My P80 Build

I built my first P80 kit the other day and have to say all the Marine Gun Builder videos are great and are very helpful. I ended up getting the Polymer80 PF940C Buy, Build, Shoot kit from MidwayUSA. It went together quite well and I had absolutely no issues with the pinholes lining up.

The main things I had to do were:

1. File down the sides of the locking block, it was too wide to fit into the frame
   
   
2. Actually spread out the rear rails since they were too loose in the slide. Along with that just a slight adjustment to the arm that keeps the trigger housing tight.
   
   
3. The usual deburring of rear rail.
   

The only other issue I had was that the trigger would not reset when first assembles until I lubed/greased everything. After applying grease and lube, it works great.

I was able to get to the range today with my PF940C. I shot a total of 150 rounds without a single malfunction using the 1 P80 mag and 2 MagPul mags. The first 100 rounds were Winchester white box 124Gr FMJ and 50 rounds of my 115Gr FMJ reloads.

There were only two minor issues, which I was kind of expecting.

1. I will need to change out the front or both sights, it shoots about 3"-4" low at 10 yards.

2. Ejection pattern was everywhere from 3 O'clock to 6 O'clock with a few landing on the brim of my hat. It is something that is common even with the Gen 3 Glocks so no surprise there.

Overall, I am very happy with the build. I highly suggest watching the Marine Gun Builder videos and also taking your time putting the frame together, deburring as needed per videos.

Thanks 5-SHOTS.

Other than shooting low, accuracy was pretty good with the Polymer 80 barrel. I'm sure a shorter front sight will fix that.

I wanted to update everyone. I took my P80 to the range today to actually test for accuracy. I had way better results this time since I was actually concentrating on my shooting skills, and remembering to use a combat hold sight picture this time. I shot two magazines (30 rounds total) off-hand at 7 yards and am happy with the accuracy. I don't know if I could call it match grade accuracy but plenty good for HD/SD Here is the last target I shot for the day at 7 yards

I forgot to add that I did change out the Gen 3 ejector for a Gen 4 ejector and it helped out immensely, No more brass to the face!

For those that Have done a P80 build or own a Gen 3 Glock, change out that ejector to a Gen 4.

mpofficer31a said:

Yup! Gen 4 ejectors seem to work best in P80s; must be the geometry.

For the locking block, I've found that if I put the locking block in the freezer and warm the frame slightly (hot water or heat gun), the locking block pops right in. Also, I use slightly under-size SAE drill bits (7/64" & 5/32") to make the locking block holes in the frame. Then I put in the locking block to full seating, and I gently push the 3mm and 4mm drill bits through the frame to ream the holes. Finally, I lightly chamfer the holes with a 45 degree countersink. This make the frame look great and the pins stay very tight.

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That is exactly how I did it on the 940C frame and also the SS80 G43 frame I just finished. Sometimes you still have to lightly fit the locking block and rear rails when building a P80, it is just part of the build.

And yes the Gen 4 ejector has a different shape/profile compared to the Gen 3. The Gen 4 is more square on the end versus the tapered end on the Gen 3 ejector.

Well I talked about the SS80 build I did a few weeks ago but never posted any pictures. I have also since finished a 940CL (compact frame, long slide) since then. I used a Polymer 80 RMR G17 build on it and put a Swampfox Kingslayer on it (for now). Here are both. Yes the 80% pistol bug has bitten me. It is almost as bad has suffering from BRD.

DT Guy said:

I like the slide on that (17? Compact/Long? The one with the FDE frame...) Can I ask who that's from?

Thanks

Larry

Click to expand...

That is the Polymer 80 brand RMR slide. It is the same slide that is on my 940C (G19) build. the exception is the 17 slide having the RMR cut. I bought it from Primary Arms. I have to say that I really like how Polymer 80 did the slide serrations on their slide.

https://www.primaryarms.com/1+Handgun-Slides/Brand+Polymer-80

Here is my latest build. Another 940CL but in 40S&W this time. All internal parts are OEM and the slide is from Rock Slide USA. Trying to find G23 and G22 parts is even harder than trying to fins G19 and G17 parts right now.

One is definitely not saving money in building a Polymer 80 pistol for sure. Personally I like the challenges just like doing 80% AR receivers. Plus I can customize them the way I want without having to buy an OEM pistol then buying replacement parts on top of that. Building 80% firearms is not for everyone. Even with parts being harder to find, it is still way easier than trying to find an actually Glock pistol in stock locally (or even online)

I have been looking into the 80% SIG kits along with an aluminum 1911 frame for a dedicated 22lr build. I have done a couple of 80% AR receivers but never an 80% 1911. The last time I built anything from scratch was while in the Army with access to a full machine shop. I was a machinist and got to work on a few test projects.

You can build a Polymer 80 for close to the same cost if you stick with all OEM parts to include the slide. You would definitely have to shop around for the best prices. The other thing to remember about doing an 80% pistol is that you do have to tweak them sometimes to get them to run with 100% reliability, using OEM parts reduces that. I also want to point out that building an 80% Polymer 80 is not like building an AR, one doesn't just install the parts and go. There is some hand fitting required when it comes to the front and rear rails on the P80. The other issue right now is finding the parts to finish a build, especially G43 parts or anything for the 40S&W/357SIG versions.

WestKentucky, I like your thinking on using a G42 to make a 32NAA. I'm still considering doing a 22TMC9R conversion or even a 38 Super using a 10mm slide with the proper 38 barrel.