[bergunx]

Hi,

I'm thinking about swapping out the metal trigger housing on my POF MP5 pistol to a more modern polymer/plastic version that will allow an ambi selector levers to be added. My question is; can "I" use all the parts within the original POF trigger pack when swapping to a poly/plastic housing unit?

I know that I'll need to also exchange the original left-side metal selector lever to a correct ambi left/right selector levers... Is there anything else I'm missing??

Since I'm doing all this work, is there anything within the POF trigger pack "I" should also replace due to any known QC issues?

Also, who would you guys recommend to do some trigger work to shorten the trigger travel and lighten the trigger pull to approx. 5 to 4.5lbs pull?

Thanks for looking!

 

[Discogodfather]

Depends on the plastic housing. If it's an original HK housing then it uses a double pushpin style, so it needs to be "clipped and pinned" or the front hole needs to be deleted and some kind of shelf added. PTR makes a cheap plastic housing that does not have the front pin and is designed to be fitted to a shelf. They cost around $100 and look like a newer FBI style housing. They also are made to use the sheet-metal safety, so you could swap the POF housing and the safety right in.

If you went original HK, then you would need to buy a "plastic housing" safety, which is slightly longer than a sheet-metal safety. All HK trigger housing supposedly are interchangeable in dimensions, but in reality there is always some fitting usually required.

I would also stay away from the newer FBI housings that are original HK, mostly because the trigger packs will drop right in, but they require the newer style of safety (the one that looks very sharp and is made of plastic) and it's not compatible with a sheet-metal trigger assembly.

There are a few ambi safeties out there for metal housings and some for using sheet metal trigger housings on plastic lowers, but you have to do some research and figure out the compatibility. DO NOT get the newer FBI style ambi safeties that cost an arm and a leg, they are NOT compatible with sheet metal trigger packs.

There are two great trigger workers out there, Bill Springfield and Denny Williams. Both are very well respected and do fine work. Check out their websites.

 

[scottinthegrove]

Depends on the plastic housing. If it's an original HK housing then it uses a double pushpin style, so it needs to be "clipped and pinned" or the front hole needs to be deleted and some kind of shelf added.

Please reread the OP. The advice was asked for a POF import. The Southern Asian guns (both POF and MKE) use a different system for attaching the front of the trigger housings. They do not have have a "wraparound" shelf added to the receiver like the original HK and US made semi auto guns. In fact the latest Southern Asian imports actually have a front push pin hole in the receiver that holds the front of the grip housing in place. A full auto grip frame housing would need modification for the front receiver "tab" which blocks the installation of a full auto trigger frame.

OP, the selector diameter of an "ambi" trigger frame and grip housing are larger in diameter than the SEF style trigger frame and grip housing. The SEF trigger frame could be modified but that is not an easy modification. There are a couple of ways to go. Cheapest would be to simply buy an aftermarket SEF "ambi" selector for a steel grip housing. It is basically a SEF selector that attaches a selector lever on the right side of a selector to be used with the left thumb. You could buy a full auto "Navy" style SEF grip housing and have it modified for use with your POF receiver. Then you could install the POF fire control in the "Navy" style SEF grip housing and buy an aftermarket SEF "ambi" selector for a plastic housing. Remember, the steel SEF housings are thinner than plastic SEF housing. So the aftermarket SEF "ambi" selector would need to be ordered specifically for a steel or plastic housing because of their wall thickness.

The third option would be the most expensive. Because of the differ diameter of the selector from SEF to "ambi" style, the entire trigger group would need to be replaced. As PP there have been several smiths listed for trigger work. Good luck with your POF trigger group project.

Scott

 

[Discogodfather]

Sorry, didn't realize POF was like MKE, for some reason I thought they just used shelf's, Scott is right. That makes things particularly difficult! I'd search more on how to convert a full auto housing into something that can fit. Good news is, full auto housings are fairly cheap as everyone assumes you need to do the clip and pin, which costs $$. You can pick up a plastic full auto navy housing for under $10 and play around with it without feeling bad at all.

 

[bergunx]

Thank you all for this valuable information!!

