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MoRivera

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Everything posted by MoRivera

  1. I don't know as of yet. Other models... Bobbed hammers...
  2. He's a shooter friend, a very good one who competes nationally and also a machinist. He's been developing a straight thread-on aluminum comp for the TS with threaded barrel, and from what I gather he's honing in on the final design. Gotten some good feedback and reviews for shooters he's made it for. Summer is when he's going to be back near his shop. Wire EDM-ed to the slide, whatever that means. Also working on some optics mounts and slide rackers as well as other comps, I believe. This is all shared with his blessing, by the way.
  3. Would require a completely different trigger bar structure as well as the frame/disconnector, if you're referencing the CZ75B or SP01. Was never designed to be anything but SAO as far as I know.
  4. Little preview of something a friend of mine has been working on....
  5. I have an extra one of these that I'm not using, was going to use it for an SP01 Project while back but didn't..... https://czcustom.com/cz-parts-all/red-dot-mounting/multi-optic-side-scope-mount-5.html When on the SP01, it was a little too far to the right which tells me it's made for the wider frame of the TS or the Shadow 2. I would have to shim it about 0.050" to center it over the slide on an SP01. As for lining up with the strange CZ downward bore angle, there's also a jig that they sell which I assume helps with that: https://czcustom.com/scope-mount-hole-drilling-taping-jig.html
  6. Update: went to the range with just the 8" upper, in the Anderson receiver, no port cover, new replacement bolt. Ran like a top, 200 rounds and change, not a single hang-up or issue, bolt locked open. 115-gr factory Blazer Brass, and 147-gr subsonic through an Omega 9K suppressor. H1 buffer. Fast strings of doubles and triples, even some tac reloads which would be the death knell before. Ejection was a consistent and healthy 4:00-4:30. So it seems so far (again only 200-250 rds) that some combination of above has done the trick, but I can't help but wonder if like before it's fine in the beginning but will soon just all go to hell again. I'm still pretty confident in my longer upper getting through a match as it has each time, but the shorter one for 'fun' matches and maybe even some home defense with suppressor...still wary. Can only tell if it's really fixed if it holds together up to 1000 rounds or so. Last round count where it went bad after refreshing the extractor and ejector springs was only around 450. Will see if CMMG will still offer some sort of replacement for the damaged bolt. At least from the looks of out (again only first 200+ rounds), the lugs/edges seems to be fine but you can see wear the brunt of the contact wear is. Except the second and third lug after the extractor seem to have their leading edges at an angle compared to the rest. Don't know if that's from initial wear or by design.
  7. Inspected the bolt closely and saw this..... Chipping on three lugs of the bolt right at the angled cuts where it engages the barrel extension and rotates. Wondering if that is having anything to do, but as mentioned no problems noticed with the 16" barrel. Others have experienced, documented here..... https://www.ar15.com/forums/Armory/CMMG-RDB-9mm-Chipped-Bolt-Lug/48-511703/ I've written to CMMG to inquire and hopefully replaced. I the meantime I have a 'repair kit' which comes with an extra bolt and extractor, etc. Will replace but wondering if it will happen again. Also wondering if I should go with some grease on the lugs, but concerned that may gum up with fouling even more.
  8. Okay so...going off the rearward movement/headspacing as demonstrated above in video, I measured it comparing my 16" barrel and my 8" barrel. With the 16" I got about 2mm of total rearward movement. Withe the 8" barrel I got 1.5mm of total rearward movement. I was expecting the opposite! Since I'm experiencing all the FTE's and stovepipes with the shorter barrel, I figured it would have more excessive headspace and not have as much leverage on the expended shell to flick it out. Does the 8" not have enough headspace? Just ejecting a dummy round/snap cap by hand, the longer barreled upper at least drops it out the ejection port. The shorter one almost never does, just lets it trundle out the bottom/magwell, no matter how fast I try to rack back. So I'm still stumped as to how the shorter barrel upper is so unreliable, whereas come to think of it I've never had a hangup with my longer-barreled upper, through a bunch of matches and a lot of rounds - except maybe one issue at the end of the magazine, which I attribute more to the magazine (P-Mag Endomag insert). That's kind of fortunate for me as my longer-barreled one is for matches, and the shorty is more of a fun gun or maybe for a suppressor, so the longer gets more use. But still, the difference is worrisome. Question...is a lighter buffer proffered for the short barrel because of less rear pressure? I was using an H2 equivalent buffer, then switched to an H1 for the 8" but still having these problems. Was wondering if I should go down to a Carbine-weight to ensure better rearward velocity/ejection with a shorter barrel?
  9. Some more notes about the head spacing and the nature of the ejector, probably already posted elsewhere but anyway..... https://c3junkie.com/?page_id=280 And headspace: I noticed that I have a bit more of this on my 8" barrel than on my 16" one. So that may contribute to why I'm seeing a lot more malfunctions with the 8".
