Tom, if you are getting actual visible lead from cleaning your barrel you are waiting too long to clean it.
If you shorten up the interval and still get visible lead, you have something that needs work on your barrel. Bad crowns, tight chokes, very abrupt chokes, or tight spots in the barrel are the usual suspects. Some can be fixed, some can’t.
Lots of airgun barrels have tight spots near the breach from lathe jaws or spiders that were too tight during machining. It’s extremely easy to put a tight spot in a 16 mm barrel. I can’t imagine how easy it would be to put a constricted area in to a very thin FX barrel. Those tight spots reduce the size of the pellet and will often produce lead deposits in the areas after the tight spot where the pellet is loose and rattles down the barrel til it comes back in full contact at the choke.
Lead is a material that forms extremely easy and it will not rebound to it’s original size after passing through a tight spot. It is reshaped and it will stay that way.
If you make a block to simulate the setscrews on the breech blocks used by many guns and find a good fitting gauge pin for the barrel, you will notice that after tightening the set screws to a very mild torque…you will no longer be able to insert the gauge pin. The setscrews will have created restrictions that will reshape the pellet as it passes through and it will lose full contact with the interior of the barrel til it hits the choke. If you tighten them hard enough it will make permanent restrictions.
Mike
If you shorten up the interval and still get visible lead, you have something that needs work on your barrel. Bad crowns, tight chokes, very abrupt chokes, or tight spots in the barrel are the usual suspects. Some can be fixed, some can’t.
Lots of airgun barrels have tight spots near the breach from lathe jaws or spiders that were too tight during machining. It’s extremely easy to put a tight spot in a 16 mm barrel. I can’t imagine how easy it would be to put a constricted area in to a very thin FX barrel. Those tight spots reduce the size of the pellet and will often produce lead deposits in the areas after the tight spot where the pellet is loose and rattles down the barrel til it comes back in full contact at the choke.
Lead is a material that forms extremely easy and it will not rebound to it’s original size after passing through a tight spot. It is reshaped and it will stay that way.
If you make a block to simulate the setscrews on the breech blocks used by many guns and find a good fitting gauge pin for the barrel, you will notice that after tightening the set screws to a very mild torque…you will no longer be able to insert the gauge pin. The setscrews will have created restrictions that will reshape the pellet as it passes through and it will lose full contact with the interior of the barrel til it hits the choke. If you tighten them hard enough it will make permanent restrictions.
Mike
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