Salt Bath Nitride Caution

[Bobr]

Had a brand new K barrel Nitrided after breaking in with 20rds cleaning between each shoot with SC and scrubbing with JB before treating, this thing was shiny clean. First 600 F match score was 568, my average is 590. The inspection with a borescope showed a solid copper streak on the top of one land from the muzzle to 4" in. After removing the copper I discovered a 1" line of pitting on the top of the land which was tearing the jackets. Sent the barrel back to K and this was there response today.
The pitting was caused by a reaction to the salt bath with copper left in the barrel before treating. But it was supper clean I said. Response was
It is theoretically impossible to remove all copper from a fired barrel due to the expansion and contraction from firing no matter how it is cleaned. Yours is not the only one we have seen with this.
$600 tomatoe stake. Just a heads up

 

[mao0720]

Sh*tty...

 

[Erik Cortina]

Who did the nitriding?

 

[nonliberal]

Ouch! Sorry to hear it.

 

[bozo699]

I heard a old boy this happened too that felt he had left a little kroil in the throat of the barrel it started croading right away in the throat area, I think they need to be squeaky clean and new before trying this.
Wayne.

 

[Bobr]

MMI, Anyone ever hear of a nitride barrel being cut off and recrowned
Thanks Bob

 

[mgx1138]

So I am surprised that the folks who do the nitriding don't have a way to clean barrels before they do the deed. Does MMI just figure that it's "buyer beware" and they're just gonna screw up every 3rd or 4th barrel they treat? Is it just up to the shooter to make sure his virtually new barrel is not going to be ruined by the nitriding process? That couldn't be very good for their business.

 

[bozo699]

So I am surprised that the folks who do the nitriding don't have a way to clean barrels before they do the deed. Does MMI just figure that it's "buyer beware" and they're just gonna screw up every 3rd or 4th barrel they treat? Is it just up to the shooter to make sure his virtually new barrel is not going to be ruined by the nitriding process? That couldn't be very good for their business.

Very good point, they should know if there process is going to work on said barrel or not, I can't imagine that they wouldn't inspect the barrel before they give in the bath, I think it should be your responsibility to send them a clean barrel or as clean as you can get it so they at least don't have to remove powder fouling but carbon is extremely hard to get out and the average shooters aren't even aware it's there, granted average shooters probably aren't nitriding there barrels either just saying you would think the would swab the barrel and check it with a bore scope before treating the barrel, so I guess I am agreeing with mgx1138.
Wayne.

 

[Bobr]

According to K there is no way "Theoretically" there word not mine that a barrel that has any rds down it can copper free.
Like I said before this thing was sparkle farkle and borescoped before shipping, it was clean. The pitting is very minor but enough to catch copper

 

[Bobr]

Anyone have any thoughts on running the Tubb final finish grit coated bullets threw this barrel, the pits are not very deep.
Thanks bob

 

[Gundog64]

How did you clean the barrel after receiving it back from MMI ?

 

[Bob3700]

For what it is worth, Once we chamber up a bbl that is going to be nitrided, it is not fired. We smooth up the throat area with lapping compound to remove the reamer/tool marks. Once they are smooth and mark free (borescope inspected), then they are sent off for nitriding. Haven't had one fail to be accurate and fouling free yet.

Bob

 

[Bobr]

How did you clean the barrel after receiving it back from MMI ?

JB and kroil on a tight patch changing every 20 strokes till the barrel turned shiny under the bore scope

 

[Bobr]

For what it is worth, Once we chamber up a bbl that is going to be nitrided, it is not fired. We smooth up the throat area with lapping compound to remove the reamer/tool marks. Once they are smooth and mark free (borescope inspected), then they are sent off for nitriding. Haven't had one fail to be accurate and fouling free yet.

This sounds like the only way to do it safely

Bob

 

[treeman]

seems to me that if they know about this problem the would use outers foul out before they treat a barrel or at least warn people about the copper problem.

 

[bozo699]

How did you clean the barrel after receiving it back from MMI ?

JB and kroil on a tight patch changing every 20 strokes till the barrel turned shiny under the bore scope

I almost bet the Kroil was the problem, it was Darrels problem with his, I bet a little was left in the barrel.
Wayne.

 

[SDDasher]

I've watched BobR1 clean his guns many times and I will be surprised to find out he left any Kroil in his barrel as he always "flushes" with something similar to Gum Out to clean any residue of the Copper Cleaner or oil from the surface of the barrel before storing. I don't mean to speak for Bob just saying........

 

[Bobr]

It was flushed with 3m brake cleaner and dry patches several times after the JB because I knew how important it was to be clean. Don't really matter what caused it, loved the yours ain't the only one we have seen comment from K.
Bottom line if you break it in like we all do with firing rds you take the chance you could end up ruining a perfectly good barrel, was it worth it no, would I do it again on an unfired barrel no. Sometimes improving things bites us in the ***.
Just a heads up
Boz, Kroil was after barrel came back not before

 

[bozo699]

It was flushed with 3m brake cleaner and dry patches several times after the JB because I knew how important it was to be clean. Don't really matter what caused it, loved the yours ain't the only one we have seen comment from K.
Bottom line if you break it in like we all do with firing rds you take the chance you could end up ruining a perfectly good barrel, was it worth it no, would I do it again on an unfired barrel no. Sometimes improving things bites us in the ***.
Just a heads up
Boz, Kroil was after barrel came back not before

I sure am sorry for your bad luck there Bob, mine has been running about like your also. My Old Daddy has always had a saying for any occasion and I know what he would say to you,...if money can fix it,....it aint broke! you think about those words before you say anything, better luck in the future Bob, I hope your next barrel is a true one holer
Wayne.

 

[Immike]

I had just received 2 barrels back from MMI when this was posted and was very concerned after reading this. I finally was able to get out today to test the barrel I was most concerned about since it had more than a break in for rounds down it. I took a gamble and it looks like it payed off this time. I cleaned it for an entire day before I sent it and threw everything at it to get it clean. I told rodney at MMI that I would assume the risk and wanted to take the chance. I am very pleased with the accuracy and how easy it is to clean. It shot sub half min at 632 yrds on our berm with ease. So far so good.