salt bath nitriding

skizzums · August 2, 2015, 06:49 PM

hello all. I was having a discussion with a shooting buddy earlier about old beat up barrels. he currently has a in nagant that he spent some serious coin on(for some reason), having the barrel cut and crowned, mild flutes, new iron sights added not to mention other craziness. he tld me he grabbed this gun from a show w/o even taking the time to really inspect the bore. we have checked it out, and it's pretty ridiculous. severe pitting from active rust, which I am helping him to correct at the moment. rifling appears string "enough" for somewhat decent shooting, we did shoot it, no better or worse than most in terms of accuracy. the barrel is extremely difficult to clean, can scrub and scrub and scrub and never get a clean wet patch out of it, always a a greenish rust color. so we have the crown plugged and kroil soaking for a couple weeks. we recently had the barrel removed, so it wouldn't be difficult to do it again.

anyways, he asked me if he could have it chrome-lined....I explained the reasons why not and he began asking about other coatings. I am king of at a loss, it seem TiN is not realy an acceptable treatment as are not some others. I began reading about "salt-bath nitriding" and it seems that on paper, this could be a viable coating for his rifle. I understand nothing is going to "restore" the barrel, but it seems like the nitride process can increase the hardness, maybe slightly "smooth" out some pitting and prevent it's return. this sounds like if it was a good possibility, more people would do it to antiques that would actually be worth the cost of such a process. so, what am I missing? is this an impossibility? will it just do nothing? will it not adhere? or am I on to something? if this is a viable option, I would also be curious about it for my own rifle.

if this is all wrong, are there coatings that will help that wouldn't run over 200-250$?

thanks for any information you have regarding the subject. please no (it's a mosin, just buy another one, or just buy another barrel) he has his reasons and it's his $$ to throw away.

James K · August 2, 2015, 07:08 PM

I am no expert on nitriding, but AFAIK it is a hardening process and has to be done on clean bare metal, not on a badly pitted bore. Since he seems determined not to either buy a new rifle or have that one rebarrelled, I really have no good answer. There is no way bore pitting can be filled in or welded up or any such. Nor can a high power rifle barrel be lined (as is often done for rimfire and low pressure CF cartridges). Some large bore barrels can be drilled out completely, end to end, and then a barrel insert sleeved in, but the insert has to be thick enough to contain the pressure all by itself, something not feasible with that already thin M-N barrel.

I can only wish him luck with whatever he tries to do, but I doubt any gunsmith has a magic answer.

Jim

skizzums · August 2, 2015, 08:52 PM

he understands the pitting will not go away, I believe he just wanted it coated as is, since it still shoots straight. but maybe a coating to prevent further pitting/damage or make his barrel hold up longer anyhow. I had read that the nitriding hardens the steel somewhat, making for a longer life. but if only clean bare metal, then maybe no answer outside of moly

Jim Watson · August 2, 2015, 10:44 PM

Probably going at it the wrong way.

One guy found a chrome lined barrel had been plated over a rough bore with a lot of reamer marks. It copper fouled and was not accurate. Since it was free, he had the plating stripped and lapped out the reamer marks. That left it a bit oversize but he said it shot a lot better as long as he stuck to flatbased bullets that would set up a bit into the rifling.

Tinbucket · August 3, 2015, 12:25 AM

Only real options are to have a Smith bore it out and line the barrel.
2 Rechamber it to a larger round and bore out barrel and re rifle it.
3 Find a new or replacement barrel.
I'm no expert certainly not on arms of that period. I suspect the steel is not that great.
Most logical thing would be to rebarrel it.

James K · August 3, 2015, 03:56 PM

On lining, see #2.

Jim

tobnpr · August 3, 2015, 08:41 PM

I think he needs to find a new gunsmith.
Guy pulled his barrel- did all that work-including fluting- and never once asked the customer, "Sure you want to drop all this coin on a pitted, rusted out barrel?"
Shame on him...

James K · August 4, 2015, 02:30 PM

In fairness to the gunsmith, I get the impression that Skizzums's friend would not have listened. Some folks just get an idea and are determined to follow it through, heck or high water.

Jim

BoogieMan · August 4, 2015, 02:39 PM

In theory the barrel could be lapped. That would smooth out the lands, possibly a button could be created to pull through the current rifling, although thats kind of pipe dreams. You would end up with a barrel thats slightly oversize (.002-.004") and could be chrome plated back down to size.
I would estimate cost in the $5k range.
Best bet is to find a barrel, flute it and install it.

jdh · August 4, 2015, 09:06 PM

The best option is just have it rebarreled.

There is no good workaround for a worn out barrel.

joe

skizzums · August 5, 2015, 04:30 AM

We have decided to attempt lead lapping. If nothing else, ill learn something new.

I told him just wait and see if it shoots well enough for his liking. My barrel looks pretty crappy as well, and not exactly precision, it still shoots around 1.5. Curious about doing a lapto mine as well, but I'd rather experiment on his first.

