I don't think I have ever seen an active Marine transfer but I have seen a couple prior service Marines come over, a couple from Motor T and an 0317. The 0317 I think he did the warrior tranfer course or whatever it is called, did jump school then RIP. He was the honor grad for the his RIP class and since he was prior service on top of being honor grad they sent him to Ranger School right after RIP. I know this because he was in my Pre-Ranger class and also they let him choose his Battalion which he chose 2/75. I think (but don't quote me on this) he said he lost rank entering, went from an E-5 to an E-4. He went straight through Ranger school and got assigned to our sniper/recce section at 2/75 upon arrival. He picked up his E-5 pretty fast, like a couple of months of being in Battalion.
Once you graduate RASP I am sure they may ask you if you want to attend Ranger School. If you get the opportunity to attend and graduate if you were an E-3 you automatically get promoted to E-4. Getting from E-4 to E-5 may take some time depending on several variables, usually there are several Tabbed E-4's waiting for Team Leader slots.
If you are not given the chance to attend Ranger School after RASP no worries, this is the time to share the hardships of being a private in Ranger Battalion which will gain you acceptance among your peers and assimilate yourself with how we (Rangers) conduct business. If your hard charging squared away like most Marines you will be off to Ranger School in no time. A former Marine in my platoon took over my team when I was getting ready to leave, the sad part is he got into an alcohol related incident and got the boot. Great guy, just a bad decision.
Talk to a Regiment Recuiter and he will be able to get you squared away. Ranger Regiment is always in need of good dudes.
Good luck man