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Main spring effect on trigger pull, P-series

41K views 49 replies 21 participants last post by  Bruce Gray 
#1 · (Edited)
I originally posted this on another forum a couple of months ago. I've learned some additional info since, corrections are preceded and followed by **.

Hammer or main spring strength, as we know, has a direct affect on trigger pull weight (nothing new there :c). With double action, or modifications of DA such as DAK, LEM etc, where the trigger is directly compressing the hammer spring for at least part of the cocking main spring compression, the spring strength's affect on trigger pull is significant. It's a mechanical thing, work (pulling the trigger) is being done through some manner of linkage and lever to compress the mainspring. In my tests below you can see this direct effect.

On the other hand, with SA the slide is doing the work of cocking the hammer fully, so the hammer spring strength affects trigger pull weight in a more indirect manner, mostly due to increased tension at the sear to hammer interface, as the sear blocks hammer "rotation" until the sear is released by pulling the trigger. Thus the effect of varying mainspring strength on SA trigger pull should be less. **I've seen a trigger pull reduction of up to 5 lbs after properly fitting a poorly fitted sear to hammer interface. This on a P938 that somehow escaped Sig factory with a trigger pull of over 12.5 lbs. I should note too, that a sear with a more positive angle cut will tent to exacerbate the ramp up of trigger pull to spring strength in SA, as it must slightly further cock the hammer and compress the main spring as the sear "cams" out of the hammer notch to release the hammer.**

So, to find out more, I did some testing with springs from Wolf and Gray Guns (GGI). ** Gray Guns told me thay purchase there main springs from Wolf, so the variations I observed are batch to batch variations in manufacturing. i.e. a spring may be labeled as 17 lbs, but the actual spring strength may vary a bit. In my tests, GGI means Wolf springs too - different batch.**

The test gun is a '99 vintage P229 DA/SA. I had previously done a trigger job on this gun, polishing internals and fitting sear to hammer. All trigger pull measurements listed are averages of 10 pulls each, all done in the same manner, holding gun stationary and pulling from mid point on the trigger, parallel and in line with slide, slowly increasing tension to break using a calibrated Lyman digital scale.

Prior to testing, I measured the installed length of a hammer spring on the test pistol, both "relaxed" and at full cock. The spring length at full cock measured 0.850".

I cobbled together a digital spring test stand using a SS draw rod. I made a hook on one end and threaded the other for a washer and nut to capture the spring. I passed the draw rod through a Delrin bench block held in a vise. And then used a digital scale (not the Lyman as it overloads at 12.5 lb) to pull the draw rod to compress the spring under test to the aforementioned 0.850" length. All three Wolf springs were close to their advertised strengths of 17, 18, and 19 pounds when compressed to a length of 0.850" (they were all about 3 or 4 ounces under their rated strength. They doubtless use a proper test rig - - so I'll call mine a little bit inaccurate - - but at least it seemed to be consistent.)

I only tested two samples of GGI's 17 lb springs **Same as Wolf, I'm guessing different batch**. Both of these springs measured just under 16 lbs on my test rig, a full pound under the Wolf 17 lb springs (this difference is also born out in the trigger pull numbers to follow).

Hammer springs were swapped out and both DA and SA trigger measurements made, no other changes were made to the test gun between spring swaps.

Wolf springs:

17 lb spring / DA 8 lb-11 oz / SA 3 lb-14.3 oz

18 lb spring / DA 9 lb- 1 oz / SA 4 lb- 2.6 oz

19 lb spring / DA 10 lb-.5 oz / SA 4 lb- 5.1 oz

(Note: you can see the trigger pull weight moving up in a non-linear fashion, with a much bigger jump from 18 to 19 than from 17 to 18 - no conclusion here, but I wonder if testing a 20 lb spring would have more dramatically increased trigger pull?)

GGI spring:

17 lb spring (measured as 16 lb.) / DA 8 lb-7 oz / SA 3 lb-13.5 oz

(Note: if you consider the GGI spring as 16 lb spring and plug it's numbers in ahead of the 17 lb Wolf, the even smaller step in trigger pull weights lends additional credence to the idea that DA trigger pull weight increases non-linearly and faster as hammer spring strength increases.)

