When you say BT, are you referring to a boat tail bullet, or the brand name Nosler Ballistic Tip?
Adding a boat tail can help with a bullets BC, but the profile on the front of the bullet is more important than on the rear. Also, the smaller the caliber, the less a boat tail effects the BC. On a 223 I'd not worry much about whether or not it had a boat tail or not. It makes a bigger difference once you get above 24-26 caliber.
I've gotten the best accuracy in 223 with loads using Hornady V-Max bullets. They are reasonably priced. The most accurate for the money that I've found is the Fiocchi 50 V-max factory load. They sell for $25/50 rounds at Cabelas. I wouldn't even spend time hand loading when I can do that well with a factory load. They also sell a 55 gr FMJ load for $20 that is pretty close. But the 50 gr load is a tack driver. My brother and were shooting a couple of weeks ago and shot several groups at or under 2" at 425 yards with that load. Out of a 1:8 Twist Tikka, so they do well with a fast twist. I usually hover around 1/2 MOA, but didn't have my 1:7 Ruger American with me that day so didn't try it at extended range.
http://www.cabelas.com/product/Fiocchi-Rem-Ammunition-Per/705991.uts?slotId=7
Adding a boat tail can help with a bullets BC, but the profile on the front of the bullet is more important than on the rear. Also, the smaller the caliber, the less a boat tail effects the BC. On a 223 I'd not worry much about whether or not it had a boat tail or not. It makes a bigger difference once you get above 24-26 caliber.
I've gotten the best accuracy in 223 with loads using Hornady V-Max bullets. They are reasonably priced. The most accurate for the money that I've found is the Fiocchi 50 V-max factory load. They sell for $25/50 rounds at Cabelas. I wouldn't even spend time hand loading when I can do that well with a factory load. They also sell a 55 gr FMJ load for $20 that is pretty close. But the 50 gr load is a tack driver. My brother and were shooting a couple of weeks ago and shot several groups at or under 2" at 425 yards with that load. Out of a 1:8 Twist Tikka, so they do well with a fast twist. I usually hover around 1/2 MOA, but didn't have my 1:7 Ruger American with me that day so didn't try it at extended range.
http://www.cabelas.com/product/Fiocchi-Rem-Ammunition-Per/705991.uts?slotId=7
