doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Firing pin, proper lenght to assure ignition.

Hello gentlemen:

Because the lack of really gunsmiths here, I do the repairs of mine and other friends shotguns.
This time is an AyA model 37 o/u, that do not strike enough the shotshells to ignite them.
I check strike force and is OK, but take measures of firing pins and the low only protrude 0.033" so I made a new firing pin with 0.060" and it is performing fine.
The upper firing pin protrude 0.046" and I think is enough tu asure the strike but yesterday it fails to ignite 1 time.
My question is, do you think 0.046" is not enough and I need to make a new upper firing pin or defective shotshells could be the cause?
For what I learned here, 0.060" is OK for making a new firing pin, but 0.046" it is also enough.

Give me your technical opinion, please. Making a new firing pin for this AyA is a lot of work (square rear part that need to make by file) but the worst part is to take out the pin from the shotgun, because you need to dessasamble all the shotgun (bolt lever).

Best,

Jose

Jose, over the years I have "heard" that .050" is proper for most guns. If your firing pin that protrudes only .046" continues to malfunction, can you alter the pin just a bit to allow it to protrude just a tiny amount more ?

Another check would be to use different ammunition and also to make sure the mechanism is properly lubricated and clean.

.046" is fine. Many of the AYA firing pins are too long and they have to be shortened to 1mm, from usually about 1.5mm--- which is best done by cutting away metal from the back of the firing pin where it is stuck by the tumbler (hammer). Of course one has to be careful and first examine the amount of headspace of the barrels as sometimes the cut in the breech end of the barrels for the shotshell rim is too deep, hence the need for a bit longer striker(firing pin).

bushveld is right , it could be a headspace type problem. This could occur from too deep of a rim cut , or ammunition that has a too thin rim. Both happen. Best and easiest if to try other ammo.

AyA strikers . When I replace one I allow it to protrude about .055" when the gun is fired . However the striker must be able to travel to a max of .075" before it hits the back of the disc . This free float or end play is essential so the the hammer when fired is not forcing the striker to it maximum protrusion and thus allows it to go forward but then back to a rest position .This allows the strikers to start lifting away from the primer as soon as the gun is opened without dragging in the primer .

Jose ,just reread your post You were talking of an O/U and I was thinking side by side . Sorry about . What you again you need to consider the free float question ,O/Us generally have more than side by sides . I would allow the pin to come out a maximum of .075" only protrude around .040"when resting on the hammer when fired . O/u tend to be a little more individual than SxS so it may mean you have to taylor each pin to each gun. Must admit that I have done so many that I largely do them "by eye " these days ,even so they some times need a bit of fine tuning ,depending on the rebound in the hammers .

Can't speak for AYA- or any Spanish made side-bys or over-unders- but with LC Smiths, which have a plethora of firing pin designs from the first baker Hammer Syracuse guns to the last hammerless ones made under the Marlin aegis- I consult the dims shown in the 1981 Brophy book first, and as you can easily recock a Smith receiver without having to employ the barrels and forearm (thanks to Alexander "Axle" Brown) I use a block of soft pine wood-placed flush against the standing breech, and dry fire the pins against that to "eyeball' check for penetration-

Y muy buena suerte con su escopeta, compadre!!!!

How-some-ever- both the depth of the rim cuts in the barrel breech, and the make of shell and primer can also make a difference-- Fiocchi shells for some time have earned a reputation of having very hard primers- it is a game of variables-- another aspect of this, IMO anyway, is also the 'post-firing" of live rounds- especially if the gun has selective automatic ejectors-all need to be in proper timing and balance--

Gentlemen:

Once again you gave me the correct direction to find the problem.

I meassure and compare the deep that a shotshell goes in 2 shotguns, one the AyA 37 with the ignition problem and the other a Winchester 101.
With the shotshells I have in hand I do this:

Brand AyA Win 101

Rio game 0.013" 0.005"
Rio Target 0.016" 0.008"
Kemen 32 0.010" 0.001"
Federal Hi Power 0.010" 0.002"

The shells go deeper inside the chamber in the AyA, as much as 0.008" and that, for sure is the cause of misfires.

Thank you!

Best,

Jose,
Do you notice a difference in recoil between the AYA & the Winchester ?

Salopian:

We are in the middle of our quail season, so we neither use 12�s or go to sporting clay courses, so in late april, when we start again to brake clays (because ther is no fair game available) I promess to check both shotguns and comment you if I feel a diferent recoil.

Best,