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As far as I have read, some nitriding does occur as a result of firing. Military researchers have been putting allot of money into developing powders that nitride the tubes of artillery pieces during firing to increase service life. Although allot of that research has been based on improving black powder propellant recipes, much of it has carried over to smokeless powder. Do a google ‘scholar search’ on the effects of nitrogen on gun tubes and you should find a few good papers on the subject.

Thanks for watching :-)

Lapping is polishing the bore nice and smooth, which can reduce the amount of time required for break in, but erosion will occur no matter what.

Great series, highly educational, watching since part one, one or two episodes a day, can't thank you enough for making this video series! Greetings from Switzerland

The cartridge will have no problem getting you out to 1500m. The rifle should be capable of very good accuracy as well, if the stock doesn't cause too many problems. You will want 1/2 - 3/4 moa for 1500m, so you may have to do some stock work if the rifle isn't up to those accuracy requirements. Typically, you can expect 1moa out of the box on these rifles, sometimes better. With load development and minor stock work if needed, this should work fine. :-)

Great information Rex. I’m watching your series again! this time, with a note pad. My wife is a high school physics teacher, and she enjoyed your presentation too👍🏾. She loves the science! Thanks for all of your work ✌🏽

Thank you so much for this info!! Exactly what I have been looking for for a long time.

Thank you for all you time and effort to make all these videos. I am an engineer and enjoy the hands on application of real world physics and find it very easy to understand your logic and reason. Keep it up and make damn sure you have hard copies that you can redistribute just in case...

Chrome lining very effectively protects rifle bores from erosion, however, due to flaking because of the differential thermal expansion of impurities beneath the chrome, this can reduce the level of precision obtainable from a chrome lined bore. If you are operating in highly corrosive saltwater environments, the benefits of chrome lining will outweigh the shortcomings. Where its very dry, chrome lining is less beneficial.

Absolutely amazing. Thanks, TRex.

You got skillz bro. Watching every video made me better. They didn't teach me most of this stuff in the infantry. This info is helping us design our next concealment system. Thanks much.

sir. I have enjoyed your videos I have been looking for info. on long range shooting been pistol man for many years due too law enforcement jobs but really enjoying learning the rifle. keep up the good info. look forward to finishing your video sniper 101.

Oops, I was trying to get to the punch line too fast. Yes, chryonising steel can relieve some of the stress built up in the lattice structure and slow the thermal cracking process thereby reducing the rate of chemical erosion due to increased surface area. All in all, it will slow chemical and mechanical erosion on the microscopic level, but will not usually translate to a significant advantage it terms of measurable accuracy retention after a given number of rounds fired.

Nitriding the barrel is actually very effective, and you are correct, it would be best to break it in first. However, you will want to be sure that you clean it very good before sending it in. You will want to accomplish a full copper removal. In this case, an aggressive copper solvent like KG12 would we warranted. Make sure its perfectly clean before you send it in or you may have a bad case of differential erosion down the road.

great video, thank you for uploading

A nice lapped bore will be better than a rough one, but erosion stills occurs. We'll talk about thermal and mechanical erosion mechanisms next :-)

Pirates at sea? Most precision rifle engagements against pirates at sea by SOF are conducted inside 100m. Ships are not very stable shooting platforms, so you can't effectively shoot at distances where the TOF of the bullet is very lengthy at all. The last rifle engagement I am aware of at sea against pirates was done at only 40m - almost point blank range. This gives you nearly a 100% hit probability.

Right on. That would be great for those 3mph whisker-ticklers.

No problem. Just make sure its nice and tight when you install it. You don't want it wiggling around. Otherwise follow the instructions step by step and it should work great.

I would be suprised if you got any measurable change in accuracy after chryonizing the barrel. Its true that it can slightly relieve some of the stress built up in the steel, but it rarely changes group sizes significantly. If its shooting 3/8" moa, I would call it plenty good.

Now you're talking my language. I'm a metallurgical engineer, so I'll have to find those papers someone referenced.

Awesome explanation on bore erosion. I'm studying this right now in my material sciences class.

I love your video series, I've been looking around on youtube for this kind of info for a while now, I recommended these videos to a friend who is also interested on the subject. I was wondering if a 111 Savage 7mm with that SWFA super sniper optic and an injection molded stock would be capable of being effective at 1500yds? The gun came with that stock and I was wondering if it would be imperative to upgrade it? Thank you very much for the work and time you put into making this series.

Good stuff....

It is surely possible but it is not very cost efficient, unless you have all the equipment on hand and lots of time. It would be less expensive to buy a new barrel.

