Everything I read says that we should always start at 10% below the maximum listed in the manuals and work up. Using the IMR loading sight as a reference and using their standard 270 Winchester, 130 grain Hornady bullet, they list maximum velocities of from 2884 to 3085. The typical commercial round is about 3060. The "standard" load of H4831 lists 3019 fps. Taking the "standard" H4831 as a reference they list starting load at 56.0 and maximum at 60.0C. Actually the 90% starting load would be 54.0. This is with a maximum pressure (60.0C load) at 51,000 CUP. Going to the Hornady website and checking their 130 grain Interlock ammunition, it is listed at a velocity of 3060 fps. Unless they have some magical powder, that means that they are running their pressure at about 50,000 CUP plus. When I check primers of fired brass in standard hunting rounds the primers are flattend a great deal more than any I have seen from my handloads at what I use as "max" loads. And I typically load at the max loads listed in the manuals. That means they are running their pressures up there close to max. So, why wouldn't I have to buy some factory loads that start at 90% (velocity in the 2850 fps range) and work up slowly to be sure it is safe in my rifle to shoot a standard commercial round that is obviously loaded at near, or over, the max listed in the reloading manuals? I understand that the companies are all lawyered up, and everyone wants to be safe in what they recommend. But has anyone ever experienced an actual case, themsleves, of a load reaching maximum pressure indications in a load that was more than 2% below the maximum listed in the manuals? In 40 years of reloading, I never have.