Author Archives: tinker1066

7.8x19mm… Trials Without (too many) Errors

Thanks to Steve Gallacci for generously providing me with small pistol primers so testing could continue!

When we last left Our Her… er, our gun, the barrel was lined for .308, but my crappy make-shift chamber reamer did not do a very good job, so while I could fire the gun the cases would not extract.

Monday the .32 H&R Magnum reamer arrived, and required no modification to ream the chamber. When fired the cartridges now ejected just fine, and the brass showed no signs of unusual pressure. Furthermore the gun fed from the magazine and locked back on empty.

What a difference a proper reamer makes! Empties now extract and eject just dandy.

Naturally the first thing to do was to test the existing loads; I anticipated some loss of velocity (from the force required to operate the mechanism) and I wasn’t wrong. The 100gr LFP over 3.5gr. of Unique made 939 fps. and 196 ft./lbs, and the 78gr LFP made 1114 fps. and 215 ft./lbs. Not bad, and I expect I can push these faster.

So, it turns out I checked one of the wildcat boxes; the 78gr. load basically has performance identical to 7.65 x 20mm French Long, which was used in the MAS 35 service pistol. While the French gun has a locked-breech it apparently doesn’t need one, given that the Helwan works fine as a straight blow-back.

OK, time to digress. A few years back when I started reloading .32 S&W Long the only .32 brass available locally was .327 Federal. No worries, I bought that and shortened it… but I shortened some of it a little too much. I set those aside, thinking that at some point I would convert them to .32 Long Colt. Remembering those I hunted them up and examined them. Very strong base, so I decided to rework them. I turned the rim down to the correct size and cut an extractor-groove. Worked a treat.

7.8 x 19mm brass made from .327 Federal Magnum. Note that there is a fairly heavy crimp; these headspace on the extractor so the crimp works fine.

Today I was at Pinto’s and came across a box of .32-caliber 100gr XTP hollow-points and decided to make the jump to a jacketed bullet load. I checked Loaddata.com to see if there was data for the 7.65 French Long and lo and behold there was. According to them a 100gr. Speer Plinker over 3.1gr of Unique makes 1030 fps. Estimated. Yeah, I was seriously skeptical; after all I’m getting 939fps out of a 100gr. lead bullet over 3.5gr of Unique. I loaded the XTPs over 3.2gr of Unique, fired up the Chronograph and had a go.

My skepticism was justified. My one shot before the Chronograph’s battery died showed 904 fps. for 181 ft./lbs. Not bad, but I’m pretty sure I can do better.

The 100gr. XTP JHPs are loaded a bit shallow in the interest of feeding easily..

The bullet penetrated 14-1/2″ into Clear Ballistics 10% ordinance gel. To my surprise it actually expanded slightly. Mind you, I wasn’t firing through denim as I was really only concerned with the velocity. If fired through four layers of denim I’m dubious it would have expanded even this much, but we’ll find out soon enough.

I might be making this sound too easy; believe me there was plenty of fiddling along the way, particularly with the magazine feed lips. I had discovered that if I loaded more than five rounds in the magazine rounds tended to nose-dive instead of feeding. Some subtle alterations to the follower, improving the feed ramp and fiddling with the magazine feed-lips seems to have corrected this problem. Time will tell. More load development is needed, and serious shooting will probably reveal other issues to deal with.

Definitely time for a trip to the range to see what’s what, even though I only have forty pieces of brass so far. There’s more on the way, though, so it’s all good.

One issue I have discovered after I had modified the Helwan magazines to work with this cartridge. Magazines for M1951s aren’t cheap, and now I have an M1951 and a rare M1951 E that don’t have spare magazines. Oops… I think I’ll be thanking my Patreon supporters again, because I like to have at least two spare magazines for each gun.

Naturally I’ll keep you posted… and try to give you a break from this cartridge!

Michael Tinker Pearce, 5 February 2021

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7.8x19mm- Closer, But No Cigar

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.

Sizing the brass using a .32 H&R Magnum resizing die. The case is not straight-walled, and it needs to be.
After running the brass into the die it’s mostly straight-walled, except for a bit at the base. Got to do something about that…
The lathe solves the problem. Of course it wasn’t that simple…

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.

Finished ammo, 78gr LFPs over 3.0 gr. of Unique.

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.

My improvised chamber reamer. It’s ugly, but it works. Mostly. Sort of.

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.

After tweaking the feed lips slightly the magazine presents the cartridge nicely and they chamber properly.

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.

The 100gr. bullets certainly didn’t lack penetration. They passed through 16″ of Clear ballistics 10% ordinance gel, then through a 4×4 and retained enough energy to do this to a .50-cal ammo can.

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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Baby Dragoon Cartridge Conversion

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.

Colt’s 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.

A Model 1949 Pocket Model reworked to fire .32 Rimfire by an unknown gunsmith.
Colt 1862 Pocket Navy converted to fire .38 Short Colt

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.

A modern reproduction of a Model 1848 Pocket Model with a .32 S&W Conversion made by Kirst.

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-

Here a picture of the gun prior to modification. The .45 ACP cartridge is shown for size comparison.
Here’s the finished gun. The loading lever has been removed and the barrel-lug has been re-sculpted to resemble 19thC. ‘Avenging Angel’ conversions of the 1851 Navy. The ammo shown is factory Remington ammunition.
I elected to leave the barrel full-length (5-7/8″) and left the grip alone, aside from refinishing it.
Here’s the gun broken down. The breech-ring carries a rebounding firing-pin. There is a port cut in the breech-ring for loading; there is no actual gate like there is on the larger-caliber conversions.
With the hammer at half-cock the cylinder can be rotated to load the chambers one at a time. The empties need to be extracted using a separate rod.
Here’s a close-up of the loading port. The gun can be carried with all five chambers loaded by resting the firing-pin between the case-heads.
Normally the rear sight would be located on the hammer-nose, but since I used a breech-ring with a rebounding firing-pin I had to cut that away. Instead I mounted the rear sight on the barrel just ahead of the forcing-cone. This gives a good 5-1/2″ of sight radius, and since the sights can’t move in relation to the barrel accuracy should be pretty good.
The casing is so short the semi-wadcutter cannot be seated to full depth. These bullets are Hornady 90gr. HBWCs. These are loaded over 1.2gr. of Unique.
Unexpectedly all the bullets showed some expansion when fired into Clear Ballistics 10% ordinance gel. The bullets expanded to .320, with expansion at the tip was to an average of .360. That’s not much, but it’s more than I expected.
As you can see the bullet expanded enough to fully engage the rifling.

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.

The holster is made from 7-8 oz. top-grain vegetable-tanned tooling leather. It’s double-needle stitched with #7 linen cord.
The belt-loop on the back is located to to hold the butt away from the hip for an easy draw.
Here’s the gun shown with an 1860 Army for size comparison.

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