Polymer 80 Malfunction

[Firefighter3932]

My full-size polymer80 9mm manually cycles ammo well. However, when I fire a round the slide kind of locks and won't cycle. If I drive fire with nothing in the chamber, it works fine. But once the firing pin comes in contact with a live round or a dummy round, it has problems ejecting because the slide won't move. Is my firing pin spring too strong causing the slide to stick or something else?

[zachomega]

How do you free up the slide after firing? Just muscling it?

I could be wrong, but the striker has already been released once you fire and will protrude from the breech face. The action should still cycle and then reset the striker. So I'd say it isn't likely that the striker spring is too strong. It is more likely something simple or mechanical. Maybe a part that needs to be fitted.

I'd check for burrs and possibly bent parts of you had to force anything into place during assembly. Additionally, make sure it is all assembled in the correct order. Sometimes missing something really simple is all it takes.

I'm not an expert on striker fired pistols. But that is where i would start.

-Zach

[Berncly]

A lot can go wrong with self built stuff, too many potential issues to be able to make a guess.
Find a friend who has experience and sit down with him to disassemble/reassemble to see if he spots the problem.
Or find some reputable step by step instruction videos and disassemble/reassemble yourself to see if you can spot the problem.
I would also take stock of what parts you used, some people have had issues with mix and match parts, better to use parts from a single kit.

[arrowtech]

I followed MarineGunBuilder on You Tube when building mine. Those 80% pistol builds are trouble if you just ignore the fact that the individual parts don’t need a bit of tender loving care PRIOR to the build. I’ve used mostly OEM parts in my slides although the slide and barrel may be third party.

[bigandy1966]

compare it to a functioning unit and see if you can spot the malfunction. sounds like the BCG is not pushing the hammer back down. something is not right in the fire control group .

[ar15jules]

I know from experience that the locking block in the P80 kits don't just "drop in". The locking block does just what you think it might, allows the breach/barrel to "lock up" during firing. If you take an unloaded locked breach pistol like a P80 or Glock and hold it horizontally and slowly press rearward on the the slide, you can see the proper "unlocking" of the breach/barrel as the rearward portion drops down, unlocks, and allows the slide to travel rearward. I would field strip the pistol, check the locking block to ensure that it is fully seated in the P80 lower. I assume that it is because it also contains the front rails in these kits. If you didn't remove enough material on the front tabs, it may be tilted. Anyway, remove your barrel and ensure the locking lug in the rear aren't bend, damaged etc. Check the barrel alone in the locking block. This is where I would start. If you have other compatible parts, try another complete upper. If it fails, it's your locking block. I've included a Glock animated operation video so you can see what I'm talking about.

[jthrelf]

Additional to above make sure your barrel/slide fit properly. I once got a combat armory barrel that just didn't fit in a Midway slide. Had to send it back.

As for the lower, 80% of P80 problems (pun intended) come from the areas not being filed and sanded enough. Be sure to take off ALL the polymer at all the spots.

Additionally make sure where the trigger bar gets near the rear rail assembly there is enough clearance. Otherwise grind off some material from the rear rail assembly in that spot. Many rear rails have this problem and it's a simple fix.

[Firefighter3932]

After checking everything I could possibly think of. I think the aftermarket finished barrel had a chamber that was too tight to eject a spent round. It ejects non fired rounds easily but has problems ejecting shells because they are larger than unfired rounds. I sanded the finish inside of the chamber and the spent round ejected a little better now with manual cycling. When I go to the range I'm going to see if it shoots correctly.

[aubie515]

Where did you buy the lower parts and upper parts from? If you say Lone Wolf, that could be your issue as Lone Wolf has a reputation of putting Gen4 parts in a Gen 3 kit. The P80 full sized frames require Gen 3 parts.

Every P80 I put together, I would take Flitz polish with a dremel polish head and I would polish all of the P80 rail parts as they are rough.

I've also never had a P80 frame work right off the bat...I've always had to run 200 rounds through the pistol before it would not FTE or FTF. Do not be upset or discourage if your P80 does not run 100% the first or second time you take it out to the range. I always run at least 1,000 rds before I trust the P80 frame.

[HKusp 45]

You can try to polish your barrel feed ramp and also use layout dye on the barrel to see if your binding up or your barrel is catching. More often than not it is not an ammo expansion issue. You can also try a different mag if your not using a factory mag. It could be your rails honestly the best way to help you is for you to upload some photos of the side of the frame assembled (Slide on) then take a clear photo of the top of the frame without the slide on. Look for excessive wear on the barrel hood where it meets the slide at the front as well.

That's where we start also you can join here https://www.reddit.com/r/polymer80/ and get more info FYI I have built a lot .... lot of these in case your wondering if I know what I am talking about. One is my carry (not these two different one) and it has several thousand rounds through it with zero issues. In fact I just finished up these this week.

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