I dunno if the last patch nerfed this. But every time you'd shoot this gun in vats, you'd get more than needed in AP to shoot again, so you were invincible. Death claws became easy. Ridiculous, I had a very low energy weapons skill too...
Or you miss a shot and get nothing, except the attention of an angry deathclaw. As stated, limited ammo restricts this "tactic".
And in a singleplayer game weapon nerfs are not really necessary. just dont use the weapon or play without wild wasteland, if you think the game becomes to easy or boring.
If you get about 150 bullets, you can clear out most areas with the best armor. I can get through the DC prominentory, where they have the enclave armor and BoS armor. I got the Mercy, and usually the rate of hit is 95%, if it misses you can just jump around until you get enough, which is a low amount of AP.