Before and After Nitride Velocities

[tunacan]

Here is a little info for those that might be interested. I have read many posts about speed gains after nitriding the barrel. Not much, but there are gains......

Varget/130 Bergers

Pre Nitride

Series, 1, Shots:, 6
Min,2771, Max,2828
Avg,2800 ,S-D, 22
ES , 57

Series,Shot,Speed
1, 1, 2782, ft/sec First 3 in this series are 36 gr
1, 2, 2788, ft/sec Second 3 are 36.3
1, 3, 2771, ft/sec
1, 4, 2816, ft/sec
1, 5, 2828, ft/sec
1, 6, 2816, ft/sec
----,----,----,----
Series, 2, Shots:, 3
Min,2754, Max,2807
Avg,2787 ,S-D, 29
ES , 53

Series,Shot,Speed 36.6 grains
2, 1, 2802, ft/sec
2, 2, 2754, ft/sec
2, 3, 2807, ft/sec
----,----,----,----
Series, 3, Shots:, 3
Min,2828, Max,2847
Avg,2835 ,S-D, 10
ES , 19

Series,Shot,Speed 36.9 grains
3, 1, 2832, ft/sec
3, 2, 2847, ft/sec
3, 3, 2828, ft/sec
----,----,----,----
Series, 4, Shots:, 3
Min,2842, Max,2857
Avg,2850 ,S-D, 7
ES , 15

Series,Shot,Speed 37.2 grains
4, 1, 2842, ft/sec
4, 2, 2853, ft/sec
4, 3, 2857, ft/sec
----,----,----,----
Series, 5, Shots:, 3
Min,2729, Max,2815
Avg,2782 ,S-D, 46
ES , 86

Series,Shot,Speed 37.5 grains
5, 1, 2815, ft/sec
5, 2, 2729, ft/sec
5, 3, 2804, ft/sec
----,----,----,----
Series, 6, Shots:, 3
Min,2862, Max,2910
Avg,2879 ,S-D, 26
ES , 48

Series,Shot,Speed 37.8 grains
6, 1, 2910, ft/sec
6, 2, 2866, ft/sec
6, 3, 2862, ft/sec
----,----,----,----
Series, 7, Shots:, 3
Min,2900, Max,2949
Avg,2920 ,S-D, 25
ES , 49

Series,Shot,Speed 38.1 grains
7, 1, 2900, ft/sec
7, 2, 2913, ft/sec
7, 3, 2949, ft/sec
----,----,----,----
Series, 8, Shots:, 3
Min,2937, Max,2953
Avg,2945 ,S-D, 8
ES , 16

Series,Shot,Speed 38.4 grains
8, 1, 2946, ft/sec
8, 2, 2953, ft/sec
8, 3, 2937, ft/sec


Post Nitride


Series, 9, Shots:, 6
Min,2895, Max,2917
Avg,2904 ,S-D, 10
ES , 22

Series,Shot,Speed 37.5 grains
9, 1, 2898, ft/sec
9, 2, 2898, ft/sec
9, 3, 2895, ft/sec
9, 4, 2901, ft/sec
9, 5, 2917, ft/sec
9, 6, 2917, ft/sec
----,----,----,----
Series,10, Shots:, 3
Min,2834, Max,2840
Avg,2837 ,S-D, 3
ES , 6

Series,Shot,Speed 36.3 grains
10, 1, 2840, ft/sec
10, 2, 2834, ft/sec
10, 3, 2837, ft/sec
----,----,----,----
Series,11, Shots:, 3
Min,2823, Max,2906
Avg,2852 ,S-D, 46
ES , 83

Series,Shot,Speed 36.6 grains
11, 1, 2906, ft/sec
11, 2, 2829, ft/sec
11, 3, 2823, ft/sec
----,----,----,----
Series,12, Shots:, 3
Min,2832, Max,2862
Avg,2848 ,S-D, 15
ES , 30

Series,Shot,Speed 36.9 grains
12, 1, 2862, ft/sec
12, 2, 2832, ft/sec
12, 3, 2850, ft/sec
----,----,----,----
Series,13, Shots:, 3
Min,2875, Max,2883
Avg,2879 ,S-D, 4
ES , 8

Series,Shot,Speed 37.2 grains
13, 1, 2883, ft/sec
13, 2, 2881, ft/sec
13, 3, 2875, ft/sec
----,----,----,----
Series,14, Shots:, 3
Min,2890, Max,2906
Avg,2899 ,S-D, 8
ES , 16

