According to Rugers web site the twist on a Ruger Mini 14 Ranch is 1:9' RH. But I believe that changed from 1:10 to 1:9 in the mid 1980's.
yes, although feeding difficulties with 5.56 ammunition aren't uncommon with the Mini 14 Ranch.
Ruger did for a time have min-14's in 1:7 twist...no longer. But they made enough of them, that they're "findable". The serial numbers are approximately: run start: 1989: 185-56000 or for the Ranch Rifle: 187-84000 run finish: 1994: 186-35000 or for the Ranch Rifle: 188-75000
The Springfield 1903 has a 1" in 10" twist rate. The later M1 service rifle also has a 1" in 10" twist rate.
One could purchase a Ruger Mini 14 Rifle gun at a Wall-Mart store, or using the online Wall-Mart site. One could also purchase a Ruger Mini 14 Rifle gun at a local gun shop.
Around $500
You need to see a gunsmith.
It will vary with caliber.
1:16
The "rate of twist on rifling" is caliber specific. To give you an answer we would need to know which cartridge the rifle is chambered for.
thank you
You must contact Ruger to avoid voiding the warranty for a correct answer.
Blue book of gun values