The NWS said it would be 54 with a light Southerly wind at 5 Mph. Noon was approaching and so was 50 deg so I packed up and headed out for a rematch. I knew that my first effort's conservative loads were in fact ultra-conservative. QuickLoad does not do a good job modeling this caliber with 125gr bullets. It remains to be seen whether it gets any weight bullet right. Nevertheless, after my first outing I was able to determine a coeeficiet to apply to the different powder characteristics from that first outing to improe QL's ability to predict the next real world results. The case capacity of the 1-fired brass went up respectably and since my magazine will accommodate a slightly longer COL, in this outing I went with 2.30. Probably could have squeaked out 2.34 in hindsight but didn't want the 125 SST dead up against the lands. At least not yet.
Despite increasing charges anywhere from 3 to 4.5gr, I still did not achieve my goal of 2900fps, though got closer with a few powders. I have some AA2200 on the way and will include it in my next outing. It is important to point out that I ended up last year with a backlog couple of outings worth of 450b exoeriments to do yet, so my next 30RAR outing may be secondary to getting old faithful some range time first.
OK, here's a very busy table of what transpired. In the case of AR-Comp and W748. Neither was going to come even close so I saved most of them to use for foulers and sighters. Could have done the same with Benchmark as far as that goes.
So three powders didn't make the cut. As predicted after my first outing, the 125 SST groups did tighten up with more velocity. My Dad's Lead Sled is not the same as a Ransom Rest. I lacked confidence in my AR skills after the last outing and figured I'd give it a try. This caliber is so tame, it was embarrassing using the Lead Sled for it. Back to my BR setup next outing.
Here's how the three best loads flew.
First up H322 at an average of 2768fps (didn't bother zeroing the scope) All groups at 100 yds
Next H335 at an average of 2812fps
Lastly, Benchmark which did get Mr Congeniality at 2654fps
I felt that all three groups were respectable given the height adjust foot on the Lead Sled wobbled a little. Despite the moderate to light recoil, the target was never in the same spot when I slid the rifle back into position after each shot. Like free advice, the Lead Sled was worth every penny my Dad paid for it.
Besides the AA2200 inbound, I may slip down to Ahlman's to give Ranshot X-Terminator an at bat as well. All of this is so that all of you, don't have to waste your money on powders that won't go the dough using 125 gr bullets. These same powder may well be sweet for heavier bullets and that determination will be made as the spring and summer progress. I will also revisit a couple of these exact loads under Hot temperatures to see how much they go up also some time this year.
This caliber promises pretty good accuracy to come. Its not even broken in yet, nor have I done much in the way of trying to enhance its performance. More to come...
Watch for a 450b Range Report or two in the coming future.
BTW, after I got home, chilled from the 15-20mph wind up my keister, the temperature continued to climb up to 64 degrees. Should have gone later, but hind sight is always 20/20.