M*CARBO Brotherhood

SUB-2000 - Hammer not locking back after pro trigger bundle upgrade SOLVED!

Ok Brotherhood - just finished “carefully” installing MCARBO SUB-2000 All In One Pro Performance Trigger Job Bundle. I’ve watched the video intently and paid attention to as much detail as possible. All parts seem to be aligned and seated properly. When I get to the point of using the small punch and wood dowel to set the hammer back, the video suggests it should “click” but that not happening. I’ve tried numerous ways, looked at each part in detail, assured all parts are seated properly and functioning according to the video instructions but I can’t get the hammer to lock back via the sear or whatever is supposed to lock it back in place. Any ideas or suggestions would be appreciated.

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@PNWmultisport welcome to the forum im sure someone here will answer your question

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Everything in the picture looks correct. Can you lock the hammer back while the grip is off? It’s a real long push with the dowel, the hammer has to rotate about 120º, maybe you haven’t gone far enough back and pushed downward at the same time?

That’s always been a PITA - I always engage the safety when I have the bolt out so the trigger doesn’t accidentally get pulled and I have to go through resetting the hammer again.

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Thanks for the reply! Yes, I’ve been trying to get the hammer to lock back without the grip assembled using my hands to hold everything in place. What’s odd to me is the hammer doesn’t seem to have any reasonable surface/notch/edge to be held by the sear securely. I’m certain it’s oriented properly, just can’t get it to catch. The hammer spring is what’s stopping the hammer from going back any further (catching on the buffer tube) than it does - it appears to be oriented properly… I think I’ll try again with the factory hammer spring.

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Try it without the hammer spring or trigger bar. That should show you how the hammer should sit when cocked - it should catch with the hammer face near horizontal or the bolt wouldn’t slide over it. The surface the sear catches on is on the bottom of the hammer, not the side. The hammer spring should not touch the tube.

I still think you just haven’t pushed the hammer back far enough and down with the dowel for the sear to engage it. If you have a long screwdrive, you could try that since you have a lot more leeway to push down on the hammer. While you still have the grips apart, push the dowel in to better see the path it needs to take.

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Thanks @phuzzy42, It was indeed the MCARO hammer spring. Visually it looks the same as the factory spring but its just wide enough at the “U” point that wraps around the hammer to catch on the buffer tube and not go back far enough to engage with the sear. I tried the original factory spring and even gave it a careful pinch to increase the tolerance inside the buffer tube - works great. I’ll reach out to the folks at MCARBO about the hammer spring tolerances.

Now that I have the necessary clearance, the mechanics of the trigger system, hammer, sear and springs all make perfect sense. I’m glad to have worked through this as I’m far more intimate with the workings of the firearm.

So now I’ve done the following MCARBO upgrades: Trigger upgrade kit (guard, curved trigger, springs), polished stainless feed ramp, buffer ring, buffer tube cover, stainless bolt kit, peephole sight, recharge handle bumper, grip-wrap and Magpul foregrip. Next up: Optic mount, red dot, muzzle break and possible sling setup.

Onto the range to burn a few rounds, not too many, just enough these days :slight_smile:

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@phuzzy42 Great advice, and trouble shooting.
@PNWmultisport. did you consider bringing some of the January’s targets with you to the range? Enter the friendly monthly competition.

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Not aware of the “January Targets”… perhaps because I’m a noob to the forum. Can you toss me a link or something on that topic? Thanks!

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Heres a good starting point Troy.
@PNWmultisport

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