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Does anyone know if the HK21 rubber pad works on surplus wood stocks?
I'm interested in the low down on how to do this (if possible) as well. The LOP/eye relief puts my cheek a tiny bit too close to the humpback in the stock configuration. I'll be monitoring this thread and searching for the referenced thread hoping to find how this mod was done.
 

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I just replaced the standard buttpad and buffer on my PTR91 with the HK21 pad and enhanced buffer from HKParts. You still know you're firing 7.62X51, but it's a pleasant "thump" instead of a punishing "slam". I'd still be at the range if that darn sun hadn't gone down!

The increased length of pull can be an issue, though. I'm 6' tall and it's about as long I can shoot comfortably.
 

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Does anyone know if the HK21 rubber pad works on surplus wood stocks?
They do not. Wood stock butt plate attaches with screws and the HK21 rubber pad attaches with clips that engage with the takedown pin tubes on the polymer stock. You would need to modify the rubber pad somehow to get it to work.
 

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I have a HK heavy buffer(forget which one) and the 21 buttpad on a SAR3-k-ish(with KAC rail, 2x aimpoint, so it a heavy gun).......and recoil is no issue at all, I can run 100's of rounds thru and I feel no worse for it. My buddies 110lb girlfriend ran that gun like it was made for her....she just kept asking for more mags ;)

only thing I don't always like about the 21 buttpad is that it can grab on my clothing when bringing to shoulder...but the plus side is it stays put once shouldered

yes, I wish the stock was a bit shorter. Worse yet is the SG1 stock on my 93, its a bit longer yet
 

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They do not. Wood stock butt plate attaches with screws and the HK21 rubber pad attaches with clips that engage with the takedown pin tubes on the polymer stock. You would need to modify the rubber pad somehow to get it to work.
As has been noted, it CAN be made to work. DedPyro posted a step by step about a year ago which outlines how. Grumpyoldretired hyperlinked the tutorial...and I recently did ESSENTIALLY the same thing, with a couple of tweaks. When I get home tonight, I'll get some pictures of my finished work and try to explain how I varied DedPyro's technique. I really needed the extra LOP to run the optic that I mounted. It's much better now.
 

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Here is a break down of the enhanced buffers that I offer. First off, stock/standard buffers are also designed to absorb the stout recoil of launching rifle grenades as well as the 7.62 NATO cartridge.
View attachment 222982

Notice the stock unit at top with the extra strength recoil spring and compression limiters. Lower unit has thinner wire, since the spring can compress more, a longer piston is incorporated.

View attachment 222984

The above pic shows the make up of aftermarket units that are available with a longer spring body housing. I have seen some with a similar length piston, some a little longer. While these units do reduce felt recoil, they are not as effective as they could be because they utilize the stock springs.

View attachment 222986

The advantages of the enhanced unit is the stock HK housing is utilized, no potential hassles of installing into a plastic vs wood stock and all the stock mounting hardware is utilized. Up to a 40% reduction in recoil can be observed. A similar setup is available for the HK A3 retractable stock as well.
Bill
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So here are a few pictures of how my CETME/HK21 buttpad conversion turned out...I basically followed DedPyro's great plan, but with just a few tweaks. I cut off the aluminum plate that extended outside of the HK21 pad entirely, so that it was flush with the rubber overmolding. This left about 1/8" of the aluminum embedded in the rubber. I also found the screws for my buttpad to be size 8's, not 10's...and my CETME buttpad was DEFINITELY RUBBER, instead of the fiber filled nylon that DedPyro encountered. I obtained some #8 1 1/2 "wood screws and used those to reattach the two halves of my cobbled up buttpad to the buttstock. Having removed the entire aluminum extension that was molded in to the HK21 pad, (except for the part that remained embedded)allowed me to fit the "adapter " CETME buttpad and the HK21 pad more or less fay (flush) to one another. Instead of using an o ring, being an aircraft mechanic, I slathered in between the two pieces with B 1/2 fuel tank sealant, and then smoothed it around the outside of the CETME adapter plate and the HK21 pad to make for a smoother transition. I let the sealant cure, then screwed it onto the buttstock. LOP issue SOLVED! It's been test fired, and not only softens the recoil, but now my eye is the proper distance from my optic!
 

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Hmm, my HK91 is soft shooting. Very reasonable to me.
 

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I have a HK heavy buffer(forget which one) and the 21 buttpad on a SAR3-k-ish(with KAC rail, 2x aimpoint, so it a heavy gun).......and recoil is no issue at all, I can run 100's of rounds thru and I feel no worse for it. My buddies 110lb girlfriend ran that gun like it was made for her....she just kept asking for more mags ;)

only thing I don't always like about the 21 buttpad is that it can grab on my clothing when bringing to shoulder...but the plus side is it stays put once shouldered

yes, I wish the stock was a bit shorter. Worse yet is the SG1 stock on my 93, its a bit longer yet
I had the same set up, with a COMPML2-2X, but with a full length SAR-3/8, vertical grip on M-Lok forearm, sniper buttstock (w/o the cheekpiece attached) with hvy buffer and HK-21 buttpad. I finally ditched the sniper stock and HK-21 buttpad, because the length and weight was just more than I wanted, and it felt slow to shoulder.

I retrofitted it with a standard A3 stock and put a PCS heavy buffer in that. That has been the best solution so far for me. LOP feels perfect.
 

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Hmm, my HK91 is soft shooting. Very reasonable to me.
Yeah, I agree. Considering the "thump" that 7.62 NATO puts on target, I feel that the recoil impulse is pretty mild. I know others have looked for some recoil reduction, but the modifications I did on mine were driven solely by my desire for a longer length of pull.
 

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I'm with ghosthk, I don't think it recoils that hard. Maybe some shooters are too used to the .223 AR and expect the same experience.
 
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