Well, now I feel really silly for not having the chronograph with me last time.
This barrel must be slick as snot. For a sanity check I clocked my old 200 AccuBond load with 95 grains of Retumbo. That load gave 3186 in the old 26" barrel. In the new 26.7" barrel it gave 3139. It looks like this barrel will take at least 2 grains more just to get back up to the speed of the old one.
I chronographed 7 rounds of 100 grains of US 869 behind the 240 SMK. Average velocity, 2879 fps. OK, I was being conservative, careful, etc which I'm all for...but now it's time to add some more powder!
It all makes sense now, the tiny bit of "feel" chambering the empty case from 102 grains before...that's what's normal. You ought to at least be able to feel you're chambering something. It's just all the rest were running at starting load pressures. That's what I think, anyway.
Time to start adding powder until I find the ceiling.
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I chronographed 7 rounds of 100 grains of US 869 behind the 240 SMK. Average velocity, 2879 fps.
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Not bad at all! I like that. 2875 f/sec is the max veloc. Hodgdon is calling for the 220 gr. SMK.
Thanks for sharing. Keep us posted!
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also as it was in the days of Lot so it shall be in the days...
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Yeah, but keep in mind that's at 55,200 psi (same as the starting loads for other powders) and with a 24" barrel--just scratching the surface of its potential. I ain't givin' up yet.... [img]/ubbthreads/images/graemlins/wink.gif[/img]
While I was surprised with the slickness of the new barrel, in the end this powder performed exactly as I had expected (or hoped) it would for this application. It'll easily match the speed, consistency and accuracy of H870. It'll beat Retumbo by a good 100 fps with this bullet. If it's nearly as temp stable as advertised, that will be a very valuable bonus (one reason I've shied away from WC872). The density is great of you've ever tried H50BMG--even the with the 104 grain load, the powder would still shake in the case even with the long 240 stuffed down to a 3.60" OAL (with fireformed cases this time). In short, a perfect replacement for H870. It's everything H870 was but better (H870 was pretty temp unstable), at least in this application.
I'd expect the typical 26" 300 RUM to top out around 99 grains in the 2950-2975 fps range with this bullet.
Now, the only piece of the puzzle that is missing for me is some heavier, higher BC bullets from Richard. I figure I can do around 2925 or so with a 250. If Richard can make one with a BC that blows away the 240, which is very possible, it'll take the old 300 RUM to the next level at extreme ranges. Of course, the 240 @ 3000 is no slouch in the meantime.