How common are tool marks in chambers

[336A]

The other day I went to the range with my Ruger .41 BH and as is customary I cleaned the revolver when I returned (I'm anal retentive about clean firearms). It apeared that I had a stuborn lead deposit in one of the chambers just before the throat. So I decided to just swab it really good with CLP and hit it again the next day, this always works for me.

The next day I went after it again. This time I looked a lot closer at this one offending chamber. What I had mistaken as leading the day prior was in fact something else entirely. When I held the cylinder up in bright sunlight and looked at it, it is a perfect symetrical line all the around the chamber It appears to be a tooling mark to my untrained eye, I have no idea why I never caught this before. I was wondering if this line is where the cartridge case mouth lies in the chamber. So I took a piece of unprimed virgin Starline brass and placed it in the chamber.

I used my mag light and peered into the chamber to see where the mouth of the case layed in relation to the offending line. I found that the line is a few hundredths/thousandths of an inch behind the case mouth. This defect does not appear to have any adverse effects as cases eject with ease, however it is very disconcerting to me. So I have a rear sight that has to be adjusted way right to hit POA/POI and now this. Is this type of defect another common occurrence that is frequent in Ruger firearms?

I really like this revolver and it is fast becoming my favorite, but dang when I spend hard earned money on something I expect it to be right. Sorry for the rant.

[ratboy]

the cylinders in my S&W revolvers are smooth as glass. the cylinders in the Taurus that i have looks like they were carved out with a spork. the SP101 i have is smooth. none have shown any difference in accuracy. the Taurus were so rough when new that i had no choice but to polish them a bit because i could not extract the cases.

[454PB]

Your description matches what I've seen after shooting .38 specials in a .357, .44 special in a .44 magnum, etc. Did you buy this gun new?

[AK Caster]

Is the revolver accurate? If it is, what is to worry about? Nothing more than a tool mark and as long as you can hit where you are aiming the adjustable sights are doing their part arent they?

[336A]

454PB yes the I bought the revolver new. AK Caster It bothers me due to the fact that the chambers should be glasss smooth. I'd expect as much if it were a Taurus however it is not. The sights I can deal with, but when dealing with products from S&W & Ruger I would think tool marks in critical areas should be non existant. On the bright side at least the barrel has all the lands which my S&W M10 did not have when I purchased that new.

[44man]

Dead smooth chambers create more head pressure against the recoil plate. Brass needs something to grip.
The last thing you want are dead smooth chambers. NEVER polish them. They can LOOK polished but be assured they are not dead smooth.

[W.R.Buchanan]

OK guys here's some info on tool marks.

Gun parts like barrels and cylinders are mostly made of some kind of Cro-Moly Steel IE 4130, 4140 4340 etc. To be blunt these steels machine like SHIP! They are extremely difficult to obtain a finish on when drilling holes reaming holes or any operation that is physically cutting the metal with another tool. Also tool life is "finite". IE there is only so many holes in one reamer, or drill and then it has to be replaced. Surface finish degrades as tool life expectancy is approached, due to the fact that the tool is not cutting as well as when it was nice new and sharp. As the tool wears it starts to smear metal as opposed to cutting it, just like a razor blade does to your beard as it grows dull.

Machinist's tend to run the tools until they are showing dimensional deviation beyond what is acceptable as opposed to worrying about the finish, and then change the tool out. This takes time and the machine is shut down while this is occurring.IE no production. Also the new tool must be bucked into the setup so it is producing good parts. This alltakes time and costs money.

I have 2 Rugers .44's. A SBH Bisley and a BH Bisley. The chambers on the SBH look like 30 miles of bad road. In fact I will polish them some day just to say I did it, however the gun functions perfectly, the cases eject easily, and the gun shoots fine, so I ask you ,,, why mess with it?

The BH Bisley's chambers look like they were done by a replicator from the Starship Enterprise. They are perfect without a single tool mark,,, period.

Here's the deal; The cylinder of the SBH was done towards the end of the chambering reamers life that was being used at that time. The BH cylinder was done early on in the tool life cycle.

Parts in a machine shop are made in runs, 100, 500, 1,000 whatever. The idea is to make it through the run with the same tools in the machine as much as possible. Obviously parts made at the beginning of the run are going to be better than those made towards the end of the run, but they are still all going to be dimensionally within tolerance, only the finish will vary, and it maynot even vary that much. This is the cost effective thing to do and makes those guns affordable to most of us.

The bigger the shop the more this matters.

Ruger is big! They have engineers that are continuously monitoring the process for efficiency. Lots of money to be made or lost in just this one facet of manufacturing.

In response to your assertions that you are paying good money for a product, that is true. BUT,,, you are getting your monies worth because none of these guns are anywhere close to perfect, they are generic guns, and you are paying for a generic product.

Perfection in the gun world costs a lot more than $5-600. It's more like $6-8 Grand for a Ruger based revolver!

Visit www.customsixguns.com to see what near perfection in a Ruger Revolver looks like and what it costs,,,starting with your gun with the tool marks in the chambers.

Randy

[336A]

Thanks for the info W.R. aside from my S&W missing some lands in the barrel I've never really had any problems. Heck as far as I know none of my other firearms have any tool marks, if they do I have never really noticed them. You gave the example of your SBH looking as though the chambers were 30 miles of bad road. Let me clarify what I'm seeing in the one chamber of my BH. The finish of the chamber is nice and polished however towards the throat there is a definitive symetrical line. The line actually looks more like a shallow cut. Since it doesn't appear to have any adverse effects I'll just ignore it.

This was a concern to me though since I've never sen this before. I didn't know how this might effect the the overall integrity of the that chamber

[W.R.Buchanan]

The problem with Cro-MOly is that it tends to tear as opposed to cut. The material tends to build up on edges of tools, and since it hardens to 60 Rc instantly any small amount that is stuck on the edge can become part of the cutting edge easily.

The ring you talk about was more than likely a result of this action. The preceeding part and the following part probably didin't have this problem. Sometimes the Built Up Edge pops off the tool after one rotation and doesn't affect much at all. Sometimes they stuck around for a while. Sometimes it is caused by a chip being dragged thru the cut just one time. There is a variety of things that can cause it, and nobody can control all of it 100% of the time

Alot of this comes from using water based coolants in the machines which just don't have the lubricity of oil based coolants.

The only real way to eliminate this from possibly happening is to ream the chambers undersized and hone them to size. That way a perfect finish is guaranteed, however the cylinder is now worth 3 times more than before.

Did you look at Linebaughs guns? They get a custom 5 shot cylinder made from scratch. I like the part where they start with your Ruger Bisley and you add $6500 to that and get a real .475 or .500 Linebaugh in return. Mind you these guns are about as good as it gets, but you have to ask yourself, "do I really need it 'that good' ?" These guns are capable killing anything on earth, but what are you going to use the gun for? I doubt you'll be hunting Elephants or Buffalos,,, But you could.

Once again it is shown that beauty is in the eye of the beholder. They say,,,"Speed costs money, How fast do you want to go?"

This obviously applys to guns as well.

I might add that Mr. Linebaugh's shop has no shortage of work in backlog, so apparently there are plenty of people who want to, and can afford to go fast.


They say,,, "there's an **** for every seat"

Randy

[336A]

Thanks for the in depth explanation Randy it makes sense. It does appear from your explanation that is what happened with that chamber.

[leadshooter5]

I have a M1905 S&W in 32-20, and it looks like it was chambered with a corncob. It shoots great, and cases fall out easily, so I don't worry about it. It does retain a bit of powder residue (Trail Boss), but nothing major.