Making a 14th century Hand Gonne

Last Fall I taught a day-long workshop on “Primitive Black Powder Firearms” for the Liberal Gun Club‘s Annual Meeting in Las Vegas. In addition to my own black powder guns, I borrowed a couple of items from friends to help fill out the historical selection, including this very nice reproduction of a 14th century .62 cal cast bronze hand gonne:

I had shot the gun previously with friends, and it never fails to put a smile on people’s faces. It’s so simple: pour gunpowder down the muzzle, roll in a lead ball (tolerances for these guns are very slack, and the ball will roll right back out if you’re not careful), add a little powder to the touch-hole on the top, and light it off when ready. Very basic. Very fun. People in the workshop loved it.

And I decided that I wanted to get one of these for my own collection.

The problem is, they’re almost impossible to find. I spent a couple of months poking around online, asking friends, and the closest I could come were a couple of simple hand gonnes made using steel. Nice, but not what I was looking for.

So I started to think about making my own, and I consulted with an old friend who does bronze casting for his jewelry business. Turned out that it was certainly possible to do such a project, but it was bigger than my friend’s casting set-up could handle. We set aside the idea for the time being.

But I thought some more about it, and figured that such a bronze hand gonne was so simple, that it should be possible to make one without casting. I could order a bar of the appropriate alloy of bronze, have a machine shop bore it out, and do the external work myself. I tried contacting some local machine shops, explained what I wanted done. Most never responded. The ones that did had no interest in the project. I was stymied again.

By then, however, I was invested in the project. Again, I thought through just how basic the hand gonne was, and I figured that if I ordered the correct components, I would be able to make one without a machine shop. In fact, as I thought it through, I realized that it would be possible to make one just using some very basic modern tools which almost anyone would have or could get at a modest price. So I set out to do just that.

And this is the result.

Now, before we go any further, let’s get a few important caveats in place:

• This is a description of how I made a black powder hand gonne for my own use
• I am not recommending that you make a black powder hand gonne
• If you do decide to make a black powder hand gonne, I am not recommending that you make it this way
• Any black powder hand gonne is potentially dangerous, and if you make one, the risk is entirely on you
• A black powder hand gonne is a firearm, and all the rules of safe handling and usage of a firearm apply

OK, we clear about that? Good.

The tools and materials needed.

So, in thinking it through, I decided that the most basic tools needed for this project would be:

• Electric drill with a 1/2″ chuck, misc drill bits
• Hacksaw
• Basic hammer
• Hand sledgehammer or small anvil
• Clamps or vise
• Metal files
• Metal chisel (‘cold chisel’, 1/2″ wide or so)
• Measuring tape/yardstick/square or similar
• Calipers

Now, some additional tools that are common, and which I used to speed up the whole process:

• Belt sander
• Bench grinder
• Dremel or similar rotary tool with various small bits
• Side-cutting pliers

Pretty basic, right? So is the list of materials needed:

• Bronze stock
• Sandpaper (various grades, starting with 60grit)
• 1/2″ iron bar stock
• 3″ common nails (x2)
• Epoxy
• Duct or box tape
• 1.75″ x 48″ hardwood dowel for the stock
• Stain/finish for the stock, if desired

In addition, I used a number of bits of scrap wood, foam, and wood screws I had in my workshop. You’ll see.

Selecting the bronze stock to use.

I knew that historically, early black powder guns were typically constructed of a type of bronze called gunmetal or red brass. This is a bronze alloy containing mostly copper, some tin and lead, and a little zinc. I spent some time looking over modern bronze alloys which were readily available, and settled on “Bearing Bronze 932” as being a reasonable approximation of common gunmetal.

The modern metal industry offers a range of different types of products. What I figured was that I could get a product called “hollowbar”, which is basically a thick-walled pipe. That would allow me to select both the overall diameter and the wall thickness. By choosing a 1.75″ O.D. hollowbar with a 0.625″ I.D., I would get a suitable length of bronze which didn’t need to have a bore drilled into it. In addition, I ordered a length of round bar stock with a nominal 0.625″ O.D. that I could use as a breech plug. Metal prices fluctuate regularly, but I was able to get both pieces shipped for about $160.

