So the finishing chamber reamer I ordered was supposed to arrive today, and with minor modification I would have been able to ream the chamber. Sadly it did not arrive, and tracking now says it will arrive Monday. I’m not a patient man, so we’ll get back to that shortly…

One thing that was needed was for the gun to be .30 caliber, which meant lining the bore. I had a short section of .308 Winchester barrel rifled 1:10. A little research showed that .30 Luger also used a 1:10 rifling pitch and shoots bullets in the same weight range as the 7.8, so I figured this would work fine. I turned the section down on the lathe, then drilled the barrel through from both the chamber and muzzle ends. the liner was a gentle press fit. I slathered it in Loctite Red and pressed it in. Voila! .30-caliber Helwan.

Of course I’d still need to cut the chamber, and ordered a .32 H&R Magnum chamber reamer, which ought to be easy to modify for my purposes. Thank you, Patreon supporters! This is of course the very reamer that did not arrive on schedule today.

Earlier in the week I was dialing in my process for making cartridges. It all starts with the .30 carbine brass.

Brass needed to be removed at the base of the cartridge using the lathe, and there was definitely a learning-curve there. It also required making a special mandrel to fit the brass. First batch of five saw three fail, but by the end I was five for five. I wound up with a total of 25 cartridges. Good enough to start.

For test purposes I loaded 78gr LFP bullets over 3.0gr. and, after some consideration and calculation, 3.5gr. of Unique, so I had some loads to test. The goal was to drive a 75gr. bullet at 1150 fps. The math suggested I could drive it as fast as 1200 fps. without creating mechanical issues with the gun, but I saw no reason to push it that hard.

When I discovered that the reamer would not arrive today, and seeing as I had all of this ammo on-hand I sacrificed a .375″ chucking reamer to make my own chamber reamer.

So I used my improvised chamber-reamer until the loaded cartridges fit easily. I used a carbide burr to cut the feed ramp, then cleaned it up with a 400grit sanding drum and a cratex polishing cone.

OK, all ready then. The rounds fit the chamber, they feed from the magazine, they extract and eject manually. Time to shoot. I set up the Caldwell Chronograph. The 78gr LFPs over 3.0 gr. of unique produced 1021 fps. for 181 ft./lbs of energy. Not bad, but far below potential. Now it gets sub-optimal- the gun cycled, but did not extract the fired cartridge. It also didn’t push the slide far enough to engaged the magazine hold-open.

Maybe the 78gr. loaded with 3.5gr. of Unique will have what it takes? Nope. It made 1147 fps. and 228 ft./lbs but again, the cartridge did not extract. On the other hand it showed no signs of excessive pressure, and the gun seemed to be handling it just fine. I decided it was time to be stupid. I loaded some 100gr LFPs over 3.5gr of Unique. This yielded 1086 fps. and 261 ft.lbs. Outstanding… but it still didn’t extract.

After looking over the gun carefully, I think the culprit is a sticky chamber. It is snug, and is not the smoothest so I am going to wait for the proper reamer, which is a few thousandths larger than my home-made reamer.

When the cartridges extract properly that will change a number of things; the slide will get more momentum transferred to it for one thing. If the pressure is too high when the slide opens it could blow the case-head. I don’t think it will, but it could. Once the chamber is properly finished we’ll see what’s what.

In the meantime if anyone has any .30 Carbine brass laying around that they’d care to contribute…

Michael Tinker Pearce, 29 January 2021

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The Colt Walker allowed Colt to rise from the ashes of his Patent Revolver Company, and in 1848 the new Colt’s first purely civilian revolver was the 1848 Pocket Model, known as the Baby Dragoon.

This was a (nominally) .31 caliber percussion revolver built on a small frame. These were provided in a variety of barrel-lengths and could be had with or without the loading-lever mounted under the barrel. They were instantly popular, and these new revolvers and their successors in 1850 (called the 1849 Model) included mechanical improvements that formed the basis for the famous 1851 Navy and 1860 Army models.

Some of these guns were later converted to fire metallic cartridges by gunsmiths, which were typically chambered in .32 Rimfire, but to the best of my knowledge Colt never did factory conversions of these guns.

Colt did produce cartridge versions of their Pocket Navy chambered in .38 Colt Short, and in modern times conversion kits for the .31-caliber reproductions were made that used the .32 S&W cartridge.

These were not exceptionally successful because (many?) .31-caliber percussion revolvers are actually .32 caliber (.320″) and .32 S&W are actually .31-caliber (.312″) Because of course they are. This meant that .32 S&W cartridges fired through the .320 bore often didn’t stabilize well, tended to be inaccurate and produced ‘keyhole’ hits.

When I decided to do my own conversion on an anonymous Italian reproduction I modelled it on the later Colt conversions and chambered it for .32 S&W. To measure the bore I forced an oversized soft-lead slug through the bore and measured it afterwards. The bore came out, as expected, at .320″. I planned on using hollow-base wadcutters to compensate for this; the skirt of the bullet would expand to fill the bore and engage the rifling.

From here I’ll tell the story with pictures-

I fired five shots over the chronograph and into the ballistic gel. They averaged 769 fps. and 118 ft./lbs at the muzzle, with an extreme spread of 36 fps. The bullets all penetrated very close to 13-1/2″ into the gel. I didn’t fire them through denim because, uh… I forgot to.

I’ll need to take it to the range for a good workout, but I’m pretty pleased with how it’s working out. I am going to mount the breech-ring on the breech with screws; very occasionally the breech-ring will move enough to momentarily bind the action.

The gun needed holster, of course. I modelled mine on the simple ‘gun-bucket’ style popular in the 1870s.

Addenda

This morning I fired the Remington Factory ammo into the gel. The bullet penetrated 10-1/2″ and wound up nose-forward. As you can see the rifling grooves are quite deep and plain. When measured the bullet had ‘bumped up’ to .320″. Apparently the very soft lead bullet works just fine, at least in the modified forcing cone of this gun. I’ll take it to the range and run some more rounds through it.

Michael Tinker Pearce, 28 January 2021