Why is there no coatings used in rifle throats to slow erosion?

[theflyonthewall]

devins.....I hope you know that coming into this thread means that we'll have to pick your brain....hehe.

Enter a new spin on the original concept of coating:

How about a replaceable throat? Instead of attempting to make things in this harsh environment of a rifle throat PERMANENT, maybe we should roll with the punches so speak? Maybe accept the idea that the throats are going to erode no matter what normally-feasible means we attempt and instead, design a throat that we can replace once it becomes eroded to the point of affecting accuracy?

Here's what I'm tossing around in my mind right now. Maybe this can keep y'alls creativity flowing? Keep in mind this drawing is CRUDE. I can draw up most anything that we need TO SCALE on paper. I just can't do it in MS Paint..lol

 

[theflyonthewall]

The ideology behind my idea is to engineer a "throat" that can be screwed into the action. The barrel can then be screwed into the new throat. The point is not only to allow the throat to be replaceable, but to engineer it so that the barrel life can be extended as long as possible. So it's quite possible that the throat itself may need to contain the throat, and possibly the first inch or two of the rifling as well.

What's understood already:
1. Machining costs are going to be higher initially than that of a standard barrel replacement.
2. The rifling would have to be "timed" between the throat and the barrel as these two become mated in assembly.
3. A clone of the original throat may need to be kept as a blueprint so that a smith could pull precise measurements from this clone to machine any future throats that a customer decides to purchase for THAT RIFLE and barrel.

What's unknown to me:
1. Is this idea as feasible as it seems to me? Or is there some massive oversight that makes it nearly impossible.
2. Can all three of these parts be mated as precisely as would be required so that one ends up with an equally accurate rifle, as that rifle was in it's unaltered form?
3. Is there a better way to incorporate a replaceable throat into an otherwise traditional bolt action rifle?
4. Can a system be designed to allow the DIY guy to change his own throats that he gets from his smith?

No one needs to worry about directly answering the above questions. I was just trying to establish what questions I have floating around in my brain in conjunction with the drawing above.

 

[royinidaho]

Here's some preliminary efforts by the army. It may be of use. Who knows? Not me?

I have no idea of what they are talking about nor what numbers Devin needs. Guess this is a shot in the dark. Though the formula looks intriguing.

I have a 270 AM that could be the sacrificial animal. A long way from 37 MM.

http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA444069

 

[theflyonthewall]

Great link Roy!

That's a tremendous amount of raw data and a good read.

For our purposes, I took notice of the thermal conductivities of the different materials in comparison to the 4340 steel and the results that showed the area immediately in front of the throat as having the highest recorded temperature readings.

What that information tells me is if we were pursuing perfection here instead of mere betterment---OR---we were looking to obtain maximum barrel life regardless of cost involved, then a non-uniform coating thickness would be required ensuring that the coating would be at it's thickest in the pre-throat area and becoming thinner as it's moved forward toward the rifling.

Truth be told though.....this idea of a throat/chamber coating seems to have merit, but are any of us equipped well enough to do the proper R&D on a donor rifle to find out how far this takes us?

As far as devins' idea goes of making an insert.....that's probably a better solution in some respects. Although cost prohibitive on a commercial level, it definitely seems to have a great deal of potential.

Yo devins.......do you think perhaps instead of a bonded insert, that maybe there is a coating process that could work just as well---even if it's life was shorter? What I'm driving at here, is if we could possibly combine ideas so that we could coat a part that was easily replaceable (like the throat idea I posted above or similar), while leaving the rest of the rifle unchanged, then we could simplify AND save a great deal of cost, in R&D.

For instance-----machine 5 identical replaceable throats (if such is feasible in a rifle platform). Then we could test each one with different coatings and establish a useable life. OR we could choose what seems to be the most promising coating material in the beginning, and test differing thicknesses, again testing for end of life.

I believe that the second idea of choosing only one coating would allow us to significantly improve throat life while keeping costs within the stratosphere.




Come on folks.....chime in!!

 

[shortgrass]

Here, you're all worried about throat errosion. I have a barrel in my shop, from a competition rifle I built, that has a known 3000 rds. thru it (.260 Rem). It needs a lot more help than just the throat!

