Bore width / barrel length ratio
Posted 09 February 2017 - 12:29 PM
So I have that tuned perfect.
I am now confident to take it up a notch and am moving onto my semi mini 28mm PAC gun.
What would the ideal barrel length be for a 28mm bore?? Will have a triple sleeved breach
Posted 09 February 2017 - 12:46 PM
That's a 20-calibre bore. I'm not sure what BP will do vs. NC powders in such guns, but a typical NC gun is about a 50-60-calibre bore. (3"x58-calibre being a common military gauge)
If you're using BP, and if the 20-calibre bore is working well for you, stay with that formula... make the bore about 28*20, or about 560mm long.
"Pyro for Fun and Profit for More Than Fifty Years"
Posted 09 February 2017 - 05:04 PM
Posted 09 February 2017 - 05:06 PM
Posted 10 February 2017 - 07:35 AM
Splitting carriages? You are probably fixen to see some barrel splitting if you are lucky. I didnt see the barrel material, i hope it's not metal, but i am sure it is.
Edited by dynomike1, 10 February 2017 - 08:33 AM.
There are very few problems that cant be solved with explosives.
Explosives are a bang up job.
Posted 14 February 2017 - 09:18 PM
After I finished fabrication the barrel was send to a close friend, a very old ( no offence Reg!! ) but extremely respected and proficient gunsmith. And it passed. Loydd your estimations were near perfect, finalising with 585mm 28mm ID smoothbore barrel with 100mm sleeved breech. I haven't chronographed it yet as I'm working up to max chafe and projectile grain weight. Ist test shot was 140 gn & 12x 8mm shot. No issues
2nd test 250gn moderate rammed with 500gn single custom cast pill. Like it wasn't there. Barely move the gun ( mind u this one is full steel workshop fabricated)
3rd test soon, 260gns rammed REAL hard pushing a 1209.12 grain custom slug. Now we'll see how she goes. I'm 100% confident, or I wouldn't push the switch. Another point, all remote fired.
It is ( I haven't received the papers but will soon ) to 550 grains BP tight packed pushing up to but no more than a 1600 grain projectile. It is genuine high velocity. I won't load any more than 280 and the current 1200 pill. That's HEAPS!!!
I fabricated a proper gas porting muzzle brake and I believe it really helps also.
Put forward your opinion please!!!
Posted 15 February 2017 - 10:12 AM
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