9mm Luger chamber forming with reamer and burnishing tool.

A chamber burnishing tool can be used to improve the surface finish of a cartridge chamber. By rolling over the surface of the chamber the rollers smooth the metal surface to a mirror finish. This process is used by many of the major firearm factories but it can be done by amateur and professional gunsmiths as well. This video shows how to use the burnishing tool and the results can be seen by examining a burnished 9mm Luger chamber.

[@greglaroche1753]

Interesting. Thanks.

[@that_escalated_quickly2720]

This not only improves the smoothness of the surface, it may increase chamber strengh too, similar to cold rolling steel. You compress the steel plastically outwards, increasing it's resistance to pressure from the casing

[@ozzistraightshooter9273]

Yes I believe it does strengthen the surface layer of the steel.

[@florentleider222]

by making the surface so smooth, the chamber walls play no role in slightly retaining the shell, which occurs normally, which means that 100 % of the pressure applies to the bolt head. Is this so beneficial ?mmm...

[@that_escalated_quickly2720]

@@florentleider222 bolt thrust is a bad thing yes, but if you take medium-grit scotch bright, you can introduce just the right roughness i found... Slight retention but no sticking cartridges anymore... I believe sticking cartridges that don't eject are far worse than some bolt slap, considering almost every production rifle should handle overloaded cartridges atleast once...

[@leokimvideo]

Nice work shiny & chrome 😜

[@ozzistraightshooter9273]

Thank you for your comments, the camera doesn't totally capture how much smoother the surface is after burnishing.

[@doodlegassum6959]

Very interesting vid. Thanks for posting

[@Yasho1973]

Hi, where can I buy this tool? What kind of reamer holder are you using? Thanks!

[@user-tx2fj2pm8w]

Muito bom mesmo

[@Virus-ug6cn]

Класс,можно видио изготовления под винтовочный патрон

[@platonicskeptic]

what hrc hardness reamer you can use to cut the chamber on 42crmo steel?

[@ozzistraightshooter9273]

42crmo is 4140 steel that is the most common grade for chrome moly barrels. Any good tool steel is about 60 on the rockwell scale and will cut 4140. I have been experimenting with carbide reamers and these do a great job on hard steel and last longer if you cut many chambers, but a tool steel reamer is fine for most jobs. thanks for your good question.

[@jerrystrader]

What brand is your, or where can I find it? Cool video

[@jerrystrader]

@@ozzistraightshooter9273 thank you

[@MuhammadAfzal-jm6cw]

Good 👍👍👍👍👍❤❤❤❤

[@user-vr2qf2de5b]

What is the name of this reamer or milling cutter with which you make such a smooth surface?

[@tastiger91]

Cogsdill was a brand I use to work with.

[@timothyurano6315]

What type of bore camera is that?

[@ozzistraightshooter9273]

It is my ozzistraightshooter ultimate for pistol barrels.

[@snoosebaum995]

first time i've seem my lathe on utoob , tell me about that tool holder [ not the cross slide ,one ]

[@jonathanluizdeandrade-zl4fe]

Camera legal que modelo e?

[@shanek6582]

How small of a diameter do they make that roller? It would be sweet to have an entire barrel blank that smooth in a 6ppc before it’s rifled!

[@ozzistraightshooter9273]

I have a tool for the 22LR chamber but it is much too short for a barrel bore. It is a good idea to burnish a barrel before rifling. I special tool would be required for a job like this and at this time there is no tool suitable.

[@user-be6ne4gp8q]

Nice

[@arpadlimanagy7018]

As camera de arma pistolas dever ter quatro sulcos para melhor expansão dos gazes gerado pelo disparos...

[@user-wt9ge6wy8v]

Could probably make some money selling those chamber rollers ..

[@MabRaty-ec7ij]

Where can I buy this tool?

[@user-vl8dy1os6r]

孔的内壁很粗糙

[@ozzistraightshooter9273]

是的，孔已钻孔，腔室仅用于说明工具的操作。 不是真正的枪管。

[@user-vl8dy1os6r]

@@ozzistraightshooter9273 What's your facebook?

