Gunsmithing Trigger Timing

[arm017]

I apologize if this is redundant or covered elsewhere, but I am struggling to get a clear understanding on exactly what trigger timing actually is despite plenty of googling/ youtubing? I am trying to set up a Bighorn TL3 with the traditional 2 retaining trigger pins. The best I can find is the explanation in this video:

https://www.youtube.com/watch?v=szy4HBg3q80


But what exactly is involved in timing a trigger- how would you adjust anything, and what is the difference between trigger timing and action timing? Does it even apply to a high quality custom action?
Thanks for the help.

 

[dirthead1]

Great question. I'm interested in this as well.

 

[LRI]

In 20+ years of this shit that is a new one. Guess I have to get the timing light back out.

 

[jbell]

in 20+ years of this shit that is a new one. Guess i have to get the timing light back out.

haha

 

[cast1]

This is not trigger timing but bolt timing and has to do with primary extraction (i.e. the first rearward movement of the case or round on bolt opening.) Look up Wheeler Accuracy on YouTube and also a Ozzie Suarez. They bolt have good info on bolt and trigger timing.

I think this is more of a problem on "blueprinted" actions where somebody has removed too much material from the lug surfaces and that cam surface he is showing doesn't help with primary extraction. You have to reposition the bolt handle so that those two surfaces interfere and provide some mechanical advantage for the first couple mm of rearward bolt movement on opening.

 

[LRI]

Ok, bolt timing. Far different subject and one I have some experience with.

First, look at your serial number. If we're talking about a Remington M700 action and the SN starts with an "RR" prefix, you are indeed a candidate for this work. Remington really dropped the ball. The handles used to be cast at a foundry company based in WI. They made a change a few years back and the new tools are junk. In a nutshell, there is zero primary extraction on an RR prefix action. It's not the receiver's fault. It's the bolt handle. The cam angles were changed for some absurd reason. They are no longer tangent and what little it has arrives far, far too late in the rotation. This is Primary Extraction (PE). "Timing" to get the cocking piece/fire control setup correctly is related, but a different topic.

I have fixed hundreds (and I mean hundreds) of these.

Accurizing a receiver where material is pulled from the bolt lugs and receiver lug abutments has a cascading effect. It retards the timing. Simply meaning it will start to pull the bolt/case rearward later in rotation. It is my opinion that any M700 being "tuned" requires that the PE be addressed. This can only be done a few ways. Rework the factory handle or replace it with an aftermarket one that has the geometry done correctly. -Not all of them do a great job at this and I personally have better luck with reworking the factory one as it gives me "divine intervention" to set it as it should be.


More info can be found here: https://www.longriflesinc.com/collec...rvice-for-m700


Happy to help.

C.

 

[Gene Poole]

In my opinion, the video above has it wrong. You want the lugs to release before you you start camming on the bolt handle ramp, otherwise the whole thing would just lock up. He's working the action without a case in the chamber which makes his whole primary extraction issue meaningless.

Personally, the RR series actions I've done (and it's only been a few so Chad certainly knows better about this than me) are not that bad. The lugs and abutments were spot on and needed very little if any cleanup leaving plenty of primary extraction with the bolt handle as-is. I have noted that the ramp angles between the bolt handle and the action are no where near ideal, and I usually replace them with a PTG handle on general principle, but the ramp angle on the PTG is only marginally better.

 

[LRI]

The attachment is a photo of the full legacy of M700 bolt handles. If you look from L to R the RR series is first. Notice the cam angle. Much more abrupt (acute) than the others. Not only does it "hit" later in rotation there's almost nothing there because it has less "rise" over the "run".

 

[arm017]

Ah, starting to make a whole lot more sense guys. Chad - you are a bad ass sir.


So the reason I brought the original question about trigger timing to the table was it was an option in the barreled action I am awaiting (IE: do you want your barreled action with trigger installation with trigger timing/ tuning) This is being built on a new tl3 action for what its worth.

..and I was trying to decide if I can simply just drift in the trigger pins myself to install the trigger of my choice, or if there is something inherently special with a gunsmith installing and adjusting the trigger.
Is it not just sear adjustment screws on the trigger to ensure the sear doesn't fall when you close the bolt? All stuff the DIY gunsmither should feel comfortable tinkering with.

But digger deeper I found one more video (sorry for all the video links) from the bench rest side of things that might be more applicable to actions with a trigger hanger instead of pinned trigger. IE: tempest, kelbly, impact actions. Is there any cross over of this concept of trigger timing when you are dealing with a tradition pinned trigger?

https://www.youtube.com/watch?v=DWnv58mfVZY

 

[g.ross]

This is the link your searching for . Send it out to a smith to re work the cocking piece , cocking ramp and work on the pin fall or just deal with cock on close.

https://m.youtube.com/watch?v=FVposuHNg0M

 

[smoothy8500]

I'm just curious what timing issue I have on one of my older Rem 700 "E" series. When dry firing I notice I have to retract the bolt very slightly to get the firing pin to stay cocked on closing. I just can't cycle by opening/closing the bolt. Is this a bolt issue or a trigger issue?

 

[g.ross]

It is not an issue ,most Remington's and custom Remington close have some degree of cock on close issues .it is how the cocking piece and trigger hand off to one another.Your having to lift and pull the bolt back until your cocking piece resets and catches on the top lever of the trigger .As you close the bolt you are feeling lugs engage, pulling against the cocking piece and further cocking the firing pin .You can file on the cocking piece but then you lose firing pin fall taking a chance at having ignition issues . Its better to send your action and trigger out to a competent smith that deals with ingition systems like Alex wheeler that has the tools and technique that will eliminate Cock on Close . I like the idea of actions with the choice of trigger hangers that will allow you to position the trigger foward or to the rear of the action to help with cock on close and correct pin fall.

 

[smoothy8500]

OK thanks. It's only a minor issue for me, but was wondering if it was signs of a bigger problem.