Both pieces of bronze arrived. As expected, they were “overcast” — meaning that they were slightly larger than the specs given. The hollowbar was 13″ long, and the bore down the center of it was at 0.585″. The round bar stock was likewise 13″, and the O.D. was 0.675″. That meant that I would need to ream out the bore to .62 cal and shave down the bar to fit the finished diameter of the breech.

Reaming out the bore.

I didn’t order a solid length of bar stock because that would have required that I have the ability to drill out the bore. Even making a smooth-bore hand gonne (with no rifling) would present a substantial technological challenge which would have required, at a minimum, a floor-mounted drill press if not an actual metal lathe.

However, by ordering the hollowbar, I would already have the basic geometry of the hand gonne provided. The hole down the center would already be established. It would just be a matter of getting the bore to the correct diameter to handle a .62 cal lead ball.

To do this, I decided that the best approach would be to use a length of 1/2″ iron rod (called a mandrel) with a piece of sandpaper at the end, driven by the hand drill. It would take time, and require frequent changes of the sandpaper, but it would give me the ability to ream out the bore with a reasonable amount of control.

This is easy to do. You just use one piece of tape applied to the back of your piece of sandpaper, with a tab of about an inch protruding past the edge of the paper. Then you apply another piece of tape to the tab, and use the overhang to secure it to the mandrel. Like so:

The next thing I needed to do is secure the hollowbar stock so that I could spend time reaming out the bore without the stock moving. I decided to make a simple sandwich of scrap wood, dense foam, and screws to hold everything in place:

Then it was just a matter of reaming out the bore slowly, frequently stopping to change the sandpaper, dump out the waste material, check the progress, and let both the drill and the hollowbar cool down. It took a total of about 8 hours over four days to do this.

But, in the end, a .62 cal lead ball would pass freely through the length of the hollowbar:

Now, one thing I want to note: when you repeatedly insert a mandrel with sandpaper from one end, that end will tend to get over-reamed. So I was careful to consistently do this from the end of the hollowbar that I intended to be where it would be mounted to the wood stock later (i.e.; not the muzzle end).

Making the socket.

The hand gonne would need to be mounted to a stock of some kind. Historically, these seem to have been just a simple stave of wood, with the hand gonne stuck on the end. That was also the style of the others I’d seen in person, so it was what I decided to do.

There were a number of ways that such mounting could be accomplished. I considered the options and settled on just creating a hollow at the end of hand gonne that would accept about a 2″ deep piece of the stock.

Therefore, to make the socket, I needed to remove additional material to a depth of about 2″. To do this, I used a drill with a 5/32″ bit (marked with tape to a 2″ depth) to create a starting set of holes in a circle:

Then I went to a 1/4″ bit to remove more of the bulk:

After this, I used the cold chisel to start to cut through the remaining material:

And then the Dremel rotary tool with a steel carving tip to remove the rest of the bulk and thin down the sides some:

I wasn’t worried about it being perfectly symmetrical or smooth at the bottom, since these areas would be hidden by the stock.

Making and installing the breech plug.

Since I was starting with a length of hollowbar, which had a hole down the center of the entire length, I needed to close up and secure the breech of the gun. The historic models and modern versions which are cast just have a closed-off breech to start with, so this step isn’t necessary.

Black powder is a low-pressure propellant, and I could have probably just gotten away with inserting a tight plug of bronze and then mounting the hand gonne to the stock. But I wanted something that would be more secure. More secure, yet still low tech (no brazing or anything). I decided that a couple of mild steel rivets through the outside of the hand gonne, and through the plug to the other side, would be sufficient. But this meant that the plug would need to be long enough put a couple of rivets through. I settled on a 2″ plug.

