Gents:
Here are some targets to illustrate load development in a double rifle.
The first shots with the .350 no2 Rigby were with 62 grains of 4350. (I use 4831 in all of my nitro doubles but it is too bulky for a small case such as this). Some data called for 68 grains but only 62 would fit in the case and that was a compressed load. Note each barrel groups well, but too far apart. For proper regulation I am looking for 2550 to 2600 fps and this load was short by nearly 300 fps. All bullets used were 225-grain Speer.
The second target was right on as to velocity, however 4198 (50 grains) saw a good group but the rife opened stiff due to excessive pressure.
By the way, all targets were shot over a seated rest at 40 yards.
Moving to a slower powder 3031, 50 grains was a bit too slow and the group opened up a bit. Velocity was still 150 fps slow.
I only had three primed cases remaining so I upped the load to 51.5 grains and the group was good.
Target number five was excellent. 53.5 grains was a perfect velocity but the rifle opened with a bit of stiffness. Ten shots here show a group about as good as it gets. Six shots were mine and four from my mate.
So, one more go on a different day. This time with 52.5 grains of 3031 at 50 yards over a standing rest this time. I've never owned a double this accurate nor do I know of one. Velocity was 2565 fps. Bullet was the 225-grain Speer. Case is now closed. Further experimentation is not needed. Group is about one inch.
Cheers, all,
Cal
