Have a new PSA 9mm Colt-style lower and a AR Stoner 9mm upper.  The feed ramp is blocking the bolt from going forward and I can't tell if the feed ramp is out of spec or I need a different bolt.  The ears on the feed ramp are around .535" high when measured from the lower and there's a small gap between the bottom of the feed ramp and the lower.  Anybody out there know the typical height of feed ramp ears?

I measure about .504" from the top of the receiver to the top of the feed ramp. No gap.

I'm here to see the solution to OPs issue.

You could likely get a new ramp, but the 'fix' many of us have had to do over the years is....file to fit. Just (slowly) file the 'ears' down and smooth them over a bit until your bolt plays nicely. I had the same issue with a Spike's lower and Faxon bolt.

That said, I don't recall there ever being a gap between the bottom of the ramp and the lower. Might be your issue.

PSA customer service never responded so I ended up ordering a CMMG 9mm ramp from Primary Arms.  While the top half of the CMMG ramp was a little taller than the top half of the PSA ramp the hole in the CMMG post was around .05" higher than roll pin hole in the PSA ramp post, so once installed it sat lower, ended up around .505" above the lower.  The Stoner bolt and the CMMG ramp don't interfere with each other, and it feeds and ejects well when manually operated, headed to the range tomorrow to test it out.

Really curious how PSA arrived at their current ramp configuration.  If you just drop the PSA ramp in the lower without its spacer it sits at around .475" and it looks like it would work fine, but of course the hole in the ramp post is misaligned with the roll pin at that point.  The spacer is weird as well, haven't seen one under any other feed ramps on Colt-style 9mm ARs.  If I had to guess I'd say the PSA ramps were originally designed to sit lower, somebody decided that it was too low, they then moved the roll pin hole down on the post, which left some of the post exposed, so they then added the spacer.

Besides the dimensions not much difference between the CMMG and PSA feed ramps.  Both look like MIM parts, same finish, same minimal amount of wobble once installed.  Neither has the dual-groove design on the ramp.  The CMMG post was significantly taller than the PSA post, had to trim around .1" off of it with a Dremel cut-off wheel (sparks!) but that went quickly.