1) Sizing to .269 to match the throat made for tight chambering of loaded rounds and further tests with bullets sized to .268 proved just as accurate.

2) Factory dies size brass unnecessarily and make for short case life causing split necks. Factory dies are ground to size necks to hold .264 bullets. My fired brass measures .271 I.D., when passed through the dies is squeezed down to .262 I.D. and then expanded back to .268 I.D. for my cast bullets. That’s a huge amount of work on the brass and to achieve a reasonable case life I have to anneal my PRVI brass after EVERY firing.

3) GC material appears not to make any significant difference to accuracy. Superb (2 MOA) accuracy has been achieved shooting Hornady commercial checks along with homemade versions fashioned from aluminium, copper and brass.

4) Definite velocity barriers exist for different alloys and these are directly proportional to the BHN of the alloy. This is down to the 8.5 inch twist and the amount of load that this fast pitch puts on the bullet. Air cooled clip on wheel weight tops out at 1500fps in my rifle. Above that and groups open up rapidly. Alloys of 13-15 BHN (nominal No 2 alloy) will handle up to 1700fps, maybe 1800fps, but to achieve 1800fps and beyond linotype hardness of 20 BHN+ is required. For plinking and target shooting hard alloy is not an issue. For hunting it is an and zero expansion can be relied upon with super hard alloy and as 6.5mm bullets have little frontal area to cause tissue damage and velocities are limited to the mid teen range I strongly advocate for bullets with a well designed hollow point to aid with terminal performance.

5) A crimp is sometimes beneficial to fine accuracy and particularly so when burning slower powders the likes of H4350 (AR2209) topped off with inert filled. Faster powder such as Alliant 2400 appear not so dependent on a crimp and often results showed a crimp to be detrimental to accuracy.

6) Primers made not significant difference in any given load. Remington 9 ½ and CCI 200 primers performed the same. Potentially using a Winchester or magnum primer with W748 may have improved groups as ball powders tend to like a hotter light.

7) Highest velocities with the heavier bullets was achieved with slow burning powder. This is to be expected.

8) Nose first sizing of the CM when cast in softer alloy eg: ACWW is preferred to avoid the potential of bending the very long bullet when sizing base first in a Lyman/RCBS style lubesizer.

I should note that all my shooting over the years has been using the iron sights on the rifle or more recently with the SeeAll sight I install in 2018 on my return from a visit to the USA. See blog write up February 2019. At no time has a telescopic sight been utilised and as such I consider 2 MOA accuracy to be very satisfactory when considered the rifle is not epoxy or pillar bedded but as it left the factory.

NOTE: Neither the author nor Cast Bullet Association Inc. accept responsibility for use of the following data. Use at own risk. ***DATA***