negetive batman, the ta648 bdc is based of the m118 ball ammo. but your spot on with it being on at 300yrds. After that the bdc is like all the rest, you have to find to use hold over. I didn't mind paying full price but I expected the bdc to work as advertised and for the price it should. I spoke to Tri and they sent me some bullistic tables they say was used for development. They stated the ta648 bdc is based on the .308 round. I was currently doing some load testing to find a middle of the load round at mag length but am currently recovering from a tough shoulder surgery. any information please let me know.
