Hybrid 100V


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Rosco P
March 29, 2010, 08:57 PM
I have found exactly zero .308 load data for this powder. Anybody else messing with it?

I think it would be nice out of a 5r with 155-175 SMK's

Thanks

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NCsmitty
March 29, 2010, 09:42 PM
Rosco P, welcome to THR.

When you cannot find load data, even at the manufacturer/distributor load site, there is usually a good reason.
In this case, it is too slow burning to work well in the 308.
Go to www.hodgdon.com site or any of the other load sites, and do some research and select a powder that gives good velocity and normal pressure.
Always go with a starting load and work up, especially when using a powder that's new to you.


NCsmitty

Rosco P
March 30, 2010, 10:23 AM
Thank you for your input. I was assuming that due to it being a great powder for .243 that it would be useable in .308 due to the case being of the same family.

JimKirk
March 30, 2010, 12:54 PM
Case to bore capacity determines the type powder. Hybrid 100V is a slow burning magnum type powder. Cartridges like the 22-250, 200 Swift, .243 Win, 25/06 and others are magnum type cartridges although they lack the magnum name. Because the 308 has a bigger bore, it's case capacity to bore ratio is better suited for moderate burning powders.

The .243 Win, 260 Rem, 7-08, .308, and the 358 Win all share the same case, but each requires different powders starting with the slower type (243) up to faster(358).

Make sense?

Jimmy K

counterclockwise
March 30, 2010, 02:33 PM
Hybrid 100V

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I have found exactly zero .308 load data for this powder. Anybody else messing with it?

I think it would be nice out of a 5r with 155-175 SMK's

Thanks

I discovered the same thing. I called Hodgdon about it. The tech on the phone said "my boss told me it was not a good application for .308" :scrutiny:

They post loads for other calibers and bullet weights all around it. I am currently using it for 7mm-08 loads. It behaves well, as far as I can tell. It is also supposedly good for .243, but I have not gotten around to it yet.

counterclockwise
March 30, 2010, 02:38 PM
7-mm-08 is only .024 smaller in bore. So, no that does not make alot of sense. I think it has something to do with protecting the gas gun shooters. I think I will try it with my .308 bolt gun anyway just to see what happens. Anybody got a starting recipe guess for 168 grain SMK?

ETA: OK, I yield! Mea Culpa! According to QuickLOAD, the energy density for H100V 3545 KJ/KG is too low for .308. You cannot get enough in the case to do much good, even with some compression. Compare that to 4080 KJ/KG for something like IMR 4895. Now I understand the "magnum" analogy. My 7mm-08 recipe for 154 SST is still slightly compressed even with the bullet out at 2.835 COAL. Fortunately, my 7mm-08 is a long barreled bolt gun.

JimKirk
March 30, 2010, 07:22 PM
CCW
You must have reread what I said, because I never said the 7-08 was a magnum type. I think you'll agree that the 243 is just about as big of case as you can use with out resorting to a super slow powder and then the returns will be lopsided as far as velocity gain per grain of powder. Maybe I should have said overbore rather than magnum. Some where there is a formula(I think) that shows when a cartridge case capcacity becomes "overbore" , I think most of the magnums are overbore, most.

I hope I don't confuse anybody else with the magnum analogy...

Jimmy K

PS.. IMR 7828 is a good powder for heavier 243 bullets, because it is so slow(close to H100v), but it would be the same as H100v in a 308 case, too slow.

counterclockwise
March 31, 2010, 01:04 AM
Jim Kirk,
Yes, the .308 case is too small to hold the required amount of H100V to do any good with the 168 gn OTM (maybe 43 grains for 2350 fps in 24" bbl.).

The .30-06 case (larger) would allow about 58 grains and give about 2800 fps, 24" bbl. The case is longer but about the same chamber bore dia.

The 300 WinMag (truly a larger chamber bore) would allow 71+ grains of
H100V and send out the 168 grain with a really good head of steam.

The 7mm-08 with my 154 SST would allow 43 grains and 2650 fps, 24" bbl., using the H100V, which I am doing.

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