7 replies to this topic

[Richtee]

I have a 1.7” heavy walled base reinforced tube with a 3” deep plug. The “barrel” depth is a full 24” I’m building some fairly heavy can shells for it. Pushing 200 grams.

 

Should I be using maybe like an 8-10 mesh coarse "cannon” type powder for these shells and that gun? While it’s pretty sturdy, I prefer to make ground salutes a little more predictable

[Richtee]

Well, I’m breaking pucks in a bit. I’ll make a dummy shell and save some coarse stuff. Just kinda worried about smoking my tube with the finer stuff and the heavy shell

[Arthur]

Coarse lift may be a good start, lots depends on the shell fit in the tube the escaping gasses are a good lubricant.

[SharkWhisperer]

I have a 1.7” heavy walled base reinforced tube with a 3” deep plug. The “barrel” depth is a full 24” I’m building some fairly heavy can shells for it. Pushing 200 grams.

 

Should I be using maybe like an 8-10 mesh coarse "cannon” type powder for these shells and that gun? While it’s pretty sturdy, I prefer to make ground salutes a little more predictable

Your mortar is sub-2" and 24" long? If so that's a super long barrel. I'd cut that at least in half, probably more to get closer to the more usual 1:5 ID/length ratio (shorter for mines...). Put a plug in the cut section and have 2 mortars (or 3...). What's the tube wall made of? 8-10 mesh BP should be fine for 2-3" tubes.

[Richtee]

Your mortar is sub-2" and 24" long? If so that's a super long barrel. I'd cut that at least in half, probably more to get closer to the more usual 1:5 ID/length ratio (shorter for mines...). Put a plug in the cut section and have 2 mortars (or 3...). What's the tube wall made of? 8-10 mesh BP should be fine for 2-3" tubes.

Yeah it is long. I kind of like the idea of longer- more efficient powder usage. Just don’t want TOO efficient usage...right? It’s hmm..lemmie toss a caliper on it... 4.4mm spiral wound cardboard, water glass soaked and “belted” at the bottom with additional wraps of craft/glue. I made it for golf balls, and it works well with the finer “normal” powder grade. I was just thinking I’m gonna be tossing cans that weigh 4-5 times more than a golf ball and din’t wanna blow it up.

 

I have about 4 more foot of the tube. Maybe I’ll just build a couple shorter ones and not sweat it. 

 

Damn does this thing send a golf ball tho With the rather inaccurate time in the air method I got 800 feet...

[Richtee]

Coarse lift may be a good start, lots depends on the shell fit in the tube the escaping gasses are a good lubricant.

It’s fairly tight. It’s a bottom fused setup. Set a short length of .125 copper tube into it for the touch hole. Golf ball has about 1/16 clearance. I of course roll my cans and have about the same with them.

[SharkWhisperer]

Yeah it is long. I kind of like the idea of longer- more efficient powder usage. Just don’t want TOO efficient usage...right? It’s hmm..lemmie toss a caliper on it... 4.4mm spiral wound cardboard, water glass soaked and “belted” at the bottom with additional wraps of craft/glue. I made it for golf balls, and it works well with the finer “normal” powder grade. I was just thinking I’m gonna be tossing cans that weigh 4-5 times more than a golf ball and din’t wanna blow it up.

 

I have about 4 more foot of the tube. Maybe I’ll just build a couple shorter ones and not sweat it. 

 

Damn does this thing send a golf ball tho With the rather inaccurate time in the air method I got 800 feet...

800 feet sounds like a pretty good altitude for a lil golf ball!  I'd be a little concerned about overpressurizing/splitting those super long howitzer barrels you have, specially launching heavy shells from long skinny cardboard tubes with a bottom hole (point of weakness). Guessing you're shooting golf balls with 5 or 8g BP (depending on how hot)? Golf ball weighs 40-something grams; how heavy are your shells? Those canisters start getting heavy--specially when they're full of crackle !!

[Richtee]

800 feet sounds like a pretty good altitude for a lil golf ball!  I'd be a little concerned about overpressurizing/splitting those super long howitzer barrels you have, specially launching heavy shells from long skinny cardboard tubes with a bottom hole (point of weakness). Guessing you're shooting golf balls with 5 or 8g BP (depending on how hot)? Golf ball weighs 40-something grams; how heavy are your shells? Those canisters start getting heavy--specially when they're full of crackle !!

That’s my concern. Was thinking the coarser powder would ease up on “chamber pressure” and take advantage of the longer barrel. The shells are prolly gonna be in the 100 or so gram range now that I ponder it .  I’m using a scientifically measured palm full of 20 mesh BP (2FA?) for the golf ball. I’ll weigh it but I’d guess about 6 or so grams. (yeah, 6 grams)