friction modifying coatings for barrels

[Aegis]

Just curious if anyone had monkeyed around with this idea yet. I got to thinking about it after talking with Site Mfg. about the use of silcon lube in the Stiffi barrels. They said it might help prevent the buildup of gelatin as the balls ablade in the barrel, and might make cleanup easier, without any sacrifices. In no terms did they claim any performance enhancement or otherwise promote this practice. The only thing they said for sure was that it would make it shiny.

In my high powered rifle shooting, I use a moly coating process that coats the bore with a very thin but very slick layer of molybdenum disulfide.

This creates an extremely slick surface in a rifle barrel, or anything else it gets on. I spilled some on the floor in my garage and it made unfinished concrete slippery.

The benefit in the rifle is that you do not have a buildup of copper and other fouling in the bore, so velocity and accuracy remain constant over a longer period of time than you might see with direct steel to copper contact. Granted this is a much different situation - vastly higher pressures and velocity, different materials, et..

Thinking that perhaps a lower coefficient of friction in a paintball barrel might help prevent barrel breaks, improve efficiency, and help shoot the barrel clean when necessary.

Any thoughts?

[ezrunner]

coatings

The ceramic barrels by J&J were marketed under this same premise. That an ultra slick barrel would shoot better. In PSP/NPPL you are banned from putting rainx down your barrel for a reason.

To test your theory, take Remington Dry lube, then using a tight fitting ball in your barrel, shoot a group @ 50ft, then break a ball by holding it half in the chamber and firing, then fire after that and see the results.

Then apply a coating of the dry lube to the inside of the barrel from both ends, and repeat the test. This is not banned by the rules and is a spray on teflon so it should give you some idea of how this would affect your system.

Empirical as it is, this still would provide more info.

-rob

[rdb123]

Re: coatings

Originally posted by ezrunner
...In PSP/NPPL you are banned from putting rainx ...

Could you expound on this reason? Thanks

[Top Secret]

Why is RainX banned? That stuff is great. How would they check?

[BlackVCG]

Sure a smoother barrel is nice, but the surface finish they're getting on good aftermarket barrels is pretty much as good as it can get to make a difference. You always want to run your paint to barrel fit on the loose side to begin with and since the balls aren't spherical to begin with it basically glides down the barrel with two contact points (the highest points of the ball). The amount of friction drag you get out of the ball is very small, considering the travel length.

Couple that with the fact that if your surface finish varies at all, you'll impart a spin on the ball that makes it travel as though you have a break down the barrel. A break down the barrel creates a really slick/uneven surface and the inaccuracy is because of the inconsistent spin it imparts on the ball.

[Aegis]

Good point. I have been thinking about the importance of the barrel crown, which I have yet to see mentioned in any paintball forum. Another holdover from high powered rifles, but think about it - the air escaping around a paintball is going faster than the paintball. If it is escaping earlier on one side, that is going to leave the ball in contact with part of the barrel and on the opposite side, a higher velocity of air affecting it.

I went out and checked out about 7 different barrels with a machinist's square, 4 of them had discernable deviations from 0 degrees square. Couldn't rig anything to measure it, but I bet it makes a difference.

[BlackVCG]

The point you were addressing, about air escaping around the ball causing deviations, is the reason why two piece barrels are more consistent over the chronograph. Just something to think about.

[hitech]

Originally posted by Aegis
If it is escaping earlier on one side, that is going to leave the ball in contact with part of the barrel and on the opposite side, a higher velocity of air affecting it.

The "blast" of air at the end of the barrel isn't enough to impart enough of a spin to affect the trajectory of the paintball (you need at least 5k rpm to have any noticeable affect). Look at the high speed photos in the data thread that show the paintball just after it exists the barrel into a stream of smoke. You can see that the "blast effect" is minimal (almost nonexistent). The pressure behind the paintball is just to low to have any significant blast. If you keep cranking up the velocity you can change that. Back in the "good old days" everyone wanted longer barrels because we had the velocity cranked WAY up.

BTW, if you are using a ported barrel there is NO blast. The pressure is released at the first hole.

[Aegis]

If that was the case, why would you feel so much pressure on your hand when shooting air to clean the ports?

[athomas]

There's nothing to hold the air back when you fire the gun with no ball in the breach. The air flows down the barrel until it contacts your hand. Then it builds up pressure again and releases out the porting. When you fire a ball, the ball is holding the air back. The pressure is already built up behind the ball when the ball passes the first vent hole. Any pressure immediately starts to release out the holes. By the time the ball leaves the barrel, there isn't much pressure left.

[billmi]

Re: coatings

Originally posted by ezrunner
In PSP/NPPL you are banned from putting rainx down your barrel for a reason.

What rule number is that?

I'm not familiar with it.

[ezrunner]

Bill :)

sorry to drift away I've been out.

Ok, there were several ref's in the national circuit (before the split) that were enforcing rules that weren't written.

One of which was that you could not put rainx down your barrel. Another was the practice of coating your revolution in turtle wax, along with your gunbody.

I don't ever recall seeing them in print, but I do specifically recall getting admonished about it. The time frame would have been 99 - 2001 that I remember this being an issue.

It was not near as big an issue as the way the trigger bounce issue was handled, that time they actually posted on their site then modified the printed rules if memory serves.

-rob

[athomas]

I remember it used to be an issue back in the early 90's. You were prohibited from putting any chemical compound in the barrel no matter what, even for cleaning (soap and water only were allowed). Supposedly, it was to prevent the possibility of anaphalactic shock if some of the chemical got into a cut caused by a paintball fired from the contaminated gun barrel. I always thought it was a dumb rule and it really couldn't be enforced anyway.