Hi Tom,

I build a lot of 1.200" diameter bull barrels for the T/C Encore that are chambered in both the 6mm-284 and 6.5-284 and have never encountered and extraction problems with either one...

For one, I cut my chambers alot tighter at the base than what most gunsmiths do and certainle a lot tighter than the factory cut chambers. In going with a rimmed cartridge, since I have complete control over the depth of the rim cut, I cut the rim counterbore to where there is .003 clearance from the breech face instead of .003 deeper or more that most guys cut from the breech face of the barrel. With the rim not allowing the case to be driven any deeper into the chamber when the firing pin strikes, headspace is held to an absolute minimum SO LONG AS THE ROUND IS NOT OVERLY SIZED AND THE SHOULDER PUSHED BACK TO CREATE EXCESSIVE HEADSPACE!!! Headspace is controlled off the shoulder but the "rim" seems to be most important for controlling it as well as helping keep the case aligned in the chamber...

I did a couple of tests back last summer that involvedusing a barrel I had chambered for the 30-30 Winchester. After developing a load that would shoot consistant 1/2" groups at 100 yardswith a heavy bull barrel, I then set the cases up in the lathe and turned the rims down to form a totally rimless case. With identical loads, these same cases now turned in loads that averaged 3/4" to 1.00"!!! I have performed many tests like this one over the years and in all instances, rimmed cases have proven to be more accurate. I also cut a lot of rim counterbores in the T/C Encore and the H&R single shots. Guys that shoot the 7mm-08 and 308 change over to using 307 Winchester brass, which is basically the same case - except that it has an identical rim to that of the 30-30 Win.. When they change over to the rimmed case, they all report an increase in accuracy....

DAVID