Jay. No offense taken. I appreciate the response. I'll take a hard look at my shooting style. Generally, I do pretty well with my other pistols, so I was attributing the results to the ammo. This configuration and load is new to me, so I'll follow your suggestion and pay close attention to my grip position and pressure. Where in the Mid-Hudson valley do you live? I used to live in Pine Bush, NY - near Ellenville mountain. My last residence before OH was in Clifton Park - just north of Albany.

Your vertical stringing could be crimp variations due to case length variations.

Ferd.
Wappingers Falls. As I think about your problem, I wonder if eliminating the crimp entirely might be a possible solution. If you have taken the time to trim all your cases to the same length, and they are all of the same manfacturer, doing without the crimp eliminates a major variable. I don't use H-110 in my loads, so I am not familiar with the powder's burn rate. However, I have found that I get my best accuracy if I don't crimp. Considering the fact that you are shooting a single shot pistol, and bullet movement is not a factor, I would try to leave a few rounds uncrimped, and see what happens. As I said, I am not familiar with H-110, and I don't know if a crimp is required to ensure proper ignition. I would appreciate it if you could fill me in on that.

I'm struggling to figure out what powder to try next in my 10 inch .357 Mag Contender. I'd like to shoot 125-158 grain jacketed projectiles. I think that I need to be moving them pretty fast. My open sights won't go low enough to get my mild, slow, lead .357 loads onto the center of the target at 25 yards. Accuracy is my primary objective. I'd also like to have something stout enough to cleanly kill a coyote, or deer, out to 75-100 yards with a well placed shot. However, most of my shooting is at the range, and I don't want to go over 158 grains, as the recoil with heavier slugs becomes objectionable for me. Thanks in advance. PS, I would have posted on the load data forum, but it seems pretty slow, and I'm most interested in what single shot folks would have to offer.

Picked up some H110 and 158 grain GDHP's. Planning to reload tonight and try out over the weekend. I'll report back. Thanks for the input.

I loaded 50 rounds of 158 grain GDHP's in new brass over H-110 (about 14.5 grains, if I recall - whatever is listed in the Hodgdon manual), lit off by Winchester magnum primers. I took them to the range today. I was shooting my G-2 with a 10 inch .357 Mag bull barrel. All shooting was done from a seated position at a bench with a decent rest. They did OK; I wasn't overly impressed with the accuracy - seemed to string vertically a lot. Very narrow pattern side to side. The blast and recoil might be stout for a .357 Mag, but along side of my 7mm TCU, they seemed fairly tame. Any thoughts as to what is causing the stringing up and down? I thought that I was crimping them pretty hard, but that's the first variable that I'm planning to experiment with.

As a former PD firearms instr. the first thing that pops into mind is your grip. If you do not exert the sme pressure on the piece for each shot, the recoil will cause the hits to string vertically. It's all a matter of recoil. Try to make sure your grip is constant, and try it again. As with anything else, takes practice.
Hope I didn't offend.