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Posted: 5/24/2026 12:36:26 AM EDT
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Hey all. I posted this on hkpro and at this point, I think folks are out of suggestions (beyond sending it to a gunsmith). I wanted to throw it up on here too, to see if there is anything else I should try. I have an hk33k build (malaysian hk33 parts hit on a special weapons receiver. The build was done a number of years ago. Unfortunately after receiving it many years ago, I threw it in the back of the safe without trying it. A few years later(about 3 years ago) I dug it out to try it. I could not get it to fire. I subsequently discovered that the gun had a very high bolt gap of .030". I dont recall what rollers were in it at the time but I subsequently put -8 rollers which brought the bolt gap down to .026/.027". Better but not within spec. I have tried a Malaysian #8 and RCM #3 LP without any substantial change in bolt gap from one to the other. As stated above it didn't fire when I tried to shoot it. Unfortunately I don't recall whether there was a strike on rhe primer. I am going to test that soon. As far as what to try next, I thought of the following options. (1) try -10 rollers although I don't think this by itself will bring the BG down to .020". However, the gun has never been able to fire a shot. If I could get it to shoot, maybe the BG would shrink to an acceptable level with the -10 rollers and after being fired. (2) buy another bolt carrier group to see if by chance that tightens it up enough. I think apex or centerfire has complete bcgs for a decent price. (3) buy an hk locking piece. Maybe that will lower the BG. (3) send it off to a gunsmith. I don't want to do this unless absolutely necessary. Thanks you very much for any input. I really want the gun to shoot! |
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Originally Posted By rssc: Osprey, shot in the dark here but do you know anyone local or somewhat local that can do this sort of stuff? Bahnhof Machine |
Now with more political fatigue.
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Originally Posted By rssc: Hey guys, Ughh, that's what I am afraid of. I was trying to find another solution before having to find a gunsmith and send it off. Osprey, shot in the dark here but do you know anyone local or somewhat local that can do this sort of stuff? Jeff at Parabellum Combat (Oklahoma) ETA: Apex has complete F/A HK33 BCG for $440. |
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Originally Posted By osprey21: Brad at Banhoff Machine is the closest I know of, he's in Minneola, FL. - solid guy, excellent work. Bahnhof Machine I contacted him. He is no longer doing hk work for anybody but some previous customers. I tried to get him to help and was prepared to drive up to him. I need something else worked on too. |
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Originally Posted By JoshNC: I don’t think Brad will work on clones. OP, that is a huge bolt gap. Nothing short of removing and reinstalling the barrel is going to solve the issue. He had told me some time ago that he would try to fix a clone build. But I don't believe he would ever do a build on clone parts. |
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Originally Posted By JoshNC: I don’t think Brad will work on clones. OP, that is a huge bolt gap. Nothing short of removing and reinstalling the barrel is going to solve the issue. Brad did a couple of barrel swaps for me on MKE AP5SDs. Real easy to work with but stays busy. I have a mini UZI I need to send him. |
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Originally Posted By rssc: Thanks. I am contemplating whether it would be worth buying a bcg, dropping it in there, and checking the headspace. Originally Posted By rssc: Originally Posted By lilMAC25: Jeff at Parabellum Combat (Oklahoma) ETA: Apex has complete F/A HK33 BCG for $440. Thanks. I am contemplating whether it would be worth buying a bcg, dropping it in there, and checking the headspace. FWIW, I am betting “not gonna make much change”, but then you’d have an entire backup HK33 BCG… Personally, I’d send it to Jeff (or whichever Smith you choose) and run with his recommendation (pull barrel and seat properly). Heck, send in a Form 1 and have Jeff press in a RCM 12.7” barrel to make it a 33K! https://rimcountrymfg.com/product/rcm-hk-style-33k-barrel/ |
| My vote is always start with the cheapest part, try a new locking piece you could have one out of spec. Next try a bolt and then a bolt carrier and play with with rollers. |
"I am gonna laugh my ass off looking out the air vent of the box car watching some of you shot in the head in a ditch when you finally realize it's time to resist." stolen from RR_broccoli
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Originally Posted By Stahlgewehr762: Make sure that there is a small gap between the front of the bolt carrier and the cocking tube support. If the bolt carrier contacts the support, you will get excessive bolt gap, and neither rollers nor locking pieces will remedy the issue. Agree with the above - might be that its preventing closure, What is odd is the matter of the gun not striking the primer - that is odd makes me think its just not closing all the way. |
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Originally Posted By Stahlgewehr762: Make sure that there is a small gap between the front of the bolt carrier and the cocking tube support. If the bolt carrier contacts the support, you will get excessive bolt gap, and neither rollers nor locking pieces will remedy the issue. |
Now with more political fatigue.
