My daughter wants to change out the semi=beaver tail forearm on her XS-Special to the Schnabel one she had on her 525. I can take the beaver tail forearm off the XS and put it on the 525 but the 525 will not fit her XS special. I have a replacement Schnable forearm and can swap out the hardware and it will fit the 525 but again, not the XS Special. I suspect the latch needs some file work but am hesitant to do so. I have relieved some of the interior wood slightly thinking this was the problem but it is not. I did slightly sand the latch from the XS special just a little and that allowed it to fit the 525 while still fitting snuggly on its original barrel.
All areas seem to fit just fine. The latch wont close at all. I have squeezed, bumped but to no avail.

Is there any harm in sanding/filing it a little more to see if I can get it to mate up? Would you also sand or file the corresponding lug on the barrel for fitting?
She uses this for Collegiate competition. The beaver tail style is just a little too wide and heavy for her.

I forgot to mention that I used the hardware off both forearms on the replacement one and it cant make it work.

Thank you. I think I have to set the latch deeper in the wood since the latch is being pushed out and wont quite fit under the lug catch.

EDIT: Yeah! I got it. Taking a few thousands off the stock under the latch mechanism did the trick.