Using the calipers, I checked the bronze rod, and confirmed that it was larger than what I wanted. I also checked by trying to insert the end into the breech end of the hand gonne, just to be safe. It was still 0.675″, so I needed to file/sand it down:

Checking frequently, I continued that until the rod would barely start to insert into the breech. Then, using the hacksaw, I cut off a 2″ long piece of it:

I did some additional sanding, then inserted it, first by hand, then using the hammer and the iron rod I’d used as a mandrel to ream out the bore:

Shaping the outside.

OK, first things first: at this point, you could rivet the breech plug in place, drill the touch-hole, mount the hand gonne, and use it. The shaping I’m about to show/discuss is not necessary to having a functional black powder firearm.

But the historical record shows that most of these were shaped and/or decorated in some fashion. Likewise most of the reproductions I’ve seen. I decided to do something similar to the design of the one my friend owns, though going with an octagon form rather than a hexagon one.

Why bother? Mostly just for aesthetic reasons. But also, the entire bulk of the hollowbar isn’t necessary for the hand gonne to be strong enough to function. You do want to have some extra bulk/strength to contain the primary explosion of the black powder, in the area that is called the “chamber”. But as the lead ball/bullet starts to move down the barrel, the pressure drops off quickly. Meaning that the barrel walls don’t need to be quite so thick/strong. By removing the excess, you can cut down on the weight of the hand gonne by about a third. I also decided that I liked the flare at the muzzle often seen on these guns, and thought it would help connect it visually to that history.

Since the final shape of the hand gonne is largely an aesthetic decision, what follows is just a quick photo-essay of the steps I took to come up with my preferred design. Also, while I started out using a file, I almost immediately shifted over to using a belt sander to get the overall shape, then a bench grinder to rough out the barrel, followed by more use of the belt sander. Basic shaping was done using a 60grit belt, then finished with a 150grit belt.

First, I marked the end of the muzzle with the basic shape I wanted:

Then I put it back into the trough to hold it in place:

I chose an octagon shape for a simple reason: it would be easier to keep it aligned in the trough while working.

Once the overall shape was defined, I started to cut down the barrel bulk:

This all actually went faster than I expected, just a couple hours work with the belt sander & grinder, with frequent stops to check dimensions with the calipers.

Securing the breech plug and drilling the touch hole.

Once I had the exterior shape mostly finished, it was time to secure the breech plug with a couple of mild steel rivets and drill the touch-hole (how you fire the hand gonne).

The first step was to carefully measure and mark the locations of the rivets and the touch-hole. I did this by using a dowel from both the back of the socket and from the muzzle. I wanted the rivets to be evenly spaced about 1/3 the way from the front and the back of the breech plug, and the touch-hole to be positioned so that it was just in front of the breech plug.

Using a Sharpie, I marked the location of each of the holes. First I used a 7/64″ bit and drilled the touch hole, centered on that face of the octagon and angling slightly back into the chamber for the black powder. This would tend to force the jet of hot gas forward away from the shooter when the gonne was fired. I used a larger drill bit to start a larger hole just on the surface — the beginning of a simple ‘pan’ to hold a small amount of black powder.

Then I selected a drill bit the same diameter of the 3″ nails I was going to use for the rivets, and drilled through the exterior of the hand gonne, the breech plug, and out the other side of the hand gonne:

Next I used the Dremel tool with a small grinding head to deepen the ‘pan’ and slightly counter-sink the holes for the rivets. I cut off the head of the nails, and inserted them through the holes, cutting them off with about a 1/8″ protruding from either side. Then these were hammered (with a hand sledge under them, though if you have an anvil that will work better) so that the mild steel filled the counter-sunk area:

Next I dressed those areas again using the belt sander and 150grit paper:

Shaping and mounting the stock.

I’d hoped to find a suitable length of oak, ash, or hickory to use as the stock. I settled for a 1.75″ x 48″ poplar dowel I was able to select at a local lumbar yard.

