No Dee, actually you lose velocity with some of these loads. The powder is burned up in the first few inches of barrel and the bullet has to glide out the rest of the length.
I did tests that confimed PawPaw's results. My loss was closer to 100fps though.
To the OP, you can't push the HBWC as hard as you can push a FBWC. I've been shooting cast lead WC's in my .357 Handi for awhile, using a Hensley and Gibbs 146gr wadcutter, and with the right load of Hodgdon's Universal, it will shoot superbly (0.6"+/-) out to 50 yards. Unfortunately, my best tests at 100 yards were around 2".
I started this as I needed to find a load that would work with the bullets I could make. I needed something a bit slower as well, as I built a bullet catcher to save my lead.
As I am an experimenting sort, I next tried trimming, flash-hole-uniforming and "neck-sizing" the brass. I sorted my bullets by weight and used BR SR primers. My rifle has a 36x scope and I had a decent BR setup that day. Groups at 50 yards were hovering around a half-inch, and the cronograph showed between 806 to 820 for 19 out of 20 shots, with one shot at 796. The same load in the GP100 grouped VERY tightly as well, but I didn't have the chrono out that day.
I'm noting your handle 'chutesnreloads'...
Interestingly enough, I experimented with breech-seating the wadcutters as well. The powder was Acc#9. I had drilled and tapped a socket-head capscrew into the side of the barrel near the rear, and built a seater and an adjustable length dummy cartridge that would permit seating the bullet ahead of the throat. I had trimmed a series of .357max brass to the longest length that the chamber would accept, and tested 10gr-13gr of Acc#9. I'd also started to test H-4227 but ran out of day. I could not obtain any better results with the breech-seating than I could with fixed loads. I'd intended to experiment with some heavier (200gr+) .357/38 loads, but was sidetracked when I stubbed a 32-40Win barrel onto my Handi, and started getting 100 yard groups that were better than my previous 50yard groups.
Sometimes I wish I had a longer atten...
ooohhh, shiny object!!