OzFclass

It's a dangerous occupation, but I'm thinking.
I ran a 243 and a 223 hunter. The 223 sings with Sierra 55gn soft points, which have a flat base, and the 243 shoots 100gn fmj's like a target rifle to 300m but I've never pushed them further. They both shoot Nosler BT's pretty well but the flat base just seems to work better.

What's the drawback that stops flat base target projectiles being made?

Tim,

Flat bases are easier to make uniformly than boat-tails, so flat base projectiles are generally regarded as more uniform and hence more accurate. BUT, they are also more prone to being affected by the wind, due to the lower BC. So they are commonly used for short range disciplines, but rarely at long range in any discipline, where wind effects are a major consideration. With high quality boat-tail bullets like Bergers available, it becomes a no-brainer for F-Class, although at the shorter ranges we shoot, a good flat-base projectile wouldn't lose out.

Alan

Parasitic drag over mid and long distance.