12-01-2023, 12:04 AM
Welcome, and nice setup. I don't have any experience with 15.5. My experience has been the sweetspot for the ARC seems to be 75-90gr range. 15.5 should work very well. The two powders I've had great success with are Accurate 2495 and VihtaVouri N135. I had some great velocities and consistency out of N135 with 87gr VMAX.
My Quickload says running 90gr Accubond 28.7gr of 15.5 should get you about 2800FPS or thereabouts. That is with 107% (compressed) fill and just under 51kpsi of pressure. I am not a fan of 103ELDXs, I can't get them going fast enough for my liking. Hope this helps.
Have fun with it, and shoot happy.
My Quickload says running 90gr Accubond 28.7gr of 15.5 should get you about 2800FPS or thereabouts. That is with 107% (compressed) fill and just under 51kpsi of pressure. I am not a fan of 103ELDXs, I can't get them going fast enough for my liking. Hope this helps.
Have fun with it, and shoot happy.
I am your uncle!