The conclusion I would draw from my test above is that the presence of the stripper tightened the group size and by and large the type of cone was immaterial. The test with no cone at all still had the outer case of the stripper fitted to the muzzle, so that bu99ers the harmonics a bit.
Hard to tell precisely, but visually I estimate the group centres to be very similar in elevation so I doubt if there's much change in BC or flight line or downrange velocity.
The rifle was a 400 classic. Pre-AT with the 3 sear trigger. Tests done in January 2006. That was before I "discovered" 7.9s badged as Webley Mosquitos - anyone remember them - and maybe I should do the tests again 8 years on. I still have the same 400 but it now has an export length cylinder, and fitting a stripper will be more difficult.