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Thanks for the info about the B5 grip, probably going to have to try one... IMHO think fatter is better for larger hands for trigger-finger placement. In my case, I’m just not sure about how the beaver tail meets up with the receiver, IIRC the Magpul K2 felt strange while the BCM seemed more natural... As an aside, I tried a Hiperfire grip and it’s monstrous, has to be one of, if not the fattest out there and trigger-wise it was awesome if you’ve got larger mitts, but the beaver tail fit was wonky too... maybe I didn’t give the different beaver tail shapes an honest chance...

For reference: here’s how steep the BCM MOD 3 grip is, and it’s fatter than most grips out there too... I wonder if the B5/Umbrella grip is fatter, because then I might want to try one? Also, tend to agree with MemphisMechanic and SergioSF that shorter vs maybe too long is better in that for most of us “shouldering” means mounting more on our chest than strictly on our shoulder, and transition speed matters maybe more just than pure stability... if you’ve got a good gun-fit you’re getting 4 points of contact vs a pistol w/ 2, even running shorter than what might be ideal for long range stability, you still get the mechanical advantage.

I totally agree, there is a place for the electronic ear pro. That said, most shooters, or most people really, don’t really get how the decibel scale works, and it works in a snowball/exponential way where a small number in dB’s means a lot more than the number might seem to appear/suggest... You could go to a rock concert at 130dB and your ears might ring for a day or two, go to a concert at 140dB and the ringing might not ever go away and one’s hearing might not ever be the same. I’ve worked in audio for a long time and am probably just a nerd about this subject, but while electronic ear pro might be popular, if you’re really looking to preserve your hearing, more NR is better, and passives are just better right now. Yes, the electronic ones let you hear more between shots, but I’ve never missed a command or a squib with passive ear pro ever. Honestly, the cheap foam ear plugs that do 34+dB NR are probably the best and muffs aren’t really ideal except for comfort’s sake. Also, and not to nerd out, electronic ear pro is based on an “active” system which uses compression/limiting of the audio signal to turn down the louder signals and turn up the quieter signals based on preset thresholds... none of the companies offering electronic ear pro will commit to exactly how fast their systems catch transients (like a snare drum’s crack, or a gun shot report), and if the transient sound isn’t caught fast enough then it doesn’t stop the potential damage...

I always wear the foamy type earplugs AND muffs indoors, I just use the foamies shooting outside (most foamies like the ubiquitous orange ones do 35dB NR which is pretty good). I purposely do not mess with or recommend electronic ear muffs because their noise reduction is generally lower rated by a significant dB amount versus passive muffs, usually 25-29dB NR. Decibels are hard to comprehend sometimes, but an extra 6dB is twice as loud! Passive are just better if you want to preserve your hearing. As for low profile muffs, I run the “Pro For Sho” muffs.... dumb name, but they’re 36dB NR and very low profile, especially for their NR rating.

I might try dropping in your old trigger and see what you get? Kind of a long shot, but since the new trigger might be interacting with the bolt differently than your old one, maybe that could be the culprit? Also, another long shot, but maybe just check the install of your Timney? I know when I pulled the Timney 683 from my PCC model (I prefer a Hiperfire) and installed it in a buddy's Gen 2, we figured out the hard way that Timney's installation directions were wrong, and we needed a different sized hex than what they had stated in order to properly secure the trigger housing correctly with the 2 little screws that press down on the plate (can't remember if it was one size up or down from what they said to use), when it's secure and installed correctly there should be no slop or wiggle in the housing at all...

LOP is something I wonder about and have been playing with too... When I first started shooting PCC I was running a super long LOP (probably ridiculously long honestly, like 15"+ because an MPX w/ adapter and tube will let you go really long and I was coming from an AR9-pattern PCC for a couple months running the stock all the way out), figured if it was a "rifle" I should run it as "rifle-ish" as possible, as I've almost always run the stock all the way out on my AR's. I'm not really sure if the long LOP was better shooting-wise (other than feeling super solid), but I DO know it made transitions to weak-side or bumping shoulders a PIA, and getting behind the optic weak-side with the other eye kind of a nightmare. Also, mounting the gun took maybe more “work” than what was ideal, partly because I was trying to mimic mounting an AR w/ a LPVO 1-6 (and it’s limited eye-relief) that’s set-up for a happy-medium between up close and getting taken out to 300-400+ yards. Fast-forward to now, and lately, after observing and getting info off of other shooters far further along than me, I've settled on a much shorter for me (but not really short) 13.25”-13.5” LOP measured middle-of-trigger to end-of-stock-butt-plate, just because I think I was missing the importance of getting a good mount every single time, where the dot just naturally lands right in front of you ready for "bang". I mean that's our "draw" in PCC, and it's huge to get that dialed. Plus, it's far easier to get behind the gun/optic weak-side with the shorter LOP. I possibly might end up going 1 notch longer at some point as I experiment, but I doubt I'd go longer than that, because I'd be compromising a good all-around gun-fit. I think there’s a tipping point usually between a notch where the gun-feel/fit goes from “quick handling” to starting to get “unwieldy”. For reference: I’m 6’2” and a bigger guy, for arms, I buy dress shirts that are 34/35 but opt for 36/37 when I can. That said, "gun-fitment" is really the thing... different body-types, different grips/stocks/handguards will yield different results. There's a podcast out there from not too long ago where Maxamundi was talking about the importance of getting a good gun-fit that I thought was really insightful... IIRC, Max said something to the effect of "Don't worry about the old adage of the stock coming to the crease in your arm..." Around 01:01:00 https://americanwarriorshow.libsyn.com/secrets-of-the-pcc-pistol-caliber-carbine-phenom-maxumundi-max-leograndis Edit: IMHO, I do think what grip you prefer has a lot to do with finding your “natural” LOP: personally I prefer grips with a shallower more straight/vertical grip angle (I like the BCM MOD3 grip) because it just feels better on my wrist and think that leads me to maybe going a bit shorter on my LOP... if I were running a more angled A2-style grip I’d probably lean towards going a bit longer...

