I have to chuckle a bit when I read about all these horrible groups out of Mosin-Nagant's. I was out shooting to 800 yards with one of my near stock Mosins a couple weeks back.
You really don't have to spend all the money in the world to have a lot of fun.
Using a Lee case trimmer and a 7 mm pilot, (what, $15??) and some McDonald's plastic straws cut up to make the shim fit the bore so it would crown square to the bore, I re-crowned that mosin.
Reload using Norma brass, the 174 grain Hornaday .3105 has an excellent ballistic coefficient. Hunting I use the sierra 150 grain .311. Varget 42 to 44 grains for low power with the sierra bullet, I pushed the Hornady with H4895, 44 grains for long distance (that's a bit hot for me well within the published specs on the Hodgdon website)
If you know how to use the Hornady tool, you can easily find the ones in the store that don't have shot out throats.
I'm still using those dag gum cheap $50 NCStar pistol scopes, mounted where the rear site dovetail, bed them with a bit of JB Weld on the dovetail.
You really don't have to spend much more than about $170 a year ago or $200 right now, to have a bunch of fun. There's a wild hog in one of my freezers that experienced this.
My dirt cheap Mosin is good to about 600 yards on my 22" ar500 target; 800 was iffy. Probably good to 300 for real hunting.