Any idea if these abominations are found in other calibers, like .45 or .380?Most people remember that aluminum cases are bad for SMGs.
Brass cases and also be a problem of they have a step inside the case.
Any brass that has a step in the case is dangerous for all guns but especially fixed firing pin 9mm SMGs. Once the top half of the case is left in the chamber, all following rounds OOB.
Known headstamps like FM, IMT, Maxxtech, and Ammoload use stepped brass.
Evil Stepped 9mm Case is Back! MAXXTech
Buyers and Reloaders B.O.L.O. MAXXTech is using the stepped 9mm cases now like FM and Ammoload. This stuff will leave a ring in the chamber causing OOBD with open bolt SMG. Beware.www.uzitalk.com
MAC 11 conversion to .22TCM?
- Thread starter Slowmo
- Start date
Well first test results are in on the KAK 22TCM barrel and unfortunately they are not great.
The first 10 or so rounds had really odd behavior in that the rounds would not even eject. At first I had the full sized CF tungsten bolt in the gun and the first two shots the rounds were so stuck in the chamber to the point where they had to be hammered out with a cleaning rod.
I switched to the lighter OEM steel bolt and things improved but ejection was really anemic (barely dribbling out of the ejection port) and I was getting sporadic FTE behavior. I probably had about a dozen rounds down the barrel when I decided to go and clean the chamber with cleaning brush, followed by a couple strokes of a 22 cleaning brush, followed by some hoppes patches to see if that would help.
After a bit of barrel cleaning the steel bolt and barrel started to work better but over maybe another 25 rounds the rate of fire sped up to what I would guess was starting to approach 2000rpm. It felt like there was a Mac Jack block installed in the gun when running 9mm, throwing brass really far, and it quickly got to the point where primers also started distending and/or popping out of the cases. Reliability to feed was also not good with many FTFs resulting in both cases and/or the nose of the projectile getting a bit mangled in the process. I saw some minor neck swelling as well but nothing like the posts above and no case separations, etc.
However, after a couple primers fully unseating themselves I called it a day for the steel bolt and switched back to the full size tungsten CF bolt to continue testing.
The CF full size tungsten bolt stopped the primers from distending or completely unseating themselves and the case necks looked just fine out but my shot timer clocked the rate of fire between 1100 and 1200rpm.
It felt speed wise almost identical to shooting the 9mm gun with the steel bolt but more of a recoil impulse given its 1100ish RPM with a 2.5X weighted tungsten bolt going back and forth and which is clearly impacting the rear of the receiver. I also had a lot of failure to feed issues with cases getting mangled or the bullet nose jamming into the edge of the barrel. Overall from a feed perspective Zytel mags worked much better than ZMags, but even the Zytels were spotty. The Recon Ordnance PAM-2 mags were just a complete no-go as every round ended up getting driven into the top edge of the barrel. I do plan to may try and tweak some Zmags or Recon mags feed lips to see if I can get the feed angle a bit better and resolve the FTF issues.
My takeaway is that the barrel out of the box must be really rough on the interior of the chamber and that was initially keep the rounds from ejecting and they would expand and glue themselves to the rough chamber interior. As the rough park or coating, etc. was worn in and smoothed out the ROF then sped up dramatically.
IMHO, the OEM steel bolt doesn't appear to have enough mass to safely shoot this cartridge in an open bolt SMG. Maybe in a semi with the weight and spring of the hammer it works OK. However, it appears at a minimum it looks you need the full size CF tungsten bolt and even then I am skeptical on the wear and tear on your receiver with a full sized tungsten bolt going back and forth at 1100rpm. Given the number of failure to feed issues you are also probably risking an out of battery at some point if/when the firing pin finds itself into the primer with the round not fully chambered.
I plan to do a bit more testing at the range later this month as I still have a decent amount of ammo. However I want to put one of the softer/thicker Lage neoprene style buffers behind the full size CF tungsten bolt vs. the thin rubber one I have in there now given the recoil impulse. I also still want to try the Tungsten A bolt with a really nice thick buffer to protect the receiver. I also ran out of time to chrono anything but will try and get that done as well.
At this point unless you want something to troubleshoot or tinker with, I would be hard to recommend buying one of these barrels and expecting it to run out of the box.
Hope this helps
The first 10 or so rounds had really odd behavior in that the rounds would not even eject. At first I had the full sized CF tungsten bolt in the gun and the first two shots the rounds were so stuck in the chamber to the point where they had to be hammered out with a cleaning rod.
I switched to the lighter OEM steel bolt and things improved but ejection was really anemic (barely dribbling out of the ejection port) and I was getting sporadic FTE behavior. I probably had about a dozen rounds down the barrel when I decided to go and clean the chamber with cleaning brush, followed by a couple strokes of a 22 cleaning brush, followed by some hoppes patches to see if that would help.
