The phrase "a solid grip" is correct and usable in written English.
It can be used to describe a firm hold or control over something, whether physically or metaphorically.
Example: "He had a solid grip on the steering wheel as he navigated the winding road."
Alternatives: "a firm hold" or "a strong grasp".
We talked for hours, but I was never able to get a solid grip on the genesis of the movement.
Adding Sanwa, which is strong in the Kansai area around Osaka, would give the consolidated bank a solid grip on the most populous part of the country.
While most people believe themselves to have a solid grip on reality, they imagine their compatriots to be gullible and chronically misinformed.
Students learn everything from hollowing out a barrel to checkering a stock — carving fine crosshatched indentations behind the trigger both for decoration and to create a solid grip.
In the 16 years he's been cooking here, Mr. Smith has developed a solid grip on both his roux and the kitchen at Upperline, in the city's Garden District.
Though Mr. Young held a solid grip on his district, Mr. Obama carried it in 2008 and again in 2012 after it had been redrawn, signaling increasing difficulties for some Republicans.
If its manifest desire to be a film is sometimes overwhelming, Cold Hands is still a solid, gripping piece of work.
However, Byun thought the first series was a "solid, gripping entertainment that pulls few punches.
Shake hands with a solid, firm grip, and look right into that person's eyes.
Rams 6-23 49ers Colin Kaepernick hits Vernon Davis for 17 yards and San Francisco seems to have a pretty solid grip on this game.
Kirk Franklin has held on to the gospel message while moving his sound, and his presentation, in the direction of hip-hop and contemporary R. & B., the genres with an increasingly solid grip on the imagination of America's youth.
