I just got for Christmas the book "The Benchrest Shooting Primer" and I've been thumbing through it for the last few days. I came upon an article on how to properly break in new barrels. Several different authors gave various opinions on the subject and although their exact regimens may be slightly different, the one thing they all preached was judicious cleaning of the bore after each shot or at the most after 4 or 5 shots untill the bore would not foul. This got me to thinking about the various rifles that I own but were not boughten new by me so the history of the cleaning is an unknown and without a scope its all a mystery. In this article Fred Sinclair gave the example of what happens each time we pull the trigger. The jacket material from the first bullet is deposited in the bore and on top of that is the residue from the burnt powder. When the next round is fired, the jacket material is deposited on top of this residue and its compressed between two layers of jacket material. This occurs with each round and the compression is extreme at 45K psi or higher and at unbelieveable temps. If you do clean your bore after say every 10 rounds but you only remove 8 or 9 rounds worth of gunk, over the span of 5 or 6 hundred rounds this buildup would be significant. How can or better yet, whats the best method to remove these years of buildup w/o damaging the bore from over-cleaning, or is there such a thing as over-cleaning?

In this same article, another gentleman wrote that while you do want a smooth bore, you can get one too smooth. He gave the example of trying to slide two pieces of glass over each other. It doesn't work very well without some type of lube as the two surfaces are perfectly mated. The same thing applies to a smooth jacketed bullet trying to make its way down the bore and his belief was that a lapped bore had a lower coefficient of drag then one that is perfectly smooth. The particulate and jacket material that Mr. Sinclair described has no place to embed itself if the bore is polished smooth. In other words if the pores are sealed it will facilitate a more rapid buildup of fouling agents. Does this make sense to anyone else? I can buy the idea of the bullets not slideing as easily but to me if the pores are sealed it should reduce fouling. My question is then could you potentially get a bore too smooth by using products such as Rem-clean or other semi-abrassive cleaners? Sorry for the long winded question but its just something that got me to thinking.

It seems to me, you are on the RIGHT ROAD!

quote:

Originally posted by shootaway:
It seems to me, you are on the RIGHT ROAD!

Yes, but to where!!

You remove the built up fouling with bore cleaner chemicals. They will break down the copper and the powder

The problem occurs when for years the fouling builds up and there is moisture involved which results in corrosion to the bore. Not so many rounds and you can ruin a bore. A few hundred rounds in that situation together with the time is all it takes.

quote:

Originally posted by cobrajet:
...and his belief was that a lapped bore had a lower coefficient of drag then one that is perfectly smooth.

These terms are not mutually exclusive.

quote:

The jacket material from the first bullet is deposited in the bore and on top of that is the residue from the burnt powder. When the next round is fired, the jacket material is deposited on top of this residue and its compressed between two layers of jacket material. This occurs with each round and the compression is extreme at 45K psi or higher and at unbelieveable temps. If you do clean your bore after say every 10 rounds but you only remove 8 or 9 rounds worth of gunk, over the span of 5 or 6 hundred rounds this buildup would be significant.

This is what I had always thought as far as the build-up increasing with each shot.

A few years ago I read an article in which the author wanted to see how this affects pressure. He hypothesized that the pressure would increase to a point where the test would have to be suspended due to overly high pressures. Long story short, once the barrel was "fouled" with a few dozen shots pressure did not increase. The real shocker was that accuracy did not suffer once the bore was fouled. From the tests he believed that the fouling only builds up to a certain point, then past this point additional shots don't increase fouling.

I think the bench rest guys have great theories but how many of them are really tested. How many bench-resters have fired more than a few shots without cleaning?

Jason

So whats a guy to do? Just clean the bore to what he believes is an acceptable level and just go on about his business? Sounds to me like I prolly dont want to ever look down my bores with a scope 'cause your prolly just asking for many sleepless nights. Can some more of you "professionals" out there comment on this subject? Come on fellas, I'm asking for help and get 4 replies? Thanks for those of you who did take the time to respond, its much appreciated.

quote:

Originally posted by cobrajet:
So whats a guy to do? Just clean the bore to what he believes is an acceptable level and just go on about his business?

