Help me my HK brothers....I have done a bad deed LOL

[Grease Gunner]

While setup at a local gun show I felt weak and purchased an HK51 project that needs some TLC. This thing looks like it functioned but there are things that need fixed....needs a proper shelf, a telescoping recoil assembly, headspace reset as it locks up really really tight, some welds smoothed out, and finally refinished. As this gun sits I would not call it a functional weapon, but rather a work in progress....got the gun, a pile of mags and even ammo to boot!

I stuck the 91 A3 on it for the trip home so the bolt didn’t go sliding out of it.

 

[MSOGDAWG]

Bro Im in for watching this project. I really want a 51 like this but in pistol format.

 

[Manofdusk]

Bro Im in for watching this project. I really want a 51 like this but in pistol format.

We build 51, 53 and 94/MP5 pistols!

 

[AGG]

Excellent acquisition--- keep us updated.

Tony

 

[spartan]

Send to @Manofdusk .

 

[Guyanaman1963]

While setup at a local gun show I felt weak and purchased an HK51 project that needs some TLC. This thing looks like it functioned but there are things that need fixed....needs a proper shelf, a telescoping recoil assembly, headspace reset as it locks up really really tight, some welds smoothed out, and finally refinished. As this gun sits I would not call it a functional weapon, but rather a work in progress....got the gun, a pile of mags and even ammo to boot!

I stuck the 91 A3 on it for the trip home so the bolt didn’t go sliding out of it.

Brother!
Cant wait to see how this turns out!!!
M.

 

[Grease Gunner]

Update-I ground off the “shelf” and have it prepped to install a new one and waiting on rollers to reset the head space. It had -4’s in it and the bolt gap was .0045!! No wonder it was too tight. I pulled a set of neuntral rollers out of a new MP5 bolt head and that opened it up to .0095 on the gap. I have +1, +2, +3 and +4 rollers on the way.

You all will love the other project I’ve been gathering parts for....and once I have the heart of the beast in hand I can start putting it all together.....lord help me I’m bitten BAD by the HK bug. Details on the parts gathering project will be posted when I get started.

 

[Grease Gunner]

Spent part of last evening working on the A3 stock to make it compatible with the HK51 host. Put it all together only to realize I went about it backwards lol There as a “delay of build” due to launching the recoil spring across the shop and spending 20 min trying to find it!

We all have to learn somehow. I hope the new rollers show up tomorrow so I can get the headspace/bolt gap set as I expect to get the stock finished this afternoon. I want to shoot my “magazine fed flash bang device” this weekend!

 

[Runinamuck]

I don't think this bunch is going to help you with forgiveness, Jealousy maybe, forgiveness, probably not.
Good score.

 

[Grease Gunner]

Well I had good and bad experiences last night with the HK51....I was able to get it to run one magazine. Took it back in the shop for a couple tweaks and when I took it back out again things went awry...after 4 rounds the split collar inside the carrier which holds tension against the recoil spring came out. It would appear that whoever cut the carrier down only pressed it back in. So this afternoon I’ll press it back in and then weld it solid....

I am so have to figure out why it doesn’t want to chamber on the slap but will feed out of the magazine. I’m sure that’s something simple I just have to find it.

 

[Manofdusk]

Well I had good and bad experiences last night with the HK51....I was able to get it to run one magazine. Took it back in the shop for a couple tweaks and when I took it back out again things went awry...after 4 rounds the split collar inside the carrier which holds tension against the recoil spring came out. It would appear that whoever cut the carrier down only pressed it back in. So this afternoon I’ll press it back in and then weld it solid....

I am so have to figure out why it doesn’t want to chamber on the slap but will feed out of the magazine. I’m sure that’s something simple I just have to find it.

Ghost Gunner, when I modify my 51 bolt carriers, I cut them down and then cut the tip and reweld it back to the carrier to the proper length, that way, the split ring insert doesn't push through. I also remove the recoil rod from the end cap, cut it and the spring down and everything works great. I'll be building another 51 this coming week and I'll take some photos of each step of the bolt carrier and recoil rod/spring modifications.

 

[Manofdusk]

Well I had good and bad experiences last night with the HK51....I was able to get it to run one magazine. Took it back in the shop for a couple tweaks and when I took it back out again things went awry...after 4 rounds the split collar inside the carrier which holds tension against the recoil spring came out. It would appear that whoever cut the carrier down only pressed it back in. So this afternoon I’ll press it back in and then weld it solid....

I am so have to figure out why it doesn’t want to chamber on the slap but will feed out of the magazine. I’m sure that’s something simple I just have to find it.

Also, the "slap feeding issue" may be caused the the cocking slot not being cut back far enough. If they used a 53 cocking tube, it will not let the bolt go back far enough to chamber a round with a slap cock. I know from experience...

 

[Manofdusk]

A

Well I had good and bad experiences last night with the HK51....I was able to get it to run one magazine. Took it back in the shop for a couple tweaks and when I took it back out again things went awry...after 4 rounds the split collar inside the carrier which holds tension against the recoil spring came out. It would appear that whoever cut the carrier down only pressed it back in. So this afternoon I’ll press it back in and then weld it solid....

I am so have to figure out why it doesn’t want to chamber on the slap but will feed out of the magazine. I’m sure that’s something simple I just have to find it.

After looking closely at the cocking slot in your close up photo, I can tell you that the locking slot on the cocking tube is NOT cut back far enough and that's why it won't "slap cock" and chamber a round.

 

[Grease Gunner]

Ok so if the cocking tube slot isn’t long enough, what are my options? Without cutting the whole gun apart obviously.

 

[Grease Gunner]

In looking at the HK51 project again I discovered that the bolt carrier has been shortened too much and that’s why I can’t get the slap as it’s not pushing the bolt carrier back far enough for a full stroke....now to fix this issue and then try it again.

 

[Grease Gunner]

IT WORKS!! Opens nicely now AND chambers a round on the slap....if it wasn’t 8:18 I’d test fire it.....I’ll be nice tonight.....but tomorrow we shall light her up!

 

[Manofdusk]

I build my 51 bolt carriers like Vollmer did, they are cut to 4.140" in length and then I use a shortened 93/33 cocking support. It looks like your bolt carrier is cut the way PTR cut's theirs.

 

[Manofdusk]

 

[Grease Gunner]

I need something you have hanging on your wall but I’m betting it’s for a customer build-I need an intact SD cage.

 

[Grease Gunner]

The other bad thing is I started in on this project with a mess. It was a mix master of parts and half ass work. I can honestly say there is NO WAY the guy I bought it from ever fired it and if he actually did, it’s a wonder it actually worked at all. I have a feeling this was someone who tried to half ass a build, totally screwed the pouch, then dumped it on someone. Either way his story of shooting it was complete bullshit lol

I can only imagine what sort of living hell someone would have gone through had they not known how to work on HK’s. I can say that this is the first HK rifle platform I’ve worked on and it taught me quite a bit. I’ve only built MP5’s up until now......and now the next project is going to be an HK21......yeah I’m going off the deep end lol