Had a chance to shoot a modern S&W. I noticed that the double action pull was substantially heavier than my factory stock 40 year old revolver. Just wondering if the newer transfer style firing pin requires a heavier main spring than the old hammer nose style or if the spring on my oldie just got tired over the years.

S&W doesn't have a transfer bar. That is a Ruger thing. S&W has a hammer block that is down when the trigger is pulled and goes back up when the trigger returns. The new style S&Ws don't require more hammer strike than the old ones, but there is a lot of variation between individual guns. Maybe the strain screw on the new one was a bit too long, maybe the mainspring is thicker, etc. The new guns can have every bit as good an action as the old ones.

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I ordered a handful of factory mainsprings a few years back and was stunned to discover how much heavier they made double-action pull. Comparing them to otherwise little-used stock factory mainsprings from a few decades back, the batch I got was straighter and measured slightly thicker fore-and-aft. In short, qualities that made for a heavy pull compared to earlier examples in the same revolver.

This correlates with the general impression posted hereabouts that current factory S&Ws using the standard mainspring (versus some of the PC revolvers with the Wolff) generally have a heavier pull than they once did.

Speculation here, but I suspect that as the production line has largely (if not entirely) dialed-out parts fitting, strain screw tuning as it used to be done -- which had the effect of lightening pull -- is no more and a mainspring and strain screw geared to a heavier pull for the widest reliability across all common factory ammo brands is used.

Slap it in, send it down the line, easy-peasy and faster output, customer gets a heavier trigger but customer service gets fewer calls about failing to ignite primers. Sort of like the way quite a few AR manufacturers overgas their guns, unnecessarily increasing recoil but "improving" reliability.

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Pickpocket

Ah, I see. I just assumed it had the same system as the Rugers I've seen all these years. The double action was quite a bit heavier than what I'm used to and it was a handy excuse for my fliers.

With a little creativity we will all of us always have handy excuses for fliers.

A good double-action trigger should be exactly as heavy as it needs to be to pop the primer and not an ounce more unless it's to shooter's preference.

I've handled plenty of current S&W revolvers and found the trigger pull ran an unpredictable gamut from absurdly heavy to perfectly good, occasionally terrific out of the box, across similar models. I think it varies from gun to gun, which is a bit funny given all the effort to standardize the production line such that parts can drop-in interchangeably, performed by assemblers vice fitters.

Still, the current ones are overall well-made and you can put an excellent tune on them, just like the old ones.

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Pickpocket

While I've never seen the S&W production line, I strongly doubt that the assemblers bother-or ever did bother- to fit strain screws. I base this on having handled umpteen revolvers over decades. While the factory trained armorers get the specs for optimal hammer spring tension and tools to fit strain screws, that's apparently never-with the possible exception of registered magnums-been a practice on the assembly line.

Some time back I ordered several strain screws for K frames. Surprisingly, they varied quite a bit in length, and this might be the issue. I've generally found all out of the box revolvers to have hammer tensions far above the factory optimums.

You do have to realize that the factory has to assume that the firearm will rarely/never be properly cleaned or cared for but is still expected to function under all conditions.

Well, the factory can justifiably assume that, but doesn't have to -- many manufactures don't and therefore provide a more out-of-the-box tuned product...for the added cost, of course. S&W offers what fits their desired margins and intended market.

Interesting to hear on the strain screw fitting or perhaps lack thereof. I certainly wouldn't think they do it now, but was under the impression per the armorer's training you reference that that's how it was once done at the factory.

Assuming then that current S&Ws are rolling out with generally heavier actions than in generations past (which I think they are), what do you think would account for that?

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Pickpocket

Back in the day, a guy brought his grandfather's K frame into the shop. Unworn tan box with blue lettering, bluing you could fall into, glorious color case hardening. After I rhapsodized about how they don't build them like they used to, I asked why it had been brought in.

"Spits lead".

Puzzled, as it showed nearly no wear, I swung the cylinder out and bust out laughing. There was no forcing cone in the barrel tenon.

The point I'm trying to make is that the way we think things were made back in "the good old days" isn't necessarily so. Otherwise you wouldn't have had armorers being taught how to optimize/blueprint the final product. And, that was, SFAIK, only for the law enforcement market. Or, maybe for special customers.

The other thing is that for most of the folks who bought firearms back then, and now, the firearm is just a tool. And, that tool has to function under any/all conditions, not just during a bullseye match. That takes/took precedence over the preferences of a comparative few. I expect that's still true when you're looking at keeping the company in business.

I do understand your preference, but as someone who spent decades using what's issued, as issued, it's surprising what you can do with what the factories make. Maybe with just a smidgen of armorers adjustments and a lot of practice.

Your particular point, mainspring tension: the factory minimums for a stock K frame .38 Spl is 52 oz, for .357 is 56 oz. I've measured many a K frame from the factory at or above 64 oz., but that was sometime back. OTOH, a tuned .38 can go much lower, but that's for playing games.

I was just wondering if the newer frame mounted firing pin required a heavier hammer strike than the old hammer nose. For me, shooting is purely playing games. Paper punching and plinking with old fashioned firearms is only a relaxing hobby. My old 19 is 100% factory original. No custom trigger work, no changes of any kind and the double action pull is far different from the new one I tried. Maybe the overall action is just a bit stiff and needs to break in a bit. One thing I'm sure of. My groups are a lot tighter with old trusty.

Springs do take somewhat of a set and let down in tension a bit after use. I've made reference in a couple of threads about how an aftermarket mainspring would lose tension over 100 rounds or so (and cause misfires) and then recover. A factory spring took care of that issue, but I made darn sure it got several hundred cycles before setting the tension. I dropped a new factory rebound spring in the same gun and the DA trigger was 10/10.5 lbs. After several hundred rounds it dropped into the 8/8.5 lb range and stayed there.

Yes, you have to break in all mechanical devices.

We must understand the terms being used here! DA trigger pull is effected by many things inside the gun works. Hammer tension is a function of the hammer against the main spring only! To the OP, your older well used gun has a much smoother action because the moving parts have become "lapped in" from years of oil and dust(lapping compound) and the springs have lost a little tension! DA trigger pull is effected by the trigger rebound slide coil spring, which has no effect on the hammer fall! A newer gun with a new rebound slide spring probably has more tension in compression that your old 19, hence the heavier trigger pull!
IMHO, jcelect

It takes a certain amount of strike force by the hammer to set off a given brand of primer. The hardest primer is generally considered to be CCI, so that would be the benchmark to set off anything that comes along. Federal is the softest, or easiest to set off. Everything else is somewhere in between.

Due to the variations listed above, and many more, you can't tell what the hammer is doing by pulling the trigger. You can isolate just the hammer and mainspring by hooking the trigger pull gage under the hammer, carefully letting the hook of the gage down on the frame, and see what the weight is just as the hook lifts off the frame. That gives you a repeatable way to measure hammer fall force independent of all the other lockworks.

If you want the lightest trigger pull that's easily obtainable, back out the strainscrew until you get misfires, then tighten it back up 1/8 turn at a time until you are getting 100% fires. Then another 1/8 turn to cover that 1 in 100. Measure the hammer tension as described above and record the number of ounces. Shorten the strain screw until it duplicates that number when the screw is tightened all the way down.

Next, get an assortment of rebound springs from 11 to 15 lb. Try them out starting with 11 and working up until you get the lightest one that returns the trigger the way you want it to.

This will tune the springs to your ammo. It does not take into account any problems the gun may have that need to be corrected, or stoning/polishing. Those items are extra. Many guns don't need anything additional, some do.

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