It's worth mentioning that no bullet is designed to take game at the muzzle. There is ALWAYS a range of velocity where the bullet should expand.

The muzzle velocity of a Bushmaster is about 2150-2200 fps. This is only the MUZZLE velocity, and not the velocity you need to achieve to see the bullet perform. A bullet designed for such a cartridge should typically be expected to have a performance range down to 1600-1800 fps, depending upon the specific purpose.

The real design factor is the impact velocity at the range intended. This is why you will typically see handgun cartridges loaded with bullets designed to perform near MV, but rifle bullets are often designed not to slow to their optimal expansion range until over 100-200 yards -- leading to exploding or fragmenting bullets if you shoot an animal too close.

Even if you can't reach the MV of a Bushmaster, it simply means that the furthest range you can expect acceptable performance is shorter fired from a ML than from an AR. For shots less than 100 yards, if you can achieve a MV of around 2000 fps, you should see the performance the bullet was intended to deliver.

With regards to the 250 FTX, I'm not sure what the rationale for interest in it is over a SW which is designed specifically for a ML unless you feel you've had over-expansion issues with the 250SW like some have. Other members of the FTX line offer unique advantages not met by current offerings.

Given the types of ranges I have heard in FTX ads, either Hornady is misleading and encouraging use beyond the design parameters of their bullets, or most of them should perform just fine in MLs out to 100-150 yds. I withhold opinion until I have shot more than targets with them, it's all hypothetical until I shoot at LEAST 3-4 deer with them.