David Tubb firing pin spring

Duo Spring

Boyd has done a very good job of describing the dual spring setup. I have personally installed one of these springs, and I like it very well. Keep in mind that these springs are stock pressure springs, so they don't have problems that are normally present with stronger springs as mentioned by Robinette. These springs are also made from chrome silicon alloy steel. This is the same type of spring steel that is used in valve springs that make millions of cycles, so your firing pin striking force will not weaken over time like a standard music wire spring. These springs also claim to decrease lock time, since energy is not lost in a radial torquing motion.

Michael
 
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I've played with one of the duo springs. Some observations: When installed the center ring between the springs can end up cocked at an angle depending on where you place the spring ends in relation to the ring. If you match the ends of the springs at the ring it is close to no angle but still not perfect. There can be a fair amount of drag felt between the ring and pin when manipulated with a pin removal tool. The ring moves back and forth on the pin when it is cycled. Does this matter? I wouldn't think we would want to add any drag/binding into this mechanism over a standard spring. Also the ring appears to be water jetted or something and isn't finished very well that adds to the drag. I made a new one with a radiused and polished inner surface and hardened it. That seemed to lessen the binding/drag. I ended up re-grinding the ends of the springs to minimize the cocking/binding/angle. I've had to re-grind ends of other springs to keep them from cocking over at the end causing drag on the pin.

Thoughts?
 
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Sounds like some very exacting detail work. I'm impressed. For some reason it reminds me of a story that is sort of related (sort of, kind of, maybe...perhaps not).

Some years back a friend and I were on one of the firing lines at a local range, shooting next to a strapping young fellow who was laboring over a plastic stocked, bipod equipped, 700 sporter chambered in .300 UM. It seems that his three shot groups (using factory ammo.) had inexplicably increased from a little over an inch, to twice that. He asked us what the cause might be. After taking a look at the bore to see if it looked particularly fouled, and learning that it had received an occasional bore snaking, I asked him if he had tightened the action screws. Turns out that he did not even know that he was supposed to. Opening my range kit, I got out the appropriate Chapman bit, extension, ratchet and handle and set about snugging up his action bolts by feel, remembering that this was a plastic stock with no pillars. After that, he sat down and shot a three shot group at an 8" orange "aiming" dot at 100 yards. It was a fresh target, and those three shots could literally be covered with a dime. Seeing that, I told him that he should save the target and put no more holes in it. I signed and dated it for him, and I am told that it has a permanent place on the wall behind his desk in the building inspection department of a nearby city. Oh, I forgot to mention that the action had one of the J lock striker assemblies, the ones with the badly snaked striker springs that rub in several places. My point is that often we (including myself) are only guessing about cause and effect, because in many cases that is the best that we can do. Over the years I have seen some improbable combinations shoot and some that should have not.
 
Great Thread :)

Thanks to all of you for an informative read and Thank You GranDmaster Tubb for continuing to stretch the box.... alla'you'se are a credit to the Shooting Sports.
 
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