  10. Crap....I'm wondering if the culprit is, of all things, this... That's on the receiver for the 8". The one on my longer barrel looks like this.... ...and I remember now specifically that I folded it over that way. Maybe that was just enough to impede the ejected round and keep it from exiting cleanly. I'm going to fold it over on the new Andersen upper and see, but I should probably just remove these doors anyway, especially on the longer one since that's more of a gaming gun. ETA: took the doors off both, so we'll see if that makes a difference. Cleaned out the extractor and the spring still looked good. From more reading up, it seems that it could be a headspace issue, especially on the 8".
  11. Okay so some strange recent issues. In addition to my rifle upper, I have an 8" barreled upper that I use on an SBR for a short/suppressed PCC (still waiting on an Omega 9K). I've had it for a while, actually got it with the BCG before getting an extra 16" barrel. Recently been getting a ton of FTE's using the 8" upper, with the brass getting all caught up inside, stovepipes, what looks like double feeds. Couldn't get through 2-3 shots before it would happen again. It was happening before with this short configuration and I thought it was the ejector/extractor springs so I changed those out, been about 475 rounds since the change. Was it the magazines (Endomag P-mag inserts)? Are the springs going already? Took the short upper to the range and was having all hangups...took the BCG out and put it in the longer-barreled upper, put that upper one the same lower and buffer...no problems! So it's specifically that shorter-barreled upper. But here's the weird thing...the problems with the short barrel have only been happening since I put it in an Aero XL upper receiver...the SAME KIND I have for my longer upper, and which runs like a champ with same BCG, same mags, and same everything else. When I had the 8" barrel in another cheap billet upper receiver before (like a Midway Stoner house brand) while I was experimenting, no problems. I put it in another Aero XL because it ran so well in my long version.....so WTF?! Maybe something inside the second Aero XL upper was out of spec, or maybe some sort of headspace issue...the barrel extension seemed to seat just the same between the longer and shorter ones, and again the shorter was working just fine with an earlier cheaper biller receiver. I took off the barrels and put it in an extra unused Andersen .458-port upper I had just laying around to see if it will run better. Will give it a try, but at some point may just go back to that cheap house-brand billet reciter if it stays reliable. Weird.
  12. Resurrecting an old thread, but I have an SGA-to-Remington butted adapter, and then use a Limbsaver butt pad. It's very sweet to shoot. https://magpul.com/firearm-accessories/stocks/stock-accessories/sgaoembutt-padadapter-remington-mossbergsgastocks.html
  13. I recently had to replace the extractor spring in my RDB setup...this was a Sprinco extra power unit that had about 1500-1800 rounds on it. When I took it out it was kinked and compressed. Was getting a lot of FTE's with the shells either stove piping or getting jammed up into the charging handle channel. Have replaced with a new Bravo Company enhanced unit and included the rubber insert just to hopefully help keep its shape. Ejector spring seems fine, but it's strange how this system beats those springs down. I find that mine runs best with an H2-equivalent Armaspec captured buffer system.
  14. So update.... Replaced the disconnector spring with a very strong unit and today at the range had no full-auto anything and everything was controllable. Fast shots, slow shots, slow trigger pulls, hard ones. So it seems I solved it but I wonder if it's just a matter of time until this new disconnector spring fails and it happens again. Had two FTE's early but it was 100% from there.
  15. Yes but this is CMMG radial Delayed Blowback system, rather than your more typical straight-blowback AR9 type system. Because of that, it is essentially interchangeable with an otherwise 5.56 lower receiver...including a 5.56-weighted buffer and trigger. Have used the same BCG in my main 16" PCC built around it as well with a Hiperfire trigger as well as with various other triggers that are not 9mm-specific but have also worked fine with blowback AR9's...such as the Rise RA-140, the aforementioned Hiperfire and Geissele models. I know that for some PCC's, the harder/faster bolt in regular blowback AR9's was making the rear 'tip' of the hammer (if it had that) strike the back of the disconnector, but neither of the hammers so far in mine have had that feature. I would have attributed just the CMC to bump-firing, but the fact that it still happened with the RA-140 right afterwards seemed too 'coincidental'. So this morning I thoroughly inspected and cleaned the BCG...spring is fine, firing pin is fine and not getting stuck through the hole in the breech, so I think that trulls out slam-firing. The new extra-power extractor spring completely cured the FTE's from before that I mentioned. I took the RA-140 apart and replaced the disconnector spring with a newer stronger one, and put an H2-equivalent buffer in. Dry-cycling and firing the disconnector seems strong and the reset definite. It was a little softer before, so tmrw I'll run it through and see if it's been solved. If it has, then I suspect it was the disconnector spring. If not, then I may have to try some others.
