I'm willing to do some slight mods, but don't have a real MP-5 retractable stock on hand to compare - I figure somone may have done it and can answer.

I've done a search and found that you can mod a real MP-5 fixed polymer stock by grinding tabs a little, but this is different than the metal onfig on the retractable stocks - not sure if the grinding to fit would ruin the metal.

The airsoft ones and new GSG "metal"/aluminum  work, but are just too lght for my liking.

Thanks for any help you can offer.

The metal end cap will not fit without being spread apart.  I am sure it can be done but not without the stock being changed to the point it would not fit back onto a standard HK again.

I have tried just about every stock there is for the GSG-5, and the only one that comes close to feeling like a real MP5 stock is the Choate side folder made specifically for the GSG-5.  This thing mounts up SOLID and doesn't feel like a toy.  Zero wobble.

It's $100 though.

http://www.hkspecialiststore.com/product_detail.php?Category=45&Page_Number=1&Index_Seq=723&Home_Page=

Yep, I have one, and you are right, It is the best ready to fit stock for the GSG for being solid and heavy duty.

I was noticing all those Real MP5 stock from ATI (I think they are paki) and thought it might be stronger and have the traditional look.