Shell/tube jams?

[bradlee311]

Hey guys, does anybody else have issues with reloadables fitting too tightly sometimes into the supplied tube? Everytime I load them I pull gently on the fuse to make sure its free flowing and able to eject cleanly. Recently I've had a few shells that wedge themselves into the bottom, enough where i have to flip the tube and bang it out. This is mostly from two kits "heavy artillery" and "Goliath." Below are links to the products

http://rgvriatafireworks.riograndevalleyarea.com/wp-content/uploads/2012/12/heavyart.jpg

http://www.kastnerpyrotechnics.com/fireworks_photos/artillery_shells/pg1/goliath_artillery_assortment.jpg

[melott001]

this in my opinion is caused by the remainder of the lift charge adhering to the walls of the inner tube. to resolve this problem attach a baby bottle brush to straight stick as an extension. stick the brush into the launch tube and rotate to clean the inner walls of the tube

[JamesFitts]

On a recent demo show we had the same problem with some random black cat shells and new fiberglass 1.75 tubes. They where TIGHT, as in I used a crow bar ( it was with in easy reach) to push them to the bottom. When I expressed my concern, boss said it was ok. None of the shells got stuck but about 10 of the tubes came out of the racks. Three went missing. Looked all around that field. Of the ones we found, they where warped and/or the coating was chipped off. None "failed" though. I feel the problem was the cheap tubes he ordered.
So lesson learned. If the shell has to be forced to the bottom of the tube, try a different tube. If it is just simi-tight (light tapping on the tube makes it slide down) should be no problem.

[Jman]

Why are you taking the shells back out once you load them? Actually a nice tight fit will produce a much better lift for the shell. I often run into this problem with excals and other can shells. Get you a wood push rod and push the shells into the tubes with the rod while holding the fuse extended away from the tube so it cannot kink up on you on the way down. Sometimes shells lean to one side or the other causing it to get lodged against the wall of the tube. You can eliminate this problem almost entirely by using a push rod on top of the shell. This will enable you to actually load the shell instead of depending of gravity to seat it in the bottom of the tube. In reality its better if the shells doesn't just free fall to the bottom anyway. In my years of loading and shooting I have found that its much better to have a slightly tight fitting shell vs a loose fitting shell. Loose shells pose a bigger problem than tight shells. Loose shells often have so much blow by that they do not lift properly creating a lower than desirable break which is not good for your audience or the local fire department.

[bradlee311]

Cool thanks for the input, I would have never known a tight fit is desired. Jman in response to why i was taking the shells out.. Once i felt they were tight/partly jammed I was afraid the lift charge wouldn't eject the shell, causing a break inside the tube or extremely low, i was being cautious. Thanks again for the advice.
My ordered DR11's from pyroboom are set to arrive in 3 days, i'll do the first shoots as you suggest to load and see how it goes.

[Jman]

Well, that certainly would be a good reason to unload it. If a shell is not seated properly in the bottom of the tube it sure could create some undesirable problems. Just be careful. When I say tight fit, I mean within reason. If you have to exert lots of energy and force to get a shell down a tube then something is definitely wrong, so keep that in mind.

[thomask280]

Consider that if a shell is tight going in it has the visco fuse on the side. After the fuse burns down it will leave extra clearance in the mortar.

[PuroJon]

Biggest problem with a tight tube is in the event of a dud. Getting the unfired but now fuse-less cartridge out of the tube is a pain, and adds unnecessary danger. Same thing when you have a fully-loaded field of mortars and having to cancel the show; those shells are not made to be stored in the tubes, and for obvious reasons.

I would rather run them with a tiny bit of slop than too tight to be pulled out of the tube easily.