280/30 load data help (EM2)

buck732

Well-Known Member
Okay, a friend and I have had a pair of Rem 700 re-barelled to 280/30 (of em2 fame). We need to provide 2x mil spec rnd for each rifle and two cartridges per rifle. While we have some period ammo we would rather not open the box.

So I am asking the assembled masses on SD that if anyone has a load, or can run the figures through quick load could they please do so. If its a quick load please could you run it with as many powders as possible.

We are looking for (all figures have come from a mil pam for the EM2) the following please.

Okay from the 1950 pam we have (also what we are trying to achieve with todays powderers).

2415 fps
31.5 grains powder (unknown)
140 grains projectile
24.5 inch barrel
23.5 inch shot travel (I am taking this to mean that it is barrel length minus chamber)
23.5 Tons/sq.inch max pressure (true)

Today;
Case (.243 winchester reformed to 280/30) 165.7 grains
+ water 208.3 grains
water capacity = 42.6 grains

If you need more info please PM me.

Many thanks

Buck
 
Here are some QuickLOAD simulations. (Used 7mm BR Rem which is around 29.5gn water cap as nearest and increased the default value up to your 42.6gn actual capacity, reduced barrel length to 24 inches for slightly shorter case. Don't know how the 23.5 tons pressure equates to modern strain gauge methods as the British armoury system used oiled cases and measured case thrust onto the bolt-face, but worked on powders that suit the application at ~45,000 psi.) The bullet used in the model was the 140gn Sierra HPBT MatchKing.

27gn IMR-4198 ................................ 85.8% fill, 2,449 fps, 46,312 psi PMax

30gn Reload Swiss RS40 .................... 83.8% fill, 2,454 fps, 42,638 psi PMax

31gn Viht N135 ................................ 97.4% fill, 2,528 fps, 45,905 psi PMax

33gn IMR-4064 ................................ 99.5% fill, 2,499 fps, 45,428 psi PMax

33gn Viht N140 ............................... 95.8% fill, 2,496 fps, 45,002 psi PMax

35gn Reload Swiss RS50 / TR140 ....... 95.8% fill, 2,499 fps, 44,277 psi PMax


Viht N140 looks a good match and has a calculated 99. whatever % charge burn. It should prove pretty untemperamental in this application being quite slow burning in relative terms.
 
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