I’d say take that tape off, regardless of the cross eye dominance... just use both eyes open and put the dot in front of whatever eye is in-line with the bore. Keep both eyes open and your brain does the rest. It’s like a lot of us shooting weak side get used to, the dot in the wrong eye doesn’t really matter, the rounds land on the dot either way... focus on the target and the dot is there. Being cross-eye-dominant arguably could be a plus, because both eyes open your “best” eye isn’t looking through lenses with a dot/1X style optic...

In my experience, the “3rd Gen” PCC version IS way less finicky, they didn’t change a lot*, but what changes they made seem to be an improvement... Still running the bolt wet tho! *Edit: 1 fairly “big” small change I noticed: the cam-pin on the new ones now is “normal” (at least on mine) and you don’t have to line up dots to reinstall it a certain direction... NOT noted in the manual which shows a 2nd Gen (way to go Sig ). So I’m guessing all the small changes maybe have made more of an impact than they seem... As an aside, just in case you you don’t already know, run the gas valve and tappet DRY. ...You can use oil/CLP or whatever to help clean it for sure, but wipe those suckers down when you’re done cleaning; you don’t want any sludge happening down there Happy MPX=bcg+wet, gas+dry

I always find it a bit strange when guys mention smaller-lensed optics being more “tube-like” or optics with larger windows having much better FOV or when manufacturers advertise such... I mean to a certain extent I get it, because casually that would seem to make sense and be the case, but actually it’s just an illusion (besides maybe a larger-windowed optic being easier to get behind or more forgiving because of where it’s mounted). Shooting both eyes open, FOV should basically be unlimited regardless of window size (if the glass is good quality), and the optic’s housing should “disappear” like one’s nose on their face does when one looks hard to the sides... I recently switched from a 510C (30mm window) to an Aimpoint micro-sized Holosun (20mm window) and haven’t noticed a difference at all (if anything, in my particular case I’ve actually picked up speed because I could mount the smaller sight better for me and closer to the bore).

I think just about anything will work if you keep the bolt wet, but I’d lean more towards something closer to oil than grease, because for a piston system the chamber/bolt gets pretty dirty quick in the MPX, and you don’t want it to turn into a sluggish slime once there’s a bunch of carbon introduced... I tend to run Mil-Comm TW-25B grease in Glocks and on larger moving parts like AR charging handles and such because it stays put, but I prefer to use FP-10 like I do on tighter fitted guns and parts with the MPX’s internals because it just seems to be slicker (plus FP-10 doesn’t smell bad if you get it all over lol). YMMV

I don’t think you can really get a blowback gun to cycle like and shoot as soft as an MPX, they’re just different animals in how they work, but I do think you can tune your dot bounce to where you like it if you play around enough and there’s certainly more variation to try different combinations over what the MPX system gives... the 5 tungsten short-stroke SCS is nearly as soft but the dot seems slower to recover, so you’ve kinda gotta find what is soft+fast with your load spring/weight wise... IMHO the dot bounce with the MPX has more to do with stock length, optic height, and good gun fit, as the buffer system stuff is already kinda one-size-fits-all soft as you’d ever bother and tied to your load. I’d work backwards from heavy to lighter, going 5 tungsten, play with springs, and maybe work lighter changing out steel for tungsten from there if you’re looking for softer shooting like an MPX, but it’s really about how fast you can shoot that second shot, so don’t be surprised if you end up liking a snappier gun, the systems are just different... the MBX buffer system set-up looks like something you’d explore beyond that...

