If you load like this with fast powders, you are asking for trouble. Why? Because the OAL is of NO consequence when comparing between different bullet shapes.

Why? Because the part outside the case is not going to give you one iota of trouble, it is the amount of bullet in the case!

Measure one of the RN bullets, measure the FP bullet. What is the OAL of just the bullet? Okay, what is the difference? All of that difference should be outside the case. If it is .030" longer, that the OAL of the assembled round should be that much longer too. If it won't fit in the cylinder, reduce the powder charge and seat a bit deeper. NEVER seat deeper and not reduce the powder charge, NEVER.

I have a simple rule of thumb for light target loads. If I seat .030" deeper, I reduce the charge by .2-.5gr. Just me, no pressure equipment.

The important issue with bullets is not the OAL of the assembled case, it is the amount of bullet that resides in the case, called seating depth. That is the critical thing when switching bullets in any load. More bullet in the case, pressure goes up. In revolver rounds, not too big of a deal, in semi-auto rounds, it can be devastating. Bullet setback is one reason for KB in firearms with unsupported chambers. A round stays at the top of a magazine, chambered several times until the bullet is smack dab on top of the powder. Bad things happen when this goes on.

Be careful, please. Reduce your load and work back up. Measure the bullets and add the difference to the cartridge OAL. If it won't fit in your cylinder, reduce the charge, reduce the OAL and run the rounds over a chronograph.

Hope this helps.

*Welcome to the forum too by the way!