elkaholic
Well-Known Member
I may have missed this but, have you checked the variation in neck wall thickness and do you turn your necks? Sometimes brass can be quite different, especially WW and RP......Rich
Velocity swing in 7mm wsm with IMR 7828ssc
- Thread starter Hiwayman92
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Hiwayman92
Well-Known Member
I took all the advice you guys gave, and shot again today. 64 grains of IMR 7828 SSC and able 175's averaged 2968, no pressure signs, loaded at 3.115". More importantly the S.D. was 15 and it grouped 3 in one ragged clover leaf.
I shot some H1000 loads as well, and the S.D. was 12 and 6.65. Respectively for 68 and 69 grains. (2,991 and 3037 fps.) THESE GROUPS WERE ABOUT 1" or less, but I haven't played with seating depth.
68 grains of IMR 7977 at 2951with an s.d. of 12 grouped about 1 inch also.
I can't believe I haven't flattened a primer yet, but I guess the long throat keeps pressure down... I'm thinking I need a ladder test on H1000, IMR7828SSC, and IMR 7977... or I keep the 7828ssc load and roll with it? Advice?
I shot some H1000 loads as well, and the S.D. was 12 and 6.65. Respectively for 68 and 69 grains. (2,991 and 3037 fps.) THESE GROUPS WERE ABOUT 1" or less, but I haven't played with seating depth.
68 grains of IMR 7977 at 2951with an s.d. of 12 grouped about 1 inch also.
I can't believe I haven't flattened a primer yet, but I guess the long throat keeps pressure down... I'm thinking I need a ladder test on H1000, IMR7828SSC, and IMR 7977... or I keep the 7828ssc load and roll with it? Advice?
elkaholic
Well-Known Member
Sounds like you are getting it figured out......Rich
Varmint Hunter
Well-Known Member
I've been shooting a 7 WSM for quite some time and your loads seem very heavy to me. Typically, a 175gr bullet would get you well over 63,000 PSI at 2,800 ft/sec. Loads that approach 3,000 ft/sec with a 175gr bullet would almost always be well over normal pressure limits.
A 160gr bullet at 3,000 ft/sec is a typical max load.
Every rifle is different and these loads may be ok in your rifle but they exceed normal limits IMO. Just a note of caution.
A 160gr bullet at 3,000 ft/sec is a typical max load.
Every rifle is different and these loads may be ok in your rifle but they exceed normal limits IMO. Just a note of caution.
Hiwayman92
Well-Known Member
I see no signs of pressure, but I'm running bullets almost 1/3rd of an inch longer than saami due to the long throat and long action. When I run book charges I'm 100-150 fps slower than what the book says it should be. I wish I could figure out how to add pics of my brass for you experts to check out for me...
Varmint Hunter
Well-Known Member
A third of an inch more case capacity would certainly reduce pressure. Looks like it is working good for you. Good luck with your project.
RockyMtnMT
Official LRH Sponsor
The 7828 load looks pretty good. I would shoot it at longer distance and see how it does. Unless there is something that you do not like about the load I don't see any point in spending time with the others. Or if you are just having a blast trying different stuff keep going.
Steve
JeffVN
Well-Known Member
I have run my 28" tube 7WSM (long throated to over 3.200" COAL w/ Berger 180 Hybrid) consistently at 2,900+ fps. No pressure and the brass lasts for well over 10 reloads. I've run at the 2,900+ node with RL-25, H4831sc, and H1000. I have no doubt you can find what you need with H1000 or the other powders that you are testing.
RL-26, IMR 7977 and IMR7828ssc didn't exist back when i developed my 7WSM loads (but my 30-06AI loves 7828ssc under a Berger 185 Juggernaught), so its potentially worth a look for me as well.
velocity consistency is only one factor in finding your load, but it all comes down to how it shoots at distance. I don't declare it done until it shoots well at 400 meters+. if it does, then it has in virtually all circumstances shot well at 1,000 yards and at 1,900 in the desert. As someone mentioned earlier, I've had loads that didn't hold super tight ES or SD but they shot bug holes and others that looked great on paper that barely held a minute.
Jeffvn
RL-26, IMR 7977 and IMR7828ssc didn't exist back when i developed my 7WSM loads (but my 30-06AI loves 7828ssc under a Berger 185 Juggernaught), so its potentially worth a look for me as well.
velocity consistency is only one factor in finding your load, but it all comes down to how it shoots at distance. I don't declare it done until it shoots well at 400 meters+. if it does, then it has in virtually all circumstances shot well at 1,000 yards and at 1,900 in the desert. As someone mentioned earlier, I've had loads that didn't hold super tight ES or SD but they shot bug holes and others that looked great on paper that barely held a minute.
Jeffvn