  16. Has anyone with the CMMG Radial delayed blowback system had it go full-auto on them? I experienced this recently with two different triggers. First was with a CMC, it was a 2-stage drop-in unit with the flat trigger, was supposed to be 2lb takeup, and 2lb break. The second stage/break feels MUCH lighter than 2lbs...so much so that I took it out of my 3-gun rifle because I couldn't ride the second stage without breaking it unintentionally, and went back to the Geissele G2S-E that Had in there. So I basically treated the CMC like a single stage with a smooth pull-through and put it in an SBR lower to shoot with the CMMG system and 8-inch barrel. But the other day during a PCC match I was getting doubles and figured I was bump-firing because the CMC's second stage was so light and since the trigger is flat maybe I wasn't letting up enough. Switched that to a Rise RA-140 that I had as a spare. But then earlier tonight at a PCC plate shoot, again I was getting doubles and triples at what felt like full-auto. This time, if I just pulled lightly I was able to do one at a time, but then if I gave it a good pull and held back, it went full auto until I let up. Kind of like a Steyr AUG;s two-stage on full-auto. That made me think it was the trigger since I had an earlier RA-140 a few years back that was doing this because the disconnector spring had compressed and kinked...so my first thought was that. But this is two different triggers in a row that were going full-auto, or so it seems. I checked the CMMG bolt group, disassembled. Have recently replaced the extractor spring and ejection was 100% as opposed to all the FTE's I was getting. The BCG seemed to be fine, the extra spring was holding back the firing pin so it didn't seem like slam-firing. And again, I was able to stop the full-auto bursts by letting up on trigger. But just wondering if anyone else has had their CMMG RDB go full auto and traced it to something in the BCG itself. The buffer is an Armaspec captured H1 equivalent. I sighted in with this a while back and it worked fine, wasn't getting any full-auto then. I use an H2 equivalent when I shoot my 16" version for PCC. I'm about to try yet another trigger group...this time probably a Larue or maybe another Geissele unit.
  17. So an update.... I was getting a bunch of FTE's and hangups, ejector seems pretty strong but took out the extractor and this is how the spring looked....an extra-strength Sprinco unit tat I put in there a while back. Sorry the the camera phone pics are blurry but I think they still show.... Spring is kinked/compressed. I don't know how many rounds but would estimate around 1700-1900. This was part of a 3-pack of extra-power springs that came with both the center plug and o-ring from Springco. Also emailed CMMG if to ask if they could send factory recommended replacements, but for now (as I have a few shoots coming up), I'm wondering if I should run one with the o-ring since I ran it with just the spring before. What do y'all think? ETA: I just put the spring in without the o-ring. But man, there's essentially no movement on the extractor when I get the pin back in, like the spring is compressed all the way. Wondering if I should clip a coil. I also installed with the 'fat' side on the bolt so it wouldn't bind in the 'keeper' hole on the extractor.
  18. Cool, I may give it a shot. Might just pick up a Sylvan as it's a bit simpler and don't have to worry as much about mag changes.
  19. So was it simply inserting the Stern and go, or did you have to fiddle with the adjustment screws at all?
  20. Interesting. I have a Stern adapter (which I used in my main PCC before getting a CMMG RDB system), and yeah I can see that you have a little adjustment with how high it sits in the receiver's magwell. I already have the Mag inserts for the RDB system and they work great....only thing I'd really be gaining with Glock mags is greater capacity than 30 rds when shooting steel or such. Really like the curved true double-stacks CZ Scorpion mags though, especially the 35-rd ones made by PSA.
  21. Probably where the sear hammer notch. So it's just enough to hold when it's cocked manually, but unfortunately once it fires it won't stop until mag is empty.
  22. Yeah that can happen on a lot of AR-based bolt carriers. I eventually just got a feel for it and use the punch to help guide it.
  23. Man....if they were able to make an AR-V lower that would work with a CMMG RDB upper.......I'd be in heaven. Albeit, that's a bit redundant since the PMAG-inserts specifically for the RDG work great. But if you want more than 30-rds/mag....it'd be kind of the best of both worlds.
  24. I did the same. The 35 was a quicker and more natural position to snap to. I was 'searching' and having to center the dot more at 45. My LPVO has 'higher and lower' end caps for the windage/elevation because one houses an extra battery. I put the higher cap up top on elevation, and the other on the side and it just stays out of the red dot window, even though it's relatively wide (Swampfox Justice), as I have it mounted ahead of the scope instead of behind. I also have the Primary Arms LPVO. As I mentioned above, if you have one cap that is 'higher' because it houses the extra battery and it's on the side/Windage, switch it with the elevation one which is shorter. They should be the same threading. But then also as I mentioned, I have my offset red dot ahead of the scope not behind it, so that may have an obstruction either way if you have it behind/closer to your eye.
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