The first thing was to shape the end to fit the socket:

Once I had it so that it fit, I needed to secure it. I decided that normal 5-minute epoxy would be sufficient for this purpose. So I did some additional undercutting of both the dowel and the socket walls (so that the epoxy would fill in those, and couldn’t just pull loose). Then I mixed the epoxy, poured it into the socket, and shoved the dowel into place. To hold everything in place for the 24 hours needed to let the epoxy cure, I used this high-tech set up:

Surprisingly, this worked, and the dowel rod was almost perfectly straight off the back of the hand gonne.

I had debated whether or not to leave the dowel round, or to put partial flats on it, or what. But once the epoxy had set, the round dowel just didn’t feel right, so I decided to go ahead and use the belt sander to shape the dowel into the same shape/dimensions as the hand gonne:

If you look carefully, you can see the slight skew of the hand gonne off to the left. It’s only 3 or 4 degrees, and really isn’t noticeable when you actually hold the thing, but it is there. I decided not to worry about it.

I wanted to have some basic surface protection for the stock, so used some dark walnut colored Danish Wood Oil I had available:

Proofing the hand gonne.

The usual recommended procedure to test a home-made black powder firearm for safety is to take it to the range, put a double load of powder into it with a lead ball, secure the firearm, and then fire it from a safe distance using a string or fuse or whatever is necessary. I’d ordered in some cannon fuse for just this purpose.

I got out to my range on a cool Friday morning, when I was reasonably sure that no one else would be there. I wanted to avoid putting anyone else at risk, on the off chance that my project didn’t work out and wasn’t safe. That is, if the thing blew up, I wanted everyone else to be clear.

I set up a large sheet of cardboard (about 2×4′), about 7 yards from the gonne. I put in 120gr of FFg black powder, twice the standard load I’ll shoot out of the thing, along with a .62cal lead ball (345gr). I then laid the gonne down on a picnic table, with a fold piece of cloth under the muzzle end to maintain a slight elevation. Then I positioned my black powder range box (minus the black powder casks) balancing on the stock just behind the gonne as a protective barrier. I positioned my usual range bag on the back of the stock to help hold it in place. And I set up an inexpensive mirror and my smart phone so the phone was protected but would record the first firing of the gonne. Like this:

I cut a 6″ length of cannon fuse, inserted it into the touch-hole. I started the camera recording, then lit the fuse. Then got about 10 yards away, on the other side of my vehicle. And this is what happened:

And here the relevant bit is in slow-motion (1/8th normal speed):

Mwahahahahaha! It works!!!

Here’s where the first shot hit:

Not bad! It was time for the second shot, using a normal charge of 60gr of FFg black powder:

I was stabilizing the gonne with one hand, while filming with the other. There was a decent amount of recoil, even with the standard charge.

I went ahead and shot it a third time, again with a normal charge, but this time holding it and shooting it as I normally would. Again, I noticed a fair amount of recoil, even given the substantial weight of the whole thing (I’d guess ~10 pounds or so). But it’s not the sort of thing that most people would mind at all.

And all three shots hit in roughly the same place at 7 yards:

Not bad.

Given the very basic design of this thing, it’s still respectable in terms of control and power. I didn’t chrono it, but based on previously checking black powder guns, I’d guess that the .62 ball was probably traveling about 800fps. That gives a muzzle energy of about 500 ft/lbs, or about what a modern .40S&W handgun would get with typical loads. In other words, it’s an effective weapon, at least at moderate range. Not bad for a technology that is almost 700 years old.

Conclusions.

To repeat myself from the start:

• This is a description of how I made a black powder hand gonne for my own use
• I am not recommending that you make a black powder hand gonne
• If you do decide to make a black powder hand gonne, I am not recommending that you make it this way
• Any black powder hand gonne is potentially dangerous, and if you make one, the risk is entirely on you
• A black powder hand gonne is a firearm, and all the rules of safe handling and usage of a firearm apply

But, after the ‘proof’ shot, I did a close inspection of the hand gonne. There were no signs that anything had shifted or been stressed. Same thing after the two subsequent ‘normal’ charges were shot. So my conclusion is that the gonne is safe, though of course I will keep a close eye on it going forward.

