velocity versus barrel length (rimfire magnums)

[subsonic]

I have seen velocity versus barrel length experiments for the 22Lr with various ammo.
Has anyone heard of results starting at 20+" and cutting off 1" at a time to see how the 22 magnum and 17HMR velocties behave as the barrels is shortened.
With the 22Lr either side of 16" the velocity begins to tail off due to excess bore friction if too long or not enough barrel if too short.

 

[mutwagn]

Hey I am new here but I believe I have the website for the answer for 17 HMR. It is posted on the Bulberry Barrel website. http://www.bullberry.com/HMRdata.html
I did a little exploring on RFC, http://www.rimfirecentral.com , and while the general consensus is 18" I couldn't find the test data.
Hope this helps, Andy