Well, the rebored barrel arrived today so my call to JES is moot.
I'll chamber some spent .357 cases to check out the ejector. It might need kissing with some fine grit wet dry sandpaper but I 'll wait to pass judgement after checking with fired and unfired cases. IIRC my Springfield, MA factory TC .460 S&W barrel ejector needed the sharp edges taken off.
I have 158 gr and 180 gr bullets, primers and H110, IMR4227, and CFE BLK powder. When I scare up some .357 max cases I'll report how it shoots. The LGS had a bag of .357 Max Starline brass a year ago very reasonable and I'm kicking myself for not grabbing it.
