I'm a follow the recipie guy, but these old Winchester's manage to get me off the reservation. The 1905, 1907, and 1910 self loaders fascinate me, but one has some uncharted/forgotten territory to cover to load for them. Last October I found a splendid example of a 1907 in a LGS. I resisted the project for months, but last month I succumbed to temptation and traded my 80's era P220 for the Winchester. They don't make ammunition for these anymore, nor brass, nor projectiles soo... The time honored way to make brass for this old war horse is to use a .357 max case shorten it, turn the rim down to .406-.410, and cut a slight groove for the extractor. Well I didn't have any luck finding any .357 max brass that wasn't being sold like it was made of gold, but .357 mag is pretty close in length and after some research I found it was a viable alternative. I made up 15 cases out of .357 mag brass (backyard engineer style on the drill press. I have a small lathe on order.) and loaded them up with IMR4227. The case is .09 short doing it this way. It worked splendidly actually, the cartridge headspaces on the rim and I have lots of .357 mag brass. Charges ranged from 14.2 grains to 15.4 grains with a (locally cast by some guy lol) 158 grain ~18bhn lubed with Saeco Gold and sized to .352. The projectile is similar to a Lyman #358665. The factory round for this gun was originally a .180gr sp sized .351 but those are also obvoiusly gold plated these days. I just did a bare bones function test firing off-hand at a 12" x ½" hanging steel plate at 30yds. I was pleasantly surprised that all of these loads functioned the action and ejected. Also surprised that my decrepit carcass got all 15 rounds on the steel. One of my groups was about 3" and I'm totally new to that gun and it's trigger is super heavy so I'm encouraged by that. With this specific set up it felt like the 15.2 grain load performed the best, so the next batch I will probably do a work up starting at 15 and working up to 15.5 doing 10 rounds each firing off of a rest and over a chrony. As far as I can see down the barrel with a bore light there is no leading. I can't really see down by the leade though. I'll watch for lead when cleaning. I can't tell you all how much it stresses me making ammo with incomplete data. So many variables and so much research and cross-referencing similar calibers and load combinations. You know how even a minor error in judgment can get a guy in trouble before he knows it. I really don't fancy myself a wildcatter. I don't know how guys like Elmer Keith stood it. I started sweating terribly before I pulled the trigger on that first round even though I was sure I covered all the bases 3 times haha. Worth it? Totally and I'd do it again for the right firearm. Sick.