Dirty Barrel with a few 22lr rounds and Accuracy

FromMyColdDeadHand

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I guess I have never done it before, but I pulled the bolt on two different guns that two different kinds of sub ammo shot through them - and even thought one had less than 20 rounds through the gun (CX) the bore looked like an obstacle course. A couple of patches with Slip cleaner, looks clean as a whistle. 10 shots of SK long Range ammo, and it looks like it has boulders in it.

I’ve never looked at a short round count barrel. I just clean when its been a couple of matches or I think accuracy might be falling off. I know about the ‘carbon donut’, but I was surprised that the bore, with two good ammo types, not crappy HV box 22lr, looked so Trashy. How can you get any kind of repeatability out of something that dirty. Or should it be that dirty? That it was two guns and two ammos, I thought it might be general.

Is this just a case of I’ve never looked and its common?
 

Rimdenter

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I guess I have never done it before, but I pulled the bolt on two different guns that two different kinds of sub ammo shot through them - and even thought one had less than 20 rounds through the gun (CX) the bore looked like an obstacle course. A couple of patches with Slip cleaner, looks clean as a whistle. 10 shots of SK long Range ammo, and it looks like it has boulders in it.

I’ve never looked at a short round count barrel. I just clean when its been a couple of matches or I think accuracy might be falling off. I know about the ‘carbon donut’, but I was surprised that the bore, with two good ammo types, not crappy HV box 22lr, looked so Trashy. How can you get any kind of repeatability out of something that dirty. Or should it be that dirty? That it was two guns and two ammos, I thought it might be general.

Is this just a case of I’ve never looked and its common?
What lenght barrel ?
 

Rimdenter

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22 and 26

I’ve seen the same thing in my AR-22s, but just assumed it was from a couple hundred rounds of cheap HV ammo. I’ve never looked at a 22lr bore with out at least 100 rounds. Holy crap there is a lot of crap in a 22lr barrel.
Short barrels you'll see some unburnt powder as well rocks.
 

justin amateur

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Even a single shot with rimfire leaves a surprising amount of detritus.
Combustion of primer and powder produces water vapor and an assortment of particulates.
The water vapor condenses on the particulates creating small wads of muddy burn residue.
That happens every time you fire a shot. That's why cleaning is best done immediately,
before it dries and hardens.
 
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mcameron

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    rimfire ammo is terribly dirty....all of it......barrels looking like garbage is complete normal after a few rounds.

    that being said, rimfire is extremely tolerant of fouling.....frankly, my match rifles go THOUSANDS of rounds between cleanings.....so long as they continue to shoot well, i dont touch them.

    with rimfire, once they achieve a certain level of buildup, they seem to stay consistent for a long time...
     
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    Pink_Mist

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    I once read that a bull barreled .22 has a life expectancy of 250,000 rounds. I cannot remember the resource but recollect trusting it at the time.
     

    FromMyColdDeadHand

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    rimfire ammo is terribly dirty....all of it......barrels looking like garbage is complete normal after a few rounds.

    that being said, rimfire is extremely tolerant of fouling.....frankly, my match rifles go THOUSANDS of rounds between cleanings.....so long as they continue to shoot well, i dont touch them.

    with rimfire, once they achieve a certain level of buildup, they seem to stay consistent for a long time...
    I had always heard about switching ammo and having to re-coat the barrel with the new bullet lube…. I had a mental image of the new lube ‘wetting’ the barrel a few inches with each shot progressing down the barrel…. After seeing the barrel, I think it is more normalizing the crap in the barrel. Interesting, at least to me.
     

    BugIn762

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    I have an Anschutz 54 and a CZ 455 varmint and both need about 15 to 20 rounds to settle in after changing ammo.

    BugIn
     
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    justin amateur

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    AM-JKLWkxaMu9dVIwB9p-2NUTfLxLW7P1Vv7GWKQ8W7yxH5eiUE2a8pqJcYwkSy_w7etNTFnmdJdW7Vx2vWlboozpbDPBUVCDPgpJjNG9py-62eNoZvi735r81UgazjJj0rJ1FWnMKsL8qxRZqpuspZ4VHoa=w156-h157-no


    Every shot leaves this in the bore.
    Every shot.
     

    grauhanen

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    justin has ably described what happens with each shot.

    To further explain, there are three basic components that make up the detritus or debris in the barrel.

    The most important for shooting accuracy is bullet lubrication. Every bullet has a lubricant, whether it's a waxy coating or a greasier material. The lube gets coated on the inside of the bore, and this contributes to consistent bullet performance. It helps prevent leading of the barrel and helps make the bullet's time in the barrel more uniform. Usually, the smoother the bore the fewer the number of shots required to achieve sufficient bore lubrication.

    The most obvious component is the powder fouling residue. Since there is moisture it is sticky and can clump together. Some powder may not burn completely and even completely burned powder leaves some residue.

    Also present priming compound made up of various chemicals and silica, or ground glass. These don't completely exit the barrel after each shot and mix with the powder fouling and lubrication.

    A major area of concern with regard to the process of firing and fouling is the accumulation of carbon in front of the chamber. When a carbon ring develops it's not visible without a borescope but it will degrade accuracy. They must be prevented or, if allowed to develop, removed.

    For a detailed explanation of what goes on in the barrel, see the excellent treatise on cleaning a rimfire bore by Steven Boelter, author of Rifleman's Guide to Rimfire Ammunition, https://docs.google.com/viewer?a=v&...Fnb2xkZW5qdW5pb3JzfGd4OjI5MDZlNWVkMDc0YTEyN2U
     
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