That sounds about right and that is all I have ever done for my hunting rifles. I do not shoot competitively so I can not speak to that.

My theory is that one either has a barrel that shoots accurately or one does not. No break-in procedure or any amount of cleaning or not cleaning is going to have much of an effect.

From experience some of my rifles shoot well with a squeaky clean barrel, but most seem to like a couple of fouling shots.


I think that most barrels are a little 'loose' and need fouling to 'tighten' up a bit to better 'grab' a bullet and properly stabilize it.


I think when you break in a new barrel you are 'wearing down' some high spots left by the machining process. By not removing the carbon and jacket material fouling, it tends to support these burrs and the next shot is less effective at lapping them away.

I think that equating the molecular attraction of two pieces of glass to that of a piece of copper and steel barrel under extreme stress is probably not the very best comparison.

For the man that is in no rush, good old Hoppes No9 will clean a barrel of all residue from jacketed bullets. I have no experience with lead bullet other than a revolver. One wet, two dry until clean. Then one wet and let it set. I let it set for 12 hours or more and then two dry. The first couple of DAYS, I will find it necessary to run several wet and dry patches after it sets.

I like Barnes bullets and the copper fouls bores much heavier than gilding metal. I can see the copper fouling in the rifling near the muzzle. It doesn't bother me to spend a few minutes a day for weeks to clean a bore, I like the smell of Hoppes. And it contains no chemicals that hurt can etch steel of damage stock finishes.

That being said, I have just received an order from Brownell's and there is some JB in it, I may be easing into a new way of life.

I think that a fire arm needs to have all the fouling removed on a regular basis. I have had one second hand rifle that was a 4 minute rifle. It was all I needed in a 308 Savage 99 and bear hunting with hounds. It wore a 4 minute red dot and always put a hole under the dot. I gave it a good cleaning and discovered that the bullets were riding on fouling and it would no longer hit a 16 inch target at 50 yards. If the fouling had been cleaned earlier, whatever reaction that took place would have never deteriorated the bore so badly.

I've found that cleaning with Hoppes Elite with a good bronze brush followed by Wipe Out (a couple of applications of both may be needed) will clean right down to the original barrel steel. Seems to clean everything out of the pores, one older VZ24 in 30-06 showed lots of tiny pitting that had never been exposed as long as I owned the rifle, not deep but tiny holes along side the lands. Firing two shots will fill it in and even JB won't show it back up. If a barrel can be cleaned back to that point there may be a chance of breaking it in for "the first time" later in a guns life.

Some of us benchresters HAVE tested the theories! most true benchrest shooters got thier start making bad rifle shoot. Thier game is measured in .001" not kills or X's

Proplinker, score shooting is measured in "X's".
Cobrajet, in the last 4 or 5 years many BR shooters have switched from Moly coated bullets to Danzac. I believe this is Tungsten Disulfide. I have seen many of them shoot an entire match (25 record shots and unlimited sighters)without cleaning their barrels. Us old farts who shoot "naked bullets" still clean regularly.

A Clean Barrel Is A Happy Barrel!

Just don't screw it up by not cleaning it without the proper equipment.

I have two rifles with douglas barrels. I have been to their shop in Charleston W VA twice. I figured who better to ask about cleaning solvents than people who do it every day.They said GMs top engine cleaner was as good as you could buy, But they still use what MR G R Douglas did in 1957.Kerosine and cutting oil.

I have found that the most demonstrative calibre for buildup/fouling for me personally, has been my .17HMR, If I shoot around 50/60 Rabbits on a farm, accuracy is immeadiately seen to fall off from tack driver to oops! I missed that one ! On stripdown of the moderator, the L'IL GUN powder residue is in the order of a wheelbarrow load , Give it's barrel a couple of Wipeout treatments, & Hey Presto! the next batch of bunnies get it through the eye, or under the chin, Ergo, A clean barrel is a happy barrel.