Guilty as charged!
I find that quite often, the best loads are above the top end of the range of charges in reloading manuals. Interestingly, I have some reloading manuals of some 40 years ago. Either the powders have gotten faster or the lawyers have prevailed!
I always proceed incrementally with caution examining for pressure signs. However, I have come to realize that when so-called pressure signs show up (Extractor marks, flat or cratered primers, sticky bolt, etc.), I'm way above the maximum load. Here an example to illustrate this point.
When I first put together my 338 Edge, I looked around for reloading data. Being a wildcat, the Edge is not covered in any manuals. I found some loads on the internet, particularly on the defensive Edge site, but most featured the 300 grs SMK. I wanted to used Nosler Accubonds 250grs for long range moose hunting (I don't trust the 300 grs SMK as a hunting bullet for heavy game). I couldn't find any loads with that bullet. So I looked loads for the 338 RUM with the same bullet in Nosler's manual and got a max load of 98grs oh H-1000 with the 250grs AB.
The 338 RUM case has an internal volume equivalent to 110 grs of water according to Quickload. I measured the internal volume of 30 modified 300 RUM Remington cases once fired in my 338 Edge (barrel break in) and got an average of 116.71 grs of H2O or about 6% more than the 338 RUM. So I decided to try a ladder test starting with 94.3 grs of H1000 and ending at 102 grs. in 0.7gr increments. I chronographed all loads on my CED M2. Here's the data and results, along with Quickload estimates for all loads:
Savage 112 BVSS
338 Edge
Shilen Select Match 28" with Defensive Edge Muzzlebrake
H-1000
CCI 250
AB 250grs
OAL: 3.815"
Case capacity: 116.71 grs H2O (ave. 30 cases)
Temperature: 67F
Load........ Test fps......QL (fps)........QL press (PSI)..QL Barrel time (in ms.)
94.3..........2817..........2847...............52, 095..........1.440
95.0..........2872..........2869...............53, 419..........1.430
95.7..........2864..........2890...............54, 779..........1.424
96.4..........2930..........2911...............56, 180..........1.392
97.1..........2917..........2933...............57, 619..........1.376
97.8..........2947..........2954...............59, 101..........1.361
98.5..........2973..........2975...............60, 626..........1.346
99.2..........2977..........2996...............62, 196..........1.331
99.9..........3003..........3017...............63, 811..........1.316
100.6........3035...........3038...............65, 475..........1.301
101.3........3056...........3058...............67, 184..........1.286
102.0........3081...........3079...............68, 955..........1.272
The speeds chronographed for each load are incredibly close to the Quickload estimates which leads me to trust QL's estimated pressure data. The case with 102.0grs of H-1000 looked exactly the same as the 94.3 grs case - no extractor marks, flattened or cratered primer, sticky bolt, etc. Yet I was probably exceeding max pressure by 5,000 psi. I suspect the pressure signs would probably show up above 70,000psi.
Interestingly, my ladder test showed plateaux between 94.3 and 97.1 grs and between 101.3 and 102.0 grs. I subsequently tried two OCW tests which suggest stable loads at 95.0grs and 101.8grs. of H-1000. I've decided to use the higher load for hunting in cool weather and the lower load for practice in the summertime.