I did one final "test" to confirm the Wolf and GGI 17 pound springs really were of different strengths. Using a Delrin plastic punch dropped down the barrel, I shot the rod out of the barrel with just the firing pin impact on the rod. The GGI 17 lb spring shot the rod approximately 3 feet high while the 17 lb Wolf spring shot the rod 8 to 12 inches higher in a half dozen tests each.

Please note that I am not saying GGI springs are of lesser quality than Wolf, or visa versa. I have no idea how they each "rate" their spring strength. I used a compressed length of 0.850" as that is what the spring measure on the gun AND that happened to be the length of compression that the Wolf springs were close to their rated weight.

After the tests, I installed an 18 lb Wolf spring in the gun.

bumper
 
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#5 ·
Good question. I guess 'cause I'm a bit of a coward. 17 works, I tried it, no miss-fires, but the primer impression is a tadge shallower than with the 18. And I think Gray Guns recommends no weaker than 18 for carry, 17 for competition. That colored my decision making I guess.

I'm working on a new to me (and almost brand new) P226 SS Elite made in 2010. Going in it has a DA of 11.5 lbs and a SA pull of just over 5 lbs. Nothing like my P229 carry with smooth DA of just over 8 and SA 3.5. This P226 has all kinds of stiff and stagy stuff going on during the DA pull. I'll report back on how it turns out.
 
#3 · (Edited)
I'm sitting here early on a Saturday morning fondling my new P226 Legion thinking to myself, "How can I reduce the DA pull weight on this thing?" I mean, it is powerful enough to catapult rocks to the moon, I think. :)

Ten pounds...yowzers. I guess I'm a bit spoiled at this point by my Wilson Combat Beretta Brigadier Tactical, which has a reduced power mainspring (the D hammer spring).

And up pops your article, brother.

Wow, talk about a home run with a first post!

.
 
#4 · (Edited)
BIG QUESTION TO/FOR ANYONE WHO HAS SWAPPED OUT THE MAINSPRING:

Have you experienced any light primer strike/fail to fire issues as a result?

.
 
#6 ·
Yes, but only with a 16 pound mainspring that was brand "X" and was over 18 months old. I don't remember where it came from.

Going to 18 or 19 solves the problem nicely but increases the trigger pull on my 220 DAO.
 
#7 ·
I guess I never did report back on that P226 SSE :(

I did a full "bumper" action job on it. This is a German frame USA slide gun. The SS frame had small burrs and machine marks in the area of the hammer pivot and this was scratching the hammer and causing a fair amount of trigger roughness. So much for the vaunted "always good" German mfging. I cleaned up the frame roughness with flat diamond hones (as they fit nicely) and that came out as smooth as a baby's posterior.

Replaced short reach trigger with standard.
Reduced sear engagement angle.
Installed hammer pivot cam/spacer (similar to what Robert Burke installs but of my own design) to remove DA pre-travel.
Installed trigger over-travel.
Smoothed action.
SRT
Installed high lift safety lever of my design.

SA pull 3 lbs
DA pull 8 lbs
 
#8 ·
So far, no light primer strikes using 17-lb mainsprings. But I only use them (along with the rest of the Gray Guns Master P-Series spring set) on competition guns. Various ammo from White Box to Blazer Brass to Freedom Remans.
 
#9 ·
The 18 lb Wolff has been my go-to for all my classic P series pistols. The type of hammer strut set-up also has a great deal to do with the feel and staging of the pull in my opinion. I prefer the old long metal "4 piece" struts assembly with an 18 lb spring, but a 19 feels good to just a slight bit more stout. Problem is changing springs out if you want to, which is why I bought extra parts and pre-loaded several assemblies to swap in and out of different pistols. My second fave is the new "E2" short plastic base setup with the short 18 lb spring. Has a very nice even pull that feels like the old long base to me and much easier to change and test springs. Last is the long base plastic. Just don't like the way it stages and loads up toward the end. Could be my imagination, but that's the only one that counts. :D
 
#10 ·
I have noticed that, but never really attributed it to hammer spring assembly variations. I believe it is because the solid, 4-piece design was contained and lack of seat, so a more solid feel. The middle-era with the long seat would logically have more flex being longer plastic, while the E2 has more metal and less flex to deal with, although both have identical springs.

