Here is a comparison video showing a CMI P1 Thunderpig hammer and a NW Comp hammer.
The NW internals are cross compatible between the NW Comp, NW Mean Green, Blue Royal, Red Baron and probably some other NW pumps I’m forgetting. The internals on the NW Spitfire are different and the information in this video does not apply to the Spitfire. I do now remember if these are NW Comp 2 (slide frame) or NW Comp 1 (Swing frame) internals. I do imagine that the sear between the slide and swing frames are slightly different.
In the video comparison the hammers are actually surprisingly similar. I immediately check to see if the P1 hammer would fit over the NW’s bolts anti kink adjuster middle. It did and slide on it easily without too much play.
One bad thing to consider is that the early P1 parts did not use great quality control so just because this hammer is close in spec does not mean they all will be.
Next thing to check is the sear geometry.
The sears are close to the same shape. I don’t have an Nw to test it in but I am going to guess the sear won’t be compatible without some cutting. Regardless, this combo can likely be made to work easier than many others internal hammer/sear sets.
I will eventually check CMI diablo internals for compatibility as well.
Pictured hammer is Nel793. Find it (sold) at:
The NW internal set was not for sale but look at photos of a similar hammer, nel1338, at (sold long ago):
Find NW and other Nelson based paintball parts on baccipaintball at:
Find NW nelson parts at:
And CMI nelson parts at: