which.204 ammo for an 18" barrle AR

[Whitetail fanatic]

I have a question about which ammo I should be using in my BUSHMASTER .204 it has an 18" barrel,I've sighted in using horaday32 gr. v-maxes but was a little concerned that they may be a bit light for 200 to 300 yard shooting I've experimented with hornaday 40 gr but had a hard time keeping them on a 1' square target at a 100 yards, at 200 yards I had 5 shot groups with the 32 grain the size of a dime. Any advice would be greatly appreciated .

[Bodei]

Look around (Cheaper than Dirt) for Fiocchi .204 in either 32 or 40 grain vmax. Box of 50 should run around $30. Warning: the 32 grainers are a hot load.
Also I use Ammoseek.com to compare online prices.