Remove all thimbles - if the rammer goes in you need to look at your inlets, if not you need to taper your rod or get a drill bit.
Kevin
Yup.
As stated earlier, pictures would help.
Start by looking at the relationship between the RR channel in the fore end and the hole in the lower fore end where the entry thimble goes, do this without the entry thimble on.
They should line up pretty much exact because the channel is used to guide the drill.
If they don't line up, that's one problem.
If they do line up, then it is either a small hole or a ramrod that is too thick. As someone mentioned, ramrods off the shelf are unlikely (as in almost never) gonna fit until you scrape or sand them down.
I'm guessing it's not the small hole. You could check this using regular drill bits. Try one at 3/8ths of an inch diameter, or whatever size the RR hole was supposed to be. This one will probably not fit. Don't lose it down the hole!
If it doesn't fit, go to a slightly smaller size and repeat until one will just fit. Then you know the size of the hole as it was drilled.
While you are doing this, you will also likely figure out if the alignment is correct. The drill bit that just fits the hole correctly should also lay straight in the RR groove.
That should all tell you what size hole it is and if is out of alignment.
Then you can decide whether to scrape the ramrod down to size or get a ramrod drill and drill it to size. I would go with the least destructive if you can.
Cheers,
Norm