Why do you need a gun at the beach? Someone kicks sand in your face?... On a deserted beach, maybe at night?.... I'd be more concerned that my gun was well secured in my car.
In the late 1970s I carried all kinds of guns on the beach all the time; M16A1s, M60s, 1911A1. I have on good word that the Marines before me carried Springfield 03s, Garands on beachs. According to the 1940s Imperial Japanese Navy Land Forces, those U.S. Marine Corps Rifles worked real well, including at night. Even the U.S. Army was in the act. Go figure. And now for an update:
The beaches from The Golden Gate Bridge south to Monterey County, California, apprx. 75 mile stretch, are home to multiple rapes and robberies every year. LE can't really say how many murders take place on the beach, but numerous murder victims are at least dumped their annually.
If the beach Park Ranger has both an AR-15 and a 12 gauge pump in the cab of his 4X4 then it's time to pack an extra reload along with those chips.