Pretty sure this noob question has never been asked before.. You know how for AR's you're not supposed to pull the brush + cleaning rod back through after pushing it down the bore, well what about first inserting the rod, then attaching the brush, and pulling both of them back through the bore?Is this acceptable or can it still have a negative impact on the bore due to the direction the spiraling is constructed?

Also, suppose you've been using a brush for pushing it through the bore with a rod for a while now. Any implications to suddenly changing the direction the bristles go by now using it as a pull-brush?

I gotta know these things. Hopefully that makes sense.

Why are you not supposed to pull the brush back through the bore? Your not going to hurt the barrel or rifling by pushing a bronze brush all the way through the bore then pulling it back.

Some say not to change the brush direction while its in the bore but here again a bronze brush isn't going to hurt anything. I think you will find that with a new well fitting brush your going to have to work dang hard to change direction with it while its in the bore and you might as well just push it all the way through. An older worn brush or a loose fitting brush will change direction while in the bore. I keep an older worn down brush in my .50 muzzy kit for when I need to scrub the crud ring out of the bore but other then that I bush the brush through all the way.

The only danger of pulling a brush out after pushing it part way through is, there's a chance the brush might get jammed and be difficult to remove.  This also ruins the brush since the bristles have to deform to be reversed while in a bore.
Normal pushing it through all the way and pulling it back doesn't damage the bristles.

As for pushing then pulling a brush in and out of the bore being somehow bad, this has been an "old wive's tale" for many years.
Microscopic bore scope inspection has found zero wear or damage to any rifle bore after experiments in labs.
In any case, a soft bronze brush stands no chance of damaging an AR-15 hard chrome lined barrel or a bare steel bore.

Now, I've pretty much stopped pushing brushes and patches through bores, especially small caliber bores simply because when pushing the thin rod flexes and rubs the bore.
Again, this is unlikely to damage a bore, but I once ruined an expensive Dewey stainless steel rod after pushing a tight patch into the bore and bent the rod by pushing too hard instead of pulling it out and using a smaller patch.

Yeah, I'm not sure why I still see people pushing brushes down the bore. It just makes sense to be pulling them through and out instead, so much easier. As far as the "changing brush direction mid-way down the bore", i'll take your word for it; this seems to be the consensus with most people I've talked to.

Only problem I have seen with pulling things through was if they came off whatever was pulling it in the bore. They were difficult to remove by trying to push them back out. Still I push them through and pull them back anyway.

^^^ That's a very good point. I didn't even think about that; they could come loose.. Something to keep in mind.