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Originally Posted By lilMAC25: FWIW, I am betting “not gonna make much change”, but then you’d have an entire backup HK33 BCG… Personally, I’d send it to Jeff (or whichever Smith you choose) and run with his recommendation (pull barrel and seat properly). Heck, send in a Form 1 and have Jeff press in a RCM 12.7” barrel to make it a 33K! https://rimcountrymfg.com/product/rcm-hk-style-33k-barrel/ Originally Posted By lilMAC25: Originally Posted By rssc: Originally Posted By lilMAC25: Jeff at Parabellum Combat (Oklahoma) ETA: Apex has complete F/A HK33 BCG for $440. Thanks. I am contemplating whether it would be worth buying a bcg, dropping it in there, and checking the headspace. FWIW, I am betting “not gonna make much change”, but then you’d have an entire backup HK33 BCG… Personally, I’d send it to Jeff (or whichever Smith you choose) and run with his recommendation (pull barrel and seat properly). Heck, send in a Form 1 and have Jeff press in a RCM 12.7” barrel to make it a 33K! https://rimcountrymfg.com/product/rcm-hk-style-33k-barrel/ I might wind up sending it to someone. It never hurts to have a spare 33 bcg laying around so I may grab one for the heck of it and try that first. It already is a 33k.... well its actually more of a dummy gun right now as it doesn't work Lol. |
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Originally Posted By StaccatoC2: My vote is always start with the cheapest part, try a new locking piece you could have one out of spec. Next try a bolt and then a bolt carrier and play with with rollers. I have tried two locking pieces with very little change in bolt gap. One was a Malaysian #8 and the other and RCM #3. I have not tried an HK locking piece though. |
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Originally Posted By Stahlgewehr762: Make sure that there is a small gap between the front of the bolt carrier and the cocking tube support. If the bolt carrier contacts the support, you will get excessive bolt gap, and neither rollers nor locking pieces will remedy the issue. Thanks for the suggestion. I checked this a few days ago. Hopefully I did it right. I let the charging handle go all the way forward. Then without lifting/camming the handle up, I slid it forward and back to see if there is play before it hits resistance. There is probably 3/16" to 1/4" of loose play before it hits something. From what I gather, I think this rules out cocking tube gap as being the issue. Please let me know if I am wrong on this. |
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Originally Posted By cherenkov: Agree with the above - might be that its preventing closure, What is odd is the matter of the gun not striking the primer - that is odd makes me think its just not closing all the way. I last fired the gun about 2 or 3 years ago. I do remember that the gun did not fire. However, I don't remember if the firing pin left any marks on the primer. I am going to test this out soon and report back! I will probably try it with a primed 5.56 case. Thanks for your help! |
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Originally Posted By rssc: I might wind up sending it to someone. It never hurts to have a spare 33 bcg laying around so I may grab one for the heck of it and try that first. It already is a 33k.... well its actually more of a dummy gun right now as it doesn't work Lol. Originally Posted By rssc: Originally Posted By lilMAC25: Originally Posted By rssc: Originally Posted By lilMAC25: Jeff at Parabellum Combat (Oklahoma) ETA: Apex has complete F/A HK33 BCG for $440. Thanks. I am contemplating whether it would be worth buying a bcg, dropping it in there, and checking the headspace. FWIW, I am betting “not gonna make much money change”, but then you’d have an entire backup HK33 BCG… Personally, I’d send it to Jeff (or whichever Smith you choose) and run with his recommendation (pull barrel and seat properly). Heck, send in a Form 1 and have Jeff press in a RCM 12.7” barrel to make it a 33K! https://rimcountrymfg.com/product/rcm-hk-style-33k-barrel/ I might wind up sending it to someone. It never hurts to have a spare 33 bcg laying around so I may grab one for the heck of it and try that first. It already is a 33k.... well its actually more of a dummy gun right now as it doesn't work Lol. Oops, I missed that. Well, sell it to me for cheap. 
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Usually it the opposite problem on these guns. I would assume you have already checked the breech face and there isn't something stuck on there? Will the bolt group collapse all the way (zero gap) when it is out of the gun? Bolt head is indeed a 5.56 bolt head? (not sure if a 9mm or 308 one would fit a HK33 carrier, but maybe someone bubba'd one on?) I doubt new parts will solve the issue, usually we go new parts to try and increase gap. Used parts can decrease gap, but if they were worn enough to shrink it that much I would be concerned with other issues they may present. |
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