What’s the actual law on min acres to hunt either bow or firearm?

It depends on what county. I know in Eastland and young counties there is no minimum amount of land. You can hunt on a half an acre as long as your projectile and game doesn't cross property lines

Best to call both your local game warden and sherrif

It depends on the county.

If you live in any type of subdivision, you also need to look at covenants and HOA rules. My friends have a new house. They all have 5+ acres each but the rules state no discharge of weapons and it goes on to identify (firearms, muzzleloading firearms, or archery). Sucks cause they get some really nice bucks in to the back yard.

Mine has the same. I shoot at least once per week.

This.

Not only the county. Towns can be more strict but not more lenient than the county. My county says 10 acres to hunt. I live on about 15 acres, but the town I live in says 50 acres to hunt. Game warden or Sheriff will know the county regs, but I wouldn't expect them to know the statutes for each little incorporated town in the county.

edited because autocorrect is just wrong sometimes.

Bird hunting would be pretty hard, shot would cross lines.

A county to my south is 10 acre minimum, my county has no minimum.

There is a state law that you cannot prevent hunting on certain acreage sizes if land was annexed after 1981.

Texas Senate Bill 1742 states which types of weapons can be fired on annexed land after Sept. 1, 1981.

"A shotgun, air rifle or pistol, BB gun, or bow and arrow can be discharged on a property that was annexed after 9/01/1981 and is: 10 acres or more, and more than: 1) 1000 ft from any public land, school, day care or hospital. 2) 600 ft from any residential subdivision and multifamily residential complex. 3) 150 ft from a residence or occupied building on another property.

A center fire or rim fire or pistol can be discharged on a property that was annexed after 9/01/1981 and is: 50 acres or more, and more than: 1) 1000 ft from any public land, school, day care or hospital. 2) 600 ft from any residential subdivision and multifamily residential complex. 3) 300 ft from a residence or occupied building on another property.

Parker county has a minimum of 10 acres to shoot any firearms.

in Bastrop county, if the property is plated, you must own 40+ acres, not 40 minimum 5

And the most important thing no matter what the law is use some common sense when shooting on a small acreage property. And for that matter even on large properties

You could hunt the property and wait for the neighbor that lives 3/4 mile down the road come by walking his dog, and then he calls the Sheriff to come by and explain the local laws.
Don't even ask how I know this!