 

[theflyonthewall]

Here, you're all worried about throat errosion. I have a barrel in my shop, from a competition rifle I built, that has a known 3000 rds. thru it (.260 Rem). It needs a lot more help than just the throat!

shortgrass.......we're not trying to lower throat erosion on calibers that are known to have acceptable barrel life like the 260 you mentioned. We're trying to find a way to have a caliber like the 7RUM last longer than it's expected 700-1000 rounds.

If successful, we might be able to have our extreme overbore cartridges a little longer than we do now before needing a rebarrel.

 

[shortgrass]

Good luck guy! Your question has already been answered. Melonite/Nitride. Make the barrel harder (after all machne work has been preformed). It's a cost effective method! Around $100 bucks when you include shipping both ways! Everthing else I've seen here, far out weighs that cost wise. And believe me, cost is everything! Everyone needs to try to come up with a way to change the laws of physics, every now and again.

 

[theflyonthewall]

No one is trying to change the laws of physics. Matter of fact, we're trying to do the opposite......finding a way to better adapt TO the physics that we know to exist.

If you read through the thread from the beginning, you'll see that this thread has been through a few changes. My original question was "why are there no coatings...." Then I was enlightened to the fact that there ARE surface treatments that are working to accomplish the same goal with generally positive feedback already established. So then the thread took a turn towards the potential to make a throat replaceable. And it is now moving in the direction of "if we can make a replaceable throat, can we coat a replaceable throat and see what life we get out of it."

So this thread especially is one that if a person just pops in without having read the entire thread, then they will likely not know where we're going.

No one is trying to re-invent the wheel here, just to build a better mousetrap....or in this case, a better elk-trap, if you will.

 

[shortgrass]

I've read the entire thread, been following it since it was first posted (just because I waited to post later in the thread means nothing!). A 'replacement' barrel sounds a whole lot cheaper than a 'replacement throat'! Are you after Minute of broad side of the barn with that "replacement throat?

 

[J E Custom]

I have been reading this thread and the discussions have been interesting to say the least.

A little history : There have been many coatings over the years that were designed to prolong
the BARREL Life and none of them has stood the test of time as far as accuracy.

A lot of the military weapons have been coated with one thing or another. The chrome lining
has the best track record for the prevention of erosion and corrosion. they even tried using a
Stellight process (This Is some very hard stuff) but apparently it was not a practical solution
and to costly.

I personally think that the throat erosion on most weapons is a by product of our need for speed
and therefore self inflicted in most cases. Before all of these High velocity cartriges throat erosion
was not a consideration and most rifles lasted a lifetime.

We have become more interested in velocity and accuracy and that has changed things.

It is simple physics: the more velocity, the more powder, the more powder the more erosion.

If you build a hot rod you can expect this problem sooner. Setting the barrel back is a simple
and proven fix. re barreling is the next thing that can be done and accuracy maintained.

I have seen barrels with the throat completely gone for several inches still shoot well because
the barrel it's self was taken care of and maintained.

There may be a coating out there waiting to be discovered that will double the life of the barrels
accuracy but for now IMO a good smith can restore a rifles accuracy better.

Just my comments on coatings.

J E CUSTOM

 

[theflyonthewall]

I've read the entire thread, been following it since it was first posted (just because I waited to post later in the thread means nothing!). A 'replacement' barrel sounds a whole lot cheaper than a 'replacement throat'! Are you after Minute of broad side of the barn with that "replacement throat?

No shortgrass, I was "after" a creative discussion with people throwing out ideas in the hope that we might just learn something. If somewhere along the line we're fortunate enough to actually come across something that has merit and could be pursued, then great! But if not, we can all still learn from each other.

On the specific "replaceable throat" concept, I was HOPING that someone with real gunsmith experience could say....."might be cost prohibitive, but could work".....or..."it's not going to have the outcome that your looking for BECAUSE........" So if you have a real-world perspective on what's wrong with it, please chime in. But just saying "Are you after Minute of broad side of the barn...." doesn't allow us to learn much.

You may be so much more intelligent than me, that this idea seems like some sort of cartoon to you, but I'm actually serious about learning something that I've never known much about. So please feel free to contribute or not contribute. But can we do it without sarcasm?

I have been reading this thread and the discussions have been interesting to say the least.

A little history : There have been many coatings over the years that were designed to prolong
the BARREL Life and none of them has stood the test of time as far as accuracy.

A lot of the military weapons have been coated with one thing or another. The chrome lining
has the best track record for the prevention of erosion and corrosion. they even tried using a
Stellight process (This Is some very hard stuff) but apparently it was not a practical solution
and to costly.

