My 1st 4inch cylinder shell

[THEONE]

It was a muzzle break, it broke about 50 meters above gun, not inside the gun, i will post the video later on. It was top fused. I almost always top fuse my shells since all are made with spollettes. The bucket was made with 3 turns of pasted craft paper. I have noticed that the BP inside the spollette is not that much rock hard. Made with a rubber hammer. It was a pasted shell. I use homemade paper tubes for spollette, i will tell you the dimensions when i got time. I use meal ballmilled BP made with pine coal. I need about 1,7cm rammed BP for about 4sec delay. With 2cm of rammed BP i got about 5sec delay. Edited March 17, 2022 by THEONE

[Carbon796]

Not that it matters much, but the bucket doesn't need to be pasted. Just the outside edge glued down when its rolled up.

 

Spolette tubes should be pretty robust, more so than a rocket tube. A ruff dimension would be 8mm ID x 15mm OD x 53mm long. Which should be useable for 5" and smaller shells. 6" and up you'll want to be about 10mm ID x 19mm OD x 75-90mm long.

 

If you don't feel like your getting good consolidation from your BP. That is most likely the issue. It can develop cracks or flake apart during handling/spiking. It can also lead to unreliable timing issues. You should also use a measured scoop. So that your ramming increments are consistent. 1/2 diameter to one full diameter, per ramming increment. Use the fines from granulating your BP. Not the mill dust, -12mesh or so. Also when ramming a spolette. It needs to be on a very solid surface, without any give. I ram mine on top of an aluminum plate. Sitting directly on my concrete shop floor. I also use a mould support for ramming them. Which generally isn't necessary with good tubes. But it's how I prefer to make them.

Edited March 17, 2022 by Carbon796

[Richtee]

It was a muzzle break,

It was a low break, and the only thing that could have happened is a spolette failure.

 

I have never used a technical “spolette” I paste/wrap visco fuse with paper to about .25” diameter, slit the end and coat with BP fines and NC. Ultra reliable. Screw all that tube making and ramming.

[THEONE]

From your above comments i believe it is due to a poor made spollette. I use homemade paper tubes 6mm ID and 10mm OD. Next time i will add some more paper to that tube to make it about 13-14mm OD. I have made about 1/2 kilo of BP for spollettes so i wont have to measure again and again the burning rate. It has no dextrin, just 75/15/10. Should i add dextrin and granulate it finely in order to use it for spollette ? I have seen Ned using meal BP for his spollette

[Carbon796]

I think early on he was using mill dust. Iirc later on he bought some fine grained commercial BP just for spolette's. There have been a couple threads on it over the years. I'm pretty sure the general consensus has been that. A fine grained BP makes a better spolette. Than one made with mill dust.

[Arthur]

MY favourite spollette is 1/4" time fuse. Cut the fuse to the exact length you want and glue it into a tube.

[Maserface]

MY favourite spollette is 1/4" time fuse. Cut the fuse to the exact length you want and glue it into a tube.

That sounds like more work than a real spollette

[THEONE]

I do not have access to time fuse yet so i am forced to use spollettes

[Carbon796]

Spolette's are better suited to cylinder shells any way. So it's really a non-issue, if it's not easily available to you. Though TF does have advantages for use with smaller inserts. Edited March 18, 2022 by Carbon796