Benchrest cannon?

[Victor3]

 I've been contemplating a smallish, accurate rifled cannon. I'm wondering what a good design would be for such a thing; something with a heavy base that could be placed on a shooting bench and fired without it flipping onto the deck.

 I've looked at Dom's "Sledge Base Fortress Cannons", and I think something similar but with trunnions, elevation screw and sights might work. Maybe a barrel with a Parrott profile and sleeved with a 54 cal black powder rifle barrel with a twist for conicals.

 Any thoughts?

 I have a cannon with a 12 ga rifled barrel in process but it's going to be about 36" long, so not suited for a bench...

[cannonmn]

A friend bought a 2-foot-long section of 40mm cannon barrel, female-threaded the breech end of bore, and made a big male-threaded plug to fit.  The plug had a cascabel knob machined onto the rear end.  He uses that plug for cleaning as he prefers to muzzle-load pre-rifled slugs he makes.  He copied a Lyle lifesaving gun wood carriage to mount it on.  Maybe I can get some pix, it is neat looking.  Uh oh, just remembered this isn't the forum for that kinda gun, so if this is moved I will understand.

[Double D]

Sounds like an attempt at a muzzle loading replica of a pre 1899 gun to me.

[mcwoodduck]

Where do you get 40mm cannon tubes?

[cannonmn]

Where do you get 40mm cannon tubes?

My friend is looking for more now, if he scares any more up I will send you an email.

[mcwoodduck]

Cool.

[Terry C.]

Of course, whatever you build, you'll need one of these...

[Cannoneer]

Victor,

 The only rifled cannon that I have is that 7.5'' CVA naval gun in .45 cal. and yeah it does do somersaults when it's fired which is probably why I haven't taken it out in years. I fire a smoothbore 15-inch steel Napoleon loaded with FFg and a patched .75 cal. ball that is mounted on a field carriage from the bench with no problems, I just have to remember to clamp a backstop down: I forgot the backstop firing a .50 cal. naval gun mounted on a truck carriage that was loaded with FFFg and a half inch ball bearing and the recoil rolled it off the bench and onto the deck but it didn't flip. I would think that with a heavy enough flat bottomed base you wouldn't have a problem with a .54 caliber rifled barrel.
I haven't seen Dominick's fortress cannon, is a photo posted on a past thread?

[Terry C.]

Re: Flipping. That's why I'm designing this platform:




It'll have its own set of tackle, and can be set up on the ground or on a bench. My field carriage is way too large for the benches around here, and the Marsilly is going to need to be restrained no matter where it's fired.

Something like this will free up your design parameters a bit.

[Double D]

Tumbling another reason for rigging up arresting tackle.

[Cat Whisperer]

I've been contemplating a smallish, accurate rifled cannon.
...
 Any thoughts?
...

Thoughts - "The Captain said to the gunner - You see the captain of the enemy ship?  I want you to put an 8" shell right in his eye!"  The gunner replied, "Which eye sir?"

[Victor3]

Victor,

 The only rifled cannon that I have is that 7.5'' CVA naval gun in .45 cal. and yeah it does do somersaults when it's fired which is probably why I haven't taken it out in years...

I haven't seen Dominick's fortress cannon, is a photo posted on a past thread?

 Boom - That's the only rifled one I have too. It was my first cannon (actually .44 IIRC). Like you've found, it's more dangerous to the match-holder's shins than to the target.

 Dom's fortress cannons are on his website, listed in the sticky up top.

 I'm thinking about something 'self-restrained' by virtue of its weight and lack of wheels. I believe this type of design might be more accurate than something that can roll. I really don't know for sure, but I'd like to experiment for accuracy.

[seacoastartillery]

     Victor3,   Mike and I will be watching this thread with a great deal of interest.  We will be doing more experiments along these lines in 2 to 3 weeks, but we are in absolute agreement that, without the weight you mentioned in your first posting, your efforts will bear no more fruit than Don Quixote's "tilting at windmills".  We are anxious to see what you come up with.  We have been constantly amazed by the ingenuity displayed by the cannon makers in this group and we are, frankly, very surprised that no one has previously posted results about a similar build.

