"You stated in your third paragraph, that approching the 950 fps with the 255 grain in your estimation would LIKELY be in the +P range. 950 fps is not my goal. Where did you come up with that?(1)
I am holding my loads at the 900 fps range and using less powder to do it. Besides that, my #12 Speer book does not even show a load for the 230 grain cast using the Herco powder. How did you conclude???????????
Later STATING that You would suggest that the 255 grain slug nearing 1000 fps, may be exceeding +P pressures. Who's loading up to 1000 fps? Where did that come from. Was someone trying for 1000 fps I didn't know about?"(1)
You loaded up to 1000 fps. I hope you knew about it, having just done it! 950 and 1000 fps may not have been your goal, but you certainly went there more than once.....so my comments were relevant. No offense, just being correct here.
As to the areas I've referred to as (1) where you ask where I came up with these things, the answer is that you yourself stated that:
"I loaded a batch of 6.8 grains of the Herco with the Lee rnfp in my Dillon SD loader.
High was 980, low was 867, and average was 909 fps."
And additionally, you stated:
"So, I gets to thinkin. I loaded up these Lee 255 grain rnfp with 6.5 and 7.0 charge of Herco. I was figuring around 850 fps for the 7.0 loads. I ran the loads over my Chrony and the 7.0 loads were running an average of 956 for a ten shot string. High was 996, (WOW) ......"
So it was you that came up with "these things." Certainly this did invite comment, and I didn't come up with it out of the blue. 996 is pretty close to 1000 fps. A "956 average" is faster than 950 fps.
You're right about comparing apples to apples.....and certainly the 255 Lee isn't the 260 Speer, in any way, shape, or form. But, if a jacketed 230, which seats in most instances more shallowly and is lighter than the 255, is Plus P at 950 fps, it's reasonable to expect a heavier, possibly deeper seated 255 may be at least in the Plus P range as well if it's achieving near equal speeds.
"There is no way for me to know what the pressure is in my load."
I certainly agree with you there, which was the whole point. All we can do is speculate, given the loading variables that are unknown. We do know that a deeper seated heavier bullet is likely to give higher pressures than a lighter or less deeply seated bullet of the same weight going at nearly the same speed.
So you see, commenting on the 230 grain load in relation to your 255 was relevant after all....if a 230 at 950 is Plus P, a deeper seated, heavier 255 going about the same speed can reasonably be considered at least Plus P as well.
That's all I'm saying. I'm stating standard pressures at these speeds with a 255 may be very questionable.