Well, it’s cool looking. I’ll give you that.

 

Interesting. No offense, but why?

 

Armscor got happy when they introduced the "9R" version with a proprietary, stub-nose bullet that they have never seen fit to offer for sale. The result is those who load for the .22 TCM9R in States like California where buying factory ammo can be a problem, find no ready bullet choices. The end result are bullets that must be seated too deeply for the nose ogive - even stubby 35 grain V-max bullets.

The right answer is found in a "new" cartridge case design shortened to place the case neck correctly for normal seating of the Armscor 40 grain HP.

To make the 22 TCM 9R a viable cartridge for reloaders. Bullet options. I think the TCM round is a neat concept, and would love to be able to really experiment with it in a Glock.

https://www.lonewolfdist.com/Detail.aspx?PROD=922519

 

Very interested in how your tests turn out. If accuracy turns out to be acceptable and I can figure out how to form the brass from 223, It might make buying the drop-in barrel worth it.

 

What velocities are you expecting?

 

I'll be honest, as with any ad-hoc cartridge development it's always a crap-shoot, because what seems perfectly reasonable when thinking it up, turns out to be a nightmare.

Loading for the .22TCM9R has "been" that nightmare for me because the case neck is too long, and way too far forward to hold any standard bullet. If the Armscor design were available and I didn't have to invest all the additional time to measure, weight, and shorten bullets, I would not likely have thought of this approach.

But as I sat there dejected at the prospect of finding ways to seat 35-46 grain bullets in a way that the necks had proper tension, and knowing that any approach meant sawing the bullets off, or trimming noses, the idea started to gel that if the neck could be set back, once all the development work is done, the end product will be nor more difficult to load for than standard .22 TCM. IF the idea works, one can still shoot factory TCM ammo for those who can get it without paying a premium on top of a fortune.

The genesis of the idea is a modified take on the "old" Ackley Improved case designs, only instead of have a chamber cut with a longer shoulder and "blowing out" factory load shoulders to fire-form brass, it works in reverse. A custom brass case head spaces perfectly and "blow forward" on firing to form to the original TCM chamber. I remember a certain brand of .30-30 ammo that had a very "undersized" body, shoulder, and neck, since it head spaces on the rim, yet when fired, blew-out and formed perfectly to the chamber and with no failure.

I won't bore everyone with the details of how the cases are formed and cut, but IF it works as planned I expect .22 TCM level velocity - or close enough.

To answer the "why" question that inevitably gets asked...well, why not. A more practical reason is because I REALLY like the performance of the 5.7x28 with handloads running at high as 2,300 fps from the FiveseveN pistol, and the Glock 19 can deliver similar velocity and power from a much smaller, more compact pistol, AND even if Armscor never made another component for the ammo, hand loaders can form their own from a near endless supply of cheap brass!

I have already started to investigate starting with a custom chamber blank and turning down a dedicated 5.56x24 liner for a Glock barrel, but IF this works as I think, and one can use this cartridge plus factory TCM ammo, well, that's even better!

I decided to give the cartridge a completely new name because for all intents and purposes it is a different cartridge that just happens to fit into a TCM chamber - kind of like a .300 Whisper vs. .300 Blackout.

 

I won't bore everyone with the details of how the cases are formed and cut

Pretty please? This is the opposite of boring. At least If the experiment works I’d like to get a basic rundown of how to make the brass. If it proves workable, I might have to buy this mold:
http://arsenalmolds.com/products?product_id=97

 

Oh, I also think the front section of the case will act as a more efficient "piston" to drive the case back since the shoulder is flatter, and less of the expanding gases will be "wasted" creating a high-pressure concentration in the space between deep-seated bullet shank and long, tapered neck. This design might explain why a lot of users report stuck cases and hard extraction. I think the 5.56x24 will work better.

 

VERY interesting project. Hopefully you'll keep us posted as you progress.

 

Managed to get out and do some testing today.
The 5.56 x 24 was loaded with 9.5 grain of Enforcer under the Armscor 40 grain JHP.
The rounds fed smoothly from magazine to chamber and headspace was perfect.

Even with a full-weight G19 slide and a below maximum powder charge the cartridge cycled the slide, albeit a bit weakly, but this is easily corrected.
Discovered the OAL of 1.169" was just a tad too long for the G19 OEM magazine. OAL of 1.165 will probably be ideal with this bullet nose profile.

