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Looks like my brain swapped 4955 and 4895 when I wasn't looking. Apologies. But the same principle applies. Get the bullet maker's optimal velocity and aim at that. From this Hornady video, Hornady claims the SST will work from 1850 fps to 3200 fps, but the voiceover suggests the best performance is between 2200 fps to 3000 fps impact. 2600 fps is right in the middle of that range and also is the velocity of the 30 Cal SST they show striking a gelatin block in that video, so I'd take that as your target impact velocity.

According to Brian Litz's detailed BC measurements for this bullet, to impact at 2600 fps at 100 yards, it would need to be going 2793 fps at 15 feet from the muzzle (Hodgdon's measuring distance), so that would be the target velocity from your gun. Based on Hodgdon's data, this would take 55.4 grains of 4955 in their gun. It is 0.4 grains below Hodgdon's starting load and above Sierra's maximum. My Sierra databook has just 53.2 grains as maximum and producing 2900 fps from a 24" barrel. Further, if I use QuickLOAD, for which a purchased lot of the powder was measured in a closed vivacity bomb test, it falls between Sierra and Hodgdon numbers, favoring Hodgdon by giving higher velocities and slightly higher pressures for a case with 71.5 grains of case water overflow capacity.

There is always some variation in powder burn rate from lot to lot. Nothing new. But in QL I had to raise the burn rate by about 14% to get to Sierra's velocities, and that's much more than the normal lot variation produces. It makes me wonder if Sierra's test gun had a tight barrel or if they had powder from an early bulk lot because bulk grade powder can vary that much. Canister grade lots are held to tighter tolerances to keep published load data valid, where bulk lots expect the user to have a pressure test gun to check his loads with. So it is a bit puzzling that the difference is quite as big as the Hodgdon/QuickLOAD and Sierra differences are.

I don't know your barrel length, but for a 24" barrel, aiming for that 15-foot velocity of about 2793 fps is not going to be a maximum load whether your powder behaves closer to Sierra's sample or to Hodgdon's data. It's not a maximum velocity for either. But if your barrel is shorter, you'll need more pressure to get there, so it depends on how much shorter it is as to whether it will become an issue.

The thing to do is try Sierra's starting load (44.8 grains in my Sierra databook) and work up. When you fire the test loads, tip the muzzle up to get the powder over the flash hole for each shot (maximizes pressure and velocity) and work up from there. In both Hodgdon's and Sierra's data you get a pretty consistent 47-49 fps per grain of additional powder (again, in a 24" barrel), so you can estimate from that what charge weight you will need to get to.
 

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Just received the print version of the Hodgdon 2021 Basic Reloading Manual from Ballistic Products. The entire back cover is dedicated to the new Enduron powders. Now I know that Hodgdon wouldn't spend a lot to market a powder that they just are going to have for a short time...but my question is that if this particular line doesn't do well, do you see them discontinuing it?

Just curious.
 

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Remembering that Hodgy merely buys what the powder manufacturers are making and selling in very large quantity for militaries and commercial ammunition factories, I don't think it's going anywhere soon. They may change the marketing around it, perhaps, but even that I doubt.
 

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The Shadow (Moderator)
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Agreed, They would have little alternative.
There is ONE American company, who actually owns their own facilities; General Dynamics.
The "Enduron" line is made in Quebec, but heretofore; isn't an issue with importation. Hodgdon's main alternate supplier, is Thales in Australia. They have been "closed for business" in terms of the sporting public, while a cleanup/revamp of the government arsenal has been taking place. I'm not sure if it's still in process, or if it's back to full-tilt-boogy. But whether from there or "across the pond", shipping is currently an issue.

Cheers
 
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