Strange occurrence with Meteor

[Dornfelderliebe]

Evening all.
Today whilst trying to hit a 1 inch target at 20 yards in the new Dornfelderlieber Schloss, my .22 Meteor went berserk.
I was firing Marksmans for about 50 shots when it suddenly made a massive bang and made a load of smoke. Now that would point to detonation but all I fired before were normal and I have not done any lubing for months.
Before this odd shots were flying higher or lower by about 1/2 inch either way but I put that down to me being a less than good shot.
The next 5 or 6 produced smoke then it quietened down to normal for the last dozen or so I thought.

Perplexed I went upstairs and fired one shot through the chrono, expecting it to be low incase the quad seal had failed letting grease through.
I use superdomes to measure power with their known weight of 14.5 grains.

592 fps I quickly put the old girl back on the wall rack for a rest.
I did wonder if the pellet fell out before the crazy shot but there was an awful lot of smoke for that and it was a proper bang.
This is the one I home tuned and I often get 580 fps dropping to about 575 but never this.

One last thing I thought I had noticed increased fps from superdomes after firing Marksmans before and assumed I was mistaken.

Any thoughts?

[harry mac]

My HW50 did this a couple of times when I first got it. When I stripped it down, it was heavily over lubed. I put it down to grease migrating forward onto the piston seal and detonating on compression.
I gave the insides a good clean out and lubed the spring and piston skirt properly and it's not done it since. It now runs at a nice, consistent 590fps.

[nishijin]

I concur. This is similar to my recent experience with the Xocet.

After rebuild and initial dieseling, I thought the chamber was nice and done. Then, after some irregular pellets I put it outside to chrono. BANG! Massive dieseling, which continued another half-dozen shots. Exactly the same as your experience.

Disassembled, cleaned to near-dry, much much lower fps but steady numbers. Rebuilt with a new seal, and absolutely minimal lube, and it has been fine for a half-tin of pellets.

My money's on lube seeping past the seal and giving you a bang.

[Dornfelderliebe]

Thanks Chaps, I'll see if it happens again then swap piston seal.

[nishijin]

Thanks Chaps, I'll see if it happens again then swap piston seal.

Don't wait if I were you, there'll be a big load of lube waiting to do it again. When it diesels it deposits on the chamber and piston exacerbating the issue. It likely needs a clean now regardless of the state of the seal.

[Dornfelderliebe]

Don't wait if I were you, there'll be a big load of lube waiting to do it again. When it diesels it deposits on the chamber and piston exacerbating the issue. It likely needs a clean now regardless of the state of the seal.

Good point and seeing as Tony L recommended I fit a sleeve, the time is now due for both. Thanks again.

I've been waiting for some bits to come back for my project Meteor Mk3 and if the guy finally comes up trumps tonight that will be next.