Ignition, esp in the action

C

Charles E

curmudgeon
OK, I *think* the consensus from the other thread that as far as the aspect of ignition contributed by the firing mechanism, longer firing pin fall is a plus, with both the weight and spring being lesser factors.

Suppose I don't want to re-time an action. Which commercial, custom actions available on the market have a longer firing pin fall? Occasionally action manufacturers give lock time, I don't think I've never seen one advertise striker fall or weight.

* * *

And if you are wiling to re-time an action, just how much is involved? You would need a new or modified trigger hanger, right? I have "timed" actions to improve when, on the bolt lift, the cam begins case extraction, but the firing pin fall would be completely separate from this. I've always though of it as "don't try this at home."
 
Charles E said:
And if you are wiling to re-time an action, just how much is involved? You would need a new or modified trigger hanger, right? I have "timed" actions to improve when, on the bolt lift, the cam begins case extraction, but the firing pin fall would be completely separate from this. I've always though of it as "don't try this at home."
Click to expand...
It's completely separate, but, basically the same thing. Just on different surfaces.

Each piece you modify will "help" with your goals, but, doing only one will not give you enough results to be of value. You pretty much need to deal with the bolt body and ramps, bolts lugs, sear, trigger/hanger, and the extraction cam. The tolerances you get to work with are basically zero.

With the ones I've done, the gun needs re-chambered when finished as well.
 
Charles,
In response to your question to which actions on the market have the longest fall, I'll remove the "custom" from the question you asked and say I don't think very many have the fall of a Remington. That really is the basic timing idea you're looking for, even if they don't use all the distance available to them in that action. Compare a Remington to a BAT and you'll see the only shortcoming of a BAT. Emulate the Remington timing using a BAT and you have a work of art.
 
With respect to the firing pin travel only, until you get into the trigger parts (sear), cocking piece and maybe pin length in the bolt body, the best you can get is an EVEN handoff. This will give you the most firing pin fall, until, and unless, you get into some "cock on closing". Now a little cock on closing aint the end of the world, and some have it and you don't even know it. But it does increase the pin travel.

So the debate continues, firing pin weight/travel/spring strength, what combination is the best?
 
Interestingly enough, the cock-on-closing effect depends on the trigger. I just got a Shilen competition trigger, and buried in the instructions is

Note: This design prevents cock on closing which can decrease the total firing pin spring pressure. For best results, we recommend using a 28 pound spring if you experience mis-fires or any malfunctions.


I put this trigger on a Tooley Orion action, which is essentially a Predator made to Dave's specifications. He may do some further work. Given (1) most poppa's are proud, and (2) I consider Dav a good friend, Dave reports that some rifles he's built on this action "shoot a whole lot better than . . . " (some customs) (you'd expect).

I grew up shooting right-right, so a RR with an ejector doesn't bother me. Most of my rifles have that configuration. Anyone who prefers, say, RL-right mini might have some issues

Without any cock on closing effect, it still has a firing in fall about .270.I don't know if the Jewell design also prevents cock on closing -- Phil?
 
Geez Charles,

I don't know how they "prevent" it cause I have both Shilen and Jewell triggers and all of the actions cock on close. If that trigger you have fits in a Remington, then I hate to tell em but it cocks on close. Now, it also has to cock on open, but that's only part of the fall. Maybe what they mean is that somehow it won't work for cock on close only. Unless Shilen triggers have changed, I don't think they control that one way or the other.
 
Hmm. The italic section in the post was a direct quote from the little sheet that came with the trigger (with the possible exception of a typo or two . . .)

(Edit)

While the trigger is new (2010) I doubt the competition trigger design has changed. Still essentially the one Mike Walker designed when Shilen made them for Remington before the final 40-X trigger made in house (also a Walker design). I imagine, but do not know, that the Hart trigger is the same design, as Hart was another company that supplied them OEM to Remington from Walker's designs.
 