Velocity averaged 1,678 fps from a 4" barrel. Temperature around 58 degrees which is pretty good considering these small-capacity bottleneck cartridges, fired from short barrels tend to really loose velocity at lower temperatures.

Recoil was close to non-existent.

 

A few more photos showing the comparison between the 5.56x24 and .22TCM.

 

So did you have custom dies made to form this brass? I’m following with interest!

 

Not yet... I made my own "conglomeration" of dies to prove out the concept, because that's a lot cheaper than having a custom sizing die made.
So far I've had to mod several sizer dies, the bullet seating die, the trim die, and even made my own case trimmer (Lee style) from a 5.7 spindle.
I can report however that once all figured out and the tools perfected, loading the "556" is no more labor intensive than the standard .22 TCM.
The finished product works fine in a short barrel Glock 19 which is significant because prior to developing my own case design none of my loads was able to cycle the G19 OEM weight slide, nor the CZ75B standard weight slide. I attribute some of this to known and reported issues with new TCM brass that seems to be a bit soft and easily stretches the necks and sticks cases, as well as trying to get by with powders that burn to fast for this cartridge. With my starting load in this case design the G19 slide did cycle - though weakly and not sufficiently to lock the slide back, nor to reliably pick up the next round, however the cartridge does FEED perfectly. My next test will be a slightly heavier powder charge and I will also see if this round will cycle the CZ75.

One thing I have discovered is that the TCM and "556" both lose a lot of velocity when the barrel drops from 4.6-5" down to 4". But there are more powders to be tried once I'm satisfied with the case making process.

 

I grafted a bullet tip to show how the Armscor 40 grain JHP seats in the TCM case. Most of the bullet shank is below the neck and protruding well into the case shoulder area. When pressure builds, this causes a concentration of pressure between bullet and shoulder which could explain why many have reported stuck cases - myself included.
The "flatter" shoulder angle of the "556" works similar to the way the 5.7 shoulder does. First there is less bullet shank protruding into the shoulder region because there is less of it, and the shoulder angle is less acute so the pressure tends to push forward. Because the chamber is more tapered, the case expanding forward to fire-form to the TCM chamber provides added push to the slide. In essence, the case is acting like a small piston just as the 5.7 case does as extraction begins and residual case pressure continues to "iron" the shoulder forward - it doesn't "stretch" the shoulder in the classic sense.
Previously I was loading the Armscor bullet to proper depth and slicing off about 3 grains worth of the tip to bring it into OAL constraint, but this resulted in a wide "meplat" that if cut to 1.165" was still too long due to how the cartridges cant in the magazine - both Glock and CZ mags. This resulted in having to slice off even more bullet weight, or go through a labor-intensive process of spinning the loaded rounds to form a bit of taper - talk about WAY too much effort!
By forming the case specifically for the 9mm action, no such after-loading antics are required, AND I'm not stuck sitting here waiting for Armscor to bless me with their proprietary bullet, or "make do" with the 35 grain Vmax with noses filed flush and still seated so deep into the case necks the nose ogive looks like the photo below.

 

One more thing. In the photos you can clearly see the "556" bullet is situated further back from the rifling than the TCM bullet, however, this is only when comparing the TCM "proper". When loaded in the .22 TCM9R the bullet would sit in almost exactly the same location as the 5.56x24 bullet relative to the barrel throat and rifling. So the bullet is making no greater "jump" to the rifling with the 5.56 than with the -9R spec.
While I haven't yet done specific accuracy testing, while testing basic performance and case changes, the bullets were hitting where the sights were pointed, though paper testing is needed.

 

This is very interesting. I'm curious to see how it works out

 

My experience with my own wildcat on a tight budget tells me don't do it unless you have the money, time and patience to make version two to correct any problems with version one. My mistakes making a round for AR-15's included making the neck too short and the shoulder angle too steep in order to maximize powder capacity.

 

More testing of the 5.56x24
Ambient temperature around 55 degrees.

40 gr. Armscor bullet over 9.9 gr. Enforcer = 1,760 fps from 4.02" barrel
This is looking better - all rounds fed and ejected with empties averaging about 4 feet.
One issue is barrel length. These small capacity bottleneck .22s tend to do much better from 4.6"-5.0" barrels.

Speer 46 gr. over 9.1 gr. Enforcer = 1,612 fps from 4.02" barrel
This round chambered and ejected very well - no malfunctions at all with spent cases ejecting about 3-5 feet.

