I have an older 116 FLSAK lefty in 300RUM. I'm not a big fan of long freebore and prefer a rifle that a mag length round will reach the lands. My factory rifle doesn't seem to have long or excessive freebore. When doing load development I usually start jammed (for consistency) and work up. Once I find a node I'll go from there adjusting my OAL.
My rifle is factory so weighs about the same as yours. I was scared of it at first because I bought it from a big ol dude who couldn't handle it. He was very tall and when he shot it from a bench he was bent over so far that the rifle basically rested on his collar bone. After five rounds down range and a low ball offer from me (I matched a pawn shop offer) it was my problem. LOL.
I bought a beartooth neoprene slip on recoil pad and stacked all the foam spacers inside it and opened the brake for my first couple of shots.
My initial impression was that it wasn't that bad. I removed some of the spacers and eventually settled on a regular limb saver slip on pad.
As far as the brake goes In my opinion it's mandatory for this caliber. I have inadvertently fired mine with the brake closed and it's pretty brutal. One thing's for sure, I knew immediately that the brake was closed without looking or having to have anyone tell me. Kind of embarrassing but I've made this mistake more than once but never more than once on the same day. LOL
If you wanted something to reach a long way well you certainly have it now. As a matter of fact it will reach a long, long, long, long way.
I haven't shot an elk with mine and I wont use it on white tails because it blows em to smithereens. I have shot two whitetail deer with mine, It was on the same day and both were reduced to purple mush in a deerskin bag at 250 yards with a Remington factory loaded 180gr sirocco bonded. Remington had so many complaints of this that they now offer ammo in 3 power levels. Choose your ammo wisely. Prior to owning this I was of the opinion that there was no such thing as too much gun or too dead. Now I have seen both.
One final thought and a word of caution. Though the perceived recoil may not seem overly bad and may not leave you with a black and blue shoulder, or even a tender shoulder, the repeated effects of shooting a .300RUM is cumulative. I was doing some load testing and sat down at the bench and fired about 40 or 50 in a day. I went home and everything was fine. I woke up the next day experiencing chest pain. My wife insisted that I go to the doctor and get checked out. I didn't even think about the previous days range session and the doc proceeded to run at least a gazillion expensive tests related to chest pain. When the results came in they said I had separated my ribs from my sternum. That's when I remembered the only thing that could have done it.
I haven't had the RUM out of the safe in a very long time.
Not sure living down in Georgia why I even keep it around. One things for sure if one of those pesky rhinos, elephants or dinosaurs ever gets in my garden, I'm ready.
Don't be scared of it just respect it and use it in moderation.
Good luck,