It looks like the author encountered reliability issues with the KKM Comp. The 417 may be slightly less effective but if reliability is there then I'd be more down for that. I know Chuck and all those guys run the KKM and maybe they found the secret sauce. But, I know Cowan did testing on the Agency and found it reliable across many ammo pressures and weight grains. Especially when compared to bare muzzle, I'm guessing the KKM and Agency are hard to tell apart. Especially being that most comps aren't even activated properly when using 115gr. If there is a slight edge with a comp compared to a stock muzzle, then I think we have to look at how much slighter of an edge the KKM has over the 417. This is coming from a guy who has shot neither, but if we look at the ransom rest images in the article, that's the conclusion I draw.
I can't comment on any comps besides the KKM. I am surprised that they experienced issues with Fiocchi 124 which I've found to be hot as hell.
I try not to post a lot here because I don't know shit about shit but I'm starting to get to know this gun setup. I know this isn't a huge sample size, especially on some of the brands but I think it's decent enough that I've figured out what the gun likes and what it takes to run it.
I shot a pretty good number of different ball ammos looking for one that had a similar POI to my chosen carry ammo. I'm probably getting close to 4000 rounds into this slide and I have not had any reliability problems or funkyness happening. My prime directive going into this space blaster project was if it detracts at all from reliability it is a no go.
All comments are with all stock Gen 5 Springs. Most numbers are rounded to 100. If it says 100 I bought 100 rounds and shot most of it but didn't continue shooting because the POI was to far off at 25y from 124 +P HST for my liking. Also some of this was shot during "No Clean November" where I was about 1100 rounds deep without cleaning.
900ish Rounds Federal HST 124 +P: No issues, KKM barrel really likes this load.
300ish Rounds Federal HST 147 +P: No Issues, shot very well from KKM barrel also.
100 Rounds Speer Gold Dot 124 +P: No Issues
100 Rounds Speer Gold Dot 147: No Issues (did not activate comp very much).
500 Rounds Winchest 124 NATO: No issues, lock back on the oldest of the old Gen3 mags.
800 Rounds Blazer Brass 124: Sometimes does not lock back on my old gen 3 mags (yea I know throw them in the trash). Runs fine on Gen 5 G17 w/ and w/o Arredondo +5 Basepad.
700 Rounds Federal AE 124g: Unicorn fart light load, I can feel the barrel locking up as it goes into battery. If my thumb is riding on the slide it does not lock back old mags or +5s, sometimes will not lock back standard cap gen 5 g17 mag.
200 Rounds Speer Lawman 124g: No Issues
100 Rounds Fiocchi 124g: No issues (did not test with old mags)
100 Rounds Fiocchi 115g: No Issues (did not test with old mags)
100 Rounds S&B 115g: No Issues (did not test with old mags)
200 Rounds Federal RTP 115: No Issues (did not test with old mags)
The 124 American Eagle is by FAR the weakest of all these ammos I shot and the only thing it does is not lock back on an empty mag. I do have a 15# recoil spring I got to mess around with and this does lock back all of the weaker ammo even on old mags. I don't use it very often because I prefer the recoil profile of the stock RSA.
All of that said, I think you'd be served well by either the 417 or KKM. One thing to consider is slide to comp fit if you plan on using it in a duty holster. I cannot use my KKM comp with a Gen 5 gun in a Safariland because of the gap between the bullnose slide and comp. I imagine that would still be an issue with the 417 but Cowan would probably be able to speak definitively to that. I spoke with KKM recently and a Gen 5 contoured comp is coming out the end of this year or early 2019.
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