P220 Hammer Spring Data

[Sensei]

I updated a couple of my older Sig P220s (one stainless and one blue) with SRTs and took the opportunity to play with the hammer spring weights. I believe that they both came from the factory with 20-21lb springs, but the stainless P220 was a bit lighter and smoother than the older blued.

The first gun was a all W. German blue P220 purchased in 1997 with a SN of G2764XX. It came from the factory with 11 / 4.5 lb DA/SA pull. I put a 18lb Wolff hammer spring in which brought the pull down to 9/4 lb. Definitely noticeable.

The stainless P220 was purchased in 2004 with a SN of G3359XX. The frame was made in Germany but the slide I believe is American. It started with a factory trigger pull of 9.8/4lb. I put a 19lb Wolff spring in which marginally improved the pull to 9/4lb. Not really noticeable.

Today, I fired 50 rounds of AE and 25 rounds of HST through both pistols. All rounds ignited just fine. I’ll shoot some Speer Lawman and Winchester next week and report back.

[Evil_Ed]

I have a 220 (steel frame version, not the ST but the black nitroned steel frame) and a 220 Compact (not Carry, but Compact; smaller frame); I tried them both with a Wolff 18lb mainspring (no other changes), and got light strikes with my reloads. I then put a Gray Guns spring kit in both, which comes with a lighter firing pin spring, a different sear spring (I don't recall if it's lighter or heavier to be honest), and also a 19lb and 17lb mainspring. I didn't even bother trying the 17lb. I put the 19lb in and tried that. The pull wasn't as nice as it was with the 18, but if it solved the light strike issue then I'd live with it.

I still got light primer strikes on both the Compact and the full size with my reloads, lighter firing pin spring or not. Not a lot of light primer strikes, maybe 5/100, but enough to shake my confidence in that spring combination and my reloads.

My reloads are random (mostly Winchester) brass, Winchester large pistol primers, and I think 6.5gr CFE pistol (or something like that, I'd have to check my notes) under a 230gr ball. I never got any light strikes with the factory springs. A second strike and all the rounds went off. I haven't tried any loads in these guns that were not primed with Winchester primers.

I swapped back in the factory springs (sear, firing pin, and what now feels like a grossly oversprung mainspring)...no more light strikes. Admittedly I've only gone ~500 rounds after the last spring swap back to factory, but I started getting light primer strikes with lighter mainsprings well before that count, so I'm fairly confident it's "resolved".

Maybe it's a Winchester primer issue; they all came from the same thousand primer box, but that doesn't seem very likely.

I've decided to just live with the factory values. A lighter mainspring really does make the Sig's DA pull that much nicer, but at least with my two examples, the trade isn't worth it, at least not with my loads. The DA pull really isn't that bad when I think of the alternative, of a click-WTF-uhoh moment...

To be fair, I've never gotten a light strike with factory ammo. Having said that, I don't think either of them have seen more than 200 rounds of factory ammo of any kind...

[Sensei]

The “internet” concensus (comments from Bruce Gray and various Sig forums) was 18lb was the lightest one should go for an EDC gun; 17lb may be used for competition. You are the first person that I’ve come across with issues using an 18lb spring.

I don’t shoot reloads but my plan is to put 250-500 rounds through each with a variety of factory loads. Any light strikes and I’ll move back up a pound. I may try Winchester White Box next since they reportedly have harder primers.

[Evil_Ed]

Someone once told me Winchester primers are harder than others, which may explain why I got light strikes with both 18 and 19lb mainsprings. I never got any light strikes with any of my loads or any factory loads (including WWB) with the factory springs...only with the lighter springs.

Maybe the lighter springs work better in 9mm/40S&W Sigs (226, 229, etc)? Those seem to be the more popular of Sig chamberings...

[TOTS]

The “internet” concensus (comments from Bruce Gray and various Sig forums) was 18lb was the lightest one should go for an EDC gun; 17lb may be used for competition. You are the first person that I’ve come across with issues using an 18lb spring.

I don’t shoot reloads but my plan is to put 250-500 rounds through each with a variety of factory loads. Any light strikes and I’ll move back up a pound. I may try Winchester White Box next since they reportedly have harder primers.

This. I got light strikes with the Wolf 17 lb VERY often and tried the 18 lb. Way less often but still occasionally. Installed the 19 lb spring and have been 100% reliable with Magtech primers as well as Winchester (two hardest brands I know of) for well over 1K now. I bought the Wolf 17-19 three spring kit. And very noticeable difference in DA pull.

[LSP552]

The “internet” concensus (comments from Bruce Gray and various Sig forums) was 18lb was the lightest one should go for an EDC gun; 17lb may be used for competition. You are the first person that I’ve come across with issues using an 18lb spring.

I don’t shoot reloads but my plan is to put 250-500 rounds through each with a variety of factory loads. Any light strikes and I’ll move back up a pound. I may try Winchester White Box next since they reportedly have harder primers.

I could be wrong, but IIRC, a 19lb was the good to go limit for carry. I’ve used that for years with the 226, changing every year and haven’t had a problem. I’d personally be nervous about a SIG with anything less than 19 for anything other than a range gun.

[Sensei]

I put 50 rounds of Winchester Service Grade 230 grain FMJ through the P220 with the 18lb Wolff hammer spring. All rounds ignited fine. This is reassuring. Another 100 rounds or so and I’ll be satisfied.

[Sensei]

Today, I put 50 rounds of Winchester White Box and another 25 rounds of Service Grade through the P220 with a 18lb hammer spring; 50 rounds of Service Grade through the P220 with 19lb spring - no issues with either pistol.

I’m now at about 200 reliable ignitions of various factory munitions through the 18lb gun and a little less through the 19lb gun. I’m pretty happy with that.

[Evil_Ed]

My light strike issues didn't crop up until around 600 or 700 rounds, with 200 rounds being a range/practice session...so 3-4 range trips, and it started to manifest. I wouldn't take 200 rounds to be "that's it, job done, it's reliable" but of course, YMMV...

[taadski]

I’ve dabbled pretty extensively with hammer springs in the P series pistols. If you limit yourself only to Federal primers (soft), you can get away with an 18, but I’ve observed light strikes across a pretty good cross section of pistols using a variety of factory ammunition and reloads. 18s are a no-go for duty or carry use IMO. Even with a 19 pound spring, you need to stay on top of regular replacement. Our duty pistols stay stock. And FWIW, I run 19s, even in my match guns.