Sorry it took so long, fellas, but I've been playing a lot with my new Lab Radar. I've been choreographing all of my doubles to compare with my old Chrony and Oehler models. No doubt the LR is the best and most accurate.
I just finished with smokeless and three makes of black powder for my 8- and 4-bores. Here are the final results of the 20-577 as copied directly from my log book and a pic of the best target.
20-577 HOLLAND AND HOLLAND DOUBLE RIFLE, 1895
26” BARRELS, RIFLE WEIGHT OF 12 3/4 POUNDS
LAB RADAR VELOCITY ON HANDGUN SETTING
NOTES:
MUZZLE AND RECOIL VELOCITIES ARE IN FEET PER SECOND
MUZZLE AND RECOIL ENERGY ARE IN FOOT POUNDS
RECOIL CALCULATIONS FROM: SHOOTERSCALCULATOR.COM
MKO FROM JOHN TAYLOR’S KNOCK OUT VALUE
ALL CALCULATIONS FROM 6-SHOT STRINGS
PART I. BLACK POWDER
175 GRAINS 3F SWISS, 650 GRAINS WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1550
MUZZLE ENERGY: 3468
MKO: 84.2
RECOIL VELOCITY: 21.09
RECOIL ENERGY: 88.15
175 GRAINS 3F OLDE EYNSFORD, 650 GRAINS WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1552
MUZZLE ENERGY: 3477
MKO: 84.31
RECOIL VELOCITY: 21.11
RECOIL ENERGY: 88.27
Notes on black powder:
Case capacity with 3F is GOEX at 172 grains, Swiss at 190 grains, Olde Eynsford at 183 grains.
This is from a measure with no drop tube or shaking to settle the powder.
GOEX won’t develop the same velocity, grain to grain, of the other two and less so with less grains in the case.
I tried to load 185 grains of Swiss and OE to compare velocity. However, I do not have a seating die so I can’t compress the powder and hold the bullet in place with a crimp. I can only do a friction fit when I press the bullet in place. So I am limited to 175 grains of Swiss and OE 3F. GOEX 3F is too bulky for an accurate comparison as I would be at only 160 grains.
PART II SMOKELESS POWDER
70 GRAINS IMR 4198, 650 GRAIN WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1643
MUZZLE ENERGY: 3897
MKO: 89.2
RECOIL VELOCITY: 15.89
RECOIL ENERGY: 50.01
77 GRAINS IMR 4198
(40%), 650 GRAIN WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1748
MUZZLE ENERGY: 4411
MKO: 94.95
RECOIL VELOCITY: 17.04
RECOIL ENERGY: 57.56
80 GRAINS IMR 4198, 650 GRAIN WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1826
MUZZLE ENERGY: 4814
MKO: 99.19
RECOIL VELOCITY: 17.78
RECOIL ENERGY: 62.64
83 GRAINS IMR 4198, 650 GRAIN WOODLEIGH SOFT NOSE BULLET
AVERAGE FPS: 1874
MUZZLE ENERGY: 5070
MKO: 101.8
RECOIL VELOCITY: 18.13
RECOIL ENERGY: 65.13
The target below was from the best regulation loads of smokeless, 80 & 83 grains of IMR 4198. 70 and 77 grains shot a bit wide as the velocity was too slow. Same as the black powder loads as I could pack enough black in the case. If I can find a proper seating die with a crimp and use 190 grains of 3F Swiss the black powder targets wll improve enough to be published.
For the target here I shot six shots of 80 and 83 grains of 4198 each. One pulled shot for flyer is 4 inches down. The two small holes at top are from a deluxe .30-30 Winchester that I used to make sure the Lab Radar was on target before I began my larger caliber shooting. Bottom line is this 20-577 is one of the best shooting doubles I have ever owned. Only my former .350 no2 Rigby ble bettered this grouping. Sadly the Rigby is with a new owner now as I'm seriously thinning the herd in my old age.