This is probably why I've recently decided to update all of my classic P's to the E2 style (also for future replacement parts availability).
 
#11 ·
I also like the old long-strut/bracket type, but it is hard to fit under various grips. 18-lb spring is as low as I would go for anything that I would actually carry. I've also found the the 18-lb can sometimes feel lighter than a 17-lb spring because the 17-lb spring is actually longer than the 18, so it kinks a bit on the strut, whereas the shorter spring compresses more straight.
 
#13 ·
Have a 229 under the bed and a 226 for all my shooting. Both have the GGI hammer, sear and spring kits from GGI. I have the Wolff 18 lbs in both. The GGI 17lb would leave some lite primer strikes and ftf. No big deal except for the 229 under the bed. That one can never have a ftf. Top quality ammo would always work even with he 17lb. Most all the ammo worked good even with the 17lb. Some gun show reloads would ftf and some Freedom Munitions ammo would ftf. All the internals are polished to mirror finish and move with little effort. Guess if I used the 19lb it would have less ftf. But like the Freedom Munitions a lot and price is right. No ftf with Atlnata Arms, ASYM or other match ammo though.
 
#14 ·
Then the problems with FTFs you are seeing coming from either primers that aren't fully seated or harder primers or both.

I solved that problem with one of my 220s by going to the 18 pound spring. I started with 16 pounds and had a few problems, then 17 pounds with the occasional problem, like 1/100, then no problems at all with 18 pounds.
 
#15 ·
bumper,

Thank you for sharing all your data. Your posts are always well written and make sense to me. The sear angle as you mentioned can be a significant contributor to SA pull weight. My oldest SIG, a P229 ADxxxx seems to have less angle that the newer ones; driven by liability concerns I suppose?

On a couple revolvers I had used a triangular shaped ceramic stick from Brownells to stone a less-agressive angle on the hammer/sear. I clamped the part in a milling machine vice, with the surface to be stoned sticking above the vise jaws a couple thousandths, stoning down to the top of the jaws to keep things flat and perpendicular, etc. This seemed to work OK but I'd be interested in learning better methods/better tools to do this. I've seen for sale, fixtures for 1911s that allow checking the sear/hammer interface, and could see making one of those for working on my own SIGs.
 
#16 ·
#18 ·
By no coincidence (they are good stuff and I'd trust Willard's judgement too!) I posted pics of the stuff he talked about. I responded to BOd42 before seeing Willard's post.

If doing just a few, might make sense to use a milling vise to hold the part to be stoned. Note that there IS a difference between a proper milling vise than what you might have on most workbenches. The jaws will be parallel and will stay so when clamping up a part, still it's good to stay near the center of the jaws. Also, UHMW-PE tape is good to have to protect the jaw on each side of the part. Ultra High Molecular Weight - Polyethylene is about the most abrasion resistant long chain polymer known. Tougher against aggregate than many steels. Yet it's next to Teflon in terms of slippery. Amazing stuff for many applications, so you should have a roll in your shop anyway.

Otherwise if you simply like tools, and you have your wife thinking that tools are off budget as far as your toy account is concerned, "Power Custom Series 1 and 2" are nice to have. Their fitting block, P226 shown above (Fits most all the P-Series).

The Power Custom jig has a kinda clunky stone holder, good, , so I normally line the fixture slide part with,. . . . yup, UHMW*, then just use the stone directly on the fixture rather than clamping it in the holder.

When buying UHMW tape, suggest getting no thicker than .006" at first. Thinner conforms to a simple bend like a 90* better than .010" and the like. None of it will conform to compound curves, as it's too strong to stretch much. Get the acrylic adhesive in preference to rubber, and be sure to degrease surfaces before application, room temp or warmer.
 
#20 ·
Thanks for the tip on the ultra high molecular weight tape. Snowmobile slide rails are made of that stuff. I had used some 3M adhesive backed plastic sheet (0.01" polycarbonate I think) that we use at work to make overlays. But that will wear during a usage like this.

Right about not all vises being created equal! My wife grants me quite a bit of latitude on the tool budget; I feel fortunate about that. So maybe will end up with the tooling. Does the fixture you show in the pic with a sear mounted, assist in achieving the desired angle?
 
