BSA1917
I was always under the impression the tighter at 100 the better, and spreads out father down range. Even with a tight group under an inch, spreads like your 400 yard group ? I shot tight groups with the .270 WCF and it only open to inch or inch and a quarter at 300.
I always shoot for the best 100 yard groups, then test at 400 yards. Since I can set up targets at 400 at my range. I can shoot steel out to 1,000 yards at our local range, but not set up paper there. I have other spots I can do that though. In general, most times it works out the way you say, but not always. That is why it is important to test your ammo out to the range you intend to hunt. It's not always a guarantee, that you best shooting ammo at 100 yards will be your best shooting ammo at 400 yards. That's not even taking conditions into the equation. We all know what winds can do to a group.
Your 270 statement is also valid. I've seen some weird stuff like that when shooting my 270's. It could be human error, luck, or some other phenomenon going on as well..
