Don’t neck size only. This was a fad among benchrest shooters in the 1990’s after one guy won a bunch doing it, but which has since been disproven and abandoned in all forms of precision competition. Full length size, bumping the shoulder for minimum clearance, around 2 thousandths. Neck sizing only is an invitation to inconsistency, and simply has been disproven - thoroughly so - as “the most accurate way.”
This thread does make COAL seem far more complicated than it is.
New reloaders get too caught up on book values for COAL. The book is not your rifle, so their COAL is just a generic waypoint, like saying Minnesota is north of Kansas… it’s not concrete directions. Reloaders will almost never be loading to book COAL, because real rifles don’t always have SAAMI minimum chambers, and bullets don’t always shoot their smallest when jumping whatever throat the books specs would promote. Seat your rounds based on your chamber, your mag, and your bullet ogives, nothing else.
A caution for those using the Stoney Point - now Hornady - OAL gauge and modified cases: if the modified cases don’t exactly match your chamber’s headspace length (and in principle, they do not, and will typically be shorter than the real length), then you are not actually measuring the correct COAL for your rifle. Bullet comparator bushings also do not give a consistent representation for all bullets approaching your leade, so even using Base-to-ogive measurements with these bushings isn’t anything more than a reference length, and will always be specific to each individual brand and model of bullet (or lot of bullets).
Bolt lift method is far and away the only reliable and repeatable method for finding your lands. Fool proof. Smoking bullets, magic markers, cut case necks, dipping cleaning rods, soft seating, etc can all be useful, but bolt lift method is the best way to get reliable and repeatable, precise results. But there are a dozen ways this task can be done, all of which work at least to some degree, so there really shouldn’t be so much confusion. Find the lands, ignore the book, and live happy.
Sounds like the OP just has a short throated chamber. Not a big deal unless he can’t chamber factory ammo or can’t seat the bullets he wants without falling into the case - at which point the choice is really to send it back to Ruger to have the throat fixed (or pay a local smith to do so).