DigitalDan: I have NO idea whatsoever, as to what you are talking about!
In a one sentence posting you have been able to confuse me at least twice and again I have no idea WHAT you are trying to say or are talking about!
What do you mean by the term "containment" in regards to the 22 Winchester Magnum Rimfire?
AND THEN - what are you trying to relay when you say "...raise lower pressures..."???
If you are "raising" something YOU ARE NOT "lowering" something - i.e. the quote from your post "current loads raise lower pressures than the originals"!
I have been shooting 22 Magnums of several types for half a century now and never had to RESTRAIN (the definition of "contain" - according to my Websters Dictionary - copyright 1986) any of those 22 Magnums!
Could you try again?
TIA
Hold into the wind
VarmintGuy