Can someone explain the differences in picatinny rails. Why do some cost 20 bucks and some cost 100 bucks, is there a difference. Is it just the brand or are they that much better with the higher cost.

thanks in advance

Brands, yes....and some are aluminum and some steel. Take your pick.
Watch out for Weaver rails...all will not accomodate Picatinny style rings.

A lot of it is just paying for the brand name.

What is wrong with weaver rails. are they a different size

Yes

There was an article a couple of years ago in either The American Rifleman or Rifle that went over the differences and the lack of QC in some products dimensions causing problems.

Poor QC and just plain schit material in some of the cheaper parts. I've bought some bargain sights that are GTG and bought some cheap, but not so bargain, rings that were so soft I could literally tear them with my hands.

any brands I should be looking at or staying away from? thanks

I’ve had good luck with Nightforce bases and rings.

Woodhits,

Well, yeah.

I have rarely encountered a set of Weaver bases that wouldn't work with various "tactical" rings, including Badger, Nightforce, Seekins, etc. But you never know until you try.

Literally ? Really ? Wow, just wow !

I used a Warne rail on the Howa Mini I put together for my grandson to use. Seemed to be good quality and fit well. I used a rail for maximum mounting flexibility, and it certainly accomplished that.

I like the ones with numbers on them, but don't think I've seen them for bolt guns.

Seekins is very high quality and have always worked for me.