On the 2250 vs. 22.250 AI I see no earthly reason for the change. Pressures drop the way they should with the AI increase of capacity. Being a wildcat I think they just pulled a number out of their butt. SAAMI shows 65,000 for the case MAX. D'i load that but remember we are dealing with a computer model. It's just a model.
On the 22-243 vs. 22/243 while the volumes remain the same it is interesting that putting a bullet loaded into the case the same distance COL yields less usable volume for the 22/243. The case length is 0.002 longer in the 22-243. It should be noted that SAAMI MAX on the 243 is 60,000 not the 65,000 listed by QL.
The 22-243 MIDDLESTEAD was is a 243 necked to 22 with a 30 degree shoulder. I wonder if this is what we are seeing. It does have a longer neck that could result in some of 2hat we are seeing as we play computer what if.
That is all I can come up with after evaluating the data as presented by QL. I'm sure someone on here will be able to shine more light on it. I have both of the 22-250's and my 22/243 is non-MIddlestead as I didn't want the custom dies for it. My real world numbers show I have 54.60 cc of H2O on tap capacity so I'm almost 10% higher than QL shows for the model. I custom the DZ to I can lao1 mo my case sizes.
An interesting exercise to say the least.
Greg