copterdrvr Posted June 8, 2020 Share Posted June 8, 2020 I built a 9mm PCC using a FM-9 lower and the build has been 100% EXCEPT...... When I use factory Glock 33 rnd mags the bolt will not lock back, HOWEVER, when I use ETS mags, the bolt locks back every time as I want it to.... I'm new to this PCC stuff and I'm confused as to why the FACTORY Glock mags WON'T lock back and the ETS mags do...... I know there's discussion about locking back, not locking back, but at this stage I want it to. I'm really confused as to why the factory mags won't do it but the aftermarket ones will..... Link to comment
jerseyglock Posted June 8, 2020 Share Posted June 8, 2020 Condition of both mags and follower. Could just be the weak spring in your 33 round mag. Link to comment
copterdrvr Posted June 8, 2020 Author Share Posted June 8, 2020 All of the Glock mags are brand new............. In fact, ALL of the mags are brand new. Link to comment
davsco Posted June 8, 2020 Share Posted June 8, 2020 maybe switch out the spring/followers between your glock and ets mags and see what happens. that might tell you whether it's the mag bodies/lips or springs/followers that are different. but in the pcc game, if you are going to slidelock, you've already lost. Link to comment
copterdrvr Posted June 8, 2020 Author Share Posted June 8, 2020 Why? At my skill level it really doesn't matter but it seems to me that it takes more time to cycle a slide if you run it empty AND a full magazine inserts easier if the bolt it open so what's the issue? Link to comment
AHI Posted June 8, 2020 Share Posted June 8, 2020 (edited) Take the upper off. put a mag that works in the lower then one that does not. Look thear is a" rod" that interacts with the mag fowler adjust it to work (bend) Edited June 8, 2020 by AHI Link to comment
copterdrvr Posted June 8, 2020 Author Share Posted June 8, 2020 Maybe this will narrow it down a bit-if I hold the rifle vertically, the bolt will lock back on all of the mags and if I hold the rifle horizontally, it does not lock the bolt back. What do I need to look at. Again, it's a FM lower. Link to comment
egd5 Posted June 8, 2020 Share Posted June 8, 2020 It sounds to me like your pcc is tuned(ammo PF, buffer weight, buffer spring strength) just right on the edge of the bolt going far enough back to catch the lock. As was said, there's probably a minor difference in the follower design that's making the difference. Trading them out should confirm that. I would try upping your powder charge just a little as the easiest thing to do before messing with buffers and springs. I like the LRBHO also, although mine doesn't always do it. But I'm ok with it as it is. The reason why is if you never run dry you won't waste valuable time with a reload. If you're trying to shoot a 32 rd stage with a 33 rd mag you're either damn good or fooling yourself. Get some mag extensions, I like Taylor freelance, and/or some 40 rd ets mags. Just load them to 38 and you're covered if you need a makeup shot or there's hard to hit steel. I have two ets 40 rd mags and they work great for me. Link to comment
copterdrvr Posted June 8, 2020 Author Share Posted June 8, 2020 (edited) Yeah, I've run three different ETS 40 round mags during my build testing and they work flawlessly as far as not jamming. The weird thing I'm referring to is that when I MANUALLY cycle the bolt it will lock back on ALL OF THE MAGS if I hold the rifle vertically but will NOT lock back all the time if I hold the rifle horizontally. I've noticed that the bolt hold open catch does NOT have a lot of spring tension on it. I've compared the spring tension of the bolt release on my 9mm PCC to all of my other AR's and it's noticeably less than my other AR's. Not sure how to increase this on the FM lower..... Edited June 8, 2020 by copterdrvr Link to comment
Larry White Posted June 8, 2020 Share Posted June 8, 2020 2 hours ago, copterdrvr said: Why? At my skill level it really doesn't matter but it seems to me that it takes more time to cycle a slide if you run it empty AND a full magazine inserts easier if the bolt it open so what's the issue? The point is not to run it empty, if you are going to have to reload do it before the gun is empty.--------------Larry Link to comment
copterdrvr Posted June 8, 2020 Author Share Posted June 8, 2020 The magazines seem to go in a lot easier when the bolt is open though... Link to comment
Larry White Posted June 9, 2020 Share Posted June 9, 2020 3 hours ago, copterdrvr said: The magazines seem to go in a lot easier when the bolt is open though... They go in a little easier if not compety loaded to capacity, down load the second mag a couple of rounds . At some point you will have to ask yourself if you want easy or fast. Also if a gun will lock back empty sooner or later it will lock back before its empty, I dont want mine to lock back, ever. Better stage planing is a key.------------Larry Link to comment
copterdrvr Posted June 9, 2020 Author Share Posted June 9, 2020 Well, I have to admit that all makes sense! Link to comment
cecil Posted June 9, 2020 Share Posted June 9, 2020 LRBHO ... are prone to breaking ... my PCC's do not lock back.. Link to comment