And overall, I’d have to say that the project was a success. It is possible for an average person, using common, non-specialized tools and a little ingenuity, to make their own reproduction 14th century hand gonne with modern materials. My total cost out-of-pocket for this project was under $250, and now I have a couple new tools as well as the gonne.

Thanks for coming along for the ride. Feel free to share.

Jim Downey

Much more black powder fun!

A couple of summers ago, I got together with some friends and we did a little black powder shooting. Well, since then we’ve talked about getting together again with even more great historical guns (reproductions) and another shooting buddy, and this past weekend we did just that.

Did I say more guns? Why, yes, I did:

Total of 21 shown, with one extra hiding in that brown case in the second pic.

I’m not going to try and give a real review of every one, but using the two pics above I will identify each gun, maybe add another pic or two of it in action, and provide some initial impressions of shooting it. So, without further ado, starting with the top image:

Top gun: Early Matchlock Caliver. .62 ball, 60gr FFg. A pleasure to shoot. This felt less bulky than the earlier guns, but you had to be careful to position the thin upper buttstock such that it was against the bicep, rather than tucked into your shoulder as with a modern style of gun. The lighter weight did make the recoil more noticeable.

Below that: Swedish Snaplock. .77 ball, 60gr FFg.  Very similar to the Caliver in how it felt, though the mechanism is a type of flintlock. The larger ball would have probably benefited from more powder (the rule of thumb is about 1gr of powder per point of caliber, to start with), but it still had no problems penetrating the 3/4″ plywood at about 15 yards.

Under the Snaplock are three small Pedersoli handguns:

1. Derringer Rider (Hardened). Uses just a #11 percussion cap to shoot a 4.5BB (standard .177 round ball). We couldn’t get this one to shoot — after the first shot, the BB was stuck in the barrel.
2. Derringer Guardian. Uses just a 209 primer to shoot a 4.5BB (standard .177 round ball).  This one shot fine, and was a fun little gun. Trying to hit anything at more than arm’s length was a challenge …
3. Derringer Liegi. This uses a percussion cap and 10gr of FFFg powder to shoot a .451 ball. The trigger is retracted until the hammer is drawn to full cock. This was actually a lot of fun to shoot, and had a respectable amount of power behind it. At about 5 yards it shot about a yard high from what you initially expected, but with a little practice …

Some pics of the Guardian and Liegi being shot:

To the right of the Pedersoli handguns is a Hand Mortar. This has a .75 chamber with a 2.5″ bore. Which, it so happens, is perfect for shooting a tennis ball …
Keith shot the first ball at our plywood target, using 75gr of FFg. The tennis ball bounced right back at us. So we reused it, this time increasing the load to 100gr of FFg, shooting it into an adjacent field. It lobbed about 60 yards. The last shot was with 120gr of FFg, and that sent the tennis ball 75+ yards. I expect that if you stuffed some wadding or such down into the .75 chamber, and tamped it appropriately, that you’d get much better performance. But we were laughing too much to think of trying that at the time.

Under the Mortar is a LeMat Cavalry revolver. The 9 chambers are .44, and we used a .451 ball with 40gr of FFFg for each. The center chamber can also shoot a 20ga shot load, but we decided not to fuss with that. We used the recommended #11 percussion caps, but #10 would have fit better. This gun was new, but the trigger was *extremely* hard to pull and cocking the hammer almost took two hands. It would probably benefit from a fluff & buff … but I don’t think I’ll run out to buy one to try it.

To the left of the LeMat is an Early Matchlock Arquebus.  .58 ball, 60gr FFg. Surprisingly easy to shoot, and reliable under the pleasant autumn conditions we had. All of us found it easy to hit close to point of aim, even with the significant delay you have with a matchlock.

