Hello, i had a New barrel chambered by a gunsmith and after firing it, found scratch marks lengthways on the brass about one quarter of the case from the rim, im just wondering how this could be caused ? the reamer is good ,whether the material during the chambering operation was not removed often enough and caused it ? or something else ? im worried after its repolished , the scratch marks might still be present as gouges going deeper than the chamber which i dont like the idea of,it wasnt a cheap barrel ,any thoughts ?
Thankyou

Feed marks from the action or the guy never bothered to cut the feed radius at the mouth of the chamber. Try feeding in a fresh cartridge gently into the chamber by hand without feeding it through the mag with the bolt, and then closing the bolt and firing it. If it comes out without marks, its feed marks.

Its a single shot falling block and the marks are in the chamber ,thanks for the replies

Knowing it is a single shot falling block makes a huge difference to the replies you may get, why did you not include this information in your post. Was it a trick question?

NO it wasnt a trick question ,why would you think that ? i was asking about Chamber Scratches specifically ,i was aware it wasnt caused by the action .so i didnt include that it was a Specific action

Pictures of the damage generally help a lot. I'm siding with the chamber mouth or the extractor cut being improperly finished and polished. I'd be bringing it back to the guy. I get uppity when I pay someone to do something and it's paid for, but NOT done!

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I get uppity when I pay someone to do something and it's paid for, but NOT done!

Me too! We have a lot of "gun plumbers" around here like that!

Sure wish you and dpcd were closer!


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I have taken it back to him ,pretty sure its not the extractor ,the scratches are definately inside the chamber ,will let you know what happens .
Made me think about re-sleeving chambers and do any gunsmiths still do it these days ?

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Originally posted by tankhunter:
I have taken it back to him ,pretty sure its not the extractor ,the scratches are definately inside the chamber ,will let you know what happens .
Made me think about re-sleeving chambers and do any gunsmiths still do it these days ?

Well, I believe I would opt for complete barrel replacement at gunsmith expense unless it is just a burr.

Please post a pic. It is actually hard to make a longitudinal scratch in the chamber. My first though is extractor. Can you feel it get marked when you chamber a round? Can you remove the extractor and then see what happens? Is it only after firing? I see, now, that you have returned it. Ok.
Gun plumber? Well, it does involve pipe fitting.

I havent got it with me its back at the gunsmith[so cant post photo sorry] ,i smoked the brass and rechambered it several times and so its not the extractor ,as scratches are in the chamber you can ''feel'' them when you put a rod in there and move it

For me, if the scratches are in the chamber and you can feel them, then it is time for a re-barrel at the gunsmith's expense. You can not polish that out without changing the chamber measurements and it sounds like it is too long for a setback and rechamber.

Normally the chamber is lightly burnished with #320 wet & dry after reaming to even out the finish and give better case adhesion. The feed radius is also cut and polished at this time. It sounds like he simply forgot to do this or he has never had any formal training in barrel & chamber work.

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Originally posted by tankhunter:
I havent got it with me its back at the gunsmith[so cant post photo sorry] ,i smoked the brass and rechambered it several times and so its not the extractor ,as scratches are in the chamber you can ''feel'' them when you put a rod in there and move it

I don't think I would tell the gun butcher you could feel scratches by wiggling a rod in the chamber. lol Kenny

speerchucker...........I am just a novice with no experience with chamber finishing. However, your assessment seems on track here. Have you ever experienced damage from a hand reamer that was pulled straight out at a slight angle? I may want to finish a chamber someday with a hand reamer and need all the info I can get before hand. Thanks. Good luck to the OP. I hope a simple tweak is all your chamber needs.

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Originally posted by speerchucker30x378:
Normally the chamber is lightly burnished with #320 wet & dry after reaming to even out the finish and give better case adhesion. The feed radius is also cut and polished at this time. It sounds like he simply forgot to do this or he has never had any formal training in barrel & chamber work.

Who was the gunsmith?

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Originally posted by custombolt:
speerchucker...........I am just a novice with no experience with chamber finishing. However, your assessment seems on track here. Have you ever experienced damage from a hand reamer that was pulled straight out at a slight angle? I may want to finish a chamber someday with a hand reamer and need all the info I can get before hand. Thanks. Good luck to the OP. I hope a simple tweak is all your chamber needs.

quote:

Originally posted by speerchucker30x378:
Normally the chamber is lightly burnished with #320 wet & dry after reaming to even out the finish and give better case adhesion. The feed radius is also cut and polished at this time. It sounds like he simply forgot to do this or he has never had any formal training in barrel & chamber work.

It's actually pretty hard to make a lengthwise cut in a chamber with the reamer. Almost impossible for that matter. If you think about it the leading edge is about 1/32 wide and it only has about 4 degrees of rake. So if you do the math over the radius of the chamber and the angle of the leading edge it's not like you are pulling a knife edge over the chamber. On top of that you usually have 2 of these 1/32nd, near flats dragging on the chambers surface at any given time. Even if you were to cock the reamer slightly and pull it out, you would be hard pressed to cut any sort of a line that wouldn't be polished out during the burnishing after you have finished reaming. I would equate it to trying to scratch the chamber with a spoon. It's pretty tough to do. Not to say it's impossible, I'm sure some Bubba has done it, but it would be damned tough.

The only way you could really do it without a lot of effort, would be to shut off the machine while still turning the reamer in and allow everything to stop in mid bite and pull it straight out. That trick would be pretty hard to pull off if you were turning a reamer in without a machine.

Generally speaking, driving reamers by hand is not good practice. It's very easy to create rings in the chamber and induce chatter doing that. It's also very hard on reamers. Reamers only get so many turns in life. Every time it makes a revolution, a day of its life is lost. It's not the amount of material it removes which wears it out, it's the number of surface feet the cutting edge is dragged over during its life that kills them and once you hit that magic number of surface feet, it's shot. It is always better to take as heavy a cut as the reamer will take. By taking very light cuts all the time you may only be able to get a half dozen or dozen chambers out of a reamer. If you load it up you may get 20 to 40 depending on the reamer size.

Mind you, I have seen far more reamers dead from misuse, rust and general neglect than I have ever seen worn out. I sold most of my wildcat reamers about 15 years ago because most of them had only been used once. I make the customers buy them now. I finally learned my lesson and figured out that old weird chamber reamers aren't all that collectable. With that in mind it's doubtful that the average hobbyist would ever get enough chamber jobs to wear a reamer out, even if he did hand chamber every one. But it is a risky way of doing it and it creates a lot of blisters ! LMAO ROFF

Thanks for the additional insight. It certainly cleared up several concerns I had on the subject. Some things are best left to those who do this on a regular basis.