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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