     Terry C.,   In an effort to beat Double D to the punch, please send your beautiful Marsilly carriaged gun and sighting device to us post haste.  We will test it for you thoroughly and extensively, after which you may visit it at any time!  Most builders have completion anxiety, but you don't, so get out there and get some photos of "External Ballistics"!!

Regards,

Mike and Tracy

something with a heavy base that could be placed on a shooting bench

 Any thoughts?

[Double D]

When you "tie" the gun down, you are going to have to beef everything up or you will break something.

My Cairo Gun will under go refurb this winter.  Besides painting it is going to be rerigged.  I am going to build a shooting platform from 4 x4's.  Then I am going to build a heavy recoil arresting line using 1/2 hemp that goes through the the eye ring on the cheeks and over the cascabel.  This arresting line will hook into a ring on the platform.  The block and tackle with 1/4 inch hemp will hook on the platform inside the arresting line and then hook on the back of the carriage over the rear axle. THis will keep the gun from flying away.

I wonder how it would work to make the entire carriage out of steel plate; trucks, cheeks, axles, everything.  Sure would dampen recoil.
      

[cannonmn]

This is the one my friend made with a 24-inch section of 40mm barrel.  The WD-40 can is 2" diameter, no powder can available on site.  Rear sight is from a US Army Krag rifle, not sure of the particular model, he's not in town now to ask.  Front sight is some typical rifle sight.

[Terry C.]

I also had one of the CVA .45 cal rifled cannons. It was this little gun that taught me the importance of restraining naval carriages.

     Terry C.,   In an effort to beat Double D to the punch, please send your beautiful Marsilly carriaged gun and sighting device to us post haste.  We will test it for you thoroughly and extensively, after which you may visit it at any time!

Um, I'll have to get back to you on that...

[Cannoneer]

 This type of static carriage looks very familiar to me; from a manufactured gun, maybe a line throwing cannon. I can't place it, maybe it'll come to me.

Thanks Victor, I looked at Dom's gun, and I think that his base would would work fine with your concept.

[cannonmn]

That's a copy of a U.S. "Lyle" Bronze Gun "C" pattern carriage ca. 1880.  I think the only difference may be that he used oak planks that were thinner than those used on the original, and capsquares are not quick-opening, hinged ones as were originals.

[Cat Whisperer]

What does he use for bullets?

[Max Caliber]

Double D, I think a carriage made entirely of metal is a good idea, the more weight the better. Here is one of my projects I am working on (slowly). This carriage is cast in aluminum as a test and I planned on casting the final carriage and trucks in zinc but now I think I will cast it all in hardened lead - depleted uranium would be better. Should weigh around 50 pounds or so and with a 20 to 24 inch barrel it would weigh around 70 pounds. Caliber will be around .75.

Max

[cannonmn]

What does he use for bullets?

He makes pre-engraved projectiles.  He could use large minie-balls like the trash can projectiles I like for larger guns, but he only uses the pre-engraved ones.  I gave him some empty US 40mm L60 Bofors-type projectiles, and he cuts the copper band off of them and tosses it (saves for scrap of course.)  Then he cuts them about in half lengthwise and uses the rear (closed) end.  He wraps a flat lead strip around a few times in the knurled area where the old band went after putting some epoxy there, lets the epoxy harden, then presses the finished smooth banded projectile through a 1" thick section of 40mm barrel to put the grooves in it.  I forget what he puts in the hollow steel projectile for weight, cast lead I think.  The banded part is now at the rear of his short projectile.  I've seen him get very good accuracy out to 200 yds, as far as he's shot it so far.  I have some of his projectiles I can get to and photograph later today perhaps.

He made two guns, identical, and sold me the one pictured, so I think I'll make a mold for small trash-can projectiles and try them if I ever get around to shooting this thing.  I think he's also taken a longer section of 40mm barrel and cast some lead projectiles directly in it s they are pre-engraved, but I'll have to ask him when he gets back in town.

[Victor3]

     Victor3,   Mike and I will be watching this thread with a great deal of interest.  We will be doing more experiments along these lines in 2 to 3 weeks, but we are in absolute agreement that, without the weight you mentioned in your first posting, your efforts will bear no more fruit than Don Quixote's "tilting at windmills".  We are anxious to see what you come up with.  We have been constantly amazed by the ingenuity displayed by the cannon makers in this group and we are, frankly, very surprised that no one has previously posted results about a similar build.

