unburned powder in barrel

[Mad Miles]

G'day.
I shot my rolling block chambered in 45-70 for the first time yesterday.  I loaded new Starline brass with 350 grain cast lead bullets, and 28-30 grains of H4198 Powder.  I got the load data from Lee Precision and from Hodgdon cowboy long range data.

When I got home from the range I took a look down the barrel and noticed quite a few large lumps (looked large looking down the barrel) about 3/4 way from the breech to the muzzle.

Today I cleaned the rifle and the first patch (dry) I put down the barrel had debris on it.  After looking closely at the particles I discovered it was powder, some of it pretty black but some unburned. 

Anyone have an Idea why I would be getting incomplete combustion?

Thanks.

[Cliff Fendley]

I got that when I tried 4198 in my 45-75. Lots of unburned powder in the barrel, some just barely charred.

[Kent Shootwell]

To light of load, smokeless needs pressure to burn. Light loads in big cartridges are problem makers. Try a different powder or a smaller cartridge.

[6MT]

Too light of load, smokeless needs pressure to burn. Light loads in big cartridges are problem makers. Try a different powder or a smaller cartridge.

I agree, that load looks too light. I shoot FCP 300gr in my 1895GBL. I use 49.0gr of IMR4198. Mind you, it's almost a bear load. But me thinks you need more powder. BTW, what primer are you using? And what's the OAL that you're seating that bullet to?

Caveat: that rolling block might not be suitable for a stout load though.

[Coffinmaker]

  6MT   

Ok, I get to break one of my bugaboos.  I usually try not to wander off into the swamp without a compass.  BUT . . . That Heathen Fad Smokeless stuff, as previously mentioned, requires PRESSURE to give complete combustion.  You must have a good, tight crimp (roll crimp better) with which to start our ignition.  Light load, wrong powder etc. etc. etc.

So why ARE you using that Fad Smokeless stuff anyway??  (Swamp).  Your rifle and the cartridge were designed for .. Wait For It .. Black Powder!!  No ignition problems with BP.  You could also opt for a good SUB like APP and do quite well.  Switch to a proper propellant and REJOICE!!

We now return to our regularly scheduled programming.  Burma Shave

[Trailrider]

For loads that light with 4198, in a case as large as the .45-70, I use a 2-inch square of single-ply toilet tissue poked LIGHTLY into the case, with the bullet doing any compressing of the paper. Crimp firmly, though not so much to bulge the case away from the bullet. I might also suggest going to a heavier bullet, say 350-405 grains.

[Mad Miles]

Thank you for you replies.
Too light a load, if more powder will get a better burn I'll try stepping up to more powder. This is the bottom of the chart.  New gun, new to me caliber, I thought I'd start right at the bottom and move up slowly.  Kinda like all the books tell us but I can do it in big steps.

I'm using Federal Premium 210M primers.  OAL 2.53"  My reloading manual Shows a 300 grain jacketed bullet with 49.2 grains 4198 will produce a velocity of 2101 fps and a pressure of 29,900 psi.  My Rolling Block is a Pedersoli, they spec their Rolling Block not to exceed pressure of 31,000 CUP/PSI.  This rifle will handle all the max loads for the 1876 Springfield as well as 1886 Winchester and 1895 Marlin loads.  The max loads for the Ruger Number 1 and Number 3 are beyond this guns Pressure limits.  Now, the manual used a test barrel of 24" and has pressure in PSI, my rolling Block has a 30 inch barrel and Pedersoli lists the pressure in PSI/CUP.  I may have to make changes to the load when using a 30"barrel rather than a 24" barrel, I don't know.  I've not enough experience reloading to have learned that yet.  I'm fairly new at this.   As far as the pressure, Pederolsi just lists PSI and CUP as if it's the same measurement.  I don't know about that either.

I didn't crimp these much as I have a single shot and didn't think I need to, but I'll crimp the next batch more.

4198 wasn't my first choice of powder for loading the 45-70 but it is the ONLY powder available to me that was listed in any load data I could find for this caliber.  It was the only powder the only sporting good store within a 10 hour round trip from home had left and I bought the only two jars. If I don't use 4198 I don't shoot, until if and when the supply problems up here ever get rectified.  I have about five pounds of H4350 that I use for loading 260 caliber for my precision rifle, but i could find no data for that powder in this caliber.

Pedersoli states their 40-60/45-90/45-110/45-120/50-70 and 50-90 Rolling blocks are made for black powder cartridges and has 'black powder only' stamped on the barrels, the 45-70 can be used with commercial smokeless cartridges or reloaded black powder or smokeless cartridges.
I couldn't use black powder if I wanted to, as there is none available around here.  I've shot Rolling Blocks, Sharps and my Marlin lever with black powder.  For now I think I'll just stick to smokeless with this gun and my 1889 Marlin.  But I appreciate your suggestion.

Thanks again for the replies.

[Mad Miles]

Thanks, I do have some 405grain bullets.  I'll give them a shot.

[ira scott]

The Lyman 50th Edition has three sets of data for the .45 70, as most manuals do. Level 1 is 1873 Springfields (Trapdoor), Remington Rolling Block, Sharps and modern replicas of any of these. Level 2 is the 1886 Winchester and Marlin 1885 and level 3 is for the Ruger #1.  The level 1 load for a 405 cast bullet is 31.5 grains of IMR 4198 (1312fps  12,400CUP) up to 35 grains for 1463fps and 17,700CUP. 4198 is actually the highlighted or preferred powder for the 405 cast lead bullet.  C.O.A.L. is 2.550"

Hope this is helpful!   B.N. Scotty

[DeaconKC]

Anybody know what category the Henry 45-70 Single Shot falls in?

[Mad Miles]

Thanks,
That's the same book I have.
It also has the max load in the next section for the same bullet and powder at 40.5 grains with a max pressure of 27,500.  So one has a range of 31.5 to 40.5 and still be below the pressure limit.  I can't see me going anywhere near that hot.

[Mad Miles]

https://exhaustnotes.us/blog/index.php/2020/03/23/developing-a-henry-45-70-load-part-1/

He doesn't list what the pressure limits are of the Henry, but he's staying in the trapdoor level.
Which is where I'm sure I'll end up.

[cpt dan blodgett]

Max Trapdoor level with heavy bullets, may well be the max your shoulder will ever want to experience.  My 1888 trapdoor with 500 grain bullets and roughly 65 grains of holy black is not fun.