Review - M*CARBO KEL-TEC P-11 Trigger Spring Kit
by Kirk Lawson

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[The M*CARBO Kel Tec P11 Trigger Spring Kit]

As I wrote in my previous article, one of the Kel Tec P11's most notable shortcomings is its very long, quite heavy, and remarkably uncomfortable, Double Action Only (DAO), trigger pull. In my effort to improve and upgrade the budget friendly P11, I installed a Trigger Spring Kit from M*CARBO. Currently selling for $19.95, M*CARBO claims that it reduces trigger pull weight by "nearly 50%." If it even came close to that, it would help tame my P11 and make it a far more comfortable, accurate, and therefore safer, shooting handgun. My P11 had a trigger pull weight which I measured at 10.12 pounds using the hanging weights method. If I could get this down to 7-ish pounds, I would be happy. So, once again, the cost was deducted from my card and a few days later a package arrived at my doorstep. While I was waiting, M*CARBO sent me a few emails confirming my purchase, inviting me to their forums, engaging in some internal remarketing by extolling their virtues, and promising a "gift" in the package. Well, I was intrigued.

The package contained the promised Hammer Spring, Trigger Spring, and Firing Pin Spring. It also did include a free gift; stickers, a discount coupon, and a welcome letter. I think the stickers are kind of neat and who doesn't like a discount coupon for more product?

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[Welcome! Here's a coupon and some stickers.]

I installed the spring kit at the same time that I installed my new trigger. All of the M*CARBO springs are a drop-in replacement with no fitting appearing to be required. The Trigger Spring fit perfectly with the RTK trigger just as the OEM Trigger Spring would have.

To replace the Firing Pin Spring, the Firing Pin Screw, a inset hex set screw, on top of the slide must be removed. Do this in a clear 1-Gallon Ziplock bag. The Firing Pin Spring keeps the Firing Pin under spring pressure and when the screw is removed, the Firing Pin will shoot out. If there is nothing to stop it, such as the palm of your hand (ow) or a clear plastic bag, then it will be launched to parts unknown. Installing the replacement spring is a reverse of the process. However, the Firing Pin must be depressed, compressing the Firing Pin Spring, and then the Firing Pin Screw must be screwed in. Again, do this inside the bag. If whatever is being used to depress the Firing Pin slips off before the set screw is far enough in, then, yes Virginia, the Firing Pin will be launched to parts unknown. Ask me how I know. Some people recommend that the Firing Pin Screw be set in with Blue Locktite but I have not found that to be necessary.

When I attempted to change the Hammer Spring, I could not drive out the roll pin ("Hammer Pin" part #276) from the Hammer. At all. It is completely frozen in. It still is. No matter how I tapped, vibrated, hammered, or whacked, the pin is in there. It is possible that someone might have Red Lock-tite-ed it at some point in its history; this P11 is a pre-owned gun. I eventually had to pop the OEM Hammer Spring off of the pin. To put the M*CARBO spring on, I had to spread the eye then squeeze it back again. When I reassembled the gun, I realized that I'd left out the Hammer Pivot Pin. <sigh> Back it out, do it again.

To ensure function, tested with snap caps, then I took some empty 9mm cases and seated Small Rifle Primers into them because Small Rifle Primers are known to be thicker cups and require more force to set off. The new hammer spring set all of them off no problems.

Of course, I immediately had to test the new trigger pull weight. While the pulling the trigger felt a lot more comfortable, the pull weight still seemed heavy. When I checked the pull weight using the same hanging-free-weight (bucket o' lead) method as before, I found that the trigger pull had reduced from 10.13 lbs to 10 lbs. WHAT THE HECK? I contacted M*CARBO to see if I made a mistake in installation or if I ordered the wrong part. M*CARBO assured me that I ordered the correct parts. They recommend a 200 shot break in period because the spring were not broken in. Honestly, I had my doubts that a break in would reduce the trigger pull by 3 pounds but I was willing to dry fire a bunch. I'll install a snap cap and/or my laser marking cartridge and run a bunch of drills. 200 rounds is only 4 boxes of ammo. The dry fire did exactly what the tech had hoped. I dry fired 500 times on a snap cap, racked the slide over the hammer 200 times (which expands the spring), and ran about a hundred to 150 laser marker drills. The trigger pull weight now measures between 5.15 and 5.17 lbs. The tech told me that usually the suggest live fire because of the speed at which the springs are moved. Nevertheless, the dry fire worked to break in the springs. A 5.12 pound trigger pull weight on a Kel Tec P11 is nothing short of amazing.

I took the gun to the range that Friday to see how it would perform. I took 3 kinds of ammo:
  • Hand loaded Hard Cast, Coated, 125 gr. Truncated Cone, over a moderate charge of TiteGroup with CCI primers (known to be "hard")
  • 124 gr. Winchester Super-X "Winclean" Jacketed Truncated Cone
  • 115 gr. Armscor FMJ "ball"
I ran the mag of hand loaded 125 gr. HC TC first. 12 rounds in one end, 12 rounds out the other end. All went bang. The M*CARBO spring set is clearly up to setting off the CCI "hard" primers and thicker cup rifle primers. Next the Winchester. 3 rounds in and I got a dead trigger. No reset. OK, I'm guessing that my gun had heated up and expanded the pre-travel screw was stopping it from resetting. I did some at-the-range pocket knife gunsmithing, worked it a few times and eventually got the trigger to reset. Two more 124 gr. Winchester TC's down range and slack trigger again. Nuts. I guess my gun really really doesn't like 124 gr. Jacketed TC. OK, so switch to the 115 gr. Armscor. 1 round down the pipe and more slack trigger.

It was clear at that point that the Trigger Spring had popped out of the groove in the Link Bar. I took the gun home took it apart, and reseated the Trigger Spring in the groove of the Trigger Bar. Saturday, I took it back to the range for more testing to see if the Trigger Spring popping out was a rare fluke or if there was a deeper issue with my gun.

I took the same mix of ammo and it all ran flawlessly.

Among other tests, I ran the NRA Pistol Instructor test with the gun. Using the P11 with the M*CARBO P11 Spring Kit and the RTK Short Stroke Trigger, I scored 90% with the hand-loaded 125gr HC TC, a crappy 60% with the 124gr Winchester SuperX TC Jacketed, and 100% with the 115gr Armscor.

The trigger is still very long, despite being vastly more comfortable and 50% lighter. Combined with the well known recoil of the P11, I had to work very hard to shoot the score. I can be accurate with it but it is much more challenging than with a larger handgun.

Still, I consider it to be a huge improvement and, because it proved "reliable" in my second trip to the range, I consider it good to carry now. The sights still need improvement, however.

Bottom line, would I recommend the M*CARBO Spring Kit? Yes, unequivocally yes.