Salt bath Nitrocarbonizing

Greg,
Break in period is just enough shots through the barrel to remove any burrs that may be present after chambering and to see potential accuracy. Don't want to send a dud to have processed you will still have a dud.

I think that you are correct about the 6's @1000 yards this is why I have gone to Charles gunsmith Ray Bowman of Precision Rifle& Tool to chamber my new 1000' F-class rifle in 7mm RSAUM, BAT M action.

I do not have my Terry Leonard stock yet. Even with 8" of show today and still sleeting I have installed barreled action on my rail gun and I will test today before I SBN process the barrel next week.
I have weighted the top of the rail with 30 additional pounds of lead shot hope it will not fly off the bench or break my fingers.


Joel
 
Jackie,
Tested 7mm RSAUM in rail gun this morning 8" show 23 deg. F first shot I thought I was in a white out I did not clear snow completely off the shooting table. The first shot cleared show.
I had to much jam creating high pressure only shot two five shot groups .500" and .625" the wind is blowing about 10-12 mpi I was a little dissaponted with the results.
The rail only moved about 2.5 " , I expected a lot more but I am shooting at a downhill target about 10' grade.
I will shout another 12 shots then I am finished until I process the barrel next week.

Joel
 
quartersnatcher said:
I had pressure problems at the last match in August due to two reasons old brass and 100 deg. temperatures. So what did I do? I dropped my charge .8 grains did not make new brass and....
Click to expand...

Joel,

do you have any explanation for why old brass could cause pressure problems?

Also, about nitrided chambers..... SLICK I'm guessing? How does this affect reaction to pressure? Does a nitrided chamber act like an oiled chamber?

al
 
al,
The brass did not cause the pressure problem the hot load and high temperature caused the pressure problems. The brass had extruded past the flex point at the base not to mention primers fell out of about 15% during competition. I should have checked the brass after resizing but I was in a hurry and I had to fly to Mexico the next day and returned to the US the day before the Nationals.
The nitrided chamber and barrel after processing exibit increased lubricity depending upon surface finish prior to processing. Some barrels show no notable velocity changes but some show average additional velocity of 30 fps.
Depends on the combination of bore size and bullet selectioon.
On a happier note I changed powder and seatiing depth on my new
7mm RSAUM mounted in my rail gun. I shot 2 foulers then two more 5 shot groups at 100' much better .197" and .236" at 2892 FPS 180 grn Berger.

Joel
 
quartersnatcher said:
Some barrels show no notable velocity changes but some show average additional velocity of 30 fps.



Joel
Click to expand...


This is very funny to me, and undoubtedly true....... but it flies smack in the face of conventional wisdom. "EVERYBODY" knows that a lubricated bore produces LOWER velocities and a rough bore produces HIGHER velocities!!!

:D:D:D

I could probably search and find 5 posts that state this as fact.....


Yet the guys who really know ballistics can show as fact that a truly lubricated bore can only INCREASE VELOCITY. I asked Harold Vaughn flat out and he simply said that the idea of lessened bore friction dropping the velocity was stupid.

Thank you for your forthright answers.

al
 
RE: Lubricated bore

Yet the guys who really know ballistics can show as fact that a truly lubricated bore can only INCREASE VELOCITY. I asked Harold Vaughn flat out and he simply said that the idea of lessened bore friction dropping the velocity was stupid.

al
Click to expand...

Question: I've tried moly coated bullets and had to use more powder to get the same velocity I did with the same non-coated bullets. Would that qualify as a drop in velocity with lubrication?

nhk
 
Al,
I am just reporting the data that I have from external reliable testing. I have also believed the opposite prior to being corrected on this fact with correct testing data.
Just as I have used a hard bolt lift as a sign that the pressure was elevated but after processing my bolt and action I no longer have this sign as a warning of higher pressure.
I now have a reliable Infrared chronograph PVM-08 to use during testing to gather velovity test data.
Joel
 
nhkuehl said:
Question: I've tried moly coated bullets and had to use more powder to get the same velocity I did with the same non-coated bullets. Would that qualify as a drop in velocity with lubrication?

nhk
Click to expand...

Not according to the engineering.

YES velocity will always drop using moly or even a light oil. But not from it's lubricative effect, it's just from burning it.

al
 
alinwa said:
Not according to the engineering.

YES velocity will always drop using moly or even a light oil. But not from it's lubricative effect, it's just from burning it.

al
Click to expand...

Al,

I never had the pleasure of meeting or talking with Vaughn as you have but I understand and trust his experimental results with moly. I'm not sure that I understand the moly is "burning" but it could certainly act as a heat sink and divert energy that would other wise drive the bullet into latent heat of vaporization of the moly.

With oil I've seen some admittedly annecdotal reults that are different than moly. Starting with a clean, thoroughly patched out but not solvent washed barrel, my first shot will show a velocity loss of about 50 fps and a lower 1K trajectory of about 1 ft. The next shot recovers most of that difference and by the fifth shot velocity is restored and the bullets are dropping into a group. If (with a prime of life barrel) I use a modest aplication of light oil to the just cleaned bore the first shot shows much less velocity reduction and also much less loss of trajectory. I don't think the oil is sucking up propellant energy like moly does but I do think it replicates the some of lubricity that a little powder fouling provides. I haven't seen the same result with fire cracked barrels. They seem to hit low and produce less velocity on the first shot regardless of bore oil.

Have you had different results with oil than I have? What do think might be happening here?

Thanks,

Greg
 
Moly effect

alinwa said:
Not according to the engineering.

YES velocity will always drop using moly or even a light oil. But not from it's lubricative effect, it's just from burning it.

al
Click to expand...

