Polymer 80 pf940c built

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  • Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    I have a Glock 22 that I installed a 357 sig barrel and a Burris red dot. Although it's great to shoot and very accurate, it's pretty big. So I ve been wanting a smaller one for a while now. At the same time I have been watching the polymer Glock 80 knockoffs for a while but thought that the plastic rear rail wasn't a good idea. So when they came up with the compact version that fixed the rear rail flaw I couldn't resist.

    So i bought a used gen three Glock 23 slide with the barrel and all parts for the upper and lower included for 400 bucks and the polymer 80 lower for 145 from eBay. The parts arrived some last night and some this afternoon and couldn't wait to build.

    It took me about an hour to carefully mill the unnecessary plastic off on my xyz vise and drill press, then sanded and polished, installed the parts that I ultrasonically cleaned last night and there you go.

    I also polished the front and rear rails on my knife sharpener, lubed, added some copper anti seize and its ready for range testing. I am planning to spend the day at the range tomorrow to test it out.

    Preliminary observations:

    The build quality rivals that of the original Glock. The nylon plastic frame appears to be similar in composition. In fact with the beefier front and rear slides I would say it is stronger than the Gen 4 Glock I have. I attempted to build my own Glock frame a few years ago so I studied how deep into the plastic the Glock rails go and was surprised that they don't go in too far.

    I think the polymer 80 design is an upgrade to the Glock because the front rail makes optimal use of the real estate between the front rails and barrel lock block. It replaces the over molded Glock rails with a cast stainless steel rail and barrel locking block unibody and they added a 4th pin to hold it secure. I think this is a stronger setup.

    They also replaced the rear Glock rails with a unibody bent stainless steel that hugs the plastic trigger mechanism housing. They also provided a stainless steel pin to replace the Glock rear trigger pin, since now this pin will take the stress from the rail, it's probably a good idea to make it metal. The rear rail is made with a thicker sheet metal than the original Glock, but still fits snugly on the slide. The tighter tolerances result in a pistol that doesn't rattle. Combining this with an aftermarket barrel with also tighter tolerances might increase accuracy. The rear rail is nickel plated, but the quality of the plating is not great given that it was flaking out of the box. With some polishing I was able to blend in the flaked plating. I am not sure the plating was needed, but the Glock rails are also plated, and it was also flaking on my Glock right out of the box. I think the plating serves to reduce the friction between the rail and the trigger bar.

    After installing everything, I tested the function and although the slide is tighter than my G22 it still cycles smoothly. I ll update tomorrow after I shoot it some.

    I only have the G22 magazines (5, 15-rounders, from before the prohibition) so i bought an x-grip extender to go with them. The only problem with the magazines is that they don't drop free, but at the same time they are not too tight either. Maybe with some sanding I can loosen them up. I think the issue here is that the thinner polymer 80 grip results in some sagging after demolding the frame. (Correction: after close inspection, it appears that the magazine catch is pushing against the magazine body and not the frame. I don't know if it's because I am using 4th gen mags on a3 gen frame)

    Bottom line, I like the frame a lot, it feels nice in my hand, aiming is very similar to the Glock. Additionally polymer 80 corrected many of the Glock flaws, such as the disconnection between the front rails and the barrel lock block, the skinny rails, the reinforced the plastic in key areas such as the front Picatinni rail area and they thickened the plastic over the Glock mechanism area, about the trigger and pins. They added a 4th pin and replaced the rear pin with a metal one. Overall, if they had a 4th gen one I would have bought it to replace my G22 frame! Next step is to buy a 357 sig barrel.

    My question is is how does the Glock company feel about polymer 80?

    In the pics below you can see a comparison between my G22 4th gen with the polymer 80 pf940c with used OEM slide.
     

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    Last edited:

    lee2

    Banned
    BANNED!!!
    Oct 8, 2007
    19,012
    Great write up and pics!
    Are there any hiccups to look out for?
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    Range report:

    Just came back from the range. I shot 50 rounds back to back, no hiccups at all. Very comfortable to shoot and accurate, other than that it feels very similar to my other Glock, I'dint notice much difference between the two grips. I shot both with gloves and bare hand. One thing I noticed was that because of the undercut on the trigger guard it provided more space for my hand and it felt almost like a full size Glock grip even though it's a compact.

    To respond to lee2, nothing special about cutting it with the mill. I didn't use a dremmel because I was worried about going too deep. I cut the rails fast (drill down and then move horizontal fast) to about a mill from the frame and then slow down, multiple passes back and forth cutting a hair each time until the mill brushed the frame. Then light sanding with a very fine sandpaper to a polish. The most time-consuming part was the plastic piece that obstructs the path of the recoil spring. My press doesn't have enough clearance to put the polymer 80 jig vertically so I cut it in the horizontal direction. Then I finished it with a round file and sanded. I made sure the spring slides back and forth freely in the grove, it was a bit tight initially and needed some sanding. Also I held the jig in the vise between 2 pieces of wood, 1 x 4s because the plastic jig deforms in the vise.
    When drilling the holes for the pins I just held it by hand on the press and let the jig center it self when the drill bit starts going down. I drilled each side separately because drill bits of that size deform easily risking misalignment. I also polished the rails a little bit.

