The Mosin isn't a Garand, and the Garand isn't a Mosin. Neither are ARs either.
Or M1As, or.................what ever. They each have their own uses or category, I shoot mine in CMP GSM matches, The Garand has its category, and the Mosin doesn't compete with the Garand, its in the Military (other) Category.
The problem with the Mosin is not the rifle, but the shooter.
Yeah they are cheap, but they don't have to be fed cheap food.
I only paid $99 for mine. Nothing special except I went through several with a bore light and found what appeared to be the best barrel.
The Clerk tried to sell me some surplus ammo, cheap stuff. Nope, don't want it, wont shoot it, even in a $99 rifle.
They didn't have any 7.62X54R brass so I bought 100 rounds of factory Winchester Ammo. Cleaned the rifle and it shot fairly well although the sight setting didn't match the group. Easy fix. I got it where it would be on at 100 yards when set on 100 yards. The sights match the impact to 400 yards, I haven't shot it farther.
I then bought some 150 gr. Sierra .311 bullets. Didn't load them hot, I think about 2500 fps. You don't need a lot of velocity to punch holes in a NRA 200 yard paper target.
I found the thing shot pretty good. Not worth a hoot off hand, but then neither do my Garand's but that's not the guns fault.
Got some stripper clips, learned to use them. Learn tech. for working the bolt in Rapid Fire, and now, except for my being too lazy to practice off hand shooting, the rifle fires respectable scores at the CMP Vintage Rifle Matches.
The Mosin isn't a Garand, it isn't a High Power AR or a Ruger Precision Rifle either. Its a Mosin, when you put effort into learning to shoot it, and use quality ammo, loaded to fit the Mosin, its a shooter.
You can, per CMP rules put a M1917 style sling on it and would get better score in position shooting, I haven't done that, I use the sling it came with.
The Rifle is 'AS ISSUED" meaning not modified so it meets the CMP GSM Rules. I want to keep it like that.
HOWEVER: A Mosin shooter in my club showed up with a contraption I just had to try. Its a mount and scope that turns the rifle into a "scout" rifle. The pin holding the rear sight comes out, removing the rear sight then the pen holds the mount on. Allen screw are set to keep the mount solid. The whole set up cost $50 from Sportsman's Warehouse. Nothing to write home about but it does add a new detention of Fun to the rifle.
You then push out the pin, replace your rear sight, and you're back to CMP legal.