I find your post about increasing the length of the .22LR will not prevent the new cartridge from being chambered in older .22LR firearms, to be completely unbelievable.
The extinct .22 Extra Long couldn't be chambered in .22 Long and .22 Long Rifle firearms at all.
https://en.wikipedia.org/wiki/.22_Extra_Long#Description
Here are the SAMI specifications for 22 LR. The COL for the Extra Long cartridge is 0.16" longer. What is to prevent it from chambering?