Series,Shot,Speed 37.5 grains
14, 1, 2903, ft/sec
14, 2, 2890, ft/sec
14, 3, 2906, ft/sec
----,----,----,----
Series,15, Shots:, 3
Min,2908, Max,2920
Avg,2915 ,S-D, 6
ES , 12

Series,Shot,Speed 37.8 grains
15, 1, 2920, ft/sec
15, 2, 2918, ft/sec
15, 3, 2908, ft/sec
----,----,----,----
Series,16, Shots:, 3
Min,2918, Max,2934
Avg,2928 ,S-D, 9
ES , 16

Series,Shot,Speed 38.1 grains
16, 1, 2918, ft/sec
16, 2, 2934, ft/sec
16, 3, 2934, ft/sec
----,----,----,----
Series,17, Shots:, 3
Min,2937, Max,2965
Avg,2951 ,S-D, 14
ES , 28

Series,Shot,Speed 38.4 grains
17, 1, 2937, ft/sec
17, 2, 2965, ft/sec
17, 3, 2953, ft/sec

 

[Jeff A]

Thanks for your work here. Is there anyway to summarize? I'm confused about your numbers. Some barrel info would also be appreciated.

 

[VinceB]

Interesting - a speed gain means that somehow the process has increased pressure. How? By making the bore tighter? Increasing friction?

 

[Jeff A]

Interesting - a speed gain means that somehow the process has increased pressure. How? By making the bore tighter? Increasing friction?

This process may reduce friction. The bore does not get tighter as the process is not a coating.

 

[tunacan]

There are 17 series.....each weight charge is a series. Series are labeled 1,2,3..and so forth. The next number is the shot sequence for that series..1,2,3

The chambering is a 6.5x47, Brux barrel, 8 twist, 26"

 

[tunacan]

The reason I posted it is because I have seen post where people argue until they are blue in the face that reduced friction equals reduced velocities.

This isn't concrete data, but I loaded both pre and post bullets identical.

 

[VinceB]

Interesting - a speed gain means that somehow the process has increased pressure. How? By making the bore tighter? Increasing friction?

This process may reduce friction. The bore does not get tighter as the process is not a coating.

Yes, I realise that one may expect friction to be reduced - but then that should result in velocity REDUCTION not an increase. So what has caused the increase is my question.

 

[queen_stick]

The reason I posted it is because I have seen post where people argue until they are blue in the face that reduced friction equals reduced velocities.

This isn't concrete data, but I loaded both pre and post bullets identical.

looks like your data may cause more of this "arguing until blue in the face"

I think a good way to summarize your results would be to simply state "Nitriding a barrel changes something."

just leave it at that... lol

 

[butchlambert]

You guys have no memories or don't read the posts. The US Army Reserve ran extensive test on this and I posted the armors results. Do a search!! I believe after much testing with machine rest showed a 2% increase in velocity. He said it wasn't an issue either way.

 

[butchlambert]

Yes, I realise that one may expect friction to be reduced - but then that should result in velocity REDUCTION not an increase. So what has caused the increase is my question.

That is not how I view friction. Myself I look at friction as drag, thus, more drag the less velocity.


tunacan -
Great test.......
Thanks for sharing
Donovan

I have to agree with you Donovan.

 

[Grimstod]

Yes, I realise that one may expect friction to be reduced - but then that should result in velocity REDUCTION not an increase. So what has caused the increase is my question.

That is not how I view friction. Myself I look at friction as drag, thus, more drag the less velocity.


tunacan -
Great test.......
Thanks for sharing
Donovan

I have to agree here to. It makes sense to my brain. Just have not seen any data to validate it till now.

 

[butchlambert]

Here is the email again.


Butch

I was the Armorer for the Army Reserve Shooting Team for over a decade so I do have quite a bit of experience with both processes.

As I am sure you know, most G.I. barrels are made from chrome molly steel which is more susceptible to corrosion than stainless steel. Chrome lining is used on G.I. bores both to extend their shooting life and to protect them from corrosion that can be a problem in battlefield conditions where maintenance is sometimes sporadic or insufficient. Chrome lining does a pretty good job of protecting battlefield weapons. One of the objections to chrome lining is that it is thought to decrease accuracy. This seems to be a valid criticism and is backed up by machine rest tests I have conducted of identical barrels (same manufacturer but half chrome lined and half not).