Nosler 35 gr. Varmageddon over Enforcer 10.1 gr.
For some reason the Lab Radar would not pick up this bullet! This has happened before but I thought it was the unit, but there must be something about the base of this bullet that makes doppler waves "slide around" it.

Primers from 9.9 gr. Enforcer/ 40 gr. Armscor

Primers from 9.1 gr. Enforcer / 46 gr. Speer

Primers from Enforcer 10.1 gr. / Nosler 35 gr. Varmageddon

The Winchester small pistol magnum primers seem to have rather soft cups easily deformed during seating. The primers on all these loads are quite flattened, yet the loads are mild and all other aspects of the fired cases indicated modest pressure.
Will probably swap over to CCI 550 primers.

View: https://www.youtube.com/watch?v=0s4sHXBH7BQ

 

More photos of the 5.56 x 24.

These are the most recent loads to be tested.

As can be seen in the photos the 5.56 x 24 is properly designed for a 9mm action.

The G19 is running a full-weight slide with the supplied .22 TCM recoil spring, shortened by two coils when working up TCM loads. The pistol cycles well with 5.56 x24 loads with its 4.02" barrel and full-mass slide.

Weight empty with magazine = 24.8 ounces.

Based on the shape of the Speer 40 grain JSP, and the tiny amount of exposed lead, it will penetrate hard targets better than the Armscor JHP design bullet. Upon impact with steel or aluminum, the nose will tend to deform inward thus enhancing penetration.

A solid copper bullet of the same profile would be ideal for maximum penetration.

 

Update on actual chronograph numbers.
Temperature = 54 degrees F.
A 4" barrel gives up a lot of velocity for a given powder charge. These same loads from a 5" barrel would deliver over 100 fps more velocity.
All of these loads do cycle the G19 full-mass slide with authority.

 

If I thought I had the ability to reproduce these loads, a conversion barrel would be in my cart. Keep us posted on your experiments!

 

It's actually not hard once the process if sorted out.
You start with a Lee sizing die in .223 Remington Improved, remove the lock ring and decapping pin, then slice the die body off about 1/4" below the shoulder (inside). Then slightly radius and polish the severed section.
Then cut the decapping pin all the way down to just an expander ball and position normally which means it will be visible protruding from the bottom of the sizer die, which we will now call the shoulder die. I also polished the expander ball top portion where it must pull back out of the case to prevent the neck being yanked forward.

Then, depending on your press, grind away enough of the upper portion of the shoulder die to allow it to screw down far enough in the press. Forget the lock ring, it's no longer relevant.
From this point on it's pretty easy. The shoulder die is adjusted to reform the shoulder from 23 degrees to 40 degrees without pushing the shoulder edge back - it stays at 0.720", and is easily verified by dropping size cases into the barrel chamber. As long as the shoulder edge is correct the cases will head space properly.

Since you must first, full-length size the case using a standard TCM die, the shoulder distance should already be set. It's worth ruining a few cases to experiment with pushing the shoulder back a little just to see it.
Now you have the shoulder set, but the neck is way too long. I've used two methods to address this, but basically we're now just talking trimming to length which is 0.935".

I started by shortening the body of a Lee trim die to allow the neck to protrude higher inside for the cutter to reach. Since I have the manual cutter, that was to say the least, a tedious, time-consuming process to remove several millimeters of brass, then chamfer the outside, as well as the inside.
I then modified a 5.7x28 length stud for a Lee case trimmer - easy actually. The length is simply cut and honed to a measured 0.935" from the cutter face to the tip, then a portion of the body will need to be reduced in diameter to match the pin size since the 5.56x24 case is somewhat shorter than the 5.7x28 case and the cutter will bottom out on the inside of the case. With the cutter modified, and the lock-based chucked in a drill-driver, trimming becomes much less of a chore and a large number of cases can quickly be processed. Fired cases push the shoulder forward, but after resizing, many do not require trimming which is a good indicator that the brass is not stretching, only being folded this way to that. While it's not necessary to anneal before resizing, it can't hurt, and will probably prolong brass life, however, I've already gotten 3 reloads on modified cases without a failure.
A member here sent me a supply of once-fired and I noted during sizing that a few came out with split necks. I suspect this is more a result of unrelieved stresses in the brass before the first firing, so annealing of all unknown brass is a good starting point.

