Pof smgpk issue

[hkshooterusp]

Anyone know if it’s possible to add material to the ejector to close the air Gabe between the ejector and bolt?

I've done it, not very difficult. Once I figured out the problem, applied an experimental bandaid, and successfully tested the rifle......

Shimming the trigger pack in the trigger housing should raise the ejector easily enough.

I fixed it properly with this. Welded a shim onto the shelf that had been welded on too low by Hesse vs shimming the pack in the frame. Rifle ran perfectly.

[bubba04]

I've done it, not very difficult. Once I figured out the problem, applied an experimental bandaid, and successfully tested the rifle......

I fixed it properly with this. Welded a shim onto the shelf that had been welded on too low by Hesse vs shimming the pack in the frame. Rifle ran perfectly.

Awesome, I guess you just welded to the bottom of the shelf and filed to fit? Eye balling my air gap to be between an 1/16 of an inch or so.

[hkshooterusp]

Awesome, I guess you just welded to the bottom of the shelf and filed to fit? Eye balling my air gap to be between an 1/16 of an inch or so.

No, I welded to the top of the shelf on the rifle. The same thing could be accomplished by adding material to the underside of the shelf in the frame but I wanted the rifle to accept any properly made trigger frame and group, not a custom made frame for just one rifle.

[bubba04]

No, I welded to the top of the shelf on the rifle. The same thing could be accomplished by adding material to the underside of the shelf in the frame but I wanted the rifle to accept any properly made trigger frame and group, not a custom made frame for just one rifle.

Ok, I think I understand but somehow I am also confused. My rifle has a swing down lower. Here is a picture of the shelf though, this is it correct?

Does this still impact the placement of the ejector, I figured the front push pin would? Or is the answer try another housing? Sure appreciate the help.

[hkshooterusp]

Ok, I think I understand but somehow I am also confused. My rifle has a swing down lower. Here is a picture of the shelf though, this is it correct?

Does this still impact the placement of the ejector, I figured the front push pin would? Or is the answer try another housing? Sure appreciate the help.

Well DUH on me. I completely disregarded that you are working with a POF and got side tracked with the issue. As you stated, the POF uses a push pin front attachment, not a shelf, so nothing I said applies. You are right, the push pin is what locates the pack/frame on the weapon and there's nothing to be done to change it. For reference, the small shelf behind the push pin on you rifle doesn't locate anything. It's simply a physical deterrent to installing a full auto trigger pack. They simply won't fit and cannot be installed.
Revisiting the thread to refresh my aging mind I can see you've done everything I have or could have recommend already.
There are a few more things you can check but they aren't easy to explain.

1) Remove your grip frame. With the trigger pack still inside, how far below the top edge surface of the grip frame does the trigger frame sit? Is it parallel to the top surface of the grip frame?

If the trigger pack isn't parallel to the grip frame top surface, is it lower in front? If so, you may be able to correct it and make it parallel by shimming under the trigger pack front end, inside the grip frame, such as another member suggested. If the pack is parallel it's normal but it still may be seated too low in the frame.

2) With the trigger pack still inside the grip frame and the selector still installed, carefully release the hammer and let the it rest forward. Take hold of the released hammer and pull up on the trigger pack. Does it move any, up and down?

If there's is excessive up and down movement (a tiny, tiny bit can be considered normal but no more than a few thousandths) then the pack is certainly not fitting the frame correctly and as said above, could benefit from some shimming.

3) Is the original trigger pack still installed in the grip frame? Have either the trigger pack or trigger frame or the grip frame been changed out?

If any of these has been changed there could be a tolerance issue that's incompatible between the parts, causing the ejector to sit way low.

