[wasatchshooter]

Greetings. I am a new member here. My Dad owned an H&K 93 back in the 1970s-1980s, buying it new and adding every cool accessory H&K offered over the years (even the loader and unloader had their own special canvas pouches) and he kept everything perfect. He sold it on the eve of the Clinton gun ban when he was low on money and was afraid it would be seized anyway. I badly miss him and I am trying to build a similar rifle, but in .308.

I have purchased a brand-new PTR-GI and I hoped I could mount my Hensoldt scope and claw mount. The scope, mount and case appear all to be never issued and the NSN on the mount is 1240-12-140-9932.

But I can't get the scope to mount, I just can't push hard enough on the lever. I could try a mallet and drift, but I want to make certain nothing is wrong first.

All of the scope appears new except for the flip-caps I added to replace the Bundeswehr ones that had a broken elastic "string". So I don't think this is an issue with a bad scope mount. It seems mechanically perfect.

The mount itself seems to work fine and it does mount on an older (wood furniture) Century CETME.

I bought this rifle specifically to go with the scope, so I would really like to get them together. I've read around on various forums for a few weeks--including here--and all the advice I find is:

1. PTR is an off-brand clone and the receiver tubes are made to the wrong size.
2. You are mounting it backwards (I'm not, and it doesn't work when I swap it around anyway). I have "Schußrichtung" pointing toward the muzzle.
3. You need to remove the plastic bumper from the back of the mount because all the clones use HK91 style mounts rather than G3 mounts. Looking at the PTR GI, this did not seem to be the case but I've been stupid before, so I removed the plastic bumper and it made no difference.
4. If you force the lever down with a tool, you will crush the tube and ruin the gun because the clones are not made properly.

I would appreciate any advice. I've looked all over and I am not a firearms newbie, though this scope mount is making me feel like one.

 

[RollerLOCKED]

I just don't have the experience to be able to say if the PTR mount cuts are generally correct or not. I would be surprised if they were, sadly... and it is true that if you try to force it on, you could really end up damaging the receiver.

The good news is that it is very likely that you are not dumb and that the receiver cuts are probably out of spec... in fact, I would be surprised if they even perform the cutting operation on the receivers. You might need to send the weapon in to a smith and have them perform the cut operation and refinish the weapon to fit the claw mount correctly.

 

[wasatchshooter]

Thanks so much for the quick reply, I appreciate it. I am hoping someone with some specific PTR knowledge will come along and fill in the missing information for both of us; apparently my post is currently in quarantine.

I've also written to PTR.

Do you have any suggestion of a smith who could do this? I want it done properly.

 

[RollerLOCKED]

I have used Parabellum (PCS) with great success but I know Jeff isn't a fan of the claw mount so he might not be able to help
Black Ops is another good company I have had great success with... Wes, I think is his name, is very knowledgeable and experienced
IDK if Dakota Tactical does repair work... but if they do, that would be a great option
I have been wanting to try Revolutionary Roller Locks for a build but I have been in a holding pattern for some time but they might be a good resource

 

[davidsog]

In some instances, even after removing the plastic bumper, the mount is still difficult to attach. There may be several reasons for this, e.g.
1. The pressure pads may be binding, possible causes are rust or debris.
2. The rifle's coat of paint -may- be to thick to allow the mount to seat properly.
3. Receiver or receiver tabs are out of spec. More likely on various G3 clones.

Remedies:​

Disassemble the pressure pads. They are attached with circlips inside the tunnel allowing use of the iron sights. When the circlip is removed, the pressure pads should come out along with seven torsion washers. If rusty or dirty, clean them with brake cleaner or similar and coat with your favorite gun oil. Remember to clean out the pressure pad seats as well. If the mount was bought from a dealer, try to return it for a replacement mount.
If you still have problems attaching the mount to your rifle, there is two options you can try.
1. Disassemble the pressure pads, and remove one torsion washer from each pad. Reassemble and check mount fit. If it still is to tight to attach properly, your receiver is probably out of spec. (You did remove the plastic bumper, didn't you?) If it is too loose, you may be able to craft some shims to replace the torsion washer you removed. Shims could be made from a set of feeler gauges.
2. Remove material from the pressure pads. This requires a very steady hand, and is not recommended. If you decide to go this route, the risk is yours.

