Ed shoots his 40MM cannon

[cannonmn]

Here's Ed shooting his cannon.  Ed and I have identical cannons made from my 40mm barrel sections (still a few available by the way.)

We didn't get into this on the video but in my opinion his novel "Boattail wadcutter" projectile design is a total failure.  That's what he was testing in the video, we'd already shot the same cannon a number of times on other occasions with more conventional projectiles, and it was deadly accurate out to the 200 yard range we had at the time.  Not so with the strange bass-ackwards ones, they separated in flight, keyholed, etc.  Don't waste yer time repeating what he did.

The rope and two-sandbag recoil system was a success however!

http://www.youtube.com/watch?v=ScNxzy1fRZw

[Ex 49'er]

Coooooollllll video.  Neat Cannon. I want one. Maybe next year.
Thankyou.

[Frank46]

Cannonman, enjoyed the video of Ed's 40mm cannon. Just curious, how did you go about attaching the trunions?. Frank

[GGaskill]

Did Ed fire any "boattailed wadcutters" as flat base spitzers?

[Victor3]

 Good to see that the barrel section I got from you will make a potenially accurate gun.

 Think I'll stick with my round ball, at least initially. Might do slightly better than Ed's superbullets 

[cannonmn]

how did you go about attaching the trunions?.

Ed had a machinist build it and as far as I know the trunnion band was screwed onto a part of the barrel that was threaded for the purpose, but I''ll ask next time I talk to him.

Did Ed fire any "boattailed wadcutters" as flat base spitzers?

No.  He thinks the CG would be so far back if fired with point forward that it couldn't work.

[epanzella]

how did you go about attaching the trunions?.

Ed had a machinist build it and as far as I know the trunnion band was screwed onto a part of the barrel that was threaded for the purpose, but I''ll ask next time I talk to him.

Did Ed fire any "boattailed wadcutters" as flat base spitzers?

No.  He thinks the CG would be so far back if fired with point forward that it couldn't work.

I'm not a cannon dude but wouldn't this be the same as shooting a rifle? Rifle bullets have a cg in the rear of the projectile. Many target bullets are hollowpoint to get the cg back as far as possible.

[Double D]

Like VLD bullets....

[GGaskill]

I would at least try one point forward.

[Cannoneer]

Cannonmn.

I don't understand - It's a 40mm rifled barrel, and Ed was using a 40mm projectile; so why wouldn't it demonstrate the proper flight characteristics if it was loaded point forward, the way it was designed to be fired?

[Victor3]

 Was there any evidence of gas leakage into the threads?

 I'm planning on making a threaded breech plug and using a 1/4" thick disk of smashed foil in the bottom of the powder bag to form a seal.

[cannonmn]

I don't understand - It's a 40mm rifled barrel, and Ed was using a 40mm projectile; so why wouldn't it demonstrate the proper flight characteristics if it was loaded point forward, the way it was designed to be fired?

Ed made following modifications to the original military 40mm steel projectile:

-Removed copper rotating band
-Cut projectile in half lengthwise, discarding rear half
-Cast a new lead base on and into projectile

I agree, if it hadn't been sc____d with so much it might retain some semblance of its original stability, but it had no chance.

[cannonmn]

Was there any evidence of gas leakage into the threads?

No, and the threads turn easily by hand to open the breech after firing.  I think the "problem" of gas leakage has been overblown by the armchair artillerists, but may depend on the fit of the threads and number of turns (threaded length and pitch.)

[GGaskill]

I agree, if it hadn't been sc____d with so much it might retain some semblance of its original stability, but it had no chance.

Still think he should try one point forward.  Even his leadified ones.  Can't be any worse than firing them backwards.

[Victor3]

Was there any evidence of gas leakage into the threads?

No, and the threads turn easily by hand to open the breech after firing.  I think the "problem" of gas leakage has been overblown by the armchair artillerists, but may depend on the fit of the threads and number of turns (threaded length and pitch.)

 That's good to know.

 Since there has been some discussion here concerning the need to prevent leakage, I assumed that it was a common problem with breech loaders. I guess a little foil must be good enough to do the job.

[Frank46]

Cannonman dare I say it?, are there more sections of 40mm bbl available?. My lathe won't go over 3" in the steady rest and I really liked the idea of threading the barrel and then screwing on a sleeve with the trunions attached. And also the screw in breech piece. I live in the oil patch here in louisiana and possibly could get the work done locally. And get in touch with one of the cane farmers to fire off a few blanks. Harvesting won't start for another few months. About all you have to watch out for is creepy crawlers that bite. Lotta them around and being hot as it has been here these last few weeks they do tend to get aggressive. Course a 12 guage takes care of that problem right proper.  As far as gas leakage that could be cured by making up a copper gasket much like the head gaskets on cars. Used flexitallic gaskets on steam lines many a time. 600 # boiler pressure and 900 degrees superheat. Steam will find an escape route and chew up the sealing faces on flanges right quick. Used the broom trick to locate high pressure steam leaks. Frank