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I'm working up a load for my Weatherby UL 7mm-08. Here's some preliminary (single shots or abbreviated string) data for the 120 NBT:
50.0 grains Big Game: 3165 ft/sec, ES 8.9, st dev 4.9 (4 shot string).
52.0 grains Big Game (2 shots): 3247 & 3277 ft/sec.
44.0 grains Varget (1 shot): 2991 ft/sec.
45.0 grains Varget (1 shot): 3062 ft/sec.
60 degree outside temp. No pressure signs. The 52 grain load was stout compared to the other 7mm-08 loads but miniscule compared to my .30-06.
Boy howdy does that bullet get moving out of a 24" barrel! Next step, accuracy at the range.
P The loads at over 3200 FPS are at a velocity considerably above any published data that I've seen, indicating likely high pressure according to conventional wisdom. Why don't you measure the CHE on a few & get back to us; ANY CHE indicates very high pressure, as in over 70K PSI, according to most who regularly post here & discount the value of CHE. I'll take a WAG & say that those loads will show .0005" CHE. MM The load and velocity comes from the Nosler manual (#6). What is CHE? P
Obey lawful commands. Video interactions. Hold bad cops accountable. Problem solved.
~Molɔ̀ːn Labé Skýla~
Member #547 Join date 3/09/2001
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Campfire Ranger
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I don't have Nosler's #6, but load data from their website shows a max velocity of 3090 with H4895.........that's a long way from 3277. The other 4 powders they list there are lower than that. And their data is from a 26" barrel.
CHE = case head expansion; "experts" here say by the time you get measurable CHE, you are waaaaaaay high on pressuer.
MM
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Nosler #6 data for the 120gr ballistic tip lists as max 52gr big game at 3262fps, 50gr at 3190fps.
Nosler doesn't post all of their loads online.
How do I measure CHE?
P
Obey lawful commands. Video interactions. Hold bad cops accountable. Problem solved.
~Molɔ̀ːn Labé Skýla~
Member #547 Join date 3/09/2001
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Accuracy in my -08 is best at 50.0 grains of BG but even at 50 gr. I am a little hot. My 22" barrel is chronographing just a hair over 3100 fps. so I'll go no higher. As a matter of fact, I am going to search out a slightly milder load that will give me accuracy as good as the above load and be happy. I bought a 7mm-08 in the first place to get away from the recoil of the faster 7s. I've tried RL 15; will try Varget, H4350, H4895, and maybe others. Just my thoughts....
If we live long enough, we all have regrets. But the ones that nag at us the most are the ones in which we know we had a choice.
Doug
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Nosler #6 data for the 120gr ballistic tip lists as max 52gr big game at 3262fps, 50gr at 3190fps.
Nosler doesn't post all of their loads online.
How do I measure CHE?
P In my experience the velocities quoted for the 7mm/08 in the Nosler manual can be as much as 200fps-250fps above what is achievable in the real world. I've had a 7mm/08 for 17 years and chronographed many hundreds of loads and none come close to the velocities published in some manuals My 700VLS 22/250 produces velocity 200fps less than Noslers pulished data with Varget/50gn bullets despite my rifle having a barrel two inches longer than Nosler's test barrel.....Go figure.
Last edited by dingo; 06/09/12.
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In my experience the velocities quoted for the 7mm/08 in the Nosler manual can be as much as 200fps-250fps below what is achievable in the real world. I've had a 7mm/08 for 17 years and chronographed many hundreds of loads and none come close to the velocities published in some manuals
My 700VLS 22/250 produces velocity 200fps less than Noslers pulished data with Varget/50gn bullets despite my rifle having a barrel two inches longer than Nosler's test barrel.....Go figure.
I'm thinking you meant that the real world is below what Nosler publishes??????????? MM
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CHE is measured with either a blade or a pin mic by measuring the diameter of the case just forward of the groove. You need to use virgin cases & measure before & after firing a test round. Measurements will be in tenths of a thousandth & as I said before the "experts" here have decreed that any consistently measurable increase in CHE means a load is too hot..........IMO, consistently measurable is .0002-.0003" You can do a search here for CHE or case head expansion.......several extensive & heated threads over the last 3-4 years. MM
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In my experience the velocities quoted for the 7mm/08 in the Nosler manual can be as much as 200fps-250fps below what is achievable in the real world. I've had a 7mm/08 for 17 years and chronographed many hundreds of loads and none come close to the velocities published in some manuals
My 700VLS 22/250 produces velocity 200fps less than Noslers pulished data with Varget/50gn bullets despite my rifle having a barrel two inches longer than Nosler's test barrel.....Go figure.
I'm thinking you meant that the real world is below what Nosler publishes??????????? MM Your right,thats what I mean.
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I bought a 7mm-08 in the first place to get away from the recoil of the faster 7s. +1 on that. I haven't worked too much with my Sako yet but 41 gr of IMR 3031 (the powder I had on hand) and the 120 gr TTSX is grouping nicely with mild recoil. Haven't chrono'd yet but should be 2900-2950 fps as a guess--Hodgdon lists a hair under 3000 fps with that load. I wonder how the 50+ gr loads of other powders at 3200 fps these guys are using compare in the recoil department?
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sambo3006......recoil is not bad, just a sharp crack....my load is 51g Big Game and 120ttsx @ 3130@ muzzle. Deadnutsaccurate...
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In my Cooper the 50.0 load of BG and the 120 gr. NBT shows a little primer flattening and an ejector shiney spot. I am first going to try partially re-sizing to make sure it's not headspace; if not, I'll reduce the load and/or try different powders. I haven't worked with the TTSXs yet, but they are on the shelf.
If we live long enough, we all have regrets. But the ones that nag at us the most are the ones in which we know we had a choice.
Doug
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