#23 ·
If it's from the same "generation"! Metal mainspring seats use the same length spring. All "Nylon" seats, whether long or short, use the same spring. The P239 is the exception, along with possibly the P225A1.
 
#25 ·
This is a very interesting, informative thread. I thought about changing the main spring on my 229s, but even though their round count is under 5k, their DA pull lightened considerably over time, and particularly after I installed the GGI straight trigger. Now they are all under 9lbs. What's even more interesting is that on my 227, the DA with the same GGI trigger is now around 7lbs. This is all with original springs. Are the springs getting that much weaker (DA pull when new on all was over 10lbs)? Or is there something about the mechanical advantage of the straight trigger plus the self polishing of the the fire control unit?
 
#26 ·
It may be to do with the "length" of the struts, creating a mechanical advantage. Do both use the same length seat, and strut?
 
#30 ·
I found out later that Gray Guns purchases their springs from Wolff. When I discussed my finding re spring strength with Wolff, they allowed as to how they'll check several springs from a run to confirm strength, but it can vary by as much as a pound either way.

So "worst" case, a 17 pound spring may actually be 18. And a 19 could be an 18 too!
 
#31 ·
I put a Mainspring-1 in mine which I’m guessing is “19” lbs. That means the only avenue left is the Action Enhancement Package. My CCW requirements are only for factory specs , no changing of springs etc . Even a slight reduction would be fine. It’s even good as is with a few thousand rounds through it.
 
#32 ·
The Factory spring used with a plastic base, is 20#, you may "smooth" the pull some, by removing the "edges" on the hammer strut, where it passes through the spring, and applying a light film of grease... here is how I modify my struts... you may also detect an improvement by going to the long strut and short seat, if you have the short strut and long seat.
 

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#39 ·
So after some testing, I seemed to have noticed that the AC springs seemed "softer" than the GGI or Wolff counterparts. I have no way of testing to get quantitative data of the spring tension itself, but I think this may be an interesting thing to look into.

Upon further inspection, I'm surprised to find that the Wolff spring was actually longer by about 1.5mm than the stock, GGI and AC alternatives. My caliper says it's OD is also slightly less.

Weirdly enough, I've been using the GGI 17lb without fail. I then swapped over to test the 16 and 17lbs from AC and started getting light strikes. The Wolff 17 fared better than the AC 17 but still had some light strikes. The 18lb AC had substantially less, the 19lb AC had none. The 17lb GGI has continuously had none as well (save for one light strike in thousands and thousands of rounds of a harder silver CCI primer, it seems that this was an ammo issue). I'm dumbfounded as to how did they rate this spring. It seems that it could be possible that my GGI 17lbs (procured from 2 main spring kits purchased separately a little more than a year ago, months apart) has a tension that perhaps could be closer to the 18-19 range. I was still using fiocchi primers, not unless I was sold primers that just look like gold fiocchis but actually weren't. Reinstalling the GGI 17lb spring, I didn't see any further issues with light strikes much like the 19lb blue AC spring. The 18lb green AC spring ran well but I encountered a light strike that then proceeded to fire after a restrike. The Wolff 17 gave me around 5 light strikes in about 300 rounds. The AC 17lb gave me a light strike on 2/5 (the first cartridge included, and I got irritated and instantly swapped springs). Weirdly as well, the DA seemed to strike stronger on some of the primers. The gun may opt not to fire a shot in SA but will fire a shot in DA more reliably. Perhaps, it's ammo related.
 
#43 ·
I would suggest counting "coils"... as years ago before all of the aftermarket industry, the common cure to lighten pull weights, were to snip off so many coils from a spring.

Just as your mention about different lengths. Wire diameter, and coil spacing prior to heat treatment, and drawing to spring temper, all made a difference on tension.

A simple spring tester, like this commercial model for testing 1911 recoil springs (shown below) can be made to test mainsprings using an eye bolt with a diameter small enough to pass through the spring.


Measuring instrument Tool Moisture meter Technology Ph meter



To "level the playing field, you would need to measure your mainspring, at it's slightly compressed, relaxed state... and then again at it's compressed length while in your pistol. The tension to compress the spring from it's relaxed length, to it's compressed length would be your comparison.
 
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#44 ·
I would suggest counting "coils"... as years ago before all of the aftermarket industry, the common cure to lighten pull weights, were to snip off so many coils from a spring.