I personally think that the throat erosion on most weapons is a by product of our need for speed
and therefore self inflicted in most cases. Before all of these High velocity cartriges throat erosion
was not a consideration and most rifles lasted a lifetime.

We have become more interested in velocity and accuracy and that has changed things.

It is simple physics: the more velocity, the more powder, the more powder the more erosion.

If you build a hot rod you can expect this problem sooner. Setting the barrel back is a simple
and proven fix. re barreling is the next thing that can be done and accuracy maintained.

I have seen barrels with the throat completely gone for several inches still shoot well because
the barrel it's self was taken care of and maintained.

There may be a coating out there waiting to be discovered that will double the life of the barrels
accuracy but for now IMO a good smith can restore a rifles accuracy better.

Just my comments on coatings.

J E CUSTOM

J E........thank you for giving us your thoughts! I for one definitely appreciate you taking the time.

I agree that our human need to "push things" (oftentimes past the practical limits) is what has led us to where we are. Good point.

It seems as though the military has actually spent a great deal of time and money on this very concept. Do you feel that their needs and our needs are different enough that some of the coatings that they've found less than suitable might actually be beneficial to us?

What I mean by that is----they're going to need coatings that can stand up to rapid-fire/sustained fire scenarios where they'll be generating a case for much quicker erosion. Has the TYPE of firing had any bearing on their experiments? I don't know. Do you?<---that's NOT said in sarcasm...lol.

If not......maybe that's something that I should research more?

Again, thank you for taking time out of your day to lends us your perspective. It's really appreciated.

 

[Pdvdh]

Good luck guy! Your question has already been answered. Melonite/Nitride. Make the barrel harder (after all machine work has been performed). It's a cost effective method! Around $100 bucks when you include shipping both ways! Everything else I've seen here, far out weighs that cost wise. And believe me, cost is everything! Everyone needs to try to come up with a way to change the laws of physics, every now and again.

10-4 on Melonite/Nitride. The technology is largely perfected over the years of usage, and the cost is reasonable, compared to the cost of purchasing and installing a new replacement barrel.

 

[Pdvdh]

No shortgrass, I was "after" a creative discussion with people throwing out ideas in the hope that we might just learn something.

But can we do it without sarcasm?

shortgrass is emphasizing cost competitiveness. Which pretty much eliminates everything compared to Melonite treatment - which is simply dipping the barrel into a hot bath solution under controlled conditions for the correct period of time.

Any kind of machining and threading within the throat area is going to be labor intensive if accuracy is going to be preserved. Labor intensive is spelled $$$ unless it's farmed out to China or an equivalent work force environment. And will make the cost of re-barreling look quite attractive in comparison.

Not to be the bottleneck in the dialog though...

 

[J E Custom]

I agree that our human need to "push things" (oftentimes past the practical limits) is what has led us to where we are. Good point.

It seems as though the military has actually spent a great deal of time and money on this very concept. Do you feel that their needs and our needs are different enough that some of the coatings that they've found less than suitable might actually be beneficial to us?

What I mean by that is----they're going to need coatings that can stand up to rapid-fire/sustained fire scenarios where they'll be generating a case for much quicker erosion. Has the TYPE of firing had any bearing on their experiments? I don't know. Do you?<---that's NOT said in sarcasm...lol.

If not......maybe that's something that I should research more?

Again, thank you for taking time out of your day to lends us your perspective. It's really appreciated.[/QUOTE]



The milatary has different needs than we do so there are systams that work better for them (Like
the chrome lined barrels that make the battrls last longer and need less maintance)

Accuracy is important to them but the main objective is dependability under battle conditions.

The Melonite/Nitride process may not improve barrel life enough for them to use it or under extreeme
heat it may break down or just not last (I am not privy to this info).

With all the money that they can spend on R&D maby they will come up with something that
will not only improve barrel life but inhance accuracy.

Everyone remimbers the Molly Craze and the hype said "Faster and better barrel life" Where is
it at now. (I fell for it to). Interestingly enough I did find a great use for it but not what it was
intended for. In a black powder barrel It improved the number of shots that could be fired
without cleaning by redeucing the powder fouling. also on copper bullets it redeuced barrel
fouling. There was a down side to it though as with many things that are supposed to end all
problems.

Longe range hunting comes with it's own set of probablems and for now we just have to live
with them until someone comes up with a "Better Mouse trap" .

J E CUSTOM