Working on my first pre-carve and have just run into the exact tapering problem you describe. Unfortunately, the lock plate has long since been drilled, tapped and installed, so it's too late to implement the fix you describe, but I will keep the above advice in mind for the future. Actually, after the lock and pipes were installed, I did taper the tipped end of the ramrod down enough to get it to fit through the pipes and in its hole. However, I recently had to open up the front and rear lock bolt holes a bit to relieve stress on the lock bolts to correct my novice first attempt at drilling them. Add to that the fact that it has rained a lot over the past few weeks and it seems that things have shifted and/or swelled enough that the ramrod that was fitting originally has tightened up in its hole such that I recently had to remove the front lock bolt to withdraw it. The front bolt (8-32) appears to have shifted somewhat to where it made a dimple in the rod maybe 1/32" to 1/16" deep (just a visual guesstimate). I will see if I can taper the tipped end down a bit more to get it to fit correctly again, but if the steel tip won't allow for enough of a reduction via filing, I was thinking that possibly I could flip it and taper the non-tipped end to fit the hole. If that fails, I will order a new rod with one of the pre-tapered tips from Kibler. The one it came with had a straight (i.e., non-tapered) profile.
Thanks,
Jay