Interesting, to say the least. I like the idea.
The concept of a rimmed version of an autoloader cartridge for use in revolvers has been around since the .45 Auto Rim cartridge came out in 1920.
Besides the .45 Auto Rim, there was the ill-fated 9mm Federal. This cartridge was a 9x19 with a .38 spl. rim, though it was not really intended for revolvers chambered for the standard 9x19 round as there were few at the time (1989). It was made for a Charter Arms revolver that was chambered just for it. Sometimes it works in standard 9mm revolvers, sometimes it doesn't, it depends on headspace, the distance between the recoil shield and the rear of the cylinder. It matters little, as Charter Arms' bankruptcy shortly after it's introduction killed it. It is mostly of interest to cartridge collectors and is not available at any reasonable cost.
There's a wildcat rimmed version of the 10mm for the Smith & Wesson revolvers called 10mm Auto Rim RMS (see ammoguide.com) that's based on the .41 Magnum case. I'm sure it could be further modified for use in .40 S&W revolvers. I encourage you to give it a try if you have a .40 S&W revolver.
A quick comparison of the drawings on ammoguide.com of both the .380 Auto and the .38 spl. led me to believe that a rimmed version of the .380 Auto could be made from the .38 spl case if the rim thickness would headspace properly. Getting out the calipers and measuring rim thicknesses of both cartridges and the thickness of the full moon clips, plus the distances from the front of the cylinder to the base of a cartridge in the cylinder, confirmed it should be close enough to work. It makes some sense that it would, as it wouldn't be a surprise that Taurus would machine the M380 the same as their Model 85 in .38 spl.
I will hereinafter refer to our wildcat as the .380 TAR (Taurus Armed Rimmed). To avoid confusion with the British cartridge called the .380 Rimmed I don't want to refer to it as .380 Auto Rim. 9x17R is just too European for me, and I thought the forum should get a plug.
There's two ways I formed cases for the .380 TAR. The hard way and the easy way.
The Hard Way: My first attempt I used a .380 Auto trim die to hacksaw the excess off .38 spl. brass, then I used a file to trim it to finish length. I ended up using a Lee case trimmer as a check and when I found it would occasionally trim a bit more off on some of the cases I quit trying to be precise with the file. It was quicker and more certain to just use the Lee case trimmer after removing the bulk of the excess case length.
Here's what I used:
1.Redding .380 trim die for the .380 Auto.
2.Redding extended shell holder for the .38 spl.
3.A .38 spl. sizing die
6.A Lee case trimmer for the .380 Auto. But use the .38 spl. shell holder of course.
RCBS also makes a trim die, but the RCBS trim dies do double duty as a sizing die. According to Redding their trim die is cut to chamber dimensions. Since we are dealing with slightly oversize (and it turns out slightly thicker) .38 spl. brass, I decided the Redding would be the best choice. The RCBS may very well work. The extended shell holder could be any brand. You need the extended shell holder or the case won't reach the short trim die when the press ram is at full height.
The biggest problem with this plan is the case wall thickness is just a tad greater on the .38 spl. than the .380 Auto. Also be careful in your brass selection. As we learned in this post... Differences in .38 Special Brass ….brass varies. A thanks to skinnedknuckles for that one. I wouldn't want to try this with that heavier walled brass. Even if it worked the case capacity would likely be less, increasing pressures. And you'd likely have problems with case bulging.
1.Resize / decap .38 spl. case
2.Lube case and run it into the .380 trim die using the .38 spl. extended shellholder and trim with hacksaw then file flush.
3.trim with Lee trimmer and chamfer / de-burr.
If you go straight to resizing in the .380 die instead of the .38 spl. die, you won't get the Lee trimmer pilot in the case due to the greater wall thickness of the .38 spl. case. This is the same reason why I don't think the RCBS trim die would work. You could always run it through an expander to open it back up though.
If you have a powerful single stage press you may be able to force that unsized .38 case into the trim die. I wasn't comfortable with it. I normally load on a progressive which isn't suitable for this purpose since there is no way to accommodate the extended shell holder. I did this on a $25 Lee Reloader press I use for miscellaneous tasks. Not the strongest press out there.
I made up 10 cases and tried them in the cylinder, making sure the revolver would cycle without the case heads dragging on the recoil shield. They cycled perfectly. I primed a case, put on my hearing protection, and chased the dogs out of the garage. The primer fired and had a solid firing pin indentation without piercing the primer. Still managed to freak out the dogs though.
The Easy Way: Buy some .38 Short Colt cases and use the Lee .380 case trimmer and a drill to trim them down from the Short Colt's nominal .765 to the .380's nominal .680 (the Lee .380 trimmer takes it down to about .672 as a trim-to length). This is much easier than hacking down .38 spl. Cases.
Somewhat surprisingly .38 Short Colt cases are available, some shooters seem to use them in some kind of action shooting. The advantage being easier ejection and more rapid reloading due to the short case. Go figure. There also seems to be some black powder application for them, maybe in Colt Navy conversions.
Starline manufactures .38 Short Colt brass and sells them. If their 500 quantity minimum is too high for you (it was for me) you can buy smaller lots from Track of the Wolf - for .38 Short Colt . I trimmed 50 cases in an hour.
The brass may not seem cheap, but you don't have to buy a .380 trim die and extended shell holder (about $50).
I mixed and matched just about every combination of .38/.380/9mm dies that I have trying to make this work. I also purchased a Lee .38 Short Colt carbide set. The Lee set worked best but I also ended up using a Lee Factory Crimp die for .380 to make it a four die set.