HK G3 claw mounts ©mg-42.net 2007

 

[egroeg]

I have to finesse it a bit when I put a claw mount on my PTR. Not much help I know, but all I can say is to make sure the fixed side is properly seated. Mine will feel like its seated, but I won't be able to lock the levers until I find the sweet spot so to speak.

Good luck, for what its worth.

 

[wasatchshooter]

I took some more photos. It does look like it should fit.

Davidsog: Thanks for the info, I had read that one but the rifle is parked rather than painted, and the scope mount is brand new so no rust or debris. Removing the bumper did me no good at all. But I appreciate that or any other help.

 

[wasatchshooter]

This is as far as I can close it. I am starting to think it is indeed me, or there is something wrong with the mount. It was so easy to close on the CETME, but perhaps the CETME was out-of-spec.

 

[chrishk21]

I have a PTR G3 and a HK mount as well
Mine will go on but it’s much tighter than going in. AK
Prob the PTR tooling not perfect

 

[wasatchshooter]

Thanks all for the ideas.

Last night I put the PTR in a gun vise and spent about an hour trying to find a "sweet spot" where it would mount. The mount was solid; I could pick up the rifle by the scope and shake it--as long as I kept a finger on the lever. Nothing was loose or rattled at all.

I could not force the lever into position without use of a tool, unless I did something like put it on the bench and put my weight on it. Even then, I'm not sure it would go.

Assuming i have the correct mount base, I either need to call a gunsmith who knows these mounts or just give up and sell my PTR and scope. It's still unfired with the box, and they are hard to get so I can probably sell them both for what I paid.

Too bad because it looks like a really nice rifle, not the way I've seen people describing the non-HK clones online at all. It feels like an H&K. And not all worn-out like so many of the Century CETMEs I've handled.

 

[wasatchshooter]

I have a PTR G3 and a HK mount as well
Mine will go on but it’s much tighter than going in. AK
Prob the PTR tooling not perfect

Can you please ell me the NSN number on your mount? Mine is 1240-12-140-9932.

 

[richk]

There are 2 bumpers underneath the mount. These are adjustable with a little work. Inside the iron sight tube are 2 locking rings to coincide with the bumpers. You'll need to remove the locking rings with a hammer and screwdriver by tapping on them until they come off the post and the bumper will drop down. Once separated you'll see that there are spacing washers. Take a few out and reassemble for fit. If you have removed all the spacing washers and the mount still does not 'claw' most likely the receiver is out of spec.
I did this to a mount that wouldn't fit on an German 91 and it worked.

 

[Doodle]

I have to finesse it a bit when I put a claw mount on my PTR. Not much help I know, but all I can say is to make sure the fixed side is properly seated. Mine will feel like its seated, but I won't be able to lock the levers until I find the sweet spot so to speak.

Good luck, for what its worth.

I will second this. My claw mount Z24 will not lock unless it is in the "sweet spot."

My sweet spot results in the plastic bumper on the claw mount having a couple millimeters of daylight between it and the rear sight drum. If you back the bumper near or in contact with rear sight drum, it will not lock. Just a tiny bit forward from the sweet spot, it will not lock. It seems to like one spot only, which likely helps with consistency in removal/reinstalling the optic.

FWIW, my PTR is the "standard black" from the CT manufacturing days, essentially the same as the GI, but with black paint instead of parkerizing.

 

[jfk]

I’ll have to ask a question it’s a popular failure for a 10 mm...or just MP5s

I took some more photos. It does look like it should fit.

Davidsog: Thanks for the info, I had read that one but the rifle is parked rather than painted, and the scope mount is brand new so no rust or debris. Removing the bumper did me no good at all. But I appreciate that or any other help.

View attachment 302885 View attachment 302886

I've had several JLD/PTR "B" series receivers (complete rolled receiver with trunion and rear sight base installed). All of them fit the factory claw mount as well as ARMS. The difference that I can see on the pic you posted is the rear sight weldment. The ones I have look closer to the factory while your pic has a different version. The difference is slight but can throw the mount off enough to cause it not to fit correctly.

Use a pair of calipers and measure the width of the rear part of the claw mount and compare it to the size of the weldment tab forward of the drum. There should be enough clearance for that rear portion to mate up with the claw mount but not too much slop for the mount to theoretically slide back and forth.