[@russbernard8666]

Weather you know it or not a perfect finish is not desirable since most of the hold on the pressure is thru the walls expanding and gripping. Perfect mirror finishes cause severe face thrust at the cartridge base. This is really critical with rounds at 30,000-60,000 cup. Do you really think those tiny lugs on a rifle are holding all the pressure??? Not so. That’s why HK literally blasts the spent round out.

[@ozzistraightshooter9273]

I know this theory but I don't believe it is true. Many chambers are hard chromed and they are among the safest and strongest military chambers. Hammer forged chambers are also very smooth and more major manufacturers are moving to burnish chambers. A rough chamber finish cannot be relied on the hold the cartridge against high pressure. As the chamber wears the finish gradually smooths out. The gripping effect of the chamber walls is something that varies as a chamber wears. To rely on this gripping effect would be unreliable and dangerous.

[@buckinthetree1233]

I have always heard the same theory. I'm curious as to what advantage burnished chamber walls have over a reamed finish. I suppose if you get a fire ball at the breech on a burnished chamber, then you will know the bolt is opening prior to the pressure dropping in the barrel. My guess is that perhaps the expanding case is still able to achieve a seal/grip even on a smooth chamber wall.

[@ozzistraightshooter9273]

Hi, These points and theories are interesting. I am trying to carry out more tests to confirm my suspicion that the smooth chamber seals better than a rough chamber. By rough I mean a chamber with circular reamer marks. I know of cases where a chamber polished with one of the fine honing bore brushes improved accuracy. The reasons are not clear. Racing drivers prefer to drive on Slicks as they give more grip than a tire with tread. Personally I don't think gripping the chamber walls is very important, I am more interested in the small amounts of gas that leaks around the cartridge case when fired. Any leakage or changes in the amount of leakage with be detrimental to accuracy. I am performing some work now on burnishing a 22LR chamber. The 22LR is such a critical cartridge. I think changes in the chamber finish may give improvements in the accuracy of the 22LR, but only tests will prove it one way or the other. Uniformity is one of the keys to rifle accuracy and I believe a burnished chamber is removing another variable in the rifle. If we rely on circular reamer marks to seal a case in the chamber it seems to me it is introducing an unpredictable variable into the rifle, which seems like it is something to avoid. Thank you for your comments.

[@buckinthetree1233]

@ozzistraightshooter9273 I would be surprised if a burnished .22 LR chamber would have any impact on accuracy. I don't believe racing slicks is a comparable comparison. Racing slicks are made of very soft rubber used on a track that is thoroughly covered melted rubber. The lack of tread is to create more surface area between the rubber tire and the rubber coated road. A chamber just needs to seal at some point along the contact surface. Nevertheless, I will be interested to see the results you get.

[@ozzistraightshooter9273]

I became interested in burnishing the chambers when I experimented with rifles with hard chromed chambers. Very smooth and no problems with extra bolt thrust damaging the rifle. I have a 100 year old Mosin Nagant rebarreled with a new hard chromed barrel. It handles hot loads with ease. I also experimented with steel cases and lacquered cases. The idea that the brass case needs to grip the chamber walls to stop the action breaking just seems like a myth. I noticed that the hard chrome chamber seems to have less signs of powder residue around the neck. We all know a tight chamber is most accurate, but this can be for many reasons. So this is what started me experimenting with burnishing. Firearms are one of those technologies that improve in very small increments and I think burnishing is a small step along the path of continuous improvement.

[@timhofstetter5654]

But why would you want to do that? You want the brass to grip the chamber wall momentarily to help combat bolt thrust. And... what would be the necessity for a 9mm Saturday Night Pop-Pop? It's not like 9mm is much of a serious caliber. Let the popcorn-eating commence.

[@florentleider222]

aesthetically appealing, but mechanically superfluous no to say contre productive.

[@miguelangelabascaltorres1472]

Habla Español

[@MrJosemoyoyi]

Momo se llama esa herramienta? Nome??