Hey everyone.  I need some help diagnosing failure to eject (FTE) issues with one of my Gen4 G19s.  I get constant FTE's and stovepiping with this G19 when I run 115gr ammo.  I have tried multiple brands of high quality factory new brass case 115gr ammo (Winchester, Fiocchi, S&B, Magtech, Federal, etc.) and the results are always the same.  I usually run a factory recoil spring assembly but I've tested it with a heavier stainless RSA w/factory weight spring and it will not run 115gr ammo.  

However, it runs 124gr and 147gr without any issues.  

I'm leaning towards replacing the recoil spring assembly, but I'm looking for some advice from others that have experience with this issue prior to throwing parts at the problem.  Any advice?  Thanks!

Here are the general specs:
Gen4 G19
Jagerwerks slide
Trijicon RMR RM0
S3F threaded barrel
TBRCi Micro-comp
Overwatch Precision Falx trigger
Dawson Precision RMR sights
Ghost connector

Probably hard to narrow down a cause since so much of the gun is after market parts, but I have seen plenty of posts here and elsewhere that the gen 4's at least until a pretty long break in period do not like light 115 grain plinking grade ammo. Shoot 124/147 for a while and then switch back to 115 after 500+ rounds. If it runs the heavier bullet weights I would just buy it in quantity. You have obviously spent a bunch of money for a tricked out gun, just spend $2 per box more for 124 grain loads.

How does it work with factory barrel? That will tell you a lot..If it runs the 115 then it's the barrel and the comp...I had to run a 11 to 13pound spring for 115 in my comp barrel to function.
If 115 doesn't work in OEM barrel then look at RSA and extractor. I suspect it's the barrel/comp.

My money is on the comp. try it with a stock barrel and I think this problem goes away.

The comp redirects gas, from the already anemic 115 grain round, that would have previously been used to properly cycle, and instead it is vents it out and away to mitigate its effects.

Problem, not enough ass remains after the comp does comp things. My expected solution, run stouter ammo (hotter 115's or heavier bullets) or you'll have to reduce the recoil spring. Good luck.

So with the TBRCi, it is recommended to run a 15lb recoil spring to run with 115 ammo.  There was a vendor somewhere that had a chart of spring weights required for factory setup, TBRCi comped, and "other". The other I assume was a KKM comp and that recommended a 13 lb spring.

It seems there are a bunch of people on here that require to run 124+gr ammo to cycle properly on a factory spring. The other solution is to run a lighter RSA spring

Your gun was a Glock 19, but my factory 19 shoots everything.

Lighter recoil spring is what you need.

This combined with 115gr probably target loads and the comp are most likely your problem.  You stated it works with 124/147 which I would hedge the bet that a lighter recoil spring would solve the problem when shooting 115gr target loads.

it's the comp. The guy that was testing the micro comp for TBRCi posted that he was running a lighter spring.
I have that comp on a gen3 17 and it was choking on 115gr ammo while right next to it my stock gen4 19 was gobbling up the same ammo.
My 17 was even malfunctioning with a 13lb spring. After getting an 11lb spring it seems I can run 115gr plinker ammo through the gun.
I think you probably need a 13lb spring for your gen4 19 to get it to function with the comp.

The whole experience has actually made me wonder about taking the comp off.  I just got a bunch of Speer Lawman 124gr that I'm going to try and see how that runs.

Thank you everyone for the input.  I suspect it's the TBRCi comp as well.  

I have a 13lb RSA arriving today and will test it at my next range session.