Below that: a Kentucky Flintlock Rifle. .50 (we used a .490 ball) with 60gr of FFg. This is the iconic flintlock for most people, and felt & shot well. Though curiously, the delay from ignition of the pan to the rifle firing seemed long to me, compared to my Mortimer (see below).

Moving to the second image of guns at the top of the post …

Starting at the top, on the left side of the image: simple Hand Gonne in brass. .62 ball with 60gr Fg. After pouring in the powder, you just drop the ball in without a patch … and have to pay attention that you don’t let it roll out again. We started the day shooting this, and all had entirely too much fun. Initially we used 40gr of Fg, and were able to pick up and reuse the ball, since it just bounced off the plywood target.

Below the Hand Gonne is my 1815 Mortimer flintlock. .535 ball with 60-80gr of FFg. I’ve written about this gun previously for my personal blog, and really enjoy shooting it. Even with the more powerful loads, there’s very little recoil … because the damned thing weighes a ton! But it is well broken in, shoots very well, and is accurate in my hands to at least 100 yards.

Under that is my new 1858 Remington Revolving Carbine. .454 ball with 30gr of FFFg. This was my first outing with this gun, and I just love it. We all were able to shoot about 4″ groups at 15 yards the first time. With a little practice, I am sure I can extend that considerably. Here’s  a couple of images of it from this weekend:

And some video:

Under that is a French Blunderbuss. .735 ball with 60gr Fg. This was the first time any of us had shot one of these muskets, and we were all pleasantly surprised at how accurate and reliable it is. I can now understand why it was considered such a valuable weapon for close combat.

Next down is the Kentucky Percussion Rifle. .50 (we used a .490 ball) with 60gr of FFg. This is the twin to the iconic flintlock up above, and shot nearly identically … except that the #11 percussion cap gave immediate ignition to the charge. A very nice shooting rifle.

Next to last on the left side of the second image is a Japanese Matchlock. .50 (we used a .490 ball) with 60gr of FFg. I had shot this one previously, but it was fun to revisit it and compare it to the other matchlocks we had. All of us found it easy and accurate to shoot.

At the bottom on the left is a 1766 Charleville musket. .68 ball with 80 grains of FFg. This gun had probably the longest delay of any of the flintlocks we shot, but was still very fun to shoot, went off reliably, and seemed very accurate.

On the top of the right side of the second collection of guns is another 209 primer only 4.5BB carbine: the White Hawk. This was *surprisingly* fun to shoot! It was easy to use, accurate, and the .177 pellet seemed to hit with more authority than you would expect, though we didn’t test it for power. All of us had to try this several time. I could really see this being a fun little thing to shoot in your basement or some such.

Below the White Hawk is a Howdah Hunter: a twin-barrel .50 percussion cap gun which we loaded using a .490 ball with 30gr of FFFg. While heavy and with a stiff pair of triggers (one for each barrel), this was easy to shoot than I expected. Recoil wasn’t bad, and accuracy was good.

Under the Howdah, hidden (unintentionally) in the gun case, is a home-made Hakenbushe (hook gun), a variation on the early hand gonne which had a ‘handle’ that was a steel spike, used for close defensive work after the gun had been fired. This one shot a .735 ball with 60gr of FFg, and like the other hand gonne above, didn’t use a patch. So you had to make sure not to tilt the barrel down, or the ball and powder would roll out.

Under that is a classic Hawken rifle. .50 call (.490 ball) with 60gr of FFg. This may be more popular than even the Kentucky long rifle, and it was a fun old friend to revisit.

Lastly, two nice flintlock pistols, only one of which we were able to actually shoot. That was the 1763 Charleville pistol, .68 ball with 40gr FFg. A classic cavalry pistol which was very easy to shoot.

The remaining flintlock is a Murdock Scottish highland pistol .52 cal. Unfortunately this one needed to have the touch-hole reworked a bit. So perhaps we’ll get to shoot it next time …

Jim Downey

Special thanks to my friends and cohorts: Jim, Keith, and Roger. I appreciate you sharing your guns and knowledge, but most of all your friendship!