    The box didn't come with instructions, but its kind of self explanatory. I also watched a couple of videos on YouTube. Other than that it's easier than an ar15 80%.
     
    Last edited:

    Chazp89

    Active Member
    Sep 1, 2017
    283
    Looks great! Keep us posted on how it holds up. Sounds like it will be good for the long haul.
     

    KJackson

    Ultimate Member
    MDS Supporter
    Apr 3, 2017
    8,613
    Carroll County
    I have been looking at this lately as a project and was wondering if there was any good reference anywhere about doing this and the various rules and regulations involved.
     

    DutchV

    Ultimate Member
    Jul 8, 2012
    4,702
    ...

    My question is is how does the Glock company feel about polymer 80?

    My understanding is that the patents on the Gen 3 design have expired, so there isn't much Glock can do about Polymer 80 or any of the other clone-parts guys. I'm sure they're keeping an eye on what the aftermarket is doing and deciding if features should be added to the Glock factory guns.
     

    whistlersmother

    Peace through strength
    Jan 29, 2013
    8,948
    Fulton, MD
    I have been looking at this lately as a project and was wondering if there was any good reference anywhere about doing this and the various rules and regulations involved.
    quite frankly, these are easier than 80% ar15 lowers. i use handfile to file out the appopriate sections instead of the enclosed milling tool - takes longer but there is virtually no screwup possible. drilling the holes makes me nervous, but even that works out.

    polymer 80 has videos and there are several videos on youtube. but running a milling tool in a drill press on "soft" polymer doesn't sound like a great idea. YMMV.

    you can visit the atf website about homemade guns. basically, if you are eligible to own a handgun: then you can make your own.

    finding the slide and upper and lower parts kits isn't too bad. midway has lower kits around $50 and glock 19 gen 3 new slides can be had on gunbroker for around $400 shipped.

    the 10rd mags can be ordered, but you'll have to go out of MD to find standard capacity mags. no hql, no 77r registration, no serial number - what's not to like?

    there is a thread around here on completing the thing. (on my phone so can't look it up at yhe moment)

    Sent from my SM-G955U using Tapatalk
     

    KJackson

    Ultimate Member
    MDS Supporter
    Apr 3, 2017
    8,613
    Carroll County
    Thanks for the info. I thought that I had read somewhere that after they were built that they still had to be given a serial number but I may be confusing it with something else.
     

    GTOGUNNER

    IANAL, PATRIOT PICKET!!
    Patriot Picket
    Dec 16, 2010
    5,492
    Carroll County!
    Thanks for the info. I thought that I had read somewhere that after they were built that they still had to be given a serial number but I may be confusing it with something else.
    SN is not required at all. For any home built firearm. Recommended, but not required.

    Sent from the 3rd Rock
     

    Jimbob2.0

    Ultimate Member
    Feb 20, 2008
    16,600
    Encouraging. Anyone dare try one of these with a high end cartridge like 10mm or .50 GI? Encouraged this is .357 sig, one of my favorite under appreciated cartridges.

    Sounds like their rail set-up is less like a glock (heavy on poly) and more like a Sig Pro/2022 which is heavy on steel embedded in poly.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    I tried to add a serial number to mine by punching in the numbers on the aluminum tag under the Picatinni rails and I almost ruined it. It can't take a punch. What was I thinking, it plastic. I might try scribing it with the dremmel. I always add a serial number to guns I built for my own records.
     

    Glock357

    Active Member
    Oct 18, 2012
    111
    Rockville, MD
    The company (polymer80) didn't make a frame for 10 mm or 45. Mine is 40s&w and will also try 357 sig once I get the barrel. A difficulty I am having is figuring out which holster to get, I discovered the the glock doesn't fit.
     

    Jimbob2.0

    Ultimate Member
    Feb 20, 2008
    16,600
    The company (polymer80) didn't make a frame for 10 mm or 45. Mine is 40s&w and will also try 357 sig once I get the barrel. A difficulty I am having is figuring out which holster to get, I discovered the the glock doesn't fit.

    Nuts, for some reason I was thinking the .50GI conversion went on the .40 frame as well as the .45.
     

    whistlersmother

    Peace through strength
    Jan 29, 2013
    8,948
    Fulton, MD
    I think the tags were meant for laser engraving. I'd avoid punching a SN into it.

    You might try contacting some IP's here to see if you can laser engraving done.

    The fed's do not require SN's for homemade guns, but I do know Hawaii requires SN's when registering the homemade gun - yes, that's right. All guns, handmade or not, have to be registered there.

    As a side note, having a SN for your own records certainly helps with tracking testing, maintenance, etc., especially if you've completed more than one of the same type. I've contemplated SN's, but can't bring myself to do it.

    Sent from my SM-G955U using Tapatalk
     

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