View attachment 200098
Weather cooperated and I got some velocities for my three Hoyt Thumper carbines.
Parameters :
Triple 7 FFFg powder, 50 degrees 45% humidity, oversized by one caliber OP wonder wad, RIO Musket caps. Each gun was shot twice from the bench prior to chronographing velocities and an alcohol swab was run in and out of the bore between shots. 3 shots were then chronographed. Last shot was with chrono removed and fired from standing to assess felt recoil
Gun # 1.............58 Cal 1:38 twist 24" barrel 500 grain minie ball .582 diameter. 100 grains powder
1. 1471 fps
2. 1496 fps
3. 1476 fps
Average 1481 fps SD 13
Recoil no more than a heavy game load in a 2 3/4" 1 1/8 oz 12 ga load
Gun # 2...........54 cal 1:38 twist 24" barrel, 485 grain conical .542 diameter. 110 grains powder
1. 1592 fps
2. 1571 fps
3. 1585 fps
Average 1582 fps SD 10
Recoil not discernably different than the 58 cal
Gun # 3.........54 cal 1:38 twist 21" barrel 425 grain .544 diameter concial. 100 grains powder
1. 1527 fps
2. 1574 fps
3. 1641 fps * powder was compressed harder than above
Average 1590 fps SD 57
Recoil...same as the others
OBSERVATIONS:
1. The powder was fully burning within the barrel. No bright flashes or smoke rings. Observer noted that no great blast/flash more than standard smokeless powder guns and only slightly more smoke.
2. Velocities realized exceed my max expectations by 80 fps to 100 fps in all three guns.
3. Bores are rough and need polishing. Lots of cutter chatter marks on the rifling and the bullet hangs up when seating it. Shot #3 in the 21" gun was seated HARD as it hung up and when pressure was applied it let go and seated much harder than the other two rounds. *I attribute the higher pressure of the third shot to the hard seating.
After cleaning then polishing these bores, I will then shoot for accuracy while adjusting powder loads. The bullets were grouping fairly well considering that I wasn't looking to group and was shifting sight adjustments to center rounds on target.. Surprisingly, the #3 21" gun needed very little adjustment to center rounds.
All in all, very satisfied with the progression. A little fine tuning on these guns, polishing the bores and after the lousy weather of the next week subsides it will be back to the range for some accuracy results.
View attachment 200081
@SDSmlf @SOLANCO @Bad Karma @Urban Coyote @Brokenbear @Relic shooter @ETipp @Dale Allen Raby @wganz @TDM @tenngun