SSA 2nd generation 115 gr SMK OTM w/cannelure, 5 shot averages:
20” barrel: ave vel = 2561 fps; 10 fps extreme spread
16” barrel: ave vel = 2525 fps; 18 fps extreme spread –– lost 36 fps from 20"
12.5” barrel: ave vel = 2384 fps; 12 fps extreme spread –– lost 141 fps from 16"
10” barrel: ave vel = 2265 fps; 27 fps extreme spread –– lost 119 fps from 12.5"
7.5” barrel: ave vel = 2035 fps; 27 fps extreme spread –– lost 230 fps from 10"
EDIT: You can see that at 16" this 115 gr is a little faster than the initial data for the 110 gr. Here's more data, including a faster yet load:
10.5" Noveske barrel, 6.8
- 85 grain SSA TSX (Tac Load): 2787, 2823, 2777 , 2804, 2809
Low: 2777
High: 2823
Average: 2800
Spread: 46
- 110 grain S&B PTS (V-Max): 2249, 2238, 2270, 2268, 2256
Low: 2238
High: 2270
Average: 2256
Spread: 32
- 110 grain Hornady BTHP: 2312, 2376, 2342, 2358, 2333
Low: 2312
High: 2376
Average: 2344
Spread: 64
So is 110 gr at 2344 fps from 10.5" the SPC2 endpoint? It is about 75fps faster than the initial (old) data. Looks like the SPC2 from SSA is about 26 fps faster too 16″ 6.8 SPC II 1:11″ SSA 110 TSX: 2575 fps, so SPC1 to 2 is about a 75 fps gain at best?
The latest data on 140 6.8 vs 139/140 6.5 is about 51 fps difference, 16" to 16", so the 6.5 is going to catch up to that almost right away. /EDIT
Interestingly, the 6.5 is getting more veloicty than the 10" at 115 gr 6.8 than the 10.5" 123 gr 6.5. Just a tiny bit more (10 fps more, IIRC), but eight more grains, but .5 more barrel... kind of a wash. The 7.5 is terrible, loses almost double in 2.5" what the 10" lost in 3.5". Can really see why LWRC is taking their 8" off market and staying at 8.5" for the 6.8. So far it looks like the lower you go, the better the 6.5 gets in comparison, at least until 10/10.5. Weird. It's a winner at 12.5 past 175y, it's a winner at 10/10.5 right about at the barrel, it's a winner in longer barrels further out...
Seems like the 6.5 is a better SBR round than the 6.8 (at least until 10.5), which seems backwards to both what seems to make sense as well as the general thought process. I'm keeping looking for data points, though.