The problem is that a 5mm reamer is too large. The pin is about 5mm, the hole needs to be smaller than that. And the tolerance of a 5mm drill bit is even bigger. A 5mm hole is .1968", the barrel pins are .197", only a .0002" interference. And a new reamer (did you stone the edges first?) is likely to grab more and be on the high side. Using gage pins, the holes through the 93 trunnion will let a .195" pin slide in easily and go all the way through. A .196" pin will start in either side of the trunnion, but won't go all the way in. I only have 2 trunnions here to check, and they are both about the same.
So for anyone else reading this, you really should use a new .195" reamer, or perhaps a well stoned or worn .196" reamer would work.
But unless you have a black-ops hole shrinker like I do, what's done is done. But don't fret, it's an easy fix. Go to www.jlindustrial.com and order a few hardened gage pins. They will be longer than you need, but you can easily grind them to length. You're really after about a .001"-.002" interference fit, and if you already have resistance with the pin, I'd get a few of them, maybe .1975", .198", and .199".
Grind it to length, press it into place, and you can even cut dimples in the end so it looks like an HK pin after installed. I did the same exact thing on my first one, since I used a 5mm reamer too, without checking what the actual hole diameter should have been. And I also didn't make my normal check of drilling and reaming a hole first in a critical application like this to check what size the actual hole will be. Chalk it up to excitment of getting my first complete build done.
So I now use a .195" or .1955" reamer and the pressing forces are back up to what they are in the original.