M*CARBO Brotherhood

Light Primer Strike On My S2K

Had my second trip to a gun range with S2K, fired 100 rounds and had two misfires. No Bang, just click. Primers had indentations, not very deep. Two different types of ammo, some reloads and Blazer Brass.

On my first trip I fired about 70 rounds, no issues. I installed internal upgrades between trips, but I can’t be sure if this is the reason (not enough shooting the gun before to be certain it worked 100%).

I do recall that someone mentioned light strikes with MCARBO hammer spring on Facebook group page. The issue was resolved by installing factory spring back. But since it’s a bit of pain to open up S2K, I wanted to explore other options first.

I’m new to guns, so maybe I’m missing something obvious here.



That person had a mangled hammer spring and that’s why reinstalling the factory one fixed the problem. Chris/M*CARBO would replace that for free, no problem, if he hasn’t already. Although rare, anything can happen in manufacturing from any company. There’s also no way to know if that person installed the spring incorrectly, which might have mangled it in the first place. They fessed up to having poor eyesight when I specifically asked how they missed such an obvious defect when first installing it.

Are you running the stock hammer spring? If so, you’ll probably have to send it back to Kel-Tec or take it apart yourself and inspect that spring. They’ll most likely send you a replacement for free. If you have to buy a new one and don’t already have it, get the M*CARBO spring kit. I have many, many rounds through my SUB2000 on their spring kit without one single issue.


I have MCARBO spring installed. And I will not be surprised to find that I did something wrong during installation.

Will open up my gun and take a look. But maybe a bit later, when trigger bar will be available.


Smart idea to wait for the trigger bar as it’s a seriously good upgrade (I got to test a prototype one and it’s definitely worth buying), especially if the reliability issues aren’t really enough of a concern for you right now to open it up. I know I hate taking the thing apart. LOL

When you do open it up, compare it very carefully with pictures of what it’s supposed to look like. There is a “split” part in the spring and you do have to pay attention to its orientation when the spring is installed. Chris made an awesome, detailed video on how to install everything M*CARBO and he goes over this clearly, so it’s easy to follow. I’ve had mine all apart twice and got it back together correctly both times on the first try by following that exact same video. :+1:


@Teddy_the_Beer I’ve had a light primer strike here and there myself. Shot about 200 rounds in competition the other day and had 2 light strike F2F in first 40 rounds and none the rest of the day. I’m gonna keep shooting until I call it a problem.


But speaking of springs, is there a recommended round count for MCARBO spring replacement?


Not that I’ve seen. I don’t ever recall seeing a round count interval for a replacement hammer spring for any firearm. Replace it preemptively or just shoot it until it breaks, I guess. LOL


Ive run roughly 1k rounds thru mine with various ammo since installing the trigger springs and have had zero issues. Like you mentioned though it was just 2 out of 100, or 2%, so if you do plan on installing the trigger bar id wait. Just dont trust the weapon with your life for now.


Yeah, that’s my plan, I guess. 2% failure is annoying, but not critical for a ‘gun for fun’. But in ‘shit happens’ kind of scenario that will not do.

I’m a bit puzzled though - if after opening my gun I’ll understand that the spring is to blame, what do I do? Ask for replacement and wait with the gun in pieces, or put in factory one and call it a day?


I’d ask for a replacement from M*CARBO. Their shipping is fast. I get stuff in three days here in Utah and they’re in Florida. But, if you want to install the factory spring, I see no problem there, either. Between the two springs functioning correctly, I seriously doubt anyone could tell the difference anyway.


I figure if you’re going to wait on the trigger bar i would contact McCarbo and see if they’ll send you a replacement along with the bar. If not i guess you could order the springs along with the trigger bar so you have everything all at once. Never a bad idea to have backup springs anyway.


When I will take the gun apart, I will do all kinds of pics!


@Teddy_the_Beer You didn’t mention in earlier posts if you tried to fire those rounds again to see if you had a “hard or dead” primer. Also if the primer is not flush or slightly below the pocket, the firing pin has drive the primer farther inward to seat it and it may not crush the primer anvil thereby giving a light strike.


Donald, I’m somewhat new to guns so I wasn’t sure what to do with misfired cartridges. So I just put them aside. I will probably try to shoot them on my next trip to the range.

With first one (reloaded) I did think that the primer is a bit too deep, but when the Blazer Brass one misfired 5 minutes later I wasn’t so sure anymore.


I’d try them in another gun you know and trust.


It would be hard to fit into my 10/22 :joy:

I only have 2 guns for now, and a hand gun is not in my short shopping list, so S2K is the only gun I can use to fire those cartridges.


Not sure what caliber yours is, but everyone needs a companion pistol that uses the same mags as their SUB2000. It’s the obvious choice. A ton of us had the pistol(s) first and that was a large deciding factor for getting a SUB2000. I know it was for me. :+1:


@Teddy_the_Beer Anytime you have a misfire with any weapon, please wait at least 1 minute before extracting it . It’s possible to have a hang fire round where the powder is still attempting to ignite. Everyone is new to guns at some point, just be safe.


I have 9mil Glock version.

It makes total sense to get a handgun that will use same mags, but there is a little catch here. :canada:

I can legally fold my S2K, put it into back pack and go anywhere, say if we have an earthquake and have to evacuate. I can even carry it openly, and RCMP will totally give me a pass once I will wash tear agent from my eyes and explain that I have a license and carry my gun legally.

I can’t legally carry a handgun. I can only take it to a gun range, and it has to be in a locked case with a trigger lock. So it will only became useful if no one cares about laws anymore. Which can happen, but I think it makes sense to cover other bases first, especially on a budget.

So no handguns in a near future.

Sorry for off-topic!


Ah, that sucks. Didn’t realize you were in Canada.