I have an HK93 that occasionally has bolt bounce problems in full auto (with my registered sear). I know a tungsten filled bolt would probably fix the problem, but, long story, I cannot do that. Is there ANY other option that anyone knows about? I'm thinking about adding material to the hammer to have it hit with more mass. Has anyone tried that? Thanks for your help.
hkindiana
A heavier hammer is not the answer and won't stop BB if that in fact is the problem.
Give me a call.
MM
Give me a call.
MM
Are you saying that your HK93 is experiencing out of battery fire?
Without replacing the bolt carrier, you should look at the rollers, locking piece and recoil rod assembly. If any of those or all are out of spec, that contribute to your issue.
Without replacing the bolt carrier, you should look at the rollers, locking piece and recoil rod assembly. If any of those or all are out of spec, that contribute to your issue.
To me adding mass to the hammer sounds like such a bad idea. That would add stress to the hammer, the hammer pin, and the pack frame. Besides, I would think an enormous amount of mass would need to be added to the hammer to push the whole bolt group back into place from the bounce. Plus the bolt carrier is not designed to be pushed by the hammer through the firing pin. I would think in very short order the firing pin would be damaged by that extra mass hitting it.
If the 93 carrier is married to a semi auto RR, have you thought of replacing the bolt locking lever spring HK 91 Bolt Locking Lever Spring with a new one? For $4.95 plus shipping, that sounds like a cheap place to start. If this is an occasional problem, maybe a brand new spring would give just enough extra holding power to eliminate the occasional bounce problem.
My understanding is the tungsten granules in a full auto carrier are in a pocket underneath the "tube" that the recoil assembly goes into on the top of the carrier. If you absolutely had to use the original carrier, the recoil "tube" (for lack of a better name) could be machined from 93 carrier. Also have the "tube" removed from a Malaysian carrier. If there is no pocket under the "tube" of the 93 carrier, the Malaysian carrier could be used as a guide for the machinist to make that pocket in the 93 carrier. Of course this would be a lot more money unless you can do the work yourself. Once the tungsten is removed from the pocket of the Malaysian carrier, maybe replacement tungsten granules could be found. That way the Malaysian carrier could still be used. As I recall the 416 buffer has tungsten granules in it. Maybe HK uses the same tungsten granules in the carriers as they do the 416 buffer.
If you wanted to try it, a hole could be drilled in the 93 carrier where the pocket should be. If there is already a pocket in the 93 carrier, just pull the tungsten from the Malaysian carrier. Once you know how big and how heavy the tungsten is in the 33 carrier is, the same size and amount of tungsten could be put the in the 93 carrier. Once the tungsten is in the carrier, weld up the hole. I would think the tungsten pocket would be in the 93 carrier, but I don't know that for a fact. Since the only external difference in a 93 carrier and a 33 carrier is the extra machining step to eliminate the "catch" trip area of the bottom of the 93 carrier. So I would think the tungsten pocket would be there in a 93 carrier. The Malaysian carriers have a buffer. But not all 33 or 33K carriers have a buffer. HK parts shows HK 33 Bolt Carrier a 33/33K carrier without a buffer. Since the 93 carrier is for a semi auto, why would HK put the tungsten in a 93 carrier? But if you have to put the tungsten in the 33 carrier, it will be a PITA.
When I have experienced bolt bounce problems, I've never had an Out Of Battery. What I have seen is a dead hammer (the hammer is resting on the firing pin) with a live round in the chamber. The hammer has pushed the carrier back into place but because the hammer is moving the whole bolt group instead of just the firing pin, there isn't enough energy to dent the primer hard enough to fire the round. I can rechamber that round and fire it, but unless the problem is fixed, it will just do it again. Good luck with your bolt bounce problem.
Scott
If the 93 carrier is married to a semi auto RR, have you thought of replacing the bolt locking lever spring HK 91 Bolt Locking Lever Spring with a new one? For $4.95 plus shipping, that sounds like a cheap place to start. If this is an occasional problem, maybe a brand new spring would give just enough extra holding power to eliminate the occasional bounce problem.
My understanding is the tungsten granules in a full auto carrier are in a pocket underneath the "tube" that the recoil assembly goes into on the top of the carrier. If you absolutely had to use the original carrier, the recoil "tube" (for lack of a better name) could be machined from 93 carrier. Also have the "tube" removed from a Malaysian carrier. If there is no pocket under the "tube" of the 93 carrier, the Malaysian carrier could be used as a guide for the machinist to make that pocket in the 93 carrier. Of course this would be a lot more money unless you can do the work yourself. Once the tungsten is removed from the pocket of the Malaysian carrier, maybe replacement tungsten granules could be found. That way the Malaysian carrier could still be used. As I recall the 416 buffer has tungsten granules in it. Maybe HK uses the same tungsten granules in the carriers as they do the 416 buffer.
If you wanted to try it, a hole could be drilled in the 93 carrier where the pocket should be. If there is already a pocket in the 93 carrier, just pull the tungsten from the Malaysian carrier. Once you know how big and how heavy the tungsten is in the 33 carrier is, the same size and amount of tungsten could be put the in the 93 carrier. Once the tungsten is in the carrier, weld up the hole. I would think the tungsten pocket would be in the 93 carrier, but I don't know that for a fact. Since the only external difference in a 93 carrier and a 33 carrier is the extra machining step to eliminate the "catch" trip area of the bottom of the 93 carrier. So I would think the tungsten pocket would be there in a 93 carrier. The Malaysian carriers have a buffer. But not all 33 or 33K carriers have a buffer. HK parts shows HK 33 Bolt Carrier a 33/33K carrier without a buffer. Since the 93 carrier is for a semi auto, why would HK put the tungsten in a 93 carrier? But if you have to put the tungsten in the 33 carrier, it will be a PITA.
When I have experienced bolt bounce problems, I've never had an Out Of Battery. What I have seen is a dead hammer (the hammer is resting on the firing pin) with a live round in the chamber. The hammer has pushed the carrier back into place but because the hammer is moving the whole bolt group instead of just the firing pin, there isn't enough energy to dent the primer hard enough to fire the round. I can rechamber that round and fire it, but unless the problem is fixed, it will just do it again. Good luck with your bolt bounce problem.
Scott
It is a dead hammer problem, not an out of battery problem. That is why i was thinking about adding mass to the hammer. None of the Malasian 33 bolt carriers that I own, or have seen, have any tungsten in them. I just spoke to MM and he offered to drill out my carrier and fill it with tungsten for a reasonable price. I've got a couple of other things to try first, but will probably go that route. Thanks for the input.
A dead hammer situation occurs when the hammer falls on a bolt that is not in battery. The bolt was in battery, tripped the auto sear, and then bounced back out of battery. More than likely your Malaysian bolt carrier does have a tungsten granules that were loose at some time. They are now frozen into a solid mass. If you review a thread from over three years ago - http://www.hkpro.com/forum/hk-long-gun-talk/138286-h-k-91-tungsten-filled-carrier.html - I had an identical problem that Mike Woodward tracked down to a bad HK21 bolt carrier. Unfortunately, you will need to get a new bolt carrier. Trying to add new tungsten to your current carrier will not correct any micro cracks that more than likely exist.
I really don't believe that ANY of the buffered Malaysian HK33 bolt carriers had Tungsten in them. I have not seen ANY with the telltale circle welds on the back, AND MORE IMPORTANTLY they were manufactured BEFORE HK started to put tungsten in carriers.
Did the Malays report any dead hammer or bolt bounce problems? I have never ever heard of any. Take your carrier to your family dentist and ask him to x-ray it for you. That will give you a definite answer.
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