I recently got my hands on a 325PD in .45ACP. Right away I took the gun to the range and I get light primer strikes on almost every other round. I'm shooting Winchester white box as well as reloaded ammo with CCI primers. Even tried some .45AR with the same results.
Anyways took the gun home and took everything apart. My first instinct is the strain screw which is fully tightened. I notice the main spring is bent so I replace it with a new Wolff spring (did not install the other springs from the kit yet). I then go ahead and cover my bases with an extended firing pin from Grand Masters.
Took it to the range and still get just as much light primer strikes. Any ideas on what else to check? I have noticed what sounds like a loose part that moves front to rear near the trigger area. This happens with all parts taken out besides the trigger (including firing pin). Could this be a factor?

Thanks in advance. This gun is slowly becoming a safe queen until I get it fixed....

You've hit on all the usual suspects (although I don't think the extended firing pin is all that useful). I think you are going to have to send it in for warranty work.

I have a m28-2 that has a serious light trigger but is not dependable with anything but Federal ammo, with which it is super dependable (Federal primers are very soft). As I never use it as a self defense weapon only as a target gun, I keep it that way.

Take out the strain screw and look at the end to see if it appears to have been filed / shortened. If so, get a new one. That is one of Bubba’s action job tricks...

You can partially cock the hammer, then hook a trigger pull gage under the ledge at the front. Gently let it down on the frame, then start pulling the gage and note where the gage reads as it lifts off the frame. That gives you a measurable, repeatable baseline to tell how much mainspring tension is on the hammer. Otherwise, you are just guessing with no way to tell what any changes have done. Check to make sure the hammer is not hitting the rebound slide as it comes down.

Here are some approximate average numbers. There is no absolute because of many variables. Every gun is an individual. Some primers may be more firmly seated than others. Primers may have been manufactured differently over the years. Gun may have a too short firing pin.
For Federal primers, you will need 40 to 44 ounces.
For Winchester primers, 48 to 54.
for CCI primers, 60 to 68.

I have a used 325NG that has been a project. It came with a bubba trigger job so all the springs and strain screw were replaced as well as the addition of a Apex XP extended firing pin. I initially used Wilson reduced power springs, which have been completely reliable in every other revolver I have installed them in, but here I had 1-2 misfires per cylinder with several different brands of ammo. I tried shimming the Wilson spring, but still couldn't get it to fire reliably. So I installed a standard weight hammer spring and kept a reduced power trigger return spring. It's really not a great solution because with the lightest weight return spring the trigger would catch and not return all the way. I moved up to a heavier spring, but now the trigger is easily the heaviest of any of my Smiths, but it's at least reliable.

I personally wonder if it's the moonclips allowing the bullets to shift away from the hammer a tiny bit when it drops. I've been thinking I might try thicker moon clips, but it's such a light gun it's brutal to shoot with anything but the lightest reloads.

Basically I'm pretty dang disappointed with it, but at least it's working right. I might get the Apex competition pin just to see if it will work more reliably with the lighter hammer spring.

BTW, have I mentioned recently how much I hate frame mounted firing pins?

Unfortunately I am not the original owner. As far as I know, warranty only applies to them.

Good idea on checking on the strain screw. Maybe I did not bother looking at it besides making sure it was tight

It looks like I will have to buy a trigger gauge. I figure I need one anyways..... the trigger on this gun is better than my Performance Center guns. I suspect Bubba work which I hope is fixable

I will test these out once I get the chance and report back. Thanks for the replies!

Its unfortunate people mess with guns to the point of unreliability and then trade them off (in my case)
As far as moon clips, I tried Buffalo Bore .45AR as well which has a fairly thick rim. It also suffered from the same problems.

I'm sure I could just cut my losses and sell it for the $700-$750 I have invested. But It wouldnt sit right with me
Last time I had this happen to me was with a 66-2. By the time I found out it had the occasional light strike, the original owner wanted it back and I ended up trading for a 57-1. I figured that was fair game!

