Late last year I decided to move away from "small" calibers, i.e. 6MMs and 6.5MMs, in favor of the .300 W.S.M. So far the decision to go that route has paid off handsomely! However, a friend of mine, John Farraggio, a.k.a. "Cognac Jack" on here, told me about a cartridge I had never heard of, The 7mm Sherman Short Magnum. After looking at the cartridge and speaking with Rich Sherman, I decided to give it a try.. My goal was to shoot the 184 Hybrids somewhere above 2900f.p.s. I like 7mm ballistics, however, the 7mm always seemed to me to be a P.I.T.A. to get tuned properly and KEEP it tuned properly. I am not a ballistician so I never could figure why I was having trouble. However, after looking at the Sherman case, it looked exactly like a 6mm Dasher on steroids! I thought "well this may be the answer to my issue"! I called Rich to get the "particulars" on his creation. I can't remember the exact dimensions but I can give you a pretty close approximation to what it is: a 7mm S.A.U.M. case shortened by 90 thousandths, the neck shortened from the forming BUT still, I believe, 40 thousandths LONGER than the standard S.A.U.M. neck. Then it is "Acklyized" with a 40 degree shoulder, however, with a somewhat "straighter case wall".. The end result is that for the shooter shooting steel or hunting, it is what the S.A.U.M. should have been!
So I decided to build one. Components: Defiance "Deviant" short action and melonited. McMillan "Kestros" stock with adjustable cheek piece and 3 way butt metal. Also that BIG 1.5" "Nitro" pad. An "old" Kelbly trigger and a Krieger 1-8.5 5R barrel and a Kahles 10-50 with the MOAK reticle. ADDITIONALLY: It should be known that this IS a proprietary cartridge and EVERYTHING has to be bought thru Rich. I got a Whidden bushing die, Forster "Ultra" competition seating die, a JGS reamer to MY specs (Rich worked with me on this one), and 7 Sherman brass ALREADY MADE UP from A.D.G. All you have to do is fireform it like any other fireforming operation.
Long story short, I got everything assembled and AFTER fireforming, I tried powders that I thought would work. H4350: I could NOT get it past 2880f.p.s without a stiff bolt lift! Why? I don't know.. H4831sc. Okay NOW we are getting somewhere. I could reach 2950 without a bolt lift issue. At 2910 it was shooting excellently at 300 meters. I took it out to a 2 man team match at 1000 yards and got A LOT of vertical. Back to the drawing board! Let's see, RL-23 is within the burn rate range of H4831sc, let's give that a try. The velocity was certainly there, however, the accuracy was not. I thought "Here we go again, with trouble tuning yet another 7mm". I called Rich and found out that this particular case L-O-V-E-S slow powders. Ok let's try H1000. Well all of a sudden this case turned on! I could easily get well in excess of 3000f.p.s with ZERO pressure signs! From 60.7grs to 61.3grs it shot almost identical groups in exactly the same location on the target at 300 meters! WHOA! Now this is a W-I-D-E window. I said "Ok, let's settle on 60.9 and take it to a match to see about vertical". Yesterday, Sunday, we had a 60 shot 600 yard match at Ben Avery. Winds were from about 7m.p.h. in the morning to 15 or so in the afternoon. The vertical was FLAT AS A PANCAKE! NO "where did that come from" vertical! The velocity is running from 2945 to 2954f.p.s. The accuracy at 300 meters hovers in the vicinity of 0.75-1.00 inch. This is for 3 / 5 shot groups I tested. Now that I know this case desires slow powders, I believe it to be an excellent 7mm to use for F-Open and Steel, for those into that game! It also should be easy to tune from hitherto forth!
So I decided to build one. Components: Defiance "Deviant" short action and melonited. McMillan "Kestros" stock with adjustable cheek piece and 3 way butt metal. Also that BIG 1.5" "Nitro" pad. An "old" Kelbly trigger and a Krieger 1-8.5 5R barrel and a Kahles 10-50 with the MOAK reticle. ADDITIONALLY: It should be known that this IS a proprietary cartridge and EVERYTHING has to be bought thru Rich. I got a Whidden bushing die, Forster "Ultra" competition seating die, a JGS reamer to MY specs (Rich worked with me on this one), and 7 Sherman brass ALREADY MADE UP from A.D.G. All you have to do is fireform it like any other fireforming operation.
Long story short, I got everything assembled and AFTER fireforming, I tried powders that I thought would work. H4350: I could NOT get it past 2880f.p.s without a stiff bolt lift! Why? I don't know.. H4831sc. Okay NOW we are getting somewhere. I could reach 2950 without a bolt lift issue. At 2910 it was shooting excellently at 300 meters. I took it out to a 2 man team match at 1000 yards and got A LOT of vertical. Back to the drawing board! Let's see, RL-23 is within the burn rate range of H4831sc, let's give that a try. The velocity was certainly there, however, the accuracy was not. I thought "Here we go again, with trouble tuning yet another 7mm". I called Rich and found out that this particular case L-O-V-E-S slow powders. Ok let's try H1000. Well all of a sudden this case turned on! I could easily get well in excess of 3000f.p.s with ZERO pressure signs! From 60.7grs to 61.3grs it shot almost identical groups in exactly the same location on the target at 300 meters! WHOA! Now this is a W-I-D-E window. I said "Ok, let's settle on 60.9 and take it to a match to see about vertical". Yesterday, Sunday, we had a 60 shot 600 yard match at Ben Avery. Winds were from about 7m.p.h. in the morning to 15 or so in the afternoon. The vertical was FLAT AS A PANCAKE! NO "where did that come from" vertical! The velocity is running from 2945 to 2954f.p.s. The accuracy at 300 meters hovers in the vicinity of 0.75-1.00 inch. This is for 3 / 5 shot groups I tested. Now that I know this case desires slow powders, I believe it to be an excellent 7mm to use for F-Open and Steel, for those into that game! It also should be easy to tune from hitherto forth!
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