Action timing

[Brad Y]

Seen this on accurateshooter.com

None of the actions Ive owned have ever been this well timed, hoping my new one is. Anyone in Aus do this timing work?

https://www.youtube.com/watch?v=V5bpBJ54KhM

[Fergus Bailey]

Peter van Meurs was doing action timing before he retired. Several of my Bats needed timing work done, though I have several Bats that did not.

[Brad Y]

Fergus- BAT's also have the luxury of the adjustable trigger hanger for timing too. Bordens come timed with a trigger. Im expecting a new multiflat action to arrive shortly from pierce. My previous round pierce was way out when I introduced a kelbly trigger to it. Another gunsmith (no longer working) got it to the point that it wouldnt shallow strike, but bolt lift was shocking and the bolt handle had a noticeable jump when using a snap cap. I dont expect the new action to have the same dramas but if it does it would be good to know if someone is able to assist with it.

[Norm]

A mate of mine had an action that was so far out of timing that it would misfire once every few shots.
It went to the gunsmith a few times with no luck fixing it.
Then I noticed that the firing pin fall was a lot less than that of a similar action. This was with a custom action and a Jewel trigger.
With a new trigger the rifle is now working properly simply by putting in another Jewel trigger.

[AlanF]

What is action timing???

[Chopper]

Are we talking lock time , the time the trigger is pulled and the time it takes to strike the primer ? Chop
I might be wrong ? If Not , Great subject

[Matt P]

What is action timing???

Alan
You've got a Barnard, don't worry about it !!!!
Matt P

[Matt P]

Fergus- BAT's also have the luxury of the adjustable trigger hanger for timing too. Bordens come timed with a trigger. Im expecting a new multiflat action to arrive shortly from pierce. My previous round pierce was way out when I introduced a kelbly trigger to it. Another gunsmith (no longer working) got it to the point that it wouldnt shallow strike, but bolt lift was shocking and the bolt handle had a noticeable jump when using a snap cap. I dont expect the new action to have the same dramas but if it does it would be good to know if someone is able to assist with it.

Brad
Depending on which way the "timing" needs to go you either have to modify the cocking piece and/or trigger, or move the bolt handle. Either way it's a time consuming exercise.
That one of the reasons I sell Barnard and Borden and nothing else !!!
Matt

[Chopper]

303 s had good reliable lock time ))) Chop

[Chopper]

And to fuel the fire ,I beleive that not all shooters get the best out of a fast lock time , some brain ,trigger and follow through, just dont match up to the best result , even though the strike is positive and consistent , the time taken in mill sec vary of strike time, and dont match the individual, some times a longer strike can make the rifle easier to use I think, for the individual , ? just my thoughts, myself ,I like the longer , Chop

[Norm]

Its not just lock time.

Action timing is correct, firstly, when the bolt is fully cocked, its lugs are in the correct axial position and in full contact, the bolt handle is not contacting the stock or any part of the action, the correct amount of firing pin fall is maintained, the desired amount of sear engagement is obtained and the desired trigger weight is set.
It also needs to have the primary extraction cam at the correct point of the bolt lift to maintain easy extraction.

[williada]

Hard to see a new action stuff up, and usually due to a shooter altering things. Action timing usually refers to getting the 3 cam surfaces with the bolt synchronised and working.

On closing the bolt, the ramp either cut into the action and rear angles of the bolt lugs enable the case to be firmly pressed into the chamber and then engage the parallel surfaces of the rear of the bolt lugs and the internal action lugs. Shooters stuff this section by lapping bolt lugs reducing or eliminating the parallel sections of the faces.

The opening of the bolt also engages the rear action cam and the front of the bolt handle which by mechanical advantage (leverage) assists rearward extraction. The gap between the rear camming surfaces should be between .005” and .010”. If it is bigger it won’t get the leverage to cam. On soft actions like the old Omark, we added to the camming effect by inserting a small rounded machine screw as a stop gap measure into the action. The other problem was, if the rear of the bolt handle did not have about .030” gap the cam did not have enough room to operate, so it felt like sticky bolt lift and a click was heard and often mistaken for the click sound of an over pressured case breaking free. If the bolt handle is touching on the rear of its handle slot in the action, you could probably bet the front lugs of the bolt were not engaged. So more problems. So if you shoot fast you don't need a second bite on the bolt handle lifting it up.

When you look at an action from the front with the bolt in place, the lugs should be perpendicular, or camming fully home in three or four lug designs. If they don’t, the usual culprit is the attachment of the bolt handle preventing full rotation of the bolt body. If the lugs are not engaged fully, you have less surface area to prevent wear and tear which will lead to group change. This wear and tear was exacerbated in the old days by shooters setting up with crush fits on headspace while shooting factory ammo.

If the front lugs are not aligned properly, this also affects the trigger bent camming on the bolt to cock it and sometimes the trigger bent gets hung up on the action groove when not in alignment (depending on the action). All of these three cam areas have to be in alignment. That’s what I understand by action timing.

As far as trigger timing goes, that’s usually related to sear engagement. That is not lock time which is the time it takes for the pin to fall to getting ignition. Most firing pins should travel about 1/4“. Any less, you get poor ignition from reduced spring pressure. The short way to fix this is to move the trigger block forward or back with a hanger or you need to find another way of altering the firing pin or sear engagement point.

[Chopper]

Truing or timing ?

[Brad Y]

Matt I know I was very tempted to get a borden but being a kack hander and wanting LBRP (and wanting it yesterday) didnt help me out much.

By what I can read online (and it seems to be a bit of a black art) most actions aren't ever 100% perfect. But obviously custom actions are usually pretty good. And while some say it really affects accuracy, others say its more important when your running and gunning and you want to minimise upsetting a gun in the bags.

[Barry Davies]

Never heard the phrase " Action Timing " before.
Looking at the video linked to Brad's post showing the bolt closing on the two rifles. If that is what is termed "action timing " then the one on the left is perfectly timed and the one one the right is less than perfect.
It comes down to having the bolt lugs lock in just as the cocking piece contacts the trigger sear.
The rifle on the right has sear contact before the locking lugs lock in necessitating a push forward of the bolt handle against spring tension making cocking somewhat difficult, much like the old military actions which partially cocked on closing as against modern actions which cock on opening.
The problem that exists with the rifle on the right can be fixed in a number of ways.
The easiest way is to work on the interface between cocking piece and trigger sear. Metal can be removed from either the cocking piece or the trigger sear until " timing" is satisfactory, BUT-- whatever metal is removed from either directly reduces firing pin fall and could result in misfires.
Another way to ease the problem is to chamfer all of the bolt lugs on the leading edge thereby assisting the bolt to " pull in " when cocking.
It really is a job for a competent gunsmith.