... because the dboys internals are absolute rubbish...
The tanaka ones are superb in comparison.
I really wouldn't even bother .
The DBoys K98 bolt /spring etc is utter bollox and un upgradable and gives about 270 FPS . The Tanaka in good form easily passes 500 FPS . Bit like transplanting a Robin Reliant engine into a Porsche .....total no brainer , in fact criminal if you butchered a Tanaka K98 to perform this abortion .
Now....... if you wanted a K98 springer that much , buy a cheap VSR clone and a DDboys woodstocked K98 rifle and you havethe basis of an interesting hybrid for less than half the price (ish) of a Tanaka K98 .
Good man , it's been done a few times before infact there is a stickied thread somewhere .....
ah here it is
Good luck ! I reckon second hand the MP001s should be got pretty cheap now, and from memory Warren at Shoot and Scoot had some wooden K98s ....