I eventually plan to evaluate powder coat and other alternative coatings in all my firearms, as time allows. Today we tested powder coat in the Marlin 357, using its pet load.
Due to deteriorating eyesight I recently had to give up on using the peep sight on the Marlin, even though I loved the way it carried and handled with the peep. Now it sports a Leopold 2.5X. Back in the day I could easily shoot sub-MOA with the 2.5X but today I struggled to even see the fine horizontal recticle. Aargh.
The usual pet load:
-- 180 grain Lov-rider with 80% meplat
-- WW sized 0.359" then oven treated
-- Winchester magnum primers
-- 17.0 gr. WC297 (a surplus version of WW296 or H110)
-- Rooster HVR lube
-- a double coat of wet black using the dry shake-with-bbs method. The coating was not particularly even as you can see.
-- I did not resize the bullets after PC.
-- HVR 1825 fps vs. PC 1815 fps.
-- HVR 0.61% velocity standard deviation vs. PC 0.45%
-- HVR 3.9" average for two 5-shot groups vs. PC 3.9"
-- It takes more than 2 groups to prove anything but for what it is worth there was no detectable difference in accuracy or velocity
-- The HVR rounds were loaded in 2013 while the PC rounds were loaded today. The 10 fps difference in velocity could easily be due to tiny differences in the powder charge in 2013 vs. today, so I consider it insignificant.
-- this load was proven to be good for 3 MOA with a 14X scope, so today's accuracy may have been limited by the 2.5X and my aging eyes. Nonetheless I'm going to stick with the 2.5X because that's what the Marlin will wear in the woods and I'm tired of swapping sights.