RickT

Tried the 507 yesterday and had no trouble keeping my right eye in the eye box. I did notice the benefit of the smaller sight (versus 510) in terms of target acquisition; much less of the visual field is obscured by the small sight. Also found the smaller circle to work a bit better than the 65 MOA.

I have a Wiland barrel (no ramp) and a Glock mag lower. It feeds just fine. Not sure why you might need the external ramp.

If you have problem with the blue loctite, go to green as recommended by Dawson when necessary. I have a rear sight that was over-filed by a gunsmith and is now "hand tight". Hasn't moved with green loctite in several thousand rounds. Green will even wick into the dovetail after installation.

Primers are the only item I'm nervous about I've got about enough on hand for 3-4 months at the rate we practice, but I'll hit up some local stores this week and see what they have. The interweb is simply "out". Unfortunately my wife is a high volume 22lr person and that stuff has become scarce very rapidly. I have a good supply fortunately.

I'll talk to CMMG on Monday. I did shoot both barrels side-by-side with the newer carrier/bolt (came with the 8" barrel) moved to the older 16" barrel. The problem, as expected, moved with the bolt/carrier. The carriers are slightly different, the older version having the additional surface at the rear of the carrier to increase total bearing surface in the receiver. I doubt that makes much of a difference. So, the old setup works, the new parts not so much.

Of course. I do have the advantage of two CMMG uppers. I won't bother to chrono, but I wouldn't expect much more than a 100 fps difference between the two barrel lengths. Regarding the PDX FTE that stuff makes for a good "thump" in our 9mm 1911s to it certain should cycle. I've put a BCM lower on the 16" upper and have loaded four Pmags with four different loads. We'll see what happens.

I have an original 16" 9mm Guard upper and a new 8" CMMG upper. I'm shooting both on an ADM lower. The long barrel runs everything including very soft (2.8 gr Sport Pistol/115gr coated) while the short barrel won't consistently eject 3.6gr loads with the same bullet. The 8" won't run 147gr Winchester PDX. It's got to be the bolt so I'll swap bolts at the next range session. Strange that this would happen with a new upper as I thought CMMG has resolved the ejector issues. Did talk to Brian at CMMG and he wants to know what I find. Obviously, they'll send me replacement parts if needed. The 8" version is a sweet gun to shoot. As always any/all suggestions appreciate.

Good points all. Setting aside the value, or lack thereof, of soft shooting rounds it isn't obvious why the energy that will cycle a 3-stage Taccom bolt in a 5.5" barrel PCC won't cycle a softly sprung 1911. Heck, the soft rounds will lock the PCC bolt back despite the heft 3rd stage spring of the Taccom bolt.

Got in before your post. Yep, wife needs very, very soft. I do want flat shooting. My heavy 16" barreled gun is flat with these soft loads but I may have to tinker with the shorter, lighter version.

Good information. I shoot SS so neither bull barrel nor light slide for me, but I might give the 7 lb. spring a try. Interestingly enough while testing some even lighter PCC loads yesterday (2.7gr SP with the 115gr Bayou bullets I found that the 1911 would actually cycle a 3.1gr load (versus my usual 3.4gr), but just barely. The temperatures are getting warmer in Idaho so I think that's part of what's going on. The Wiland barrel rifle is just at 5 lbs. and my wife needs the softest load I can make. When I get the tax stamp for my 8" CMMG upper I'll experiment with loads. I have plenty of WSF which would be a good powder for 145gr bullets and would likely create more of a push. Being also new to PCC I've got to experiment on recoil management, not that there is much, but a heavier bullet should help keep the reticle on target.

Currently using 115gr Bayou with Sport Pistol in both platforms for Steel Challenge. I'm new to PCC, but wife and I have put >150K rounds through our handguns. 3.4gr SP is about as soft as will cycle the 1911, but both my 16" (full rifling) and Wiland barreled PCCs will cycle with 2.8gr SP. I've been using in the 1911 a 9 lb. recoil spring and 19 lb. main spring forever. I don't need the 1911 to run softer, but I'm an old guy who likes to tinker. Is there a message in this data that I should try backing off on the 1911 springs or is there something about the PCC recoil/ejection dynamics that just lets them run with that little charge? I'll probably just take my backup 1911 and change the springing, but I'd be interested on anything someone might have to offer on this phenomenon.

Agree 100%, but I'll give the 507 a try.

I have a 512 on what is now my wife's PCC toy. We both really like the circle dot for steel challenge, but I'm intrigued by the smaller circle on the pistol sight variants. Anyone running one of these on their PCC? Opinions much appreciated. The trade is small eyebox, but the cheek weld is your friend and the small sight will be less intrusive in the visual field.

Shooting steel challenge I don't have to worry about PF. The softest loads that cycle reliably are ADM lower with CMMG RDB 16" barrel: 115gr Bayou, 2.8gr Sport Pistol, 1.145" FM Lower w/ Wiland 5.5" barrel: 115gr Bayou, 2.8gr Sport Pistol, 1.115" I'm going to try 2.7gr, but I'm probably as low as I can go. My wife having taken over the FM lower rifle I'll be running an 8" CMMG upper on the ADM lower once I have the tax stamp in hand. We'll see if that shorter barrel works with the same 2.8gr load. Both rifles are very soft shooting.

