Canadian Airgun Forum

I removed the barrel shroud and found a surprising amount of coarse lead flakes/granules, which appear to be the kind which results from inaccurate chambering of pellets.

I had removed the shroud when the gun arrived, just to see how an FX was arranged, and there was no "powder smoke soot" and no lead granules.

The shroud's rubber seal is in place and the shroud has always been snugged, so IDK how the lead could make its way into there.

Has anyone had this experience?

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Slavia 618 .177
Webley Senior .22
Jelly SUPER 4.5 mm
Webley Viscount .177
Kral Mega Marine Walnut .22
Artemis PP750 .22
FX Streamline .22 walnut
FX Streamline .22 composite
FX Dynamic 500 .22

I have noticed lead flakes around the breach area on some of my break barrel springers. I'm guessing that the flakes come off the pellets when the air pressure flares the skirt engaging the rifling and engraving the skirt. It sounds like most of the detritus gets shot out of the barrel, and the shroud provides a handy catchment.
That's my best SWAG. (scientific wild a$$ guess). It's worth less than half of what you paid for it.

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Theory is when you know how something works, but it doesn't.
Practice is when something works, but you don't know why.
In my shop, Theory and Practice are combined!
Nothing works and I don't know why.

Two lathes and too many projects

I'm wondering if, like Rick suggests, from inside the cupped base. I have seen little chunks of lead in the bases of cheaper pellets oft times
and this alone is a good reason for washing pellets. Sy Pitaway gives a good run-down on washing them using a 4cup measuring cup and a
strainer. I guess you could google it. Took some digging but found one.
This one is Davey, I think.
https://www.youtube.com/watch?v=eQXiZFy ... nHuntersTV

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Best Wishes
Daryl

If you are clipping the shroud, the accuracy should be terrible. Is this the case? A barrel that does not have a concentric bore can result in clipping the shroud. Easy enough to see if you can see both ends of the barrel.

If the lead is not well done, that can do some shaving as well and as Rick suggested, it could end up in the shroud.

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Tim
CAFTA Governor and lifetime learner

It's not a case of pellets clipping the shroud. Initially, I thought that was certainly it, but the shroud seals by an O ring to the barrel and action, at the rear. The barrel has two O rings, one on each end of the chamber. It's a pretty standard arrangement in that sense.

The front/muzzle end of the shroud threads onto the barrel muzzle thread, making the cavity between the barrel and the shroud a dead air space. IDK how lead bits could get into there, unless they came past the front barrel (chamber) O ring, and also past the shroud O ring.

The shroud O ring is a fat one, universal O ring #207, while the original seemed not to be a tight fit to the barrel, so I replaced it.

OTOH, that ring appears to simply be a cushion seat for the shroud to the action bore, around the barrel. It shouldn't be needed to seal anything, especially as one can shoot without the shroud, with some sacrifice of accuracy.

I also replaced the barrel O rings, 10mm x 2 mm, which seal the barrel to the action block.

My working hypothesis is that the bits were blown past the front barrel/chamber O ring, and the shroud O ring, into the shroud to barrel cavity.

A few hundred pellets should show whether the new O rings blocked a leak from the front of the chamber.

One of the aspects of the hypothesis which trouble me is that velocities seemed very consistent on the chronograph, while I would expect them to vary more if the chamber was leaking.

Probably, I'm overlooking something obvious.

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Slavia 618 .177
Webley Senior .22
Jelly SUPER 4.5 mm
Webley Viscount .177
Kral Mega Marine Walnut .22
Artemis PP750 .22
FX Streamline .22 walnut
FX Streamline .22 composite
FX Dynamic 500 .22

I still think the bits of lead are from inside the cavity of the pellet. When the pellet exits the bl. the blast out to the inside of the 'cavity' likely sucks the bits out of the back
of the pellet or the drop of pressure allows them to withdraw and the centripetal force 'throws' them outwards. The rotation of the pellet likely helps move the particles.

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Best Wishes
Daryl

You didn't mentioned anywhere that you washing+lubing your pellets, so I think as well the bits of lead are from pellets, inside cavity or just stick to body.
Usually after each session of shooting my Impact MK2 I am removing the shroud to access the liner, which I am removing for cleaning.
I am well washing and well lubing and baking lube to pellets, and still I have a thick layer of lead powder stick to the barrel when I remove the shroud. Not sure for Streamline shroud but I guess all recent FX shrouds have a rear directing airstripper port in the end cap, earlier (2020 and earlier) models didn't had that opening.

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FX Impact MK2 PP - heavy modded
Edgun Leshiy2 - heavy modded
and a lot more scopes with great glass

I would think the lead debris is going down the bore when you shoot, not sneaking through seals. If for any reason, lead is left in the barrel after a shot, the next shot will blast it out. Anything that does not exit the barrel is left in the dead space of your shroud.

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Tim
CAFTA Governor and lifetime learner

The comments regarding the lead particles possibly leaving the muzzle of the barrel and exiting into the barrel shroud appear to be accurate.

I was skeptical about lead passing the barrel seals, but it appeared to be one possible route, plus the front O ring had a nick out of it.

OTOH, power was as expected and velocity variation was ~ 0.7% and I would have expected more variation in the case of leakage.

I managed, with help from my son, to manage to place the right degree of illumination at the right angle from the breech end of the shroud tube, to allow an angled endoscope to see that there is a kind of bridge in the muzzle end of the shroud, ending about 2-inches back from the muzzle end of the shroud. This "bridge" is the threaded attachment to the muzzle threads on the barrel, and it has large "windows" (actually more of a frame with the rest open) which make the muzzle end of the shroud mostly open to the muzzle of the barrel. That explains, better, the relative quietness of the Streamline versus, my other PCPs which are tuned to similar velocities.

This "internally vented shroud" does that job well, especially as compared with the noise level when the shroud is off the barrel.

So far, no online searches have brought up better photos.

I took some photos by camera, in the link below, but the ones from my endoscope (different app) have disappeared. I will try to take a new set in case someone is interested in what can be seen.

Time to check prices on smaller diameter endoscopes.

https://www.dropbox.com/sh/zq5oqxzhl3ts ... 3IHka?dl=0

_________________
Slavia 618 .177
Webley Senior .22
Jelly SUPER 4.5 mm
Webley Viscount .177
Kral Mega Marine Walnut .22
Artemis PP750 .22
FX Streamline .22 walnut
FX Streamline .22 composite
FX Dynamic 500 .22