Exploding Modulator
- Thread starter jjohnsonlta
- Start date
Has anyone ever had this happen to them? I was shooting using a barrel attached chrony doing a shot string. On one of the shots the front part of modulator with chrony attached blew off and hit the floor. The other pieces I poured out of the shroud.
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Looks like the moderator sagged on the end of the barrel and the pellet struck the internals. In the first and second pictures baffles appear to have been hit well off center.
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@jjohnsonlta just curious, what is the brand name of the moderator? Is it a screw on or slip on? Was it caliber specific and did you up-size one caliber above what you installed it on? Trying to get a little more detail. Thanks...
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That's a long one. It would not take very much at all to cause that one to start clipping. Those are 3d printed "guts". They are not supposed to take a hit from a pellet. It looks like they did. You probably had a little clipping going on and once a bit of plastic was bounding around in that tube it was only a matter of time till the pellet and the plastic tried to occupy the same space at the same moment. 
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The long piece in the pic is the barrel shroud. It's off my 1358 Beeman. The shroud which is plastic split I noticed also. I purchased the moderator off ebay being for the 1357/1358 Beeman. It was a glue in. It was super short which I liked. The chrony is super lite and I have had it mounted several times. I don't think it was the issue. I luckily had a modulator that was given to me that threaded on which I am now using. Probably OldSpook has the right call on what happened. Just a real surprise when it happened.
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Yup, had it happen when pellet gets caught up in baffles due to a misalignment. As well had guts BLOW OUT when the gun it was placed on had excessive dwell, which in turn over pressurized LDC internally.
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Now imagine if the muzzle pressure was 30,000 PSI instead of 750 or 1,000 PSI.
I think that explains why Alphabet org is not interested in air gun moderators.
My apologies to the op for wandering off topic.
EDIT : the use of the phrase "3 letter organization" was a substitution done by the word police software. I have nothing to hide from BATF.
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Think it would work on this???
You mentioned the shroud split. I could not see a photo of the split in what was posted. Was the split clean and straight or did it radiate from an apparent impact point? Did you notice any visible bend in the mod assembly with it attached? Traditional baffles don't give much longitudinal strength to a plastic shroud where a monocore would. I can't image the muzzle pressure alone would be enough to split the shroud unless it was flimsy material to start with. This thread is iinteresting since I'm a mechanical engineer and failure analysis is part of what I do.
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The split shroud, which is thin plastic tubing, I think was due to the fact that the moderator was glued in. It wasn't a straight looking split. I will try in a few days to snap a pic of the shroud.
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Here is that pic of the shroud I forgot to post. I had to stick a finger in to help it show up better.
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Thanks for posting that. I don't see any signs of an internal impact as the cause of the split. Is it possible to split the rest of the should open and inspect the interior? From the photo where your finger is in the shroud, it looks like the shroud is maybe only 0.5mm or so thick. The weight of the chrony would impose a flexing stress. Was there any noticable sag to the shroud with the chrony mounted? If there was even a slight sag that could have caused a pellet strike on one of the baffles, destroying the baffle as illustrated in your initial posted photo. Curious do you know what baffle was hit/destroyed the worst? Was it close to the muzzle or further back?
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Thanks for your interest. The chrony I was using weighs less than 5 ozs so I don't think sag was the issue. The modulator only sticks two inches beyond the shroud. After it happened I basically just poured the pieces out of the shroud and didn't pay too much attention to the pieces Didn't notice the crack in the shroud either. At this point I am just moving on and caulking it up to airgun experience. It will remain a mystery I guess.
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