I installed only the Apex aluminum trigger in my .45 and my Lyman gauge shows 4.2#. I hate the factory hinged plastic triggers and have Apex triggers in all my M&P's.
FWIW, I had some eject issues with my M&P 9L CORE and my Glock 19 using 115 gr. ammo. My solution was installing weaker recoil springs. I'm using a ISMI 13# spring in my 9L and a Wolff 15# spring and guide rod in my G19. Both run flawlessly now using any ammo, 115 gr. range ammo to 147 gr. +P...
I don't like the M&P 2-piece hinged trigger and have Apex triggers in my Shield 9 & .45 and Pro CORE. A light, crisp trigger helps accuracy a great deal.
First malfunction at 1,985 rounds fired, leads me to believe you should clean more often. I'm thinking the problem is carbon in the extractor channel. Remove the extractor and spring, soak them, and brush the channel.
I have Apex triggers, sears, extractors, etc., in all my M&P's, Shields, and Glocks. Apex people are very dedicated and customer oriented.
Why do people keep using Frog Lube? I have tried just about everything and now exclusively use Slip 2000.
I haven't changed any springs, only the trigger (and did some polishing.) I will install the sear and striker block only. I'm advised these upgrades will give me about 4- 4.5# pull, which is what I want.
Got the CORE, jpoint and trigger. Sighted-in at the range for an hour and shot 100 rounds of 115 FMJ. I'm hitting bullseyes but not especially tight groups. I'm thinking the trigger needs a lighter pull, so I ordered the Apex fully machined sear and ultimate striker block.
This is a fun...