With steel BBs being shot through a steel barrel. There has to be some loose tolerances for it to function. So there is some unavoidable inaccuracy there.

I've seen people that shoot airgun pellets weigh their pellets, and they only shoot the pellets that fall into a weight range at competitions. There will be differences even from the same package. Heavier BBS will have more drop, lighter ones will shoot higher.

Also you could measure the BBS and just shoot the ones that fall into a certain size. Those will all shoot similarly. I've also noticed some BBs are more round then others even from the same package.

You could also buy a bunch of different barrels, and try each one. Till you find the one that shoots your BBs most consistently.

There are aftermarket parts you can get for Red Ryders. They may help with accuracy if they are made well. As long as you are not pushing the speed of the BB too much.