This is something that has been cooking for several weeks now.
How far can you shoot a 357 Magnum Revolver (not a singleshot), use all six cylinders, and still group 10-12 inches?
I'm talking about a group on a steel target.
What do you think?
Or even better what have you accomplished?

Off-hand?

No.
Benched, prone or seated with a field rest.
I will be using a scope as well.

My FA 353 is crazy accurate. I've only shot it to 140 from the hood of the truck in the couple of sessions I've had but the group was just over 1.25" with 2 of the 3 shots in 1/2". The box fell over in the makeshift range and I didn't shoot the 4th one in the cylinder. It would be interesting to see how far you could go and keep that 10-12" group you speak of though. We cleared the turkeys in Raton this year with SCHunters 353, that was with cheap factory ammo. I think that was just over 400 but I can't remember for sure right now. He may remember.

The optics will make a huge difference as far as power to keep the shots consistent once you get out there a ways to ensure the same hold, at least it would for me. Set up with a standard handgun scope versus a riflescope rig I guess is what I'm thinking. Look forward to seeing what you come up with.

My goal is 6-shots at 500 yards on a 10-12" piece of steel.
Will go further hopefully

It definitely has an "arc" out there

Unless you have some pretty nice sights to adjust, the drop on a 180 grainer will be about 220 inches. You will be aiming up into the clouds and that is hard to hold. Elmer Keith had notches on his front sights for that kind of shot. The bullet will barely be moving and not have the strength to punch what you are aiming for. A deer would have a real good head start in a "spend all night trying to find a wounded animal " contest.

Using a scope.
Eyes are not good enough for irons and still be precise

Four inch S&W 19, one shot with factory ammo at 12 inch gong at 100 yards. Tickled to make first shot over improvised fence post rest. As to hold over with iron sights, with a six inch sight radius / 4 inch barrel, 1/4 inch of front sight blade gives 750 inches of hold over at 500 yards. A Speer 158 grain at 1300 fps, zeroed at 100 yards, "only" needs 400 inches of hold over. Twice the sight radius would allow only half the correction with the same sight height. Theory and practice are a whole different thing. I asked a custom gunsmith who put three gold wires across the front sight blade of a well known gun writer's handgun about this. He maintained you run out of front sight long before you get to serious long range. For me, 100 yards is long range!

Ernie, when we were shooting at the 550 yard rams in Raton, I found the flight of the 240 XTP interesting. They do about 1525-1550 from the 10" Super with that load. They were all over the place. It seemed like the bullet was losing stability. The big 315 grain SWC bullet from the rcbs mold does a little over 1400. It would knock the rams over and when you missed, you were throwing dirt on the targets. Very very consistent. I found that interesting as we shot that day. I don't know what range the XTP was losing it but they did fine out to about 400 yards. After that, I got erratic performance. Don't know how that will be with the 357. Maybe the smaller diameter will help out. Can't wait to see what you do.

Right now I have a bunch of #8350 Sierra .38 Caliber (.357) 170 gr. FMJ Match bullets coming my way.
I'm thinking the longer, more streamlined bullets will do better.
Appreciate the info.
This will sure be walking on new ground for me, but I like a distance challenge!
May have to get a faster twist barrel--Who knows...

The 400m (440 yard) turkeys took a "pounding" from American Eagle 158 JSP's, once we figured out the hold. Significant drop to say the least! I look forward to see what the Franken-Ruger will do at range, and Glenn is right, the Bushnell 2-6 left a little to be desired at that distance

Right now I am looking at a Burris 2-7 with Ballistic plex and target turret (no holdovers).
I may go to a rifle scope, but with 170's and 180's, there may just be too much recoil to safely do it.
Won't really know till I get it, and start using it for myself.
My FR will have a 13" barrel.
Anyone have an educated guess what my MV will be with 170's or 180's?