Last edited:
But if you look at the trigger, how could it know the bolt rotation to not cock when closing?

I'm sure there must be some reason they wrote that but for the life of me I can't think what it would be. They must be talking about using it in some action I'm not familiar with.
 
My guess is that someone other than Walker added that bit of rhetoric down the line...... I mean...??? ... it either HOOKS, or it don't.

And it goes PAST, or it don't.

It's a timing thing.

I'm with Phil

al
 
As the bolt is opened the cocking piece is held in a vertical position by the shroud. It climbs the cocking cam to the top, and falls into the detent at the top of the cam that keeps it from accidentally going back down the ramp, as the bolt is opened and then pushed forward (Or when the bolt is removed from the action). As the bolt reaches the front of its stroke, if the trigger engagement surface of the cocking piece is too far forward relative to the surface of the the trigger's top lever that it engages, they touch, before the bolt handle is turned very far down, and in order for the bolt to continue closing, and be pulled into final longitudinal position by the cocking cams that engage the locking lugs, the striker spring must be compressed. This shows up as increased effort as the bolt handle is lowered, and is further evidenced by the back of the cocking piece increasing its protrusion from the back of the shroud as the bolt is closed. When the bolt is finally in its closed position the cocking piece is in a more rearward position than it would be if the the timing was correct, and the length of the pin fall is increased, by a small amount. This is what is referred to as cock on closing, when talking about an action that is designed to cock on opening.

With proper timing, the cocking piece is not stopped by the trigger until it has come slightly off the peak on the cam side of the detent. (Farther along in the closing of the bolt,) As the bolt is closed farther, you can see the back of the cocking piece fall an almost imperceptible amount into the shroud as the bolt is closed, and by the time the this happens the rear surfaces of the locking lugs are off of the closing cams and further closing of the bolt does not compress the striker spring, with the attendant effort that would be required.
 
Last edited:
Boyd, excellent narrative! I've only had one action that had cock on closing (other than a 96 Mauser). All the others were easily in the pin fall category, to one degree or another. The hangers BAT supplies gives some adjustment, but even with the trigger positioned all the way back, there is still some fall after the cocking piece clears the back of the bolt. It seems the manufacturers are erring on the side they would rather have the pin fall instead of some cock on closing.

Regarding a Remington, I asked Kiff to make some cocking pieces with different measurements to the face of the cocking piece, so some adjustment could be made. Don't know if it ever got off the ground.
 
I wasn't interested in going into that much detail, but It's pretty clear you 'get' it.

Boyd Allen said:
With proper timing, the cocking piece is not stopped by the trigger until it has come slightly off the peak on the cam side of the detent. (Farther along in the closing of the bolt,) As the bolt is closed farther, you can see the back of the cocking piece fall an almost imperceptible amount into the shroud as the bolt is closed, and by the time the this happens the rear surfaces of the locking lugs are off of the closing cams and further closing of the bolt does not compress the striker spring, with the attendant effort that would be required.
Click to expand...

"Proper timing" is somewhat subjective here, as for me, "proper" means adding some cock on close. The gun is going to get disturbed either on open or close, who cares which? By having it happen on both, neither one has to do as much work to produce the same amount of fall. (Provided you make your own angles on the ramps). So, the ramps do not 'have' to be as steep and thus, the bolt can work easier for a stiffer spring. A Remington picks up approx .060 of additional fall when you close the bolt because of the cock on close timing. I don't see any downsides to doing that. Especially since the ramps on the receiver are a shallower angle than those in the back of the bolt (engaging the sear cam), and have more engagement surface (in a 'properly made' action), so there is less felt friction on them.

Wayne,
Bruce Thom pulled some parts from production before they were finished and I finished them myself. Basically doing what you asked of Dave Kiff. I did that years ago, probably 5 or 6 anyhow. I know of one other shooter I told about doing that and he did the same on his Bats. They've shot pretty good since too.
 
You must log in or register to reply here.
Back
Top