Mathew - I applaud your honesty!!!
Indeed that pin replacement does require some slight ''jiggling'' of barrel to ensure the barrel lug slot is back enough to be available. Best advice I'd give is - do not force pin in!
Even a tighter pin should move with gentle taps from a mini brass hammer - and if not then a check to see if the alignment is right or not.
In my vids or the slide show vid, or even PDF, I think I do mention this need to ''jiggle''. True tho, some folks may not always realize this and so - a useful reminder.
That pin is hard - so to raise burrs the pliers must have been sharp jawed!!!