WTK: How to Solve a HK Interface Claw Mount Fitting Issue

[Yahamshari]

Hello.

The HK interface claw mount I recently sourced does not allow enough clearance to properly mount the top of neither of my HK91s. It does not align with the y-axis.

• Both of my rifles are original German HK91s - a 1979 A-1 and 1979 A-3
• Surplus Bundeswehr HK interface claw mount (NSN 1240-12-140-9932)
• Removed the plastic bumper
• Direction of fire arrow points towards the muzzle
• Mount fits fine on rear sight base
• Mount does not touch ejection port buffer

I compared it to my A.R.M.S. #1 claw mount and discovered that the issue is the thickness and extra step of the pictured HK metal grips. I can visually see the issue and hear the thump on the top left side of the receiver. By the way, even though the bottom of the A.R.M.S. mount is wider by 1/16" to 1/18" than the HK mount, the delta has no adverse impact on the fit since both mounts clear the top of the receiver.

















This RFI is cross-listed on HKPRO.

Thank you.

 

[SubRosa]

Something is not right. I've mad many (over 2 dozen real HK-91 & 93 rifles), and never had a problem locking down a factory mount on any of them.

If you file on that mount, it will probably be ruined.

The arrow on the bottom means shooting direction, some people actually force it on the other way.

I have noticed some specimens have a tighter block on top, due to a thicker coat of the epoxy finish HK used. That is a place to use a micrometer and see if it is too narrow, preventing a proper bottoming out in that block.

 

[Klaus]

Also check the groove at the rear sight base mentioned in #3. I had that issue one time with mid 80s 91.

HK G3 claw mounts ©mg-42.net 2007

 

[Yahamshari]

 

[Yahamshari]

 

[Klaus]

That claw mount has a wider stance and looks like its for a re enforced reciever like a 21/23 possibly.

 

[SubRosa]

That ARMS mount is aftermarket, not an HK product. Good quality, but it's tolerances are more liberal...

The Hensoldt scope assembly was matched to a particular G3 rifle.

G3's were Parkerized, not painted. The HK91 being 'painted' can make the rear sight landing gap or bottom a bit tight, due to that coating. Carefully removing a bit of that coating is usually necessary to make the mount latch.

​

 

[AGG]

Do the 2 rear vertical tabs on the top receiver (just forward of the rear sight base) interfere with the mount in any way?

Tony

 

[Yahamshari]

Do the 2 rear vertical tabs on the top receiver (just forward of the rear sight base) interfere with the mount in any way?

Tony

Yes, the inner part of the front tab on the top receiver hinders the corresponding unnecessary ridge on the bottom of the claw mount from resting all the way in. I bought a set of files and I am going to file next week a bit off both.

 

[AGG]

Yes, the inner part of the front tab on the top receiver hinders the corresponding unnecessary ridge on the bottom of the claw mount from resting all the way in. I bought a set of files and I am going to file next week a bit off both.

Don't do anything to the receiver--- or to the mount for that fact--- have you tried a newer claw mount (i.e., not an older one for a G3, but a newer one for the HK91 with the 2 raised tabs on the top of the receiver)?

Tony

 

[Yahamshari]

Don't do anything to the receiver--- or to the mount for that fact--- have you tried a newer claw mount (i.e., not an older one for a G3, but a newer one for the HK91 with the 2 raised tabs on the top of the receiver)?

Tony

I don't have a newer HK interface claw mount, only an A.R.M.S. #1 that I was considering selling but I decided to take it off my ad. I tried to unscrew the scope from the HK mount but it seems the Bundeswehr loctited it. It would not budge. I was hoping to get around the hurdle by installing the scope on the A.R.M.S. mount and calling it a day even though it would not be true to a 1979.

 

[AGG]

I have a claw mount with the 1" ring inserts--- although it should work, I wouldn't want to sell it, not knowing 100% that it would work.

Tony

 

[Yahamshari]

Generally, are these HK claw mounts designed to fit both 91 and 93 receivers? I am disappointed the one I sourced is not fitting my 91 A-3.

 

[AGG]

Generally, are these HK claw mounts designed to fit both 91 and 93 receivers? I am disappointed the one I sourced is not fitting my 91 A-3.

Yes--- they should work on the HK91/93/94 equally well.
Something out of spec on that particular mount.

Tony

 

[Yahamshari]

A fellow HK enthusiast advised that he had the same issue. He suggested checking out Post #7 in the following link and the corresponding photos of his issue in Post #19. He recommend filing only the claw mount, if possible.

NEW QUESTION: recommended tools for claw mount?? (Was Price check - SG1 and A3 retractable stocks) - AR15.COM

... and I thought I was the only one dealing with this issue! I will check again carefully and if I determine filing the ledge on the lower side of the HK claw mount is the only solution then so be it. I won't touch neither of my receivers. The easier route would be to somehow loosen the two stubborn screws holding the scope to the mount then I can put it on my A.R.M.S. #1 which fits like a glove on both receivers and call it a day.

 

[AGG]

Keep us updated.

Tony

 

[Yahamshari]

Update - I used a Dremel to grind some of the Aluminum off the bottom of the claw mount. The fit is secure. Scoping the A-3 is now complete.

 

[AGG]

Excellent--- thanks for the update.

Tony