Increasing striker spring strength will increase the trigger pull. I
think it increases the takeup more than the break, but I've never actually used a scale to check. My G23 has an increased striker spring. I guess I could tear down the gun and swap springs, if you're interested.
Also, to decrease trigger pull, you want an
increased power trigger spring, and also to drill a hole in your trigger bar. The normal trigger spring pulls back on the trigger, and up. An increased power one would decrease the takeup more than the break, since it would be pulling up harder as well as back. Drilling a hole above the normal trigger bar hole and attaching the spring there makes it pull up less hard, evening things out. It's supposed to be great for removing the transition between takeup (just moving striker) and break (moving striker and also lowering cruciform). It's extremely hard to do though, unless you've got a drill press.
Current mods:
TIG welded feed ramp, fully supported chamber (shouldn't affect trigger)
Striker hood machined off at 45 degree angle
Polished internals
3.5# connector
Machined trigger bar tab (part that hits the connector) to eliminate overtravel
Everything measured at the middle of the trigger. Also the trigger bar tab, side of the frame, and connector were bone dry since that's easier than trying to keep it consistently lubed while taking the thing apart over and over.
-------Wolff 6 pound increased power striker------------
NY-1 trigger spring housing
only (no coil spring):
takeup 5 pounds, break 7 pounds (what I leave the gun at)
No trigger spring(trigger must be held to rear while racking slide to reset):
takeup 5 pounds, break 6 pounds (best feeling, but holding trigger while racking slide is a no-no; grinding down NY-1 housing until it pushes with the bare minimum resistance to reset the trigger may get similar results)
Standard trigger spring:
takeup 4 pounds, break 5.5 pounds
I'd like to be able to test the standard trigger spring in a raised hole, but the darn Glockmetal they use in these things is the hardest stuff in the universe. I've gone through 3 drill bits (2 cobalt, 1 titanium, low speed with lubricant) and they've barely made a dent in this thing.
NY-1 normal trigger spring with spring:
takeup 6 pounds, break 8.5 pounds (increased takeup is from friction from the spring housing shoving against the trigger bar)
------standard weight OEM striker-----------
Ouchie finger time. Man, I hate changing striker springs. If I lose those darn spring cups, I'm going to be mad.
Whew, that was gratifyingly uneventful. The gun now makes its old "clack" noise, instead of the "clonk" of the Wolff spring.
NY-1 housing only:
takeup 4.5 pounds, break 7 pounds
No spring:
takeup 4.5 pounds, break 6 pounds
Standard spring:
takeup 3 pounds, break 5.25 pounds
NY-1 entire thing:
takeup 5 pounds, break 8.5 pounds
So if you're going for a smooth trigger pull with minimal transition between takeup and the break, an increased power striker spring is good, and an increased power trigger spring plus a raised hole would be even better. If you're going for a "crisp" trigger, I suggest filling the gun with sauerkraut.
I may be willing to do the same tests with a 5.5# connector, if you pay me money or gun parts or something. Glocks may be easy to detail strip, but it was still kinda time-consuming.
I did try the 5.5# connector with standard springs (both) out of curiousity, and ended up with 3 pound takeup and 7 pound break. Yuck.