I recently acquired an 1873 Springfield Trapdoor (.45-70) and fired my first rounds (handloads) through her this past week. The groupings were a lot better than I anticipated. However, upon close inspection of the spent cases, I noticed a series of dents (3 in particular) and scratches that uniformly appeared on all of the cases at the 6 o'clock position.



I cleaned out the bore and took a cleaning brush and vigorously scrubbed the chamber back and forth several times in an effort to dislodge debris or rust scale that may be the culprit but my efforts were to no avail as the dents continued to appear on the spent cases.

I then chambered a couple of loaded rounds and removed them to determine if the damage only occurred when the rounds are fired. When I extracted the loaded round, the cases showed galling but no dents as with the spent cases.



I managed to take a few photos of the chamber and was able to capture what appears to be three pronounced ridges in the chamber that matched the dents on the spent cases.  The chamber looked heavily pitted but otherwise unremarkable except for the three ridges that could easily be seen.







I took a sharp pick and gently scraped the largest ridge (closest to the lens) to see if I could dislodge whatever was there but was unsuccessful. To my naked eye, the ridges appear to be formed by galling of the metal rather than rust but I can't tell without having the chamber inspected with a bore scope. My thoughts are to have the chamber inspected with a bore scope and if it is galling, to have the chamber gently reamed with a something like a flexhone of the correct dimension. Of course, this could be the wrong thing to do. Thus, i turn to all of you for your thoughts and opinions.

Has anyone had any similar experiences? Your comments/recommendations are welcomed.

TIA

~F

What could cause galling in the chamber? I would thing the brass case and lead bullet would be too soft to damage the steel.
Unless you clean it with an air chisel?

What could cause galling in the chamber? I would thing the brass case and lead bullet would be too soft to damage the steel.
Unless you clean it with an air chisel?

The rifle is nearly 130 years old. I have no idea what could have caused the galling and pitting as well as the ridges seen  over that period.  Perhaps a stuck case was left in the chamber when black powder was used as a propellant for the 45-70 and the case was pried out.

My mistake, I was dazzled by your beautiful photos and forgot about the part where you recently acquired the rifle. In that case, it could be anything. Hopefully somebody has a good borescope you can use.

Nice job with the pictures.  Careful use of a finish reamer would probably be able to clean that up.

Thanks. Reaming seems to be the consensus.  I didn't realize that the pics would come out so large until after I posted them. When I clicked on the thread and the pics opened up, I had the Keeanu Reeves expression... "Whoa!"

Looks like artillery shells in the pics

https://www.amazon.com/TEKTON-6680-10-Inch-Half-Round/dp/B000NPPC0A/ref=sr_1_6

Just to knock down the burrs until you can get some fine grit in there?

those half circle ridge marks almost look like the previous owner was trying to force in wrong sized steel casings or something?  Like cartdriges that were too short, but wider diameter

those half circle ridge marks almost look like the previous owner was trying to force in wrong sized steel casings or something?  Like cartdriges that were too short, but wider diameter

Are you referring to the markings on the brass?

nah the chamber. those half rings in the brass match up to those gouges in the chamber.  I wonder if that was a result of an amateur reaming job gone bad.

I spoke to John Perriera yesterday. He said the trapdoor is difficult to work on because the rifle is old and the steel used is a lot softer than the steel used today. If you remove the barrel from the receiver,  you risk damaging the threads,  the receiver or both.

He thinks the damaged was caused by the improper removal of a stuck case. For some reason,  people often think that a rat tail on a file is an appropriate tool to remove stuck cases. He has seen his share of damaged chambers caused by the use of a file.

He suggested using the material from a green scotchbrite scouring pad to take down the sharp edges and living with the scuffed brass cases. According to him, a reamer or flex hone would open up the chamber which is not ideal. The tapered 45-70 case makes cleaning up the chamber more difficult that if the walls of the case was straight  He also mentioned that the green scotch Brite pads are more agressive  than 0000 steel wool. Steel wool will not remove bluing whereas scotchbrite pads will.

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Thanks for the update fartcocker!  I'm surprised the rat tail of the file could get that deep into the chamber, isn't the brass itself obstructing the chamber?

Hi idk if my input is bad or negligible but I say definitely not rust. The highest ridge is casting a decent shadow and I haven't seen rust form in a straight line in my life.

With that said. Would those silver scrubber work? Kind of like those green scotchbrite pads. Think sechaeaii, Wal-Mart, young guns had. It's usually used for cleaning sinks of rust. I used it to give my old rem 870 a good cleaning and it never took the bluing off. Maybe some flitz polish would help too. I doubt you'll be able to move any metal material away by hand. Using a drill is a different story.

Good luck though

Thanks for the update fartcocker!  I'm surprised the rat tail of the file could get that deep into the chamber, isn't the brass itself obstructing the chamber?

Perhaps depends on how big of a mallet one uses...

Thanks for the update fartcocker!  I'm surprised the rat tail of the file could get that deep into the chamber, isn't the brass itself obstructing the chamber?

John didn't say the burrs in my rifle were caused by the use of a file. He merely suggested that a file may have been used because that's what he often sees. Whatever it was that was used surely did more damage than was necessary. 

Hi idk if my input is bad or negligible but I say definitely not rust. The highest ridge is casting a decent shadow and I haven't seen rust form in a straight line in my life.

With that said. Would those silver scrubber work? Kind of like those green scotchbrite pads. Think sechaeaii, Wal-Mart, young guns had. It's usually used for cleaning sinks of rust.

Are you referring to the Big 45 Frontier Metal Cleaner, the ones that look like stainless steel scouring pads? http://big45.com/
It may work.

I did soak the chamber with some ed's red for a day or two before attempting to gently scrape the burrs hoping that it was just something stuck in the chamber or rust but had no luck in removing the burr.

Yup that one. I think it may be stronger than scotchbrite. Rip some off and wind it/ wrap it around a bore brush thats roughly the size of that chamber with some flitz should maybe help? Lol idk. I never had that problem before so I'm really not sure.