[dezelrig]

My new G3K with flemming sear will fire a 4-6 round burst and then something inside the pack will not reset correctly. I have to recycle the bolt carrier by hand and it will fire another burst and then won't run until I cycle by hand again.

This is my first attempt at Class 3 full auto, so these gun parts have never been assembled together (sear, pack, gun).

Should I send the pack with the sear to someone competent? or is there something I'm missing.

Gun is HK-91 original with all original parts, and a new c/p navy lower. The lower was "sear ready" and I just put my flemming sear in it to make it go.

 

[mlm]

The first thing I would do is call Adam Webber and order a hammer that is timed for use with flemming sears. Try the new hammer and see if it works. If it does not work then I would look into sending it to an HK smith to be timed.

 

[RyanH&K21EOwner]

G3K with Flemming Sear trigger pack...

Completely a timing issue with the Registered Flemming H Sear...

Make sure you have the 18 ' locking piece for the G3K...

You'll need to have the hammer and sear pack re-tuned for the G3K gun...

 

[dezelrig]

what should I expect to pay for retuning?

who's competent and what is their contact info?

once it's retuned will i be able to just throw the pack in a 9mm lower and not worry about it?

 

[AviatorDave]

So it fires just fine in single fire mode? I bet so.

What's probably happening is that when firing in full-auto, the carrier is hitting the trip lever and releasing the catch too early, so the hammer is riding forward with the carrier. Sometimes it has enough speed to fire, sometimes not. It probably always will on the first shot, because in that case, the hammer is held back by the sear, not the catch.

I'd bet that all you have to do is change out your likely unmodified hammer (if you post some pics I can compare it to some of mine and tell you if it's been retimed or not) for one that's been timed. All that's done to "time" it is to cut the full-auto notch a little deeper since the registered sears are a little different length than factory catches.

I think you can get timed hammers for $50 or so, and you won't have any down time, and won't have to ship off your pack with your $14,000 registered sear in it.

 

[dezelrig]

1. The locking piece is not stamped with any #, so I only assume it's a #18.
2. Yes, it fires just fine in semi auto.
3. The hammer in the top of the picture is the hammer I'm using (in the navy pack), and the hammer on bottom is taken from a SEF pack that has been set up for my sear (I'm not using the SEF lower b/c I have no c/p housing for it).

 

[AviatorDave]

Are you positive you haven't either switched the hammers by mistake, or maybe just typed the picture description wrong?

I have an SEF pack setup for a Flemming sear, and the hammer looks exactly like the TOP one in your picture, except it has the hammer spring strut pinned to the hammer.

I also have a Safe-single-full true MP5-N pack that is completely unmodified. It's hammer looks exactly like the one you have in your bottom picture. And while I don't have an unmodified SEF pack, I do have some non-navy style 0-1-25 packs, their hammers also look like the one on the bottom of your picture.

So... the hammer in the bottom of your picture does not look like it has been modified to work with an SEF pack, it looks like one out of an unmodified navy pack, but your top hammer looks like one modified for an SEF pack.

Also - please post a picture of the side of your pack frame so I can see the sear hole locations. Depending on where they put it, it may require different modifications to the hammer.

 

[dezelrig]

1. No. I'm 100% sure I didn't switch hammers or captions. The top hammer is from the "sear ready navy pack" and the bottom hammer is from the "sear ready sef pack".

The top hammer has definitely been modified because I can see where the further most tip has been rewelded.

The bottom hammer has been ground slightly on the front in 3 places. This may be from the factory, or done to fit the sef pack.

Pack on top is navy and on bottom is SEF. Notice the trigger sear on sef pack has been ground down, while the navy is unmodified.

Again navy on top, SEF on bottom. The sear axle holes on both packs line up perfectly.

 

[dezelrig]

I lined the 2 packs up and the sear axle holes, as well as the hammer holes line up perfect.

Mabe I should just try the bottom hammer in the Navy pack and see if it runs.

1. Will a potentially unmodified hammer destroy my $14000 part?

2. If a non #18 locking piece is used, what will happen? Would I even notice anything?

Thanks for the help so far guys

 

[AviatorDave]

I lined the 2 packs up and the sear axle holes, as well as the hammer holes line up perfect.

Mabe I should just try the bottom hammer in the Navy pack and see if it runs.

1. Will a potentially unmodified hammer destroy my $14000 part?

2. If a non #18 locking piece is used, what will happen? Would I even notice anything?

Thanks for the help so far guys

Ok, your navy pack has been correctly modified. You can see where they welded up the old hole and redrilled the new hole.

Let me take some pics later today of mine both installed and locked back and uninstalled. In the meantime, if you can take a pic of your hammers so that you are getting the shot perfectly straight down on the side it might help. In the one pic, they are at a slight angle.

If you get some that are perfectly aligned with the axle hole, I can superimpose mine on top and see if there are any differences.

 

[dezelrig]

Yeah the navy has definitely been modified, and so has the hammer in this pack. I can see the rewelds.

More pics:

 

[dezelrig]

Turns out the hammers and etc. were ok.

The bolt carrier (reweld by urbach) was a p.o.s.
Replaced with factory full auto and it runs fine.

Thanks for the help.

 

[rext]

Thats odd?But glad it was that simple!

 

[AviatorDave]

Ja, that is weird. Another reason I don't like rewelded carriers no matter who makes them.