Get ready for a longish read.
I started this process with a 357 mag single shot. Found out that in order to tighten the shot groups, the bullets have to fly faster. Ended up putting 357 Max powder load into a 357 mag casing. Using Lil Gun and it does reduce the pressure. I have no pressure issues.
Ruger released the M77-357 and I jumped all over it. The magazines suck but the gun is excellent and can shoot an inch at 100 if you make a science out of it. If not, the bottom of a soda can at 100 yards is doable all day long.
I shoot 158 gr XTP FPs over a load of Lil Gun as a 0-100-120 yard load. 1,900 fps 14 deer so far, 1 ran (185# buck - XTP FP blew rib pieces out the backside at 25 yards), other 13 were DRT. It is an awesome setup.
Started trying to reach 150 yards and found that is where the pistol bullets no longer work. Went from bottom of soda can to about 6 inch groups.
About this time my wife was hunting with it and seen a mature buck between 150 and 200 yards away. She told me she needed a gun with more reach.
Got a 350 legend Ruger American Ranch Rifle w 16 inch barrel. 3-9x40 BDC scope. Am in the process of figuring this gun out, it shoots an inch at 200 yards. Just a tad over an inch at 250 yards cause I was shooting off a dirt berm. Close to 1/2 inch (0.58 - outside to outside) at 100. Minimal recoil. Thing is a laser but you do have to account for the rise and fall. Mine is zeroed at 150 or 175 yds and good to 200-225 without worry using a 3 or 4 inch rise/fall. Use first hash mark at 250 yards and is 3 inches low.
I've shot about 12 diff bullets, even .357 mag bullets resized to .356 so they'll fit in the chamber. Yeah - been having fun. Found the Hornady FTX 165 gr bullets and still loading over Lil Gun. 2350ish fps. These will expand to 800 fps. Shot 2 deer with em so far - 1 DRT, other fell, got up and ran 100 yds w dble lung and good blood trail (painting trees after 50 yards).
During the process, found FURY BULLETS. Pointed soft point cup & core bullets. You can get 158, 170, 180 gr in .355, .357. They expand and stay together above 2,600 fps and down below 1,200 fps but no-one knows how far down. They shoot excellent in both .357 and 350 Legend.
Started with .357 and use same load of Lil Gun, loading 158 gr Fury soft point. Have a fixed 4x scope on the .357 so not trying to shoot groups but shoot an 8-inch plate at 200-255 yards with the 357 mag and ring it every time. Haven't shot a deer with this combination yet but want to - would do it at 200 without hesitation until it tells me that something isn't right. Can use the 165 FTX in 357 mag single shot, it's too long for the M77-357.
The 158 Fury's have shot 2400-2450 fps in the 350 Legend. I have some 170s to try in there.
With your 250 yards and straight wall requirements, the 350 Legend is the gun for you. Recoil is less than .243 and the 150 gr + projectiles give a good account of themselves. If you reload, the sky is the limit.
If you want to maximize your 357 mag, try some 158 gr Fury bullets and it will give you 150-175 yards easily. If you have a lever action, it would have to be first and second shots only.
Good luck!
Pic shows loaded Fury 158, XTP FP 158, then 158 flat point, 180 gr XTP HP, and the Fury 158 bullet.
