Was this common back in the day? Chamber cut question

[Beaumont78]

1875 dated .45 back powder cartridge gun (43 Beaumont caliber)

Upon re- forming / fire forming with cream of wheat i noticed the brass forming in the neck in an odd way. Bore scoped it and there's a groove cut in the neck part of the chamber.

Brass length was a bit longer then spec, but if i were to cut it to spec then the brass would still be over that cut. It's not from firecutting or something, this was done with a tool on a lathe (intentionally or unintentionally, this is what i'm trying to figure out...)

The bore still had some cosmolene in it, and it's pretty much mint, so I don't think it's been messed with since it left the arsenal..

Anybody knows what's up with this?

[roadie]

Possibly scored by a chip when it was chambered. There looks to be another just below the half way point on the neck as well which is nowhere near as deep.

[Scrounge]

Possibly scored by a chip when it was chambered. There looks to be another just below the half way point on the neck as well which is nowhere near as deep.

I'm not by any means an expert, but I think you're right. I've seen something like that in a part I was reaming, and that was from a chip on the class reamer I was using. Scrapped the part and re-did it after wiping the reamer, and the new part didn't have anything like that in it. It was just a roughly 2" long cylinder with a reamed hole and countersunk at both ends, like a standoff or something.

[Beaumont78]

Possibly scored by a chip when it was chambered. There looks to be another just below the half way point on the neck as well which is nowhere near as deep.

Thanks for the input.
I thought of that but it's cut perfectly at a 90 degree angle, i really doubt it's scored or gauged. The second one you see is because i'm using a combination of dies since i do not have the actual die set (really expensive). That second one closer to the shoulder fireformed out after i fired it again. But it's the one half way up the neck caused by that cut in the chamber that does not make sense to me.
Perhaps i was using too much red dot (12 grain packed in, some toilet paper, then cream of wheat up the neck and then a paraffin plug up to the case mouth)
The brass might not flow into that ring when i actually start using cast bullets.

[Beaumont78]

Here's some more pics, it looks too clean a cut to me to be from scoring or gouging (i'm no machinist though..)

Anyone have a Dutch Beaumont and a borescope, willing to have a quick peek at theirs to see if it's there as well?

[Jedman]

It couldn’t be the way the reamer was ground as if there were a larger diameter in the neck portion when the reamer was pulled out it would cut the portion of the neck behind the same diameter.
It could have been caused by a chip but usually the chips won’t cut the same material the barrel is made from but if the reamer somehow had a small piece of a flute break off from being overloaded with chips the hard tool steel could make a scar in the chamber like that.
You could probably make a lap from a lead boolit of the right size and polish that portion with grinding/ lapping compound and make the neck portion smooth.

Jedman

[john.k]

Blackpowder military guns often had strange ideas(to us) so they could keep firing after 100 rounds or so put through them.......Thinking these guys who made the guns were primitive dummies is common today ,but quite wrong...similar to the notion you hear so many times ..."there were no specs for the chamber"...and "the guns were made to any old size"..or "they couldnt measure very well"

[Rich/WIS]

Is it possible that a previous owner ringed the neck using some sort of wad over the powder charge that was not seated tight to the base of the bullet? Don't think fire forming with CoW would do it, but given the age of the gun and the softer steels used at the time suppose it might be possible depending on what you were using as a wad to hold in the CoW.

Is the case the same diameter in front of the ring? You said the case is longer than original, is this the end of the original chamber?

[Beaumont78]

Is it possible that a previous owner ringed the neck using some sort of wad over the powder charge that was not seated tight to the base of the bullet? Don't think fire forming with CoW would do it, but given the age of the gun and the softer steels used at the time suppose it might be possible depending on what you were using as a wad to hold in the CoW.

Is the case the same diameter in front of the ring? You said the case is longer than original, is this the end of the original chamber?

Thought of ringing for a moment as well, but that drop off / cut is 90 degrees on bolt end, then the cut on the bottom is flat and is parallel to the cut of the neck, then straight back up and finally has a slightly rounded edge on the muzzle end.

Brass trim length specs are all over the map. I've read the following indicating different brass lengths;
-11x50r caliber
-11x52r caliber
-Case length 2.04”
-trim to 2.100"
-trim to 2.040"
-The cases from Buffalo Arms are Star Line 50-90 necked down. They are right about 2.1" long and they fit, at least the gun I'm loading for.
-trim to 2.200" (in my chamber)
-11.35x52R Dutch Beaumont M78
The Dutch Beaumont Was Introduced By The Dutch Military In 1878 The 52 MM Case Was Used For The Beaumont With The Modified Magazine System. This Will Not Fit The Single Shot Beaumont M 1871
-Both the 11.3x50Rmm and the 11.3x52Rmm Beaumont cartridges are commonly mistaken for the .43 Egyptian and in fact, they are not the same. However, the .43 Egyptian cartridges may be fired in both the Beaumont chambers. The 11.3x50Rmm may also be fired in the Beamonts chambered in the 11.3x52Rmm, but not the reverse.

Starting to get real curious about the findings of other Beaumont owners when they borescope theirs

[country gent]

Not real sure what it could be , Im thinking it was done after though. Maybe a broken case being extracted, or as stated a chip gaulded to the reamer for a brief time. Some semi auto rifles today have fluted chambers to slow extraction but those are longitudinal cuts. Another though that pops in my head is a sleeved chamber to repair a damaged one where the surfaces didnt quite match

[Cap'n Morgan]

The sleeved chamber theory makes sense. If you sleeve a chamber, the parting line should lie in the neck area and below the case mouth to prevent pressure creeping into the joint. However, a correctly executed sleeving should only leave a hairline joint, and not a groove as seen in the pictures.

[country gent]

Done correctly,and pulled together tight the joint will be invisible. Gored over sized and faced square with a very slight under cut in the corner. The sleeve turned and faced square with a small 45 om the corner drilled true and pressed in. the joint will be a tight fit and not show. Facing the internal shoulder is tricky.

[Scrounge]

1875 dated .45 back powder cartridge gun (43 Beaumont caliber)

Upon re- forming / fire forming with cream of wheat i noticed the brass forming in the neck in an odd way. Bore scoped it and there's a groove cut in the neck part of the chamber.

Brass length was a bit longer then spec, but if i were to cut it to spec then the brass would still be over that cut. It's not from firecutting or something, this was done with a tool on a lathe (intentionally or unintentionally, this is what i'm trying to figure out...)

The bore still had some cosmolene in it, and it's pretty much mint, so I don't think it's been messed with since it left the arsenal..

Anybody knows what's up with this?

I've been going though the multitude of duplicate files on my computer trying to reduce the clutter. Found this note in the instructions for the Grizzly T10667/10668 Bald Eagle Floating Reamer Holder kit:

Galling in the chamber from chips
packing in the flutes can tear the metal surface
in the bore and create grooves in the
chamber.

Sounds like you nailed it to me.

[Beaumont78]

"Galling in the chamber from chips packing in the flutes can tear the metal surface in the bore and create grooves in the
chamber."

Yep, that's most likely it.