 

[RWO101]

I want to do the same thing. I have clipped and pinned before but I have a POF MP5K and wondered how things would match up.

 

[Thunderpig]

I want to do the same thing. I have clipped and pinned before but I have a POF MP5K and wondered how things would match up.

+1 Let us know what you go with and how well it works. I would like to do the same.

 

[Hk1776]

Stay away from Bill Springfield he worked on a PTR trigger pack of mine and it wouldn't reset afterwards, he also "worked" on my FAL trigger and the weapon would fire while on Safe after that. So f#### dangerous!!. He never returned my calls after that and I wasn't even mean about it.

 

[rickj1nd]

Stay away from Bill Springfield he worked on a PTR trigger pack of mine and it wouldn't reset afterwards, he also "worked" on my FAL trigger and the weapon would fire while on Safe after that. So f#### dangerous!!. He never returned my calls after that and I wasn't even mean about it.

Wow... Sorry to hear that. Bill has worked on MANY of my packs and firearms to my complete satisfaction.

 

[Nehalemguy]

OP.........I have a MKE that I installed a plastic SEF housing on. I purchased two surplus G3 trigger housings for $9 each, practiced on one to make sure I cut it down correctly, and then cut the second one down in 15 minutes. Super easy. The MKE trigger pack fit great and the new housing fits better than the original.

 

[GolfBravo]

So, I've swapped the metal POF trigger housing with a Navy trigger housing and am now experiencing problems. I had to do some fitting, but it fits now. Replaced the safety lever, so it fits the polymer frame.
The issue is, that the same trigger pack (semi only, SEF) works perfectly well in the metal one, with the POF safety lever.

However if I fit it in the same trigger pack into the Navy, polymer grip, with the longer safety lever, the gun sometimes experiences bolt ride. This either causes a missfire or full auto burst.

Any ideas on how to remedy this? I'm not from the US, so such a mishap is not a punishable offense.
Many thanks for your assistance & help.

 

[hkshooterusp]

What is "bolt ride"?

 

[GolfBravo]

What is "bolt ride"?

It's when the hammer does not lock in the rear position after a shot and follows forward on the back of the bolt. Sometimes it causes a missfire and sometimes it sets the round off causing a burst or a double tap.

 

[hkshooterusp]

It's when the hammer does not lock in the rear position after a shot and follows forward on the back of the bolt. Sometimes it causes a missfire and sometimes it sets the round off causing a burst or a double tap.

Thanks. Most of us call that "hammer follow" in the USA or simply say "the hammer follows the bolt".

Difficult to diagnose without seeing the unit. I'd check the pack to housing fit to see if the two are binding up somewhere and possibly causing the sear spring or pin to be slow or sluggish.

 

[Bluerogueone]

The POF metal housings have a block below the semi position keeping the selector from going to the F position. In the semi (E) position, the sear will catch the hammer, but in the F position, the sear will not catch it in the POF packs. Since your new housing probably doesn't block the F position, I would stick to the E position. If you were in the US, where the laws are different, I would suggest just putting the trigger pack back in the metal housing.

 

[GolfBravo]

Hmmm, interesting. But this happens even on the E position. Actually, the gun functions the same in either E or F position as the trigger pack is semi only.

 

[GolfBravo]

Well, I have narrowed it down to the selector. If I use the original POF selector, the trigger pack works fine in the metal housing. However if I use an original H&K selector for the metal housing, the sear does not cock the hammer when the trigger is pulled to the rear after the shot. Same goes if I use an original H&K selector that is designed for the polymer housing (...it is slightly longer, to compensate for the polymer housing being thicker/wider).

Any ideas if the same thing would happen with the Magpul selector?

 

[unnamed]

Well, I have narrowed it down to the selector. If I use the original POF selector, the trigger pack works fine in the metal housing. However if I use an original H&K selector for the metal housing, the sear does not cock the hammer when the trigger is pulled to the rear after the shot. Same goes if I use an original H&K selector that is designed for the polymer housing (...it is slightly longer, to compensate for the polymer housing being thicker/wider). Any ideas if the same thing would happen with the Magpul selector?

I've got same problem with Magpul lower and selector. Installed original/metal lower back.