Re: 7mm r-m 140g TTSX
TF, Barnes recommends a minimum of 1800 FPS to open their bullet reliably. I would say that you can shoot the full distance at deer with these bullets until you drop below the 1800 fps velocity. I have shot several muleys with these out of my 7mm rem mag. They are wicked mean! I'm shooting right around 3250 FPS with IMR 4831. With my velocity, I could shoot to 800 yards and still have over 1000 ft lbs of energy when the bullet strikes. Both energy and velocity would be adequate for a mule deer at 800 yards. Realizing this is the hard barrier and shots would idealy max out around 700-750 yds. Barnes are a great choice. The 140 grain bullet will not let you down if you do your part. I have seen the in action and am impressed.
If you always do what you've always done, you will always get what you've always got.