Maybe this is fun.
125 yds with a 45cal. I guess it will do it but you could watch the slug fly through the air. They leave the barrel at around 1000fps. By time they get to 125 yds what are they traveling? 68 fps. Most snipers could probably duck out of the way when they saw the flash of the muzzle. If your talking 357, 327, 41 or probably any other rnd beside a 45 then it would be realistic
Boogieman is poking fun of course but;
Let's see Hornady TAP 230 gr. jhp from a 5" barrel leaves the muzzle at a claimed 950 fps with 461 ft pds of energy, at 125 yards it's doing 855 fps and 360 ft pds of energy.
The Remington 230 gr jhp leaves the same barrel at 835 fps. and at 125 is doing 751 fps with with 289 ft. pds. of energy left to it, enough for serious hurt and a good momentum to penetrate.
No need to look at faster 200 gr. loads and bullets cuz ya get the point from the above.
Time of flight at that range is .41 seconds. So it is plausible for a sniper to duck under cover before the bullet reaches him, if he's really sharp.
With less than one second to see the round coming and duck and with 30 + rounds coming your way you'd likely have to be a Matrix type ducker or be on the Professional Dodge Ball circuit, if they had such, to be able to force a miss.
But it's irrelevant because the "sniper" was already laying down and decided to stay put and not move as he was protected by his Brock-A-Brella.