Elric
Well-Known Member
http://www.thefirearmsforum.com/threads/7mm-super-mag.46065/#post-1366914
"If anyone is still interested, I have lots of loads for the 7SM, an Elgin Gates creation based on the 357 SM case. As usual there are many variables. Remington (R-P) and Federal brass used to differ by 2 grains water capacity (Federal was thinner with 24 gr water capacity); I don't know what new Starline 357 Max brass would be and if it is thicker, all the loads I mention may be too HOT and should be reduced at least 2 grains each and by at least 5 grains for case forming. Loads given below were using Fed Ni 357 brass.. I settled on Rem 7 1/2 BR and Fed 205M primers which were very consistent. The case forming leaves a very short neck which will split after only a couple of reloadings unless annealed starting with the first time. I typically used 140 gr SPBT bullets seated to 2.325 COAL and 160 gr HPBT bullets seated to a COAL of 2.475 for the chamber in my TC 7SM 10" barrel. Due to their long ogive, 168 HPBT bullets could be seated to a COAL of 2.630. COAL seating length makes a huge difference in case capacity and powders such as IMR 4198 would be compressed with anything over 19.0 gr. But 27.0 gr of H4895 under 168 HPBT seated to 2.530 gave me 1800 fps, sd of 11.5 in 60 deg weather for example and slammed the rams to the ground (the only distance I used the 168s at). Using 26.5 gr of H322 with 140 SPBT seated to 2.475 gave 2000 fps with sd=14.5. 120 Nosler SPBT bullets seated to COAL of 2.340 under 23.5 gr of IMR 4227 gave 2200 fps, but with sd of 62.5 whereas 22.5 gr of 2400 seated to COAL of 2.336 gave 2274 fps, sd of only 8.5. The usual warnings of working up to loads and inspecting for pressure signs, etc, etc., should all be followed when using a little documented cartridge like this one. But I enjoyed working with it since it saved powder compared to others (7BR and 7 IMHSA in particular). 7TCU was very similar but had a slightly longer neck with less powder capacity but was very popular due to its basis on the .223 cartridge."
Huh-huh?
http://www.midwayusa.com/7mm-super-magnum-7mm-357-maximum/br?cid=9957
http://forum1.aimoo.com/IHMSA/categroy/7mm-Supermag-Case-Forming-1-697659.html
http://www.singleactions.com/TheSuperMags9.html
"If anyone is still interested, I have lots of loads for the 7SM, an Elgin Gates creation based on the 357 SM case. As usual there are many variables. Remington (R-P) and Federal brass used to differ by 2 grains water capacity (Federal was thinner with 24 gr water capacity); I don't know what new Starline 357 Max brass would be and if it is thicker, all the loads I mention may be too HOT and should be reduced at least 2 grains each and by at least 5 grains for case forming. Loads given below were using Fed Ni 357 brass.. I settled on Rem 7 1/2 BR and Fed 205M primers which were very consistent. The case forming leaves a very short neck which will split after only a couple of reloadings unless annealed starting with the first time. I typically used 140 gr SPBT bullets seated to 2.325 COAL and 160 gr HPBT bullets seated to a COAL of 2.475 for the chamber in my TC 7SM 10" barrel. Due to their long ogive, 168 HPBT bullets could be seated to a COAL of 2.630. COAL seating length makes a huge difference in case capacity and powders such as IMR 4198 would be compressed with anything over 19.0 gr. But 27.0 gr of H4895 under 168 HPBT seated to 2.530 gave me 1800 fps, sd of 11.5 in 60 deg weather for example and slammed the rams to the ground (the only distance I used the 168s at). Using 26.5 gr of H322 with 140 SPBT seated to 2.475 gave 2000 fps with sd=14.5. 120 Nosler SPBT bullets seated to COAL of 2.340 under 23.5 gr of IMR 4227 gave 2200 fps, but with sd of 62.5 whereas 22.5 gr of 2400 seated to COAL of 2.336 gave 2274 fps, sd of only 8.5. The usual warnings of working up to loads and inspecting for pressure signs, etc, etc., should all be followed when using a little documented cartridge like this one. But I enjoyed working with it since it saved powder compared to others (7BR and 7 IMHSA in particular). 7TCU was very similar but had a slightly longer neck with less powder capacity but was very popular due to its basis on the .223 cartridge."
Huh-huh?
http://www.midwayusa.com/7mm-super-magnum-7mm-357-maximum/br?cid=9957
http://forum1.aimoo.com/IHMSA/categroy/7mm-Supermag-Case-Forming-1-697659.html
http://www.singleactions.com/TheSuperMags9.html
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