One of the rumors I've read - to pass Californian drop tests S&W installed a too-short firing pin that is prone to ignition problems. They will replace it with a longer pin if you send it back.

Or, if you install a longer pin yourself and stay with stock springs I bet you'll cure it.

This whole thing is definitely making me rethink my desire for a 625, though.

I have several moonclip guns with light actions that I use in competitions. They are all reliable. If a gun is in proper mechanical trim, it will do fine, moonclips or not. If it's not fine, there is some reason, you just have to root it out and fix it. That can definitely be easier said than done sometimes. Every gun is an individual, they don't all have the same combination of problems.

The factory firing pins that are too short is a real thing. There are lots of those floating around. To me, the minimum length is .495. I like the Power Custom extended ones the best. I like the firing pin in the frame better than on the hammer. Everyone has their own opinions, this is mine. Worth at least what you paid for it.

Replacing the strain screw with a new one of the proper length (there's at least two different lengths) would be my starting point too.

I'm unfamiliar with Grand Masters extended length firing pins. What is it's OAL" ?

Nothing wrong with frame mounted FPs, in fact I prefer them. As mentioned, the factory is infamous for installing marginal length FPs.

Some factory S&W firing pins run .485"-.490" long & are the ones likely to cause a problem. Their others run .495"-.499" & have been fine for me. The two factory S&W FPs I just ordered from MidwayUSA were .498" long & had the broad rounded nose.

Sure wish S&W would go thru their parts bin & throw out all the .486" F/Ps & stop installing them in new guns.

(Note however: I have at least two S&W revolvers that have the short factory FPs, .483-.486" long, & they are still fire reliably & have never needed changing.)

The last Apex XP FP I got was long (.500") but had a pointed nose. The broad nose FP I got from them previously worked better, IMO.

The C&S extra length FP is .510" long, has the broad rounded nose & worked better than the pointed APEX. It basically looks like the round nose APEX used to. Don't know why APEX changed them as they never replied to my emails.

I've quit buying APEX firing pins & am sticking with the C&S firing pin, as of now.

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MolonLabeTX: Have you checked for excessive endplay in the cylinder? Excessive gross headspace can cause troubles too because the cartridge/primer are too far forward.

It's my opinion, beyond an obviously too short FP, that little differences in gross headspace clearances can add up to make one gun more likely to experience light strike over another of the same model.

I decided this after trying to pinpoint the reason why my 625PC would have light strikes (using 45AR case) but the same firing pin in my 325TR did not. A longer FP resolved the trouble & the exact cause was never definitively pinpointed.
(My new 325/625s run .095" to .097" gross headspace; from the cylinder face to the recoil plate/frame.)

Also, some brass have slightly shallower primer pockets than others and with the primers firmly seated to the bottom some will be ~.001-.002" below flush. Another brand, with slightly deeper pockets, maybe be ~.008-.010" below flush, when firmly seated.

Combine the three, marginal FP length, a little extra gross headspace, & deep primer pockets, some guns are just more reliable with an extra length FP. All my 325/625s have one (along with a factory mainspring & strain screw) and will reliably fire 45acp handloads (using CCI primers), without moon clips.

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Here's some examples showing the maximum forward reach of the different firing pins in my 325TR

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S&W firing pin
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APEX firing pin
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C&S firing pin
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Waiting for the break of day

I say Grand Master but it is a Power Custom extended firing pin. I was reading the package when writing this and it has "Grand Master L.L.C." written on it as well.

The Wolff spring is the standard strength spring. I could try switching back to the stock spring but as I said, it has an unnatural blend in it. Not like any S&W I own. When the hammer is back it curves normally then has a sharp angle towards the top. I thought it was strange....

That's interesting but it didn't answer any of the questioned I asked in trying to help you.

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Waiting for the break of day

I’ve sent in several guns to S&W over the years and I was not the original owner. They never asked if I was and didn’t charge me a dime.