After a bit of barrel cleaning the steel bolt and barrel started to work better but over maybe another 25 rounds the rate of fire sped up to what I would guess was starting to approach 2000rpm. It felt like there was a Mac Jack block installed in the gun when running 9mm, throwing brass really far, and it quickly got to the point where primers also started distending and/or popping out of the cases. Reliability to feed was also not good with many FTFs resulting in both cases and/or the nose of the projectile getting a bit mangled in the process. I saw some minor neck swelling as well but nothing like the posts above and no case separations, etc.
However, after a couple primers fully unseating themselves I called it a day for the steel bolt and switched back to the full size tungsten CF bolt to continue testing.
The CF full size tungsten bolt stopped the primers from distending or completely unseating themselves and the case necks looked just fine out but my shot timer clocked the rate of fire between 1100 and 1200rpm.
It felt speed wise almost identical to shooting the 9mm gun with the steel bolt but more of a recoil impulse given its 1100ish RPM with a 2.5X weighted tungsten bolt going back and forth and which is clearly impacting the rear of the receiver. I also had a lot of failure to feed issues with cases getting mangled or the bullet nose jamming into the edge of the barrel. Overall from a feed perspective Zytel mags worked much better than ZMags, but even the Zytels were spotty. The Recon Ordnance PAM-2 mags were just a complete no-go as every round ended up getting driven into the top edge of the barrel. I do plan to may try and tweak some Zmags or Recon mags feed lips to see if I can get the feed angle a bit better and resolve the FTF issues.
My takeaway is that the barrel out of the box must be really rough on the interior of the chamber and that was initially keep the rounds from ejecting and they would expand and glue themselves to the rough chamber interior. As the rough park or coating, etc. was worn in and smoothed out the ROF then sped up dramatically.
IMHO, the OEM steel bolt doesn't appear to have enough mass to safely shoot this cartridge in an open bolt SMG. Maybe in a semi with the weight and spring of the hammer it works OK. However, it appears at a minimum it looks you need the full size CF tungsten bolt and even then I am skeptical on the wear and tear on your receiver with a full sized tungsten bolt going back and forth at 1100rpm. Given the number of failure to feed issues you are also probably risking an out of battery at some point if/when the firing pin finds itself into the primer with the round not fully chambered.
I plan to do a bit more testing at the range later this month as I still have a decent amount of ammo. However I want to put one of the softer/thicker Lage neoprene style buffers behind the full size CF tungsten bolt vs. the thin rubber one I have in there now given the recoil impulse. I also still want to try the Tungsten A bolt with a really nice thick buffer to protect the receiver. I also ran out of time to chrono anything but will try and get that done as well.
At this point unless you want something to troubleshoot or tinker with, I would be hard to recommend buying one of these barrels and expecting it to run out of the box.
Hope this helps
This is what many people are reporting with the newer RI 1911 22TCM pistols. It may need a break in period. My barrel did, I remember needing to polish the chamber. it was not shinny when new.
The primer problem says it all.
This is helpful information. Good job. I think you should report your result to KAK.
Last edited:
A&S Conversions
UZI Talk Life Member
Have you considered using the factory recoil spring with the full size M11/NINE sized CF(W) bolt? That might ease up on the pounding that the rear of the receiver would experience. If you are already experiencing that high a cyclic rate with the full size tungsten bolt, I would not use the A1 tungsten bolt. I would think that just like in 9mm, the A1 bolt would have an even higher cyclic rate.
Scott
Scott
A&S Conversions
UZI Talk Life Member
Previously posted the energy level was around 2.5 times that of 9mm. I looked up the round and I found this listing:
At that level of energy, it seems to me that that level of energy is way too much for the M11/NINE open bolt subgun system. I don't think that much energy can be handled by the factory blowback system. I would think that an upper like the Lage or S.A.B.R.E. gas operated AR system would be a much better fit. Good luck with the project.
Scott
| 40 gr (3 g) Pointed flat nose | 2,800 ft/s | 696 ft⋅lbf |
At that level of energy, it seems to me that that level of energy is way too much for the M11/NINE open bolt subgun system. I don't think that much energy can be handled by the factory blowback system. I would think that an upper like the Lage or S.A.B.R.E. gas operated AR system would be a much better fit. Good luck with the project.
Scott
Is it dictated by energy, momentum, or something else? While the bullet has more energy, the bullet has less momentum than a 9mm (no idea about powder charge for the TCM). That bullet has about the same momentum as a 115gr bullet going 975fps, which would be a weak 9mm load.
I have actually considered putting a stronger recoil spring on the CF bolt along with a softer/thicker buffer. I have those parts on my standard steel bolt and just need to swap the spring and buffer from my OEM steel bolt over to the full size CF bolt.