zzt Posted June 9, 2020 Share Posted June 9, 2020 (edited) 20 hours ago, copterdrvr said: I'm new to this PCC stuff and I'm confused as to why the FACTORY Glock mags WON'T lock back and the ETS mags do...... Glock mags sit lower in the magwell. The ETS sits higher. Try this. Put one round in the Glock mag and push it up into the magwell and hold it there while firing. The bolt should lock back. FWIW, the two mags handle ammo differently. With one 147 JHP factory load the Glock mags make the round hit the feed ramp and set the bullet back. They work perfectly in the ETS mag. I have some 147 RN loaded to 1.145" that will not work in the ETS mags. The round hits the top of the chamber and jams. They work perfectly in the Glock mags. BTW, after a while trying to tune your gun and load for minimal dot bounce you will probably go to short stroking. The the bolt cannot loack back no matter which mag you use. Edited June 9, 2020 by zzt Link to comment
copterdrvr Posted June 9, 2020 Author Share Posted June 9, 2020 Again, all great responses-thanks! I have a POF buffer tube installed with a .308 JP carbine spring and a Blitzkrieg heavy duty hydraulic 9mm buffer and the gun is VERY smooth. I did have their weight installed on top of the buffer but I found that for me I got a bit more bounce when the rifle went back into battery so I took the weight back out... Link to comment
Walli Posted June 9, 2020 Share Posted June 9, 2020 Did you get in touch with FM-Products? They have the reputation to be very responsive and they should have the most experience. P.S. FM lowers do have one of the better bolt hold open designs. If you want it to work, it should work with Glock oem magazines. Link to comment
copterdrvr Posted June 9, 2020 Author Share Posted June 9, 2020 I did in fact contact them and in my opinion they are the best on working with customers and answering questions. I can't recommend them more and their products are awesome. He told me what to do but I may wait a bit to see if I really want to use his recommendations. It's simple to do but I may not need to worry about this feature. I need more time on the gun. Link to comment
MemphisMechanic Posted June 9, 2020 Share Posted June 9, 2020 I don’t know anyone who is serious about competition use of their PCC who is running a gun which locks back. Both of my lowers with that feature saw them rapidly removed. Link to comment
copterdrvr Posted June 9, 2020 Author Share Posted June 9, 2020 Again, I'm not seeing the detriment to having this capability-to the PCC shooter, how is this a negative? Link to comment
ck1 Posted June 9, 2020 Share Posted June 9, 2020 (edited) 2 hours ago, MemphisMechanic said: I don’t know anyone who is serious about competition use of their PCC who is running a gun which locks back. Both of my lowers with that feature saw them rapidly removed. I think the reason for this is because most of the PCC's out there that advertise LRBHO as a "feature" don't really work reliably/correctly... and with many of them, worse than not working reliably/correctly, they tend to also decide to lock-back when they're not supposed to and screw people up as well. For competition, none of us want to reach slide/bolt-lock or we've already screwed up by running dry, which is a no-no because it means we should've reloaded (or not missed so much lol). Incidentally, this is also why a lot of Limited pistol shooters disable their pistols from reaching slide-lock when empty, because getting lock-back on a 2011 is pretty much never 100% because the mags are so finicky, and the guns also tend to get locked-back at inopportune times and screw people's runs up... So if LRBHO is unreliable, yeah, ditch it. But, if a gun's LRBHO mechanism works 100% correctly and reliably, and doesn't get activated prematurely, then there's no real reason to remove/disable it, because theoretically, under match conditions it should never activate or be used (unless, again, one screws up and forgets to reload), or unless one wants it to. I shoot an MPX and the LRBHO works perfectly, so it never gets used at a match unless I screw up (or purposely run empty, which sometimes I do depending on the game or the stage). In fact, with some mandatory reloads depending on the game, a reload and dropping the bolt is always quicker than a reload and racking it. IMHO, I actually prefer all my guns that don't have issues with premature slide/bolt-lock to lock-back when empty as they should... because for me, an open/locked-back bolt/slide means "cuss, reload, press bolt/slide release", which is faster than "click, cuss, rack to clear imaginary malf/jam only to realize I'm actually empty, cuss again, reload, rack" hahahaha... Edited June 9, 2020 by ck1 Link to comment
copterdrvr Posted June 9, 2020 Author Share Posted June 9, 2020 Thanks for the response-makes perfect sense!!! Link to comment
egd5 Posted June 10, 2020 Share Posted June 10, 2020 Yes, ck1 nailed it. Having it doesn't hurt a thing as long as it works correctly. I am only on my 2nd pcc and have never had the bolt lock back when the gun wasn't empty. But, then again, I have never messed with frankenguns. I've only had a Colt and a JP. They just worked. Link to comment
copterdrvr Posted June 17, 2020 Author Share Posted June 17, 2020 Well, you were right about the ETS mag difference FOR SURE. I know have three of the 40 round and four of the 31 round ETS mags and they ALL lock the bolt back with no issues whatsoever. Thanks for the info! Link to comment
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