pressure at max loads than for modern powder, and not really any major difference in velocity with 255gr bullets.
Click to expand...

Factory smokeless loads were commonly loaded into the 1700 fps range after 1900.
 
jethunter said:
Factory smokeless loads were commonly loaded into the 1700 fps range after 1900.
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Is there a particular book you're looking at with those speeds? I have 3 different books and the charts are quite limited and not much over 1400fps with jacketed 255gr.
 
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