Rifle: Ruger #3
Caliber: 45-70 Govt.
Sight: Red dot
Bullet: Hornady 350 gr. RN
Question: Using this bullet, (gun likes it) what do you consider to be max. velocity safely reachable? I want to use this combo for big bears. Before you think I am totally nuts, my partner will be backing me with a .458, and he really knows how to use it. What I would like is a load that you have some experience with. Books are great, but you tend to learn more from life.
Thanks

Hmmm. A Ruger #3 in 45-70 loaded hot. You must really be into pain. Sorry, I couldn't help it. I have both the Ruger #1 and #3 in 45-70. I once fired some 500 gr. cast lead bullets at 1500 plus FPS from that #3. Mine is quite minty so I never put any kind of recoil pad on it and even with the Past recoil sheild, the damn thing hurts.
I only shoot my home cast bullets in my two Rugers. One load I like, although it's hotter'n hell is Elmer Keith's old load of 53.0 gr. of IMR-3031 with a 400 gr. bullet. Considering the change in burning rate from Du Pont's version of 3031 to IMR's version, that load may now be too much.
At any rate, I believe that most likely, IMR-3031 would be my powder of choice for working up that load. Personally, I would look at a bullet a bit heavier, and would probably use one of my 400 gr. bullets cast hard for penetration.
Paul B.

I would use or match the PMC load , they use that same bullet with pressures of 37,000 psi ,I think. It's said to be very accurate and performs very well.

Last year at the Austin Texas gun show I saw a #3 375 winchester converted to 375 H&H. The owner said it was an event when shot.

You don't have to worry about pushing the Ruger #3. I shot loads in my 45-70 that were listed in the 458 Section.

Between 2350 and 2450 FPS, if you can stand it! The gun certainly can! I have used OVER 60 grains of RE 7 with the 350-grain bullet in my No. 1, and it also generates over 55 foot-pounds of recoil!

In a No. 3 with that buttplate, I guarantee you'll need a new rotator cuff!! Bon Chance, mon ami!!

Even with a pad (I could not stand the stock though it was comfortable enough with factory loads) a little Ruger No3 can be ferocious: with a good supply of 3031 and a 450 grain cast seated all the way out (it was a bore dia paper patched at the base) recoil was something... I could stand to shoot it well enough, but I had to guess the elevation. What kind of red dot sight are you using? I haven't tried them yet, but I picked up some Hornady 350 interlock for general purpose, are we still in the same ballpark on loads?

45LCShooter
The sight is a rather elderly Bushnell, w/30mm tube. I find that if I aim properly, (both eyes open), it finds its way to the exact spot I want to hit all by itself. Love it. The heaviest load I have tried so far is 59.6 IMR 3031. Although the book calls for 2200fps w/this charge, all I am getting is around 1900. I am going to switch to magnum primers for the next batch, just to see what that does. However, using it as it is, three shots at three woodchucks at about 100 yds left no survivors. I have all the confidence in the world in the bullet and sights. What I would like is more velocity. I would really like a true 2200 fps. As to recoil, I can shoot the thing off a bench all day, as long as I have a 20 lb. bag of shot between the butt plate and my shoulder. Shooting it offhand, or kneeling, in hunting clothes is no problem at all. I don't intend to go prone unless I have no other chioce. In other words, If I am not sure I can kill it from offhand, kneeling, or sitting, I pass on the shot. The way I see it is if your back-up has to shoot, you failed.

Almost forgot. I have heard that the butt stock from a Ruger #1 can be put on a #3. I have heard this conversion referred to a Ruger #2. If this is really possible, considering the difference in the shape of the action lever, I would probably go that route. Does anyone know if this is really possible, the amount of work involved, or a 'smith who can do it? This way I can leave the original stock in factory configuration for possible re-sale at a later date. Probably will never sell, but what the hell.

Yes. You can put a Ruger #1 stock on a #3. I have a friend that has a #3 in .375 Win. that has a #1 buttstock on it. You do have to alter the lever a bit though.
Your biggest problem though will be locating a stock. Ruger will not sell you one, so you'll have to find one that someone has taken of a rifle because they are building a custom job with better wood.
I need to replace a forearm on one of my #1s and Ruger insists I send the gun to them for replacement. Apparently, they feel we are too stupid or too incompetent to do it ourselves.
Paul B.

I have #1's in .458WM and .375H&H. The action will handle what you give to it. MAX loads (500 gr at 2200fps in the 458) are no big deal. I guess I don't bruse much. My friend and I did 30 and 50 rounds each. He was black and blue from collar bone to elbow and I had a only tinge of yellowing in the shoulder. It did hurt for over a week though.

What I'm saying is that your shoulder will be the limiting factor. At the end of the shooting session we both were firing from left shoulder.