Once you determine there is enough width, you will need to adjust the height of the tab with a small needle file. All you need to do is take a few even passes to square the edges up. This is something almost nobody addresses as a builder. My gut instinct tells me the claw mount cuts are correct since that is done during a final die forming operation. Your issue is not a big problem, just something not realized by the average owner. You will need to touch up the area with some paint

 

[Doodle]

Here's pics of my PTR with and without the claw mount installed...

 

[davidsog]

Davidsog: Thanks for the info, I had read that one but the rifle is parked rather than painted, and the scope mount is brand new so no rust or debris. Removing the bumper did me no good at all. But I appreciate that or any other help.

It looks like you are focusing on the rear bumper and not the correct pressure pads to adjust. The pressure pads are not adjusted by removing them except to add or remove spacers used to adjust the amount of pressure they put on the top of the receiver.

richk tries to steer in the right direction:

There are 2 bumpers underneath the mount. These are adjustable with a little work. Inside the iron sight tube are 2 locking rings to coincide with the bumpers. You'll need to remove the locking rings with a hammer and screwdriver by tapping on them until they come off the post and the bumper will drop down. Once separated you'll see that there are spacing washers. Take a few out and reassemble for fit. If you have removed all the spacing washers and the mount still does not 'claw' most likely the receiver is out of spec.
I did this to a mount that wouldn't fit on an German 91 and it worked.

The website I posted gives the instruction for adjusting the two pressure pads found underneath the mount.

Disassemble the pressure pads. They are attached with circlips inside the tunnel allowing use of the iron sights. When the circlip is removed, the pressure pads should come out along with seven torsion washers. If rusty or dirty, clean them with brake cleaner or similar and coat with your favorite gun oil. Remember to clean out the pressure pad seats as well. If the mount was bought from a dealer, try to return it for a replacement mount.

HK G3 claw mounts ©mg-42.net 2007

If your mount fit on a Century CETME rifle I would be willing to bet that the pressure pads had to be adjusted in order to fit that Century Arms rifle.

 

[wasatchshooter]

Thank you, davidsog for the very detailed explanation, I had read that page but I had (incorrectly) read that the reason to disassemble the mount was if it was dirty or greasy. Since mine was new, I didn't worry about that.

I had then seen richk's comment, and I am attempting to get time to figure out how to take apart the mount. I had two sick kids over the weekend but I hope to get time in the next two days; I will follow-up here and let everyone know what happens and what thing or things I have been doing incorrectly.

Oddly enough, it just went onto the Century CETME with no issues. But that probably does represent a problem with the rifle; it didn't have the proper registration points.

 

[wasatchshooter]

FWIW, I did hear back from PTR on this issue today:

I discussed your issue with our technician, who has been working on this platform for over 20 years. He stated that in most cases with the claw mounts, you have to do some fitting to the mount for them to set on the rifle correctly. He stated this was true, even when fitting them to HK rifles, which is why the HK rifles had matching serial numbers with the claw mounts, for the most part. You will have some where they will fit without modifications but most of the time you may need to tweak the mount to make it work.

I've not seen HK mounts with serial numbers, but that doesn't mean it is not true.

 

[hkshooterusp]

Lots of good info above. All I'll add is do not use a tool to latch the locking lever. I've never, ever seen a claw mount damage/bend a receiver but I have seen the pin the locking lever's slot sheer off. Don't do it.

Oh, and BTW, I think PTR's comments are BS. I've never had to "fit" a claw mount to an HK brand rifle. Or a Springfield/EBO or a FMP rifle, for that matter. Ever.

 

[davidsog]

Thank you, davidsog for the very detailed explanation, I had read that page but I had (incorrectly) read that the reason to disassemble the mount was if it was dirty or greasy. Since mine was new, I didn't worry about that.

I had then seen richk's comment, and I am attempting to get time to figure out how to take apart the mount. I had two sick kids over the weekend but I hope to get time in the next two days; I will follow-up here and let everyone know what happens and what thing or things I have been doing incorrectly.

Oddly enough, it just went onto the Century CETME with no issues. But that probably does represent a problem with the rifle; it didn't have the proper registration points.

You are welcome! Take care of those kids and when you get time....

Take the C clips off the top of the pressure pad using two screw drivers. Hold one steady and push or lightly tap on the on other to slide the C clip back. You should be able to remove the pressure pads and count the washers. You can also pry the C clip with an angled O-ring pick.