Just as your mention about different lengths. Wire diameter, and coil spacing prior to heat treatment, and drawing to spring temper, all made a difference on tension.

A simple spring tester, like this commercial model for testing 1911 recoil springs (shown below) can be made to test mainsprings using an eye bolt with a diameter small enough to pass through the spring.


View attachment 324994


To "level the playing field, you would need to measure your mainspring, at it's slightly compressed, relaxed state... and then again at it's compressed length while in your pistol. The tension to compress the spring from it's relaxed length, to it's compressed length would be your comparison.
That's some awesome bit of kit and will be on the look out for that, thanks Willard! That picture has easily allowed me to imagine what bumper made to test with in his first post.

Weirdly enough, I have at least 3 GGI 19lb mainsprings that don't have the same number of coils (a couple were 14 coils from an SRT kit, and others 13, from master spring kits), but are all rated 19lbs. OD is generally 6.24mm based on what I read from my caliper, total length seemed to be the same at 32.7mm (apart from Wolff's longer 17 with 34.3mm) and ID seemed to be around the ball park of 4.00-4.04mm. The measurements have me stumped, even if they probably are made of the same material.
 
#49 ·
Hi sorry I'm a newbie here but
I have a 229 question.....
The few seconds on my two pistols are I bought new a 226 about 10 years ago...I'm in California it does not have the California groove cut in it at the top of the barrel, I think it's a round indecater or something like that (?) It is a DA/SA SRT SS Elite I did a package thing at the factory they went through polished everything up made everything look nice check out the action replace the springs with Grey's stuff ,G2 modern grips etc.... To me it works great I got in a car accident I was down for about a year-and-a-half I was in the hospital for 6 months and I pick the thing up after almost a year-and-a-half of not shooting in fired up really respectable group so never had any problems with it really like it..... Maybe because our slides ride high I've never had an issue with the locking lever or decocking lever..... I think I'm going to leave it alone at this point I have a 357 Sig barrel for it and it was a 40 frame to start out with I have the 22 slide on the top so I can fire 22 with it with my kid if I want to Life goes on.. .

But I had to start thinking about CCW, and I looked at smaller varieties but the way the 229 just feels so good in the hand and everything is close to muscle memory I say this without ever firing this particular one I fired other stuff then all of a sudden we have this craziness happened the day that I was picking it up I had a two-hour wait to pick it up then I had to get the 357 barrel modified to CA , cut the groove in it....That took three weeks because of all the gunsmiths being behind here so I just got it back...... I probably should fire it and get used to it before doing anything on it but I know my 226 so I kind of know what I want I think somewhat....
even though there's been this work on it it has the regular stock mainspring on the 226, I'm happy with it so far because the action is so clean after being rework that I don't notice the extra poundage....
Hi I have a few questions on 229 being a CCW
one person in this thread I think the person who started it say something to the effect that Grey recommend 17-pound for notch but 18 pound for concealed carry? Is that true? I want everything to be smooth and working and happy if I ever have to use it...so it's a
229R-40-ESE-CA manufacturers part number
798681434725 sku
1596
Sig Sauer P229 Enhanced Elite CALIFORNIA LEGAL - .40S&W.

the guy who cut the groove in the 357 Sig barrel to make it California compliant took both the 40 that it came with and the 357 Sig fired a half box through it went through it did a field strip field clean polish to become a little bir here and there and didn't charge me anything except for the initial charge for the barrel work, just been gone through with an educated eye at least

I have a gray guns fat guide rod
I was going to put on legend decocking lever and legend slide release... Just to make it as smooth as possible being CCW,

I looked at the $39 legend adjustable trigger.... But the footnotes down below on Grey's site say California probably not legal it wasn't totally concise but I think mr. Gray is giving me a warning also if I was going to do this in a CCW it'll probably be inspected so I need to probably just keep everything chill unless anybody has any advice on that or what would I gain with the adjustable trigger I'm not super familiar because I haven't played with one before....I don't know if I want to put legion grips on it they're kind of cool but these are pretty cool to the stock ones unless somebody has any advice on that as well?

Sorry for my marathon post... Now I've introduced my two firearms that we're dealing with my other post will be much shorter and also set up a profile so it's at the bottom of my signature etc....
Thanks guys
 
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