I havben't had much trouble in Storymode (Wintermute) with the rifle.
Yes It's hard because of the missing skills. But so far 2 out of my 4 shots were a hit that ended in a killed wolf and deer (wolf was a direct kill, the deer needed some following).

Could you write down how you did it? I haven't tried the game yet as official release but in case I agree with you (I hate low accuracy in games) it might come in handy and for others as well.

You can probably do this with a mod or save game editor. You can find a few on ModDB and on Github.
The current release of TLD even has a custom difficulty option on-board for Survival mode, not sure if this is entirely possible but there's a lot you can tweak now from within the game.

Just get the TLD Savegame editor. In there, you'll find your characters stats and skills, so you can increase the rifle skill to a realistic number. Don't use that editor too much though, or you really do skip all the gameplay and training of skills.

But personally, I am able to tell apart the front from the back of a rifle, and not waving it around is within my capabilities, as well. If you're similar, around 25 for that skill should be okay.