How to check Action/trigger timing?

P

P.Ericson

Member
"Vibrating bolt handle when fireing issue"

I realized that I might have used the wrong words when I named this thread... I should probably have named it "moving bolthandle issue" instead.

I have tried to find more information about "timing", but haven´t found a thread that explain the "whole package". I have a 6ppc with a Bat SV action, and it shoots good, but not really "lights out".

So, how do I check my action and trigger for timing issues? What should I look for? I have noticed that I have a bit of vibration in the bolthandle when I dry fire on a empty chamber. Placing four stips of electric tape under the bolthandle (about 0.02") cures this. Is this a issue that should be fixed?

My trigger hanger is marked "0" "30". Installed in the "30" position, I cook my firepin about .01" when closing the bolt. When used in the "0" position, the firepin drops about .02" before engaging the sear. Change the triggerguard to a "20"?

What more should I check for?

Regards,
Peter Ericson
 
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I have seen those films before. They are great:) But, as far as I can measue, the bolthandle sits as close to the action as it can, and the caming is as close to perfect as possible with my limited knowledge.

To me, it just looks as if the bolt rotates a bit to much when closing. There are areas that have been ground (sp?) out both in the action and in the bolt, I wonder if it´s possible that they have just ground of a bit to mush material from the action and bolt?
 
Peter...I asked the same question in regards to my Hall action..I did not get a difinitive answer as to firing pin fall distance etc...I think the best thing to do in your case is to move the trigger to different positions in the trigger hanger and see if you notice any improvement in accuracy...I don't think the bolt handle movement on an empty chamber is relavent..and make sure that your bolt handle is as far down into the closed position as it was designed at the factory..because if you back up the bolt handle you are moving the non-ramp side of the bolt notch toward the cocking piece...and in worse case could cause the cocking piece to drag on the side of the bolt body when the firing pin falls...
Now moving the trigger in the hanger will affect the position when the cocking piece of your bolt engages the sear of the trigger...the only real effect will be increase firing pin travel, and more spring energy applied to the firing pin...
Now if increased spring tension improves accuracy (which I cannot prove) it would be somewhat based on decreased lock time (firing pin speed to the primer)...I think the reason that BAT makes the trigger hanger with multiple mounting positions is to let you increase or decrease bolt lift tension and make the action a little smoother and faster to cycle when you go to the "run and gun" mode when the condition is holding...
If your accuracy is suffering, I suspect that your gun is out of tune for the condition, or your barrel is no longer competitive, or last of all you are not seeing the right condition for best accuracy...

Good luck
Eddie in Texas
 
Eddie,

Wouldn´t adding material to the bolt handle (or action) actually have the oppisite effect? Moving the non-ramp side away from the cocking-piece? (at least it did so in an xp100 action I had before)

Anyways, after a closer look it doesn´t look as if the bolt is over-closing. The straight part of the bolt notch lines up perfectly with the trigger cutout in the action. One thing that might cause the slight lift of the bolthandle, is if the radius at the bottom of the cutout aren´t matching the radius of the cocking piece.

But, as you said, this might be a non-issue. As for the triggerhanger, I will try and find a different one.
 
"Wouldn´t adding material to the bolt handle (or action) actually have the oppisite effect? Moving the non-ramp side away from the cocking-piece? (at least it did so in an xp100 action I had before)"
Peter, you are correct...I was in error...but I am sure that moving the trigger via the hanger will answer your question about timing and hand-off affecting accuracy..
 
Unless something is bad out of whack I doubt bolt timing is really going to affect the accuracy of your gun. If the bolt lift and closing are nice and smooth and the extraction isn't a battle then look elsewhere. I would be more inclined to look at the bedding, bbl, chambering job, bullet selection, load development, brass age/hardness, wind reading, bag handling, etc.
 
Of course the simplest answer in driver´s error, and frankly, I´m not the best shooter around. But, I want to have the best possible equipment, so when I do my best, the equipment won´t let me down.

My main concern with this thread was to figure out if the bolt movement was OK, or if I shold have it fixed. To me, it feels strange to have a moving bolt.

As said, I have no extraction problems, so maybe the word "bolt timing" was wrong. Sometimes I don´t find the right words then I type english.:eek: Lets rename the title of the thread to "moving bolt handle when fireing issue" instead...
 
You have 'bolt handle jump when dropping the firing pin on an empty chamber'. Remove the decapping stem from your sizing die and size the case leaving the dead primer in there. Then put this case in the chamber and pull the trigger and see if the handle jumps.
 
crb said:
You have 'bolt handle jump when dropping the firing pin on an empty chamber'. Remove the decapping stem from your sizing die and size the case leaving the dead primer in there. Then put this case in the chamber and pull the trigger and see if the handle jumps.
Click to expand...

If it should move on a fresh primer something should be seriusly wrong... When a case with a spent primer is used, I can dryfire about three times before the bolt starts moving again.

One thing that I have noticed is that the cocking piece on the fireing pin bottoms out compleatly in the bolt notch when spring is not compressed. Neighter one of my remington actions does this. Is it suposed to be this way? I guess that thats where the vibrations come from?

Anyways, I´m not trying to blaim any gunsmith or so, no one has done anything wrong. Just trying to figure out if everything is alright or not. I won last years 2-gun nationals here in sweden with the gun, and got a bronze medal at the european championship, so the results I´m getting with the gun isn´t disasterus. Just want to make sure everything as as good as it can be.
 
I am not familiar with the design of the BAT. On Remington clones a shoulder on the firing pin bears against the bolt body just behind the bolt face. The cocking piece is not bottomed out in the cocking ramp cutout.
 
Just got the answer from my gunsmith here in the US. He confirmed that everything wasn´t as it should be, and explained the answer. I let you guys know when I have fixed the movement issue.
 
P.Ericson said:
I realized that I might have used the wrong words when I named this thread... I should probably have named it "moving bolthandle issue" instead.

I have tried to find more information about "timing", but haven´t found a thread that explain the "whole package". I have a 6ppc with a Bat SV action, and it shoots good, but not really "lights out".

So, how do I check my action and trigger for timing issues? What should I look for? I have noticed that I have a bit of vibration in the bolthandle when I dry fire on a empty chamber. Placing four stips of electric tape under the bolthandle (about 0.02") cures this. Is this a issue that should be fixed?

My trigger hanger is marked "0" "30". Installed in the "30" position, I cook my firepin about .01" when closing the bolt. When used in the "0" position, the firepin drops about .02" before engaging the sear. Change the triggerguard to a "20"?

What more should I check for?

Regards,
Peter Ericson
Click to expand...

I do not think you're imagining a problem.

I think actions need to be "tuned" sometimes....

I do not know how to fix it :)

Here's a recent thread on the subject.

http://www.benchrest.com/forums/showthread.php?t=61667

al
 
So, here is the problem.:)

The cocking piece on the fireing pin is bottoming out in the bolt notch/cut out on the bolt before the fireing pin is hitting the right place on the inside of the bolt (can´t find the right words). Instead of having two parallel surfaces hitting each other, two rounded surfaces meet up under great speed and force. If the radius of the surfaces that meet doesn´t line up perfectly, vibrations will occur.

Simple fix, turn the cocking piece out until it doesn´t hit the bolt:D The only problem right now is that Bat Machine seems to have put loctite on the threads. Well, I will fix it eventually.
 
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Generally Loctite can be loosened with heat. Not a lot of heat, just play a torch gently over the area and see if it loosens. It would help if you can see the color of the loctite. From the color someone can perhaps give you the temp rating. I'll go look at a BAT, meantime if the right person sees this they'll know.

al
 
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