I suspect the A bolt would be an even high cyclic rate than the full size unit but there is a lot more room for a big squishy buffer behind the A bolt.
At the end of the day you may very well be right that its just a bridge too far in an open bolt SMG system like an M11/9.
Once upon a time I became briefly interested in the 5.7x28 and researched reloading for it. Apparently those cases have a special coating or lacquer of some sort that I believe is meant to aid in extraction. I wonder if something could be going on where the front of the case is still gripping the chamber walls while the thicker rear web and case head are stretching backwards. Might explain the primers popping out.
A&S Conversions
UZI Talk Life Member
Most 9mm that I am familiar with usually listed as having 350 to 400 ft/lbs of energy from the manufacturer. The the ammunition specs that I posted above have almost 700 ft/lbs of energy. I don't know how you are getting momentum. My understanding is Force = Mass X Velocity. Hence the energy is listed in foot/ pounds. Having double the force (energy at the muzzle) of standard 115 grain 9X19, a standard steel OEM M11/NINE bolt is just over one pound of mass. The full sized CF(W) bolt is somewhat over two pounds. So I would imagine that for the ammo that I listed with a standard recoil spring in a CF(W) bolt, I would think that the cyclic rate would be around that of the factory 9mm configuration. The only downside would be that the receiver (and the shooter holding that receiver) would be dealing with about double the energy of the factory configuration. To me the factory configuration is quite a handful. Double that energy dumped in the same amount of time, sounds like it would be difficult to control. YMMV.
Scott
Gaujo
UZI Talk Supporter
Ok solid I'll pick up some Ameriflage. Otherwise looks like I was doing it right.
I usually hand it to the stranger next to me at the range and say, "Want to try?"
Mass x velocity is momentum, not force. Force is mass x acceleration. Force x time is impulse, which results in/interchanges with momentum. Energy is 0.5 x mass x velocity^2.
When a force acts upon two bodies to propel them in opposite directions from one another (imagine a round detonating in space and propelling the case opposite from the bullet and powder) momentum in each direction is equivalent. Energy is not. The lighter body will have more energy while the heavier body will have less energy. That’s why a shooter can fire a bullet with 1000fpe while the shooter is not subjected to 1000fpe of recoil energy. But in a simple system like a bolt action, the momentum of the ejecta (bullet and gas/unburned powder) coming out the muzzle is equivalent to the momentum of the recoiling rifle.
My point is that the TCM actually has less momentum than a 9mm. If you imagined that same imaginary explosion in space between a TCM round and a bolt vs a 9mm round and a bolt (ignore that there is no barrel to build velocity), the TCM should produce lower bolt velocity because it has less momentum. In the real world, I’m not sure how that all plays out with friction, such as between the case and the chamber walls resisting rearward travel, etc.
StenAtopia
Well-known member
12ga?
A&S Conversions
UZI Talk Life Member
Sorry that I didn't look up the formulas. I should have. So I won't get in the weeds with the science, my understanding of ammunition is that to express the power of a round of ammunition, most manufacturers list the foot/pounds of energy at the muzzle of various types of barrel lengths for the application. It is my understanding that pistol calibers have their energy measured at the muzzle of a five inch barrel.
You state above that "My point is that the TCM actually has less momentum than a 9mm." I have certainly seen where 230 grain .45 ACP ball ammunition knocks down a steel target with much more authority than a 115 grain ball 9mm ammunition. Both rounds have around 350 ft/lbs of energy at the muzzle depending on the manufacturer. I have also seen 5.7X28 27 grain ammunition, that is also listed around 350 ft/lbs, need to have a burst of three to four rounds to knock down the same steel target. So by your calculations, TCM has lower momentum. I will give you that. With a 40 grain bullet at 2,800 ft/sec equals 112,000 and 9mm 115 grain at 1180 ft/sec equals 135,700. Since 112,000 is a lower number, it certainly seems that TCM has less momentum. But by using the same calculations, a 55 grain bullet going 3,000 ft/sec (5.56X45 NATO) equals 165,000. And 230 grain .45 ACP at 830 ft/sec equals 190,900. In my book, .45 ACP has no where near the power of 5.56X45 NATO.
Certainly momentum would be a good indicator of how well a round would impart energy to a steel target to knock it down. But momentum doesn't seem like a good way to judge the power of a round. I would imagine that is why ft/lbs of energy at the muzzle is how ammunition manufacturers use ft/lbs as an indication of the relative power of each round. A .45 ACP round at around 350 ft/lbs is no where near the power of 5.56X45 NATO at around 1,200 ft lbs. So TCM listed above at 796 ft/lbs seems like it has twice the power of 115 grain 9mm at 350 ft/lbs. YMMV.
Scott
Please Visit our Sister Sites Below
Please consider becoming an UZI Talk Supporter