just about any size compressor will work for filling the gun direct.
there's a lot of members that buy the GX compressor directly from GX.. I have a Omega trail charger that I got around 8 years ago and it has been great.. just fill and bleed off..I'd prefer though if it had the external transformer inside the case for a nicer setup.. seems like I saw they have a model like that.. but I have seen them in the GX line.
GX also sells a duel battery compressor, uses 2 cordless drill batteries for 1 hour run time.. and it's even got auto shutdown like my Omega trail charger.
Mark
 
Hello folks I'm wondering which compressors the best bang for ur buck that will work for this hw44 I just got.any accessorie tips and where's a good place to purchase these things.thanks and happy new year
Your Weihrauch HW44 pistol has a tiny air cylinder with a max fill pressure of 200bar - you could easily hand pump it.

If you choose a compressor, a GX CS2 for $250 is well matched. You don’t want/need a high powered compressor for that little air cylinder.

-Ed