Thank you

MV??? You will usually still have a very similar MV curve with or w/o chryonising the steel, although I have to admit each peice is very different and it is possible in a barrel with particularly stressed steel that this treatment could reduce things like heat flex, which can accelerate bore erosion in localized regions of the bore indirectly affecting MV in the form of more erratic variations towards the end of the bore life. Is it usually worth it? No. Can it help a stressed barrel, yes.

Is there a different cleaning process for .22lr as far as the "correct" way to clean? I know a lot of people that are into using them for 200-300 yards, which would be "long range" for a .22

"I could talk for hours on that but I'm not going to, because you would want to die." .... BEST LINE EVER

his question was about how it would effect chemical erosion. Whether it would slow down the erosion. Not whether it effects accuracy.

Given the chemical effects on a barrel, what are your thoughts on having a new barrel nitrided after initial break-in?

So, for a custom barrel with a polished bore the life of that barrel is not prolonged? I thought that the lapping would decrease the amount of friction due to it's smoothness thereby prolonging the life of that barrel.

Does anyone know where to find the paper with the microstructure of the rifle barrel. I am a metallurgical engineer and I used to take electron microscope images like these for a living. What these images typically show is difference in chemical composition in the steel. All traditional steels have metallic crystals in them and depending on the composition of these crystals they will appear as differnt colors in the micrograph. When you look at the bulk phase of the steel in the images shown in this video, you notice these crystals as different colored shapes. The shape of these crystals depend on many factors and is quite complicated which yields to a certain amount of randomness to the exact shape. However in thes photos, crystal shapes and proximal locations are repeated over and over again like a patterned quilt. It is as if someone took a photo of an actual micrograph and copied and passed it over the entire area of the bulk steel. Futhermore, how they took images of a barrel at differnt levels of erosion is a mystery. To get an image in the SEM you must cut a piece off the barrel which would destroy that section preventing that part of the barrel from being used again. Yet somehow (magic?) They are able to test that same piece over and over again and show images of the barrel wearing down? I don't know where this image came from but if it is a electron micrograph then this is likely heavly doctored to present the data that they wanted to present.

I inherited a rifle setup from my father that I'm going to setup for long range, its a sako action, 300 weatherby mag with a pacnor barrel that was chryonised and fluted about 25 years ago. Nice fiberglass stock and the barrel is floated and still shoots a 3/8" group at 100yds with my my questions is how will the effect of chemical erosion be increased or decreased by the prior cryo treated barrel? I've read that chryonising was widely believed in but actually has little effect on stainless.

oh, gonna take the serious note, alright man fine with me. But yes, he does make amazing videos.

What to do with a "shot-out" barrel? Can it be re-bored for a larger caliber?

hey Rex, what do you think of molly bullets? does it help with repeatability/constancy/accuracy

Right on. Sounds like a very well designed program. However, I would still be a little nervous to encourage guys to learn to how to use a ballistic computer in the field before they know how to do it the old fashioned way. You and I may be OK, but new folks need to learn to do this the old way first, so it's permanently burnt into their brains. EMP, cold weather, and cashed batteries can't render your paper charts useless :-)

So with all this explained in this video how much longer would u estimate your bore life to be before it's time to replace the bore and how many rounds also any suggestions on what powder to use when reloading? Thank you Rex in advance I appreciate your videos and am looking forward to your response. I have watched part 37 38 &39.

"Because you would want to die" LOL

O.K. --- so you are making a case for chrome lining (or some type of surface treatment) the chamber & the bore...yet, all of the top rated shooters (that I know of) stay away from pretty much anything but chrome moly for their 'accurate' barrels. What about Tennifer, or similar surface treatments? A Glock's exterior surface is extremely durable/resistant to chemicals & moisture. Is it cost? Watching and learning. Thank you.

Rex, would lapping the rifle bore reduce the possiblility of errosion in the rifle bore?

Anyone know what happened to the Sniper 101 series of videos that TiborasaurusRex created? They were awesome. I can only find this video and maybe 2 more, the rest are no longer posted. Thanks.

..if you upload it , they will come

Sorry, if this has been answered already... Does the beneficial affect of nitrogen in the bore during combustion create an environment where Nitriding occurs? It seems the bore is plenty hot for the steel to accept the nitrogen into the lattice structure. Or is the nitrogen the result of a buffer affect reducing the chance of interactions for the more corrosive gases? I spent a few years studying metallurgy alongside my pursuit of mechanical engineering - this video I found very entertaining!

Rex, are you a Chem Eng?

7mm mag

hello rex, i know you might not have the time to answer this question but maybe someone else might chime in. i shot some korean surplus ammo ( 30-06) and cleaned when done with windex but forgot to dry properly and lightly oil so it rusted up. i cleaned with pb blaster and a copper brush and a little bit of mothers mag polish. bore looks ok, am i doomed? did i ruin my barrel? have not shot it yet, should i just start the break in procedure again? thanks in advance. hope your feeling better.

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