So lead bullets only in trail boss?
That is what has been stated. I haven't looked but you'll probably find the listing for Trail Boss in a separate Cowboy load category and those bullets are almost universally lead. Because Cowboy loads tend to be quite light and running a plated bullet under 600 fps. is just begging to get a squib stuck in your barrel.
BTW, do
NOT try using that SR7625 in your 38 special loads, I've done that and SR7625 is extremely position sensitive in the 38 special. Pointing the barrel down prior to a shot resulted in a muzzle velocity of only 400 fps. and pointing the barrel up resulted in a velocity of 700 fps. That is a near 50% swing in the velocity the is dependent of the position of the powder in the case.
The good news is that I expect you'll find SR7625 is a fantastic powder for mild shooting target loads in the 9mm. I use SR7625 in my 40 and 45 ACP target ammo and while it produces mid range velocities it does it with less muzzle flip or recoil than a comparable Federal Champion loading.
You don't need to weigh your charges 2 or 3 times, just once is good enough. The key to not producing a double charge is to charge a full tray of cases and before putting bullets on top you take a penlight and look at the entire tray to insure every case is pretty much even. If you have a case that wasn't filled or double charged a case the difference will be distinctly obvious.
Finally, if you are using a powder measure it's a good idea to use a bit of applied Statistics to determine if your powder measure is consistent enough with the powder you are using. What you want to do is run a Capability Study to determine the Standard Deviation. BTW, SR7625 meters wonderfully so almost any powder measure will have a load to load variation of +/- 0.04 grain or less. Cant tell you how Trail Boss meters, haven't ever used it. I can tell you Unique and Longshot both vary by +/- 0.2 grain from my RCBS Competition Measure, so those powders get every single charge weighed by hand.
Finally powders on my "good" list, meaning they meter very well. Accurate #5, #7, and #9 meter very well. Also Hodgdon H110 and Winchester 296, grain size is comparable to the Accurate powders. You can probably assume that Accurate #2 is the same as the others although I've never used it. Vihtavouri 3N37 and SR7625 are slightly courser than the previous powders but this doesn't impede the metering quality at all and it does produce a powder that is basically leak free in the Lee Perfect Powder Measure. BTW, leakage issues with Accurate powders in the Lee measure is why I now do all my loading with my RCBS Competition measure. It wasn't cheap to purchase but it doesn't leak and it doesn't tend to jam with powder particles between the drum and housing like the Lee measure does when using a very fine grained powder.
