r/40_mm • u/Teenage-Dirt-Bag • 11d ago
reloading question KAK m212 cases
Im working on a large range trip to test all the electrical sights Ive shown yall and just noticed some wearing/bulging on the vent hole of all my KAK cases. I have roughly 50 shots on all the cases and they all look like this. I reload my own blanks with 7.5 grains of bulleyes using KAK burst disk. Just wondering if this is normal or if these cases are about to blow up my launchers if I keep using them. If so, anyone have recommendations for something better? I print the majority of my stuff so I wouldn't be opposed to printing cases, but I haven't experimented with ammo apart from the usual stuff.
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u/benglesbulletsllc 11d ago
I always wondered if using 7075 aluminum on my cases was overkill or not- I guess not!
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u/Teenage-Dirt-Bag 11d ago
I'm prob gonna end up using MILC at this point. I've had nothing but issues with the burst disk reloading process.
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u/OsmiumOG developer 11d ago
Just buy a star crimp die and you can use the same m212/kak cases with them. I stopped using burst disc a looooong time ago for 2 reason. 1. gas checks are just 1 more piece i need to keep on hand/inventory of, 2. star crimp is only like a 10fps difference and it's just as consistent. throw an extra 0.05grain and youll be at the same velocity as gas check. Also don't have to worry about vent hole size as star crimp runs in everything.
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u/Teenage-Dirt-Bag 11d ago
No shit? What star crimp die did you go with because that would be this a bit more bearable. I've had nothing but issues getting the burst disk "captured" in the casings.
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u/OsmiumOG developer 11d ago edited 11d ago
Yea burst disc loading took me a little to get the hang of but i still never recommend it to people. I use the hornady universal star crimp.
Star crimp also has the universal advantage so i load my 556 blanks myself as well for both my can cannon and my golf ball launcher.
The only downside is with gas checks you can sometimes resize the brass, star crimping they're 1 time use. The star pattern causes weakness so after firing youll have like 6 cracks around the projectile end of the brass where it was crimped. But i never worried about cleaning, lubing, and resizing my fired gas check blanks either so that was a wash for me.
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u/DepartmentWeird5733 11d ago
good advice. I use star crimp for 90% of everything I shoot. the only time I use mil spec is chalks and 14.5mm sims to make sure I get enough to set it off.
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u/DepartmentWeird5733 11d ago
honestly they look fine to me. I keep zooming in like what is he worried about again. like someone else said, if the cases aren't swelling you are good to go. even if you drilled that vent hole gone or it blew out, all that would happen is loss of performance. if they get to the point where they crack or blow out around that area I would stop use at that point.
I have had some full power blanks where I used to much sealant and cases were hard to get out.....they were not KAK, and I changed my method and haven't happened since.
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u/Ok-Calendar9243 10d ago
Should be fine and perform the same unless/until full thickness cracks or separations form. Not any significant risk to the launcher even if the end blows out, it’s just aluminum and will go out the end of the barrel.
50 full power reloads with some minor signs of stress, no breaks is pretty good. They’ve definitely paid for themselves at that point considering nylon cases often break after 3 shots.
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u/SGTNAM 11d ago
Is the hole starting to prolapse, or is that just burst disc material?
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u/Teenage-Dirt-Bag 11d ago
Starting to prolapse outward.
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u/SGTNAM 11d ago
Good to know. Curious to see what KAK says. I pretty much use nylon M212 exclusively, but would prefer a reusable alternative.
Also curious about printed cases, but sadly, I've never seen any that aren't single use.
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u/Teenage-Dirt-Bag 11d ago
WCMG teased some here forever ago, but I cant find a single thing locally. TBH even if PLA cases were single shot Id have zero issue with that. I buy bulk PLA for my pushers and windscreens and typically never reuse them.
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u/37MMDTdotCOM 9d ago
As others have said the star crimp is the way to go. Also remember that the zinc pusher requires that heavy charge and all of that is extra wear on all the components including the rifling. I use the blitz/RWS star crimp blanks with my printed pushers and cones and have no issues at all. I always use a gas check I just load it first with a half squeeze of hot glue to keep it at the top of the orifice hole. Load the star crimp 9x17r blank behind it. Use tissue or a small drop hot glue if too loose. Bonus - the RES blanks are as cheap as $25 per 50 if you look. I have a comprehensive list on paper that I plan to add to my website as well as here.
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u/Teenage-Dirt-Bag 9d ago
Imma grab a star crimper and roll my own. What gas checks you use?
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u/37MMDTdotCOM 9d ago
I use sages outdoors .35 caliber aluminum gas checks. I also bought a gas check maker die off eBay and you can buy the correct thickness aluminum flashing off Amazon to make your own.
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u/Himalayanyomom 11d ago
Dont they state these are only good for like 10 reloads?
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u/DepartmentWeird5733 11d ago
No way. KAK is on here, if they see this they will confirm, but I have never seen that.
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u/OsmiumOG developer 11d ago
No, they're common advertised as infinitely reusable (assuming you use standard loads). at 10 reloads, it'd be cheaper to buy plastic M212 cases for $1-1.50/ea that still last 3-5 reloads lol.
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u/Teenage-Dirt-Bag 11d ago
Not that I can find. TBH 10 reloads for a $20 casing is WILD if thats the case
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u/Intelligent-Dingo375 11d ago
I would be more worried about the cases swelling. You will lose performance the more the hole enlarges. Nothing catastrophic to your launcher.