Yeah, I’d just try running the bolt wet and bet it’ll run and lock back fine... I know there’s not much use for LRBHO in USPSA, but it’s nice to have everything working correctly. FWIW/IMHO while the MPX is it’s own animal, for me, since there’s more moving parts than a blowback gun, I tend to think it makes more sense to treat it like a gas .556 AR, and for me that means running it wet. YMMV

I’ve got about 2k of the Syntech 130gr through my “Gen3”, nerf-gun-soft and accurate without a single issue and I’ve never once cleaned the gun... That said, I run it very wet and lube the bolt a bit before every session/match. Which Syntech, 130gr PCC-specific stuff or “Action Pistol” 150gr..? I ask because I run the 150gr Syntech in my pistol, but have never tried the 150gr in the MPX, so the heavier bullet variety might act differently

Doesn’t bother me.

I run Hiperfire’s own “Hiperswitch”, it’s a 60 degree ambi that’s decent, and it’s 100% despite the silly name lol

Just mentioned this in another post, but figured I’d post it on its own in case any other MPX shooters came across similar weird issues I was having... When I first got my MPX put together I was experiencing some pretty weird issues with the gun just not sitting/feeling right, and with optic height, them seemingly being too low at a normal AR absolute co-witness height, and then with a riser added being maybe too much “heads up” with an odd chin/cheek weld; this is with a TTI stock adapter mounted as it looked natural with the adapter covering all the available pic slots on the butt of the receiver... Then I read somewhere that the MPX receiver is taller (like Sig’s MCX) than a traditional AR-type receiver, and noticed that TTI was mounting their adapter 1 pic notch lower than I had it mounted on their more recent MPX’s... So, turns out, if you put the barrel and buffer tube against a straightedge, the adapter mounted 1 pic notch down is closer to keeping the stock in-line with the bore, otherwise mounted higher, most of the buffer tube and the stock is actually higher than the barrel. Anyways, an AR absolute co-witness optic height = a lower 1/3 height on an MPX, and with the stock adapter mounted 1 pic notch down, feels exactly as it would on an AR. Conversely, with the the stock adapter mounted higher, an AR-height absolute co-witness optic will be lower and feel like it’s on a low mount... YMMV, some guys might actually like the buffer tube up high, but for me remounting the stock lower cleared up a bunch of what was feeling awkward about the MPX for a couple months, so maybe this helps someone out there...?

For me, I’m preferring the “3rd Gen” MPX PCC over any of the blowback guns I’ve run... without doing much of anything, it’s A LOT softer shooting then any buffer system tinkering ever got me and I’ve got next to no dot movement (if an aimed-pair is more than 1-2” apart it’s 100% me and not the gun), running factory 140ish pf ammo. I’m somewhere between 2500-3000rds without a single hiccup of any kind and without a single cleaning yet (I do run it wet AF though, adding lube pretty much every session), I’m purposely not cleaning it in order to see when it stops? I know it’s got to be about do for a cleaning though. That said, I’ve never even shot a single round through it without having already added a *TTI stock adapter + BCM SOPMOD stock, which I know contributes a lot to how solid and “locked in” the gun feels shouldered, helping to mitigate dot movement. *FYI, figured out the TTI adapter works best and is more truly in-line with the bore when set 1 pic notch “down” from where it looks like it should naturally be mounted (this is how Taran Butler is mounting them on all more recent MPX builds), and this also fixed the mystery of why my optic height felt so wonky compared to an AR, as the MPX has a greater sight-over-bore distance than a traditional AR... an absolute co-witness AR height optic = lower 1/3 on an MPX.

I bet these might might fit the Foxtrot Mike lowers as well, since they’re virtually identical to the PWS...?

Cool, hope it goes well! Btw, when I said I run it “wet” I mean like almost dripping lol! Thus far I’ve been lucky with my MPX as so far it’s been more reliable than other blowback guns I’ve had, and it’s just a joy to shoot because it’s so soft and flat shooting even at a higher pf, hope yours works too!

I would try running the bolt really wet (if you aren’t already), and letting your mags sit loaded for a few days to break in the springs, and then try some more factory ammo...? I haven’t cleaned mine at all through 2000+ rounds and 2 matches now, and it has been flawless, but I’ve only shot factory stuff (cheap 115gr Tula and/or Syntech 130gr PCC-specific stuff), both well above 140pf and it still kicks like a toy nerf gun compared to a blowback gun. BUT I’ve oiled the bolt very wet (I mean lube all over the bolt) before every shooting session or match... so might be worth a try?

Well, I stand corrected, looking at the times on stages I totally thought the laser helped, me being slower looking for the laser dot killed me in time versus guys I was shooting with just winging it fast Plus for me on certain targets I have to admit I was pausing a bit to decide to go optic or laser; too much to worry about for me at my level...

Whatever, that’s like an opinion man

Well, how do you shoot around impossible to get behind the optic barricades..?

You haven’t seen it yet then. Experience is what you get right after you needed it lol.

Idk, I guess if you wanted to, do it. Just think as rules stand laser>2nd dot IMHO