What I've found is that different guns perform differently based on what ammo I feed them and what lube I use.

For ammo, follow the gun's manual to the letter. Within those limits, test with different loads and brands until you find one or more that works well. Some guns I own are really picky about what loads they shoot accurately and reliably, and others will take anything I try in the correct caliber and work fine. I'm not fond of using steel-cased ammo in guns that weren't designed for it, though.

As far as bore cleaners go, many work well. I use Hoppe's or Shooter's Choice because that's what I was taught to use when I was a sprout. Breakfree CLP works for this but tends to need a bit more elbow grease.

For lubrication, I tend to use a Tuf-Cloth and Tuf-Glide on most of my guns, with excellent results. Friends who shoot AR-15s a lot recommended that I use Mobil 1 Full Synthetic to lubricate my new AR-15. So far I'm well pleased. Breakfree CLP is in the gun care kit in my BOB, as I can use it to (as it says) clean lubricate and protect -- I can keep any or all of my guns up and running if it's all I have.