So those are the tools needed to make the 5.56x24.

Once you have the tools, the process is no different than standard loading except for shoulder sizing after full-length resizing.

On the press I'm using for this project - RCBS Turret, I ended up using Blue Lock-Tite to anchor the shoulder sizer to correct depth once I was happy, because the die tends to rotate during operation. If the die isn't adjusted quite far enough, cases can come out with a slight flair just above the neck-shoulder junction. This doesn't hurt anything, but it does reduce the amount of neck length providing full grip on the bullet. The Lee sizing dies have an annoying, yet useful feature that helps get the shoulder size perfect, and that's the vent hole they have conveniently located on the shoulder portion of the die. When forming the shoulder, you KNOW it's right when the case comes out with a tiny imprint from the air vent evident on the shoulder. This doesn't hurt the case at all, but it's a good visual that you've pushed the neck-to-shoulder junction down as far as possible.

I don't bell case mouths for loading, but I do give them a good chamfer using a Lyman case prep tool which has a long-taper chamfer versus the Lee which has a short-taper chamfer, versus the RCBS which has a taper right in the middle.

Oh...one more die to modify!

The Lee seating die really sucks as it comes from the box. I don't know WHAT they were thinking when they sent this one out the door, but it looks a lot like a die nobody ever actually used to seat bullet with in the given case!

The seating stem has a small ledge that allows it to protrude very little into the die body. For this reason many have reported having difficulty seating bullets in the .22 TCM"9R" because the seating stem does not extend far enough. In fairness to Lee, MOST bullets tend to have more stick out than 3.5mm, which is Armscor's work-around for making the .22 TCM cycle through a 9mm length action. Another problem is that it's impossible to keep the bullet sitting straight in the case mouth while feeding it into the die without excessive chamfer or belling of the case mouth.

So, I pulled the seating stem, chucked it in a drill-driver, and used a Dremel to reduce it's diameter all the way up to about half-an-inch short of the top. (The actual distance doesn't matter, just as long as the tip slightly sticks out the bottom) This allows the stem to drop all the way down to just peeking out of the bottom of the seating die. This also means a bullet can be seat FLUSH with the case mouth if one so desired! Reassembled I inserted a 124gr. 9mm TC FMJ bullet into the adjusting cap as a spacer.

The way it works: When seating the bullet, position it in the case mouth, then slowly raise it and insert the nose into the small cone-shaped opening on the bottom of the steam. This stabilizes the bullet and prevents it from tipping, and it glides right on up to be seated. With this modification I've had no more ruined cases, or sheared noses on bullets.

The only thing I haven't yet done is add a Lee Factory crimp die to the mix. Of course it too will require modification by shortening the sliding crimping sleeve to match with the shorter 5.56x24 case. This means removal of 0.09" or 2.286mm for those who prefer to work with positive numbers. In my experience, Lee Crimp dies have been spotty in terms of consistency. I've had some that do a wonderful job of putting just the right crimp on, and others that the collet barely reached the case neck due to the sleeve being too long. I suspect, the 5.56x24, like the 5.7x28, will benefit a great deal from some amount of crimp. In the 5.7x28, adding a crimp can bump velocities 100-150 fps at the same powder charge, and even though the 5.56x24 requires a slower powder to reliably cycle, I'm thinking 0.002-0.003" of crimp might produce some interesting results. Does it need it...not really.

After my last round of test loads I switched from Winchester primers to CCI because the Winchester primers have softer cups and flatten out with less pressure. These last loads show expected flattening of primers, but they still have generously rounded edges. Case head expansion has proven to be generally less than 0.001" with case body expansion about 0.200" above the crimp groove being around a thousandth as well. I don't think these loads are anywhere near "maximum" in terms of pressure, but available powder space will be the limiting factor. While the "book" on the .22 TCM is around 40K psi, in reality it can easily go 15K psi more and then some. Since the round has relatively weak breech thrust by nature, we find ourselves in the enviable position of being able to push the chamber pressure without worrying about early unlocking as is the case with rounds like the .45 Super and .460 Rowland. While the latest loads have good ejection, the cases still travel little farther from the gun than about 3 feet.

What the 5.56x24 (and by inference the .22 TCM) really needs is more barrel length to take advantage of those slow-burning powders.

