HELP! Been trying to develop a new long distance capable loads for my 7mm STW.
Have chronographed a number of test loads and cannot get my feet on the ground.
Rifle: Shilen DGA-M, new 26in, 1 in9" stainless barrel under a S&B PMII 5x25 DT cm scope. Have shot in new barrel with over 75 shots w/ correct cleaning process. Gun shoots consistent 1/2"MOA @ 100yds. Having problem getting FPS up over 3000 fps. Load specs: Federal 215 Lr. Mag Primers, Fireformed (once fired) Rem Cases, Retumbo Powder and Ber ger 168 gr. VLD bullet set off lands @ 0.030"
Test bullet used: 168 gr Berger VLD Hunting
Have chrono'd 5 shot groups as follows:
7MM STW BERGER 168 GR VLD ----AVG FPS COUNT
String 1 78.1 GR Retumbo ----------2924.8 ----5
String 2 78.3 GR Retumbo ----------2814.7 ----5
String 3 78.5 GR Retumbo ----------2817.6 ----5
String 4 78.8 GR Retumbo ----------2868.3 ----5
String 5 79.0 GR Retumbo ----------2942.5 ----5
String 6 79.8 GR Retumbo ----------2919.8 ----5
String 7 80.5 GR Retumbo ----------2896.5 ----5
String 8 81.0 GR Retumbo ----------2904.5 ----2
My objective is to push load up over 3000 fps. Note String 1 load has high 2924.8 avg. fps, String 5 load is highest but still can't get bullet past 3000 fps.
Shot in barrel using several boxes of commercial HSM Gold Trophy (same) 168 gr. Berger VLDs, chrono'd HSMs loads at 3195 avg. fps (20 rounds).
Pushed powder load to big time max in String 8, but more Retumbo doesn't seem to push 168 gr. Berger any faster using 2 grains of addtional powder?
CAN ANYONE GIVE ME SOME ADVICE ON WHY?
Have prepared new test loads using other powders, RL22, IMR 7828 and 4831SC. Just need to get down to the range to test and chrono.
ADVICE WELCOME!
Have chronographed a number of test loads and cannot get my feet on the ground.
Rifle: Shilen DGA-M, new 26in, 1 in9" stainless barrel under a S&B PMII 5x25 DT cm scope. Have shot in new barrel with over 75 shots w/ correct cleaning process. Gun shoots consistent 1/2"MOA @ 100yds. Having problem getting FPS up over 3000 fps. Load specs: Federal 215 Lr. Mag Primers, Fireformed (once fired) Rem Cases, Retumbo Powder and Ber ger 168 gr. VLD bullet set off lands @ 0.030"
Test bullet used: 168 gr Berger VLD Hunting
Have chrono'd 5 shot groups as follows:
7MM STW BERGER 168 GR VLD ----AVG FPS COUNT
String 1 78.1 GR Retumbo ----------2924.8 ----5
String 2 78.3 GR Retumbo ----------2814.7 ----5
String 3 78.5 GR Retumbo ----------2817.6 ----5
String 4 78.8 GR Retumbo ----------2868.3 ----5
String 5 79.0 GR Retumbo ----------2942.5 ----5
String 6 79.8 GR Retumbo ----------2919.8 ----5
String 7 80.5 GR Retumbo ----------2896.5 ----5
String 8 81.0 GR Retumbo ----------2904.5 ----2
My objective is to push load up over 3000 fps. Note String 1 load has high 2924.8 avg. fps, String 5 load is highest but still can't get bullet past 3000 fps.
Shot in barrel using several boxes of commercial HSM Gold Trophy (same) 168 gr. Berger VLDs, chrono'd HSMs loads at 3195 avg. fps (20 rounds).
Pushed powder load to big time max in String 8, but more Retumbo doesn't seem to push 168 gr. Berger any faster using 2 grains of addtional powder?
CAN ANYONE GIVE ME SOME ADVICE ON WHY?
Have prepared new test loads using other powders, RL22, IMR 7828 and 4831SC. Just need to get down to the range to test and chrono.
ADVICE WELCOME!
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