If you study how the unit operates you can see what the goal is. The bolt travels rearward over the top of the rearmost portion of the ejector, lifting the front of the ejector into the slot in the bolt head. Typically it's the front part of the grip frame that's located too low, stealing some of the travel that the bolt lifts the ejector. Essentially, the ejector can't throw that far. We are looking for reasons for that travel to be limited. The picture you provided of the bolt face and ejector shows the ejector is not reaching as high in the slot as it should be and this is a major problem for positive ejection. Either the bolt isn't pressing down far enough on the rear of the ejector or the front of the ejector is stopping at it's limit and is simply located too low. As another poster said, without seeing it in hand it's difficult to determine where the issue is.

Something else. This is hard to determine or explain but here goes. The trigger pack should be as close to the bottom of the receiver as possible. If you remove the grip frame and look at the bottom of the receiver you'll see a pair of tabs on each side of the receiver opening. The trigger pack itself should be basically contacting these tabs when it and the grip frame are installed. If it does not, the pack is sitting too low in the grip frame, even if the grip frame is located properly. Since this area cannot be seen when the weapon is assembled it can be hard to determine if the parts fit correctly. If you can determine the pack sits too low inside the grip frame you may be able to shim the entire pack up until it's snug. You'll know if it's too high because the grip frame will be hard to get back in place so the stock can be reinstalled, so use less shim.
As you make changes you can see instant results by assembling the weapon and cycling the bolt while observing the ejector in the slot. You want the ejector as high as it can go without impacting the bolt head.


You've indicated another problem, the one where the top round of the magazine misfeeds and the bolt head jams against it as it tries to enter the chamber. More often than not this is a faulty magazine. If good quality and undamaged mags are being used the problem would lay in the mag catch being damaged, modified, or otherwise defective in some way so that it's holding the magazine too low in the mag well.
Are the feed lips on the magazines damaged in any way? Are they scraped along the top and work flat? Do they look clean and undamaged? Is there any evidence that they bolt or carrier have been impacting the feed lips?

There's a lot of info in these forums to disseminate and I don't envy the guy new to the weapon system trying to diagnose problems. You may find it would be easier to contact one of the board member HK guru gunsmiths to help you with a weapon inspection. The fee associated with having experienced eyes look over your rifle and repair it might be small compared to the amount of stress and money spent trying to figure it out, spending money on guesses and unneeded parts.

[bubba04]

Well DUH on me. I completely disregarded that you are working with a POF and got side tracked with the issue. As you stated, the POF uses a push pin front attachment, not a shelf, so nothing I said applies. You are right, the push pin is what locates the pack/frame on the weapon and there's nothing to be done to change it. For reference, the small shelf behind the push pin on you rifle doesn't locate anything. It's simply a physical deterrent to installing a full auto trigger pack. They simply won't fit and cannot be installed.
Revisiting the thread to refresh my aging mind I can see you've done everything I have or could have recommend already.
There are a few more things you can check but they aren't easy to explain.

1) Remove your grip frame. With the trigger pack still inside, how far below the top edge surface of the grip frame does the trigger frame sit? Is it parallel to the top surface of the grip frame?

If the trigger pack isn't parallel to the grip frame top surface, is it lower in front? If so, you may be able to correct it and make it parallel by shimming under the trigger pack front end, inside the grip frame, such as another member suggested. If the pack is parallel it's normal but it still may be seated too low in the frame.

2) With the trigger pack still inside the grip frame and the selector still installed, carefully release the hammer and let the it rest forward. Take hold of the released hammer and pull up on the trigger pack. Does it move any, up and down?

If there's is excessive up and down movement (a tiny, tiny bit can be considered normal but no more than a few thousandths) then the pack is certainly not fitting the frame correctly and as said above, could benefit from some shimming.

3) Is the original trigger pack still installed in the grip frame? Have either the trigger pack or trigger frame or the grip frame been changed out?

If any of these has been changed there could be a tolerance issue that's incompatible between the parts, causing the ejector to sit way low.