Steel Challenge loads in both my Wiland barrel PCC and 9mm 1911 with Sport Pistol are dirty, but pretty easy to clean up using M-pro 7, a very mild solvent. Typical session is 300+ rounds and the guns continue to function just fine.

Is the see-through the same in both red and green versions? My green 510C puts a yellowish cast on the outside world, probably expected if the reflective coating on the optics is biased to the green. If this is the case the red version should shift things toward cyan. Any observations? I do like the sight (one on of my PCCs); I would expect the smaller circle to be a bit better for steel challenge, but the 65 MOA still works better for me even with my surgically-enhanced right eye.

I finally finished up my S&B primers without ever getting them to work well in the RF100. My recommendation would be to avoid these primers in the RF100. Regarding my WSP comments, above, I switch from S&B to Winchester and the WSP primers are running perfectly, this without touching a thing. So, the "lost recipe" has been found; I just wish I knew what it was. I'm not touching anything and if this keeps up the 15K of CCI primers will get left to my grandkids; I'll stock up on WSP. The second thing I notice following my shock at how well the infernal device worked with the WSP primers was the different sound the primers make getting loaded into the press. The WSP (and CCI) primers make a racket at they roar down the tube. It always sounded as though the S&B primers were sticking/dragging in the tube and, sure enough, I had a few instances of primers not getting fed into the shuttle (1050) even though no jam was present.

I put together an upper with a Wiland barrel and Taccom extreme bolt/3-stage buffer. I can run a load softer than will work in my 9mm 1911 steel challenge gun. The guys at Wiland indicated they had seen velocities down near 700 fps, but I don't know the bolt/buffer combination. I can say that my setup (115gr Acme, 3.0SP, 1.11") is very, very soft.

I did a quick check with 15 and 33 round Glock mags loaded and empty. The mags are definitely not in contact with the bolt. Yes, the mag release is easier when the mags are empty and the release is definitely stiffer with a loaded 33 round mag, but I think that is somewhat do to the weight of the mag dragging on the mag release interface. Found an easy solution, simply re-position my index finger toward the rear edge of the release. The additional leverage worked just fine with loaded 33 round mags.

ck, Thanks for the response. First thing I noticed is that the 33 rnd Glock mags are a bit snug going in, but that's a good thing versus SGM which are very sloppy in the magwell. No doubt why they don't run and are, specifically, called out by FM as not suitable for their lower.

Completed switch from AR-15 lower to Foxtrot Mike. Upper uses Taccom 3-stage buffer and extreme bolt. Rifle functions 100% with Glock 33 round mags and is incredibly soft shooting. The only minor issue is the difficulty of releasing the mag on a closed bolt during "Unload and Show Clear". I can easily circumvent by ejecting the chambered round and locking the bolt back, but I'd prefer to either a)find a fix or b)determine that there is no fix, it's just "life".

At a recent "outlaw" USPSA indoor evening match I managed to do the follow: 1. Didn't check all my mags to make sure they would drop free on a reload. My only excuse: I normally shoot steel challenge. 2. Didn't pay enough attention loading my mags and, yes, one upside-down primer. At regular matches I case-gauge, and "almost" always at least look the primers when loading mags 3. Loaded mags (partially full) from my last SC match and realized I had loaded with my PCC rounds which look identical. Realized the issue and unloaded what I though were all the PCC rounds. Wrong. Had a failure to eject followed by a double feed when trying to clear. Excuse: I'm using up a bunch of Acme bullets which you can get in any color as long as it's red. Still, a lot of fun and being a)old and b) competing against much younger folks with a weapon light, RDS and 20 round mags I just try to come in mid-pack with my 9mm 1911. Any day you get to shoot is a good day.

115gr Acme, 3.0gr Sport Pistol, 1.11" OAL will cycle with the Taccom Extreme bolt and 3-stage buffer. 3.0gr is on the edge so after I run through a few hundred rounds I'll be loading 3.1gr. Recoil is, to say the least, minimal and great for steel challenge. I can't go any longer with the Acme bullets, but I've got some new cases that I'll use to experiment with OAL; my current lot of cases are worn out. Replaced AR-15 lower/Endomags with Foxtrot Mike lower/Glock mags. Endomags cycled 100% but having to use empty mag to eject a chambered round was a bit inconvenient.

Rebuilt my PCC with a Foxtrot Mike receiver (had been using Endomags). I swung by the range last night with only a 33rd SGM mag and a 10 round Magpul. I know SGM mags are not supposed to work and, no surprise, they didn't. I was puzzled by how sloppy the SGM is in the magwell, the Magpul a bit less so. I did insert a Glock mag this am and there was absolutely no fore/aft wiggle. Hopefully the Glock mags will feed in this morning's test. Are the SGM's slightly smaller in cross section to speed up mag changes?

Thread is OBE. Decided to go dedicated with a Foxtrot Mike stripped receiver. Stern looks solid, but more expensive than going with a receiver. Only reason to but this receiver under one of my ARs would be the nice 3.5 lb. trigger, but I can always upgrade one of my BCM lowers trigger-wise.