Mike and Tracy

 I beg to differ, M&T - I think someone here has freely posted in detail about the accurate cannons they build. A little different than what I envision, but many of the same concepts apply.

 It was you guys who got me thinking about accurate cannons. Been on the back burner along with other ideas, but I hope to have my 12 ga rifled cannon soon. I think it will do the job, and I may learn something with it that will be helpful for my benchrest cannon project. It would be great to see others make something and post their findings.

 Thanks for all you're teaching us here. I've learned a ton about accuracy in cannons from your posts.

[Victor3]

 I see you've got some cardboard there, all ready to box it up. Where shall I send payment?

 Solid looking gun there. I want one.

 Is it a fig newton of my imagination or are those left-hand threads on the plug?

[EL Caz 66]

Cool looking cannon and all, but my only concern is the threaded breech plug. I can see getting away with this in a firecracker cannon, how long will the threads withstand the high pressure built on them over time. especially when the cannon is be used to fire live rounds.  my 2cents.

Ed

[Cannoneer]

That's a copy of a U.S. "Lyle" Bronze Gun "C" pattern carriage ca. 1880.  I think the only difference may be that he used oak planks that were thinner than those used on the original, and capsquares are not quick-opening, hinged ones as were originals.

 Thanks, you saved me from having to surf. I was relatively sure it was a life saving gun's mount, I just couldn't get my gray matter to pin it down as to which one.

[KABAR2]

Cool looking cannon and all, but my only concern is the threaded breech plug. I can see getting away with this in a firecracker cannon, how long will the threads withstand the high pressure built on them over time. especially when the cannon is be used to fire live rounds.  my 2cents.

Ed

Ed

How much different is this from a muzzle loading rifle?  they all have threaded breeches there hsa been little concern with those.

I can see an issue with a cast barrel and a sleeve with threaded breech due to no way to inspect the threads,

but his system looks well maintained, with a good long thread I doubt failure would be an issue.

Allen <><

[EL Caz 66]

Allen,

I'm no expert but I believe their is a difference, the charge in a muzzle loading rifle is far less then a cannon per weight of its projectile. Most muzzle loading rifles do have a screw in breech plugs and a tang mount which is secured into stock and the cannon breech is just sitting on the elevation screw without any recoil support as in a rifle. Sure you can inspected the threads all you want, hear it goes again its all based on loads being used while shooting projectiles and the amount of pressure that builds in the breech area. and that freind is my 2 scents.

Ed

[Double D]

I can understand the concern with threaded breech plugs.

If it was a weak system, rifle barrels would not be screwed into rifle actions. Rifle actions may lock the case in the chamber with some sort of moveable breech block, but the strain of firing is transmitted to both the breeck locking surfaces and barrel threads. The spiral of the thread increases the surface are to absorb/resist the pressure.   P.O. Ackley demonstrated the effect in his testing of action.  He did make barrel threads fail with some very high pressure loads. But more often than not some other portion of the action failed first.  You can read about in his books the Reloaders Handbook, Vol2. 

I have made cannons with both  v and acme threads for cannon breech plugs with no I'll effects. I just made sure the face the breech plug was interference fit, seated against the inside back of the barrel so high pressure gasses could not get in the threads.   

[cannonmn]

Is it a fig newton of my imagination or are those left-hand threads on the plug?

Nope, these go righty-tighty, lefty-loosie.


Re:  concern about gas effects on the threads

I think it would be wise to put a gasket or o-ring between rear of "chamber" and face of breech plug.  We don't use one now but it is so easy to do, why not?  Seems many kinds of larger hardware store gaskets might work, or a copper disk, although I think i'd try something just a bit softer than copper so I wouldn't have to tighten the breech plug so much.  The gasket or seal doesn't have to be perfect, it would be easy to replace it each time you took the gun out to shoot.

Good suggestion, thanks, will be implemented before I shoot it.  Dang, even stiff paper or cardboard might work, that's what they used to put inside the bases of shotgun shells under the brass.  Might even try a disk or ring of lead, soft enough to squish out and seal off all gas.  Or nylon, or pvc, or.........

[Frank46]

Could you use copper roof flashing to make your gasket between the breech plug and back end of the bbl?. Should be plenty scraps at the local scrap yard. Just a thought. Frank