If you study how the unit operates you can see what the goal is. The bolt travels rearward over the top of the rearmost portion of the ejector, lifting the front of the ejector into the slot in the bolt head. Typically it's the front part of the grip frame that's located too low, stealing some of the travel that the bolt lifts the ejector. Essentially, the ejector can't throw that far. We are looking for reasons for that travel to be limited. The picture you provided of the bolt face and ejector shows the ejector is not reaching as high in the slot as it should be and this is a major problem for positive ejection. Either the bolt isn't pressing down far enough on the rear of the ejector or the front of the ejector is stopping at it's limit and is simply located too low. As another poster said, without seeing it in hand it's difficult to determine where the issue is.

Something else. This is hard to determine or explain but here goes. The trigger pack should be as close to the bottom of the receiver as possible. If you remove the grip frame and look at the bottom of the receiver you'll see a pair of tabs on each side of the receiver opening. The trigger pack itself should be basically contacting these tabs when it and the grip frame are installed. If it does not, the pack is sitting too low in the grip frame, even if the grip frame is located properly. Since this area cannot be seen when the weapon is assembled it can be hard to determine if the parts fit correctly. If you can determine the pack sits too low inside the grip frame you may be able to shim the entire pack up until it's snug. You'll know if it's too high because the grip frame will be hard to get back in place so the stock can be reinstalled, so use less shim.
As you make changes you can see instant results by assembling the weapon and cycling the bolt while observing the ejector in the slot. You want the ejector as high as it can go without impacting the bolt head.


You've indicated another problem, the one where the top round of the magazine misfeeds and the bolt head jams against it as it tries to enter the chamber. More often than not this is a faulty magazine. If good quality and undamaged mags are being used the problem would lay in the mag catch being damaged, modified, or otherwise defective in some way so that it's holding the magazine too low in the mag well.
Are the feed lips on the magazines damaged in any way? Are they scraped along the top and work flat? Do they look clean and undamaged? Is there any evidence that they bolt or carrier have been impacting the feed lips?

There's a lot of info in these forums to disseminate and I don't envy the guy new to the weapon system trying to diagnose problems. You may find it would be easier to contact one of the board member HK guru gunsmiths to help you with a weapon inspection. The fee associated with having experienced eyes look over your rifle and repair it might be small compared to the amount of stress and money spent trying to figure it out, spending money on guesses and unneeded parts.

Holy smokes thank you for taking the time to respond. You got me thinking. I tried to get a hk parts aluminum trigger box to work with my housing. It was a really tight fit and I felt like I was forcing my lower closed. Well I decided to test fit the boxes and compare how they sit in the housing. To my surprise the aluminum one sat a couple mm higher in the housing. I then tried installing just the ejector and here is the picture of how it fits now.



Compared to this old picture.



I think this is it! How does that gap look now?


That said this aluminum thing sucks so I may just by a new housing that isn’t damaged and see how that fits with my old trigger pack.

[hkshooterusp]

The ejector in the new pic looks much better. It could be yet higher but it's a great improvement. Lose the aluminum housing and go back to the original steel housing then give it a drive at the range, report back. Hope this improves things for you.

[bubba04]

The ejector in the new pic looks much better. It could be yet higher but it's a great improvement. Lose the aluminum housing and go back to the original steel housing then give it a drive at the range, report back. Hope this improves things for you.

I modified my pof trigger pack and took it out and was able to fire about 220 rounds of factory Amoy without any failures. It did choke later near round count 300 on my Low power reloads. It has not shot factory loads reliable before. So this is exciting. Thank you for the help!

I have a new grip frame, trigger box, and some rifle extractors coming tomorrow. I think this sucker will be fixed then.

[bubba04]

Well holy crap I think the trigger pack was the issue. I changed it out with a gillie pack and see attached picture. There is literally almost no gap between the ejector and bolt now.


I greatly appreciate the help here. Cost me a few buck in parts but I am confident this sucker will run like it’s supposed to this weekend.

[bubba04]

The ejector in the new pic looks much better. It could be yet higher but it's a great improvement. Lose the aluminum housing and go back to the original steel housing then give it a drive at the range, report back. Hope this improves things for you.

With new trigger pack this gun runs as designed. It’s a hoot to shoot. Thanks again for all the help.