Gunsmithing TL3 trigger timing

[TommyD11730]

Hey guys. So I'm thinking about buying a TL3 action. I see on their Web page they mention trigger timing and sending in your trigger if you like.
Could someone explain trigger timing. What exactly to they check/adjust?

Thank you.

 

[JR1200W3]

The trigger and action interface between the trigger sear and cocking piece ramp. When you close the bolt the cocking piece catches on the sear and compresses the firing pin spring. When you pull the trigger the sear drops and the cocking piece slides over the sear as the firing pin rockets forward powered by the compressed spring. A person can file the cocking piece ramp that the sear engages to remove some material. This reduces the spring compression and the action feels "smoother" as you close the bolt.

If you remove your bolt, flip it over so you're looking at the bottom. The cocking piece sits in the shroud and you'll see an angled "ramp". You can file that ramp, maintaining the same angle. Every couple of strokes, clean the shavings out, put the bolt back in the action and watch the pin on the back of the shroud pop out as you close the bolt. You can measure how much it protrudes when the bolt is closed and cocked before you start so you have a base number to compare as you periodically check the protrusion during filing process. There isn't a standard amount of protrusion I could tell you because it depends on the relationship of the individual trigger sear and cocking piece.

I'm pretty sure Zermatt just has cocking pieces with different size ramps. They swap out cocking pieces to remove some of the protrusion. I'm fairly certain they don't tune your cocking piece; you just get a generic fit.

Here's some warning. All this does is improve the feel of your bolt closing. If you remove too much cocking piece it's possible to get light strikes. The fix would be to get a new cocking piece from Zermatt.

I've "timed" 5 Zermatt actions on Jewell's and TT's. All have improved the feel of the action. I carry a spare firing pin assembly when I go to matches. I don't get light strikes on any of them.

 

[kthomas]

Another way of going about it is a trigger that you can "time" - the only one that I'm aware of is the BnA TacSport trigger.

You can get different top sears to match up with different actions and their cocking piece. Once you get the correct top sear, you can make small adjustments with a set screw to real dial in the interface between the trigger sear and the cocking piece.

The advantage of timing your trigger is that you can really optimize the interface between the trigger and action - and what this accomplishes is a very nice an light bolt lift and close. Be careful though, if you take off too much sear engagement, you can have issues with light strikes or AD's. So it is a balancing act.

 

[JR1200W3]

Timing the action to the trigger won't have an impact on bolt lift. Only on close, when you cock the action. Bolt lift feel is a function of the angular cut in the bolt body that a different part of the cocking piece has to ride up.