With moly coated bullets I did one of two things, either 1) jam the bullet into the lands or 2) crimp the bullet if I was limited by magazine length, to try and slow the bullet's departure. The reason being that the drop in velocity is due to a lower pressure curve due to less friction in the bore and the bullet is exiting under less pressure. If the pressure curve was equal for a non-coated and a moly coated bullet then the velocity of the coated bullet would be higher due to lubrication as the engineers stated. That is why more powder is required; to regain more pressure.

Trying to jump a moly coated bullet for optimum accuracy is trickier than finding the jump for a non-coated bullet and you have to hit it +/- 0.001" and it will be less than for a non-coated bullet. nhk
 
This looks interesting, if not for the rust protection alone on a hunting type rifle. Does this process affect the through hardness of a steel, such as with a bolt or action? and what about a mild steel that is already case hardened?
 
Greg Culpepper said:
Al,

I never had the pleasure of meeting or talking with Vaughn as you have but I understand and trust his experimental results with moly. I'm not sure that I understand the moly is "burning" but it could certainly act as a heat sink and divert energy that would other wise drive the bullet into latent heat of vaporization of the moly.

With oil I've seen some admittedly annecdotal reults that are different than moly. Starting with a clean, thoroughly patched out but not solvent washed barrel, my first shot will show a velocity loss of about 50 fps and a lower 1K trajectory of about 1 ft. The next shot recovers most of that difference and by the fifth shot velocity is restored and the bullets are dropping into a group. If (with a prime of life barrel) I use a modest aplication of light oil to the just cleaned bore the first shot shows much less velocity reduction and also much less loss of trajectory. I don't think the oil is sucking up propellant energy like moly does but I do think it replicates the some of lubricity that a little powder fouling provides. I haven't seen the same result with fire cracked barrels. They seem to hit low and produce less velocity on the first shot regardless of bore oil.

Have you had different results with oil than I have? What do think might be happening here?

Thanks,

Greg
Click to expand...


Hey Greg,

I really don't have a clue. I haven't oiled a bore for 20yrs except for storage. I patch out squeaky clean and dry after using Butches. Rinker says that energy is lost in consuming oil in a bore.

al
 
Full disclosure

Joel:

I think a more balanced understanding of the results should be presented. Some have been succesful, but not all. Are you going to make any comments relative to the times that this process has turned a very good barrel into something that could not shoot under a 7 at 100 yds?

Greg Reed
 
Greg,

This batch of barrels were processed at another company that I am no longer working with. This is the main reason I will no longer process used barrels with unkown or high round counts not knowing the internial surface finish. I have informed everyone that contacts me that processing used barrels is not a very good idea and the risk associated.

Their was only one person that contacted me directly and said that they had a problem with this lot of processed barrels Bart.

I had heard rumors of others that were not happy with having their used barrels processed while as was with the other company with that one lot but they talked with everyone else but did not notify me of any issue.

Is this an accurate statement?

Joel Kendrick
 
I need to back up a little here re my statement "but I AM planning on a big ol' BAT 'M' ......"

BAT is closed until next week so I haven't been able to ascertain steel used in my 'M' but I'm suspecting that I've been premature in my statement. At this point I AM NOT stating as fact that it's safe nor reasonable to just send in a BAT action. I'm hesitant to state that my action is "17-4 precipitating stainless" and hesitant to state that "17-4 is NOT safe to treat since it begins to move at 900F"....... and that 416 SS is the one that's OK to treat because I'm just parroting terms here with no real understanding.

I'm still wading through information. My earlier statement was pretty positive whereas currently I'm NOT :)

Still sorting it out......

I WOULD love a black BAT but not at the expense of my cabeza.

al

al
 
Al,
You are correct with you statement about the 17-4 material drawn back at 900 deg F. This is why I must know the material and heat treat history before processing like we discussed on the phone. The process temperature we are using is 980 deg. F if the aging or draw back is less than 1000 deg F I can not process components and maintain targeted compound zone without reducing core hardness by 18%.
Please check with BAT to find out material information. When I checked with BAT on my action Bruce informed me it was 416R and he gave me heat treat info before I processed. If you can not obtain the heat treat information for the material to be processed please do not send for processing.
We can not process 17-4 SS material.

Joel Kendrick
 
quartersnatcher said:
Al,
You are correct with you statement about the 17-4 material drawn back at 900 deg F. This is why I must know the material and heat treat history before processing like we discussed on the phone. The process temperature we are using is 980 deg. F if the aging or draw back is less than 1000 deg F I can not process components and maintain targeted compound zone without reducing core hardness by 18%.
Please check with BAT to find out material information. When I checked with BAT on my action Bruce informed me it was 416R and he gave me heat treat info before I processed. If you can not obtain the heat treat information for the material to be processed please do not send for processing.
We can not process 17-4 SS material.

Joel Kendrick
Click to expand...

Thanks Joel,

And from BAT's website, material spec sheet, they use 17-4 normally.

I'll have to find out if this has changed. Hopefully their records include this information re my own action.

al
 
Joel,

Can you make a general suggestion on how many rounds might be too many before proceeding with this process? I have a 7WSM barrel that I've fired exactly 150 rounds out of it as of yesterday. The bbl seems to be really hammering and I'd love for it to last a while. Not owning a bore scope, I do not know if the 150 rounds of break in I've done on the barrel are enough to have done any appreciable damage to the throat. The powder I am using has a really slow burn rate compared to the other favorite powders for this caliber and I have my fingers crossed that this may have saved some of the throat enough that you can process this barrel for me. Although, the slower powder does require about 8 more grains than the other fav powder for the 7WSM. :confused: I think the average acceptable like of the chambering is around 1600 rounds, if that is the case, I've already used 10% of that.
 
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