August 2, 2015, 06:49 PM	#1
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	salt bath nitriding hello all. I was having a discussion with a shooting buddy earlier about old beat up barrels. he currently has a in nagant that he spent some serious coin on(for some reason), having the barrel cut and crowned, mild flutes, new iron sights added not to mention other craziness. he tld me he grabbed this gun from a show w/o even taking the time to really inspect the bore. we have checked it out, and it's pretty ridiculous. severe pitting from active rust, which I am helping him to correct at the moment. rifling appears string "enough" for somewhat decent shooting, we did shoot it, no better or worse than most in terms of accuracy. the barrel is extremely difficult to clean, can scrub and scrub and scrub and never get a clean wet patch out of it, always a a greenish rust color. so we have the crown plugged and kroil soaking for a couple weeks. we recently had the barrel removed, so it wouldn't be difficult to do it again. anyways, he asked me if he could have it chrome-lined....I explained the reasons why not and he began asking about other coatings. I am king of at a loss, it seem TiN is not realy an acceptable treatment as are not some others. I began reading about "salt-bath nitriding" and it seems that on paper, this could be a viable coating for his rifle. I understand nothing is going to "restore" the barrel, but it seems like the nitride process can increase the hardness, maybe slightly "smooth" out some pitting and prevent it's return. this sounds like if it was a good possibility, more people would do it to antiques that would actually be worth the cost of such a process. so, what am I missing? is this an impossibility? will it just do nothing? will it not adhere? or am I on to something? if this is a viable option, I would also be curious about it for my own rifle. if this is all wrong, are there coatings that will help that wouldn't run over 200-250$? thanks for any information you have regarding the subject. please no (it's a mosin, just buy another one, or just buy another barrel) he has his reasons and it's his $$ to throw away. __________________ My head is bloody, but unbowed

August 2, 2015, 08:52 PM	#3
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	he understands the pitting will not go away, I believe he just wanted it coated as is, since it still shoots straight. but maybe a coating to prevent further pitting/damage or make his barrel hold up longer anyhow. I had read that the nitriding hardens the steel somewhat, making for a longer life. but if only clean bare metal, then maybe no answer outside of moly __________________ My head is bloody, but unbowed

August 3, 2015, 12:25 AM	#5
Tinbucket Senior Member Join Date: January 17, 2015 Posts: 355	salt bath nitriding Only real options are to have a Smith bore it out and line the barrel. 2 Rechamber it to a larger round and bore out barrel and re rifle it. 3 Find a new or replacement barrel. I'm no expert certainly not on arms of that period. I suspect the steel is not that great. Most logical thing would be to rebarrel it.

August 3, 2015, 08:41 PM	#7
tobnpr Senior Member Join Date: August 1, 2010 Location: Tampa Bay Posts: 4,556	I think he needs to find a new gunsmith. Guy pulled his barrel- did all that work-including fluting- and never once asked the customer, "Sure you want to drop all this coin on a pitted, rusted out barrel?" Shame on him... __________________ Remington 700/Savage Rebarreling /Action Blueprinting 07 FFL /Mosin-Nagant Custom Shop/Bent Bolts Genuine Cerakote Applicator www.biggorillagunworks.com

August 4, 2015, 02:39 PM	#9
BoogieMan Senior Member Join Date: April 4, 2012 Location: South Jersey Posts: 2,217	In theory the barrel could be lapped. That would smooth out the lands, possibly a button could be created to pull through the current rifling, although thats kind of pipe dreams. You would end up with a barrel thats slightly oversize (.002-.004") and could be chrome plated back down to size. I would estimate cost in the $5k range. Best bet is to find a barrel, flute it and install it. __________________ Concentrated power is not rendered harmless by the good intentions of those who create it. Milton Freidman "If you find yourself in a fair fight,,, Your tactics suck"- Unknown

August 2, 2015, 07:08 PM	#2
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	I am no expert on nitriding, but AFAIK it is a hardening process and has to be done on clean bare metal, not on a badly pitted bore. Since he seems determined not to either buy a new rifle or have that one rebarrelled, I really have no good answer. There is no way bore pitting can be filled in or welded up or any such. Nor can a high power rifle barrel be lined (as is often done for rimfire and low pressure CF cartridges). Some large bore barrels can be drilled out completely, end to end, and then a barrel insert sleeved in, but the insert has to be thick enough to contain the pressure all by itself, something not feasible with that already thin M-N barrel. I can only wish him luck with whatever he tries to do, but I doubt any gunsmith has a magic answer. Jim

August 2, 2015, 10:44 PM	#4
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,543	Probably going at it the wrong way. One guy found a chrome lined barrel had been plated over a rough bore with a lot of reamer marks. It copper fouled and was not accurate. Since it was free, he had the plating stripped and lapped out the reamer marks. That left it a bit oversize but he said it shot a lot better as long as he stuck to flatbased bullets that would set up a bit into the rifling.

August 3, 2015, 03:56 PM	#6
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	On lining, see #2. Jim

August 4, 2015, 02:30 PM	#8
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	In fairness to the gunsmith, I get the impression that Skizzums's friend would not have listened. Some folks just get an idea and are determined to follow it through, heck or high water. Jim

August 4, 2015, 09:06 PM	#10
jdh Member Join Date: July 4, 2012 Location: Blooming Grove, Tx. Posts: 21	The best option is just have it rebarreled. There is no good workaround for a worn out barrel. joe

August 5, 2015, 04:30 AM	#11
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	We have decided to attempt lead lapping. If nothing else, ill learn something new. I told him just wait and see if it shoots well enough for his liking. My barrel looks pretty crappy as well, and not exactly precision, it still shoots around 1.5. Curious about doing a lapto mine as well, but I'd rather experiment on his first. __________________ My head is bloody, but unbowed Last edited by skizzums; August 5, 2015 at 09:04 AM.