Help with HK91

[bullseye]

A friend of mine has an HK91 with a bipod problem. One of the legs goes too far foreward. I have not seen it and he hasn't really looked at it apparently. What could be the problem(I know this isn't much to go on)? Is there a stop pin(roll pin) that stops the leg from going foreward, or is it a notch on the leg that could be messed up? I haven't actually seen one up close so I have no clue myself. Any help would be much appreciated.

[rustypirate]

There is a spring loaded plunger in the leg that engages with a notch in the head. The bipod may just need cleaning, but I have one of the aftermarket steel bipods that look like the real HK ones, but the springs in it are not as good, and that could cause this symptom as well.

[JayGeeWentWorth]

I also have an aftermarket bipod with the same problem. If anyone has a solution I'd like to know it as well.

[rustypirate]

I disassembled mine, and polished up the locking surfaces, then replaced the springs with stronger ones.

[Seattlefungus]

Rustypirate has the right of it. The ProMag and POF both are fairly good knock offs. But the stops need a light filing and a stronger spring set helps. There is a flat stop at the end of the sweep. (Moving from locked against the handguard to locked in the standing position.) polishing the sweep surface and making the two stop positions more positive fixes the problem. A round file or Emery cloth to the inside of the lock shaft is a help too I used a Dremel with a section of coat hanger wrapped in emery cloth held with duct tape, used air to blow it out and put Breakfree on a Qtip on the shaft and moving parts.... Whole job take less than an hour. What a difference...

[JayGeeWentWorth]

I disassembled mine, and polished up the locking surfaces, then replaced the springs with stronger ones.

Would you mind telling me where you got the springs at?

[jfowl31]

ditto to what Jaygee said... where are these springs you speak of?

[bullseye]

Thanks for the info so far, I'll run it by him tomorrow and see if it solves his problem.

[rustypirate]

I happened to see some springs at my local hardware store that were close enough to the right size.

[JayGeeWentWorth]

I think I got mine taken care of. :rockon:

First I filed down the surfaces on the base of the bipod where the pins lock into as I found that the pins were not going in all of the way. I also filed on the pins some too so I could get an even better fit. I didn't know where to get new springs so I decided to make a couple of spacers that would, in essence, make the springs stiffer by compressing them more. I recently did a clip and pin job on a grip frame and I found that the pin used to attach the handguards and trigger packs had a nearly perfect diameter for a spacer in the legs of the bipod. Since all I needed for the clip and pin job was the two ends of the pin, there was plenty left over to make the spacers. The spacers don't need to be very long. I would say 1/8 in. or maybe slightly more. Make them too long and you won't be able to press the release buttons down all of the way and the bipod will be, more or less, permanently fixed. Getting the right length for the spacers is kind of a fine line, but with a little work it can be done.


On another note, I managed to break one of the lock washers that holds the retaining pins in place that connects the base of the bipod to the legs. Does anyone know the size and where I can get a replacement?

[rustypirate]

I just picked up another of the all steel bipods today. A local gun shop had one left, along with an MP-5 magazine. I paid $70 for the bipod and $25 for the mag. Sometimes you can find a deal out there.

PS, brand new, both items.