As you are aware most barrel "wear" is in the throat area. So eventually the hot gasses from the burning of the gunpowder will eat thru the chrome lining at the throat. It is rumored that at this point accuracy will plummet but I have not found that to be true. (Or if true, it is overstated or maybe only occurs for that short period when there is both chrome and bare steel in the throat simultaneously - just at the point of initial break thru.) Chrome lined barrels can continue to shoot well for thousands of rounds after the bare barrel steel at the back of the barrel (throat) has been exposed due to erosion of the chrome lining. Another criticism of chrome lining is that it can flake off later in the life of the barrel resulting in poor accuracy. Obviously, this could also cause maintenance problems if the user is depending on the chrome to ward off corrosion and thus is careless in his bore cleaning. If corrosion is allowed to occur pitting will result and that will ruin accuracy for sure.

Barrel pitting was one of the reasons I got involved in Salt Bath Nitriding. I was loosing nearly as many expensive match grade barrels to improper maintenance (causing pitting) as I was to wear out. This was under the relatively benign target shooting conditions. Obviously given the reputation of degraded accuracy, using chrome lining wasn't an option. So for the past couple of years I have been Salt Bath Nitriding all of my match barrels and haven't had a single one exhibit any pitting. During that 2 yr. period shooters have put anywhere from a few hundred rounds to thousands of rounds on said barrels. I don't know how long the coating will persist so at this point I am still evaluating it as a preservative. I don't know what will happen in another year or two when these barrels get more wear on them. Salt Bath Nitriding goes on both inside of the bore and on the outside surface. So, instead of 2 manufacturing steps you have combined them into one. Salt Bath Nitriding doesn't degrade accuracy one iota, unlike chrome lining. This was the first thing that I verified when I began using the process. I broke in a bunch of barrels and then machine rest tested them for group. I recorded and kept the targets, cleaned up the barrels, and sent them to MMi TruTec for the Isonite process. When they came back I reassembled them on the same receivers with the same torque settings, same bolt carrier assemblies, same flash suppressors, etc. Then they were retested with the same ammo lots. NO degradation in accuracy and about a 1% increase in muzzle velocity.

Chrome lined barrels seem to clean up rather easily after a range session. I found the ease of cleaning of Isonite coated barrels to be similar to chrome lined barrels. The Isonite barrels clean up the easiest of any non chrome lined barrels I have ever used. Isonite can be applied to either stainless or chrome molly but the factory needs to know what steel you are sending them because the application process varies a bit. Again, I only have about 2 yr. of cleaning experience with Salt Bath Nitrided barrels. I don't know if the ease of cleaning will continue as the barrels get more rounds on them. Generally speaking, most non coated barrels get harder to clean later in life. Although stainless has a reputation of being corrosion resistant it isn't corrosion proof (I have had plenty of them return pitted) so I coat both my C.M. and my SS barrels. The Isonite on the outside of the stainless barrels cuts reflection down so my shooters like it.

I mentioned flaking of chrome lining inside the bore. Joel Kendrick is my contact at MMi TruTec, the company in Arkansas that does my Salt Bath Nitriding (they call it Isonite). He was mentioning using the Salt Bath Nitriding inside the bore prior to chrome lining it to get a better adhesion. He is currently working with one of the military contractors (maybe F.N., but don't quote me on that) relative to this process. He has given me permission to give out his contact information so I have cc'd him in my reply to you. He can give you the specifics of any testing and evaluation that has been done relative to this process and can give you quotes, etc. should you just be interested in the Isonite by itself as I use it.

One last quick note on chrome lining. Such barrels have the reputation of changing point of impact when heated up. I have found this to be very true. It may be due to the way the different metals (chrome molly and chrome) expand inside the bore. What ever the reason, it does happen and, again, this was verified on a state of the art machine rest. Isonite doesn't exhibit this characteristic.

I am sure you are well aware of some of the things I covered. Lacking specific questions, I just sort of used a shotgun approach which ended up being fairly long. If I left anything unanswered please feel free to get back to me. I have enabled my Spam Blocker to allow your e-mails to come in with out the automated hate responses that Earth Link sends out. I am sure Joel would also be glad to clarify the technical aspects of the Salt Bath Nitriding process. So far I am very pleased with it.

Best of luck!
Carlos


I thought he said 2%, but it was 1%.