Reply by Cato

Noone- last time I hung some crown, not my favorite task in home DIY, I cut a scrap piece and positioned it to determine the size nailer strip that would need to go behind it.

That way I was able to measure the length of fastener that would work. At that time I did not have my 18ga. nailer only a 15 ga. so I used the length fastener I needed. The 15 did leave quite a bigger hole than I would have liked and I believe I used 1.5 inch fastener, but it has been awhile since my last crown ceiling work.