Whiscombe JW50 power restrictors

[Cloud 9]

I am just starting to get to know this new rifle and its shooting behavior.  I attached my chrony results for my new to me Whiscombe JW50.  You can see initially the velocity spread was really large, so I quickly switched to my sorted and lubed H&N FTT pellets.  After switching to 4.51mm head size, the velocity dropped a little.  I went to Ace hardware and purchased 5mm x 0.8 x 5mm stainless Allen head set screws. When I got home I locked the screws inside (2) 5mm jam nuts I purchased, put them in a vise, and drilled a hole in them on my drill press. 
I made (3) restrictors:

• Stock ID .093" dia

• ID .083" dia

• ID .102" dia

I made the stock one as a first try, and then the larger one to increase the velocity of the 4.51mm H&N FTT pellets.  I made the smaller restrictor, because I noticed that 4.50mm H&N FTT pellets were shooting 815fps and I need to slow them down to under 12 ft/lbs. with the larger restrictor installed, and shooting 4.51mm pellets, the average is 777fps (15fps faster with an orifice .010" larger). Anyway, it seems to be shooting about right now.  After I get my new scope, I'll sight it in and start shooting to see how it groups, and then adjust the HOTS.