Even with 1gr below starting loads (should be about 38-40k PSI, and is a relatively fast powder for the range used for this caliber), I learned this weekend that my .308 puts out a nice flame once the sun starts approaching the horizon
. I'd say the flame seems about basketball-sized. I can't say it is particularly louder since I never shot it with the 22" barrel, but it doesn't seem any louder than other guys on the bench (even .223 shooters, oddly enough). And, realistically, probably any .308 rifle will put out flame in low light, so that probably isn't an accurate metric.
I haven't seen any particular accuracy issues, though I haven't really experimented with many bullets or powders.
I don't think a .223 would be bad.
And you should always wear hearing protection, at least when target shooting. It may not be
painful, but 20 or 30 years from now when your ears ring constantly and your most common phrase is "what?," you'll wish you'd gone ahead and protected your ears
.
IMO, unless I was going for really long-range shooting (and needed the flat trajectory and higher impact velocities), the 200fps loss isn't a big deal to me.
I do wonder how taking a few ounces off the end of the barrel made the trigger feel heavier, though?