Proper generated private key wil be in the 254,255,256 bits range, wih a random search it will be not feasible. So to search within a specific range will be more succesfull. I do respect my friend scorta...but you also need to have a look a this repo...https://github.com/pikachunakapika/BitCrack this repo is a fork of this repo https://github.com/brichard19/BitCrack...the difference with the Picachu fork in comparisson to the original is the added flag -r (random)...so that means you can search within a specific keyrange, with applying flag --keyspace with also a random mode...this means bigger change for succes (read also the original repo of BRichard, all flags what you will see there are also applicable with the Picachu fork...so only added the -r flag (random).
Also a big advantage of this repo's will be, they run on GPU...their is a version for CUDA (Nvidia) and OCL (AMD, Intel) depending on your GPU you will get a speed between 1 and 250 Mkeys...the app of scorta runs on CPU and will have a speed between 5 and 10 k pro CPU core...so that's a huge difference here...