Add just an inch and bullet speeds jump by over 100 fps. Add two inches and the results are even more impressive, and this is where the 5.56x24 can really beat the 5.7x28! The 5.7x28 works best with faster powders, so adding another two inches of barrel doesn't benefit it as much as the 5.56x24, and the 5.56x24 has a much stronger head/web with full support versus the 5.7x28 which has no case support for the last few millimeters that sticks out of the barrel, though 5.7 cases ARE very thick-walled at that location.

 

Hello do you sell the .223 improved die by any chance?

 

 

This turns out to be a very consistent and potent load from the G19. It feeds well, and cycles the slide with authority. The only downside is that a 4" barrel is too short to extract the best velocity from the 5.56x24 (or .22 TCM9R) though 1,768 fps / 319 fpe isn't exactly terrible.
This load clocked 1,866 fps / 356 fpe from the 4.53" TCM9R barrel in the CZ75.

Note the flattened primers with evidence of blanking on the shells taken from the TCM9R barrel in the CZ. This has been a consistent finding with this barrel and I suspect the cause is an undersized chamber due to an electroless plating that is also very rough, causing cases to become stuck. The same loads have never stuck in the Glock TCM9R chamber from the same company, however the Glock barrel is not plated, and the chamber appears much smoother.
Fired cases from the "CZ" chamber are very rough with imprint pitting.
Since this test the CZ chamber has been honed and polished and awaits further testing.

 

The G19 started as a fresh Poly80 build so I started testing "TCM" loads at the same time I started testing the new build. Original TCM9R loads had trouble with the full-mass slide and Armscor spring, so I cut a few coils to lighten the load.
Between that test and the next I shifted from the .22 TCM9R cartridge profile to the 5.56x24 Rowell, and subsequent testing produced full cycling though a bit weak with failure to lock back or consistently eject (full mass slide).
The first level of powder bump solved the cycling issue, but the G19 still had a problem with the slide remaining fully locked while the trigger was being pulled. The striker spring force caused the slide to be pulled back just enough to result in weak strikes and failed ignition. I chose to focus first on load development, then worry about refining the gun.
My last test with different bullets, powder, and charges went well, so I have now shifted to getting the Glock system dialed in. To counter the slide closure problem I borrowed an idea from my Rowland work and added a short section of standard weight, round wire recoil spring about .75" long inserted on the non-captive guide rod first, with the Armscor supplied TCM spring added. The slide now cycles as cleanly as before, but with more positive "snap" into battery and no pull-back induced by trigger pull.
The 22 ounce G19 with a 15, or 17 round magazine is likely to become a viable carry option after a few more tests. The gun is a lot smaller than the FiveseveN, about the same weight, and delivers comparable or better velocity - especially with the Speer 46 grain JFP.

 

I may have missed it earlier but where did you get the barrel?

 

With a BC of just 0.094, the Speer 46gr JFP still shows some interesting trajectory numbers compared to Speer GDHP in 9mm.

The Speer 46 gr (BC 0.094):
10 yards = "0"
50 yards = +0.7"
71 yards = "0"
100 yards = -2.3"
150 yards = -11.3"
The bullet is supersonic out to 110 yards, going transonic at 70yards (0.137 sec) out.

The 9mm 124gr GDHP (BC 0.134):
10 yards = "0"
50 yards = -0.9"
100 yards = -9.2"
150 yards = -26.6"
Starting at 1,150 fps, this bullet is just supersonic and mid-transonic from the muzzle to 150 yards.

 

The more common load for the 5.56x24 is the Speer 40 grain spire point with a BC of 0.144 at a measured 2,015 fps versus 9mm 124 grain GDHP at 1,150 fps.

5.56x24 40 gr. SP........ 9mm 124 gr. GDHP
10 yards = "0" ........... 10 yards = "0"
60 yards = +1"........... 60 yards = -1.8"
100 yards = -0.2"........ 100 yards = -9.2"
140 yards = -3.8"........ 140 yards = -22.4"
180 yards = -10.1"....... 180 yards = -42"

The 5.56x24 MTL = 0.4 MOA
The 9mm MTL = 1.3 MOA
MTL = muzzle-target-line

The 5.56x24 is supersonic out to 225 yards, going transonic around 155 yards.
The 9mm is supersonic to around 10 yards, then subsonic.

At 150 yards the 5.56x24 is delivering velocity and energy equal to the .22 Magnum at the muzzle - fired from the same length barrel.