The Lee .38 Short Colt set has a .38 spl sizing die, and a .38 Auto seating die. This is the only seating die that worked. Several posts I read said this set also has a .38 S&W expander die, and it does appear different than the expander in the .380 set, it mics out at .355 and my .380 mics out at .353 and the expander is a different length.
Other seating dies either allowed bullets to be seated canted at times, or burnished the cases a bit to the depth of the bullet.
Depending on which case I'm using (Starline .38 Short Colt or cut down .38 spl) I get some minor to minor + case bulging where the bullet is seated. The Starlines would chamber fine but about half of the loaded .38 spl cases wouldn't chamber. I ran them through my Lee .380 Auto Factory Crimp Die and it smoothed them out nicely and they chambered perfectly, so I would add a .380 FCD to the Lee .38 Short Colt set if you want to load yourself some .380 TAR.
Case capacity is the same as near as I can tell, I compared the weight of five different cases in .380 TAR vs .380 Auto, both empty and water filled, and the weight of the .380 TAR varied .1 gr to .2 gr on either side of the .380 cases with the .380 TAR averaging in at .1 gr heavier so it's the same to minutely larger case capacity. .380 load data should work fine, especially with the slightly heavier brass we've made.
I loaded a lighter than spec charge of 2.5 gr of Bullseye in my first batch of .380 TAR over some 95 gr Winchester FMJ, the same flat point they load in the .380 WWB. They fired perfectly. Firing pin indentations looked perfect.
My second batch was loaded with 3.1 gr of W231, also seemed fine. I won't go into “accuracy” with a DAO pocket pistol but it shot as well as any factory ammo.
Is this a pointless exercise? Pretty much. There's nothing the .380 TAR can do that the .38 spl can't do better. Basically I've just reinvented the .38 Short Colt. Or a .38 Shorter Colt if you will. But if you have one of these little revolvers and don't like the hassle of the moon clips or poking them out with a stick, why the hell not? It was a fun experiment.
There you have it, taurusarmed.net's first homegrown wildcat: the .380 TAR.
Followup: I highly recommend you use the LEE FCD. Without it, bullet pull is sometimes an issue.
Last edited by glenwolde; 02-15-2017 at 10:09 PM.
Interesting, to say the least. I like the idea.
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The 2nd amendment is not about hunting or shooting sports, it is about the citizens of this country having the means to protect themselves and the states from the tyranny, oppression, and misery of an over powering government. Modern rifles are a means for the citizens to stand up to an over powering government.
Taurusarmed.net Where are you map?
Ya dun good. Wildcats and logic do not always go together. Even if what you start out with seems logical at the moment. In your case you started and ended with a logical line of thought and made it work. Rimless revolver rounds in double actions lend themselves to your type efforts. I enjoyed reading about your thought process and how you arrived at the finished product. I cut some 45 colt cases to 45 acp length for a Tracker in 45 acp because auto rim case rims were too thick. Then found out the cowboy action shooters had wanted a short case and a company had made them to 45 acp length to work with acp dies. For cutting cases Harbor Freight makes a mini chop saw that works great.
The real test of all this is "DO YOU FEEL PROUD LIKE A NEW DADDY"??-LOL
stuff like this is always challenging to the mind and a lot of fun for many people.
Maybe Remington will come along and offer you a million bucks for the rights to produce the 380 Auto Rim ammo?
of course didn't Taurus discontinue that pistola??
if so that might put a crimp in the production line!
Retired Firefighter, Advanced Georgia Master Gardener, Hazardous Material Response Member, Certified Hazardous Material Incident Commander, 1911 Addict and General Gun Lover.
Currently Professionally Retired Old Person.
That one is much nicer than the old one. It looked like a 4" hand grinder mounted on a small stand. The clamps were crude but most of us made our own. The "blade" is a thin fiber weave like a cut off disk but they last a long time on brass. The one you show may be better, looks a lot better. I have used trim dies on things like the 357 Herrett and an old friend told me about the small chop saws. Have not used the trim dies in years. I make a small jig for the case and after cutting usually just debur the mouth inside and out. Tapered cases require the jig to allow for taper but straight wall cases don't.
To conclude, is it worth the time & effort to:
1. Cut down .38 Special cases and trim as required
2. Load and factory crimp?
Since you don't lose the cases in a revolver like you do in a semi-automatic, you just need to cut cases every now and then to replenish lost or scrapped cases. You no longer have to play with moon clips. However, Glenwolde, you seemed a little pessimistic?
... And I liked those stellar clips. Faster and smaller than speedloaders, and won't lose any brass as the cases eject still in the clip...
You don't need a lot of brass with this little gun, I think most people aren't going to shoot more than 100 rounds at a time. If you shoot 100 rounds you'll need to load and unload 20 moon clips. That's a time consuming pain in the butt, to me. I think the clips are $10 for 5, so that's another $30 for moon clips beyond the 5 they give you. The moon clips don't last forever either, they get bent or loose eventually.
As to whether it's worth it, that's up to the reloader. If you don't reload this isn't worth it. If you already reload for the .38 spl and .380 as I do, this isn't a hard cartirdge to add. To many I'm sure this is an ingenious solution to a non-existent problem. To me this was more about my interest in reloading as a hobby. I like the moon clips for carrying a reload, just not for practice at the range.
Once I figured it out, I now know that all I would have needed to buy besides the Short Colt cases was a .38 Auto seating die and a .38 S&W expander. I already had the sizing die, the case trimmer, shell plate / holder, and the .380 FCD.
Last edited by glenwolde; 06-08-2012 at 05:45 AM.