Anybody using W748 in .303?

[bladeracer]

Happens to be some available locally, but I'm not finding much load data for it.
Burn rate is right around AR2206H so I'm sure it'll work okay.
But perhaps there's a reason I'm not finding load data for it?

[No1_49er]

As with all things theoretical, and using suitable caution, QuickLoad suggests that around 41gn of 748, with a 174gn Sierra MK, will put the pressure around 2890bar (SAAMI max 3378) and velocity 2525fps.
39.6gn of 2206H pressure 2887bar and 2490fps. Both those fill the case to around 86%.
Not saying that it's ever been tried, but possibly worth a trial.

[bladeracer]

As with all things theoretical, and using suitable caution, QuickLoad suggests that around 41gn of 748, with a 174gn Sierra MK, will put the pressure around 2890bar (SAAMI max 3378) and velocity 2525fps.
39.6gn of 2206H pressure 2887bar and 2490fps. Both those fill the case to around 86%.
Not saying that it's ever been tried, but possibly worth a trial.

Yep, I was figuring 40gn to 41gn would get us in the 2400fps ballpark with 174gn bullets.

[JimTom]

I have data for 303 and w748 with 150 and 174gn bullets mate if you like.

[JimTom]

Check your PM Bladeracer.

[bladeracer]

Check your PM Bladeracer.

Much appreciated, JT!

[Oldbloke]

Here, in an old Winchester manual.

Resized_Screenshot_20220622-195431_Open_Office_Viewer.jpeg (204.4 KiB) Viewed 1535 times

[bladeracer]

Here, in an old Winchester manual.

Resized_Screenshot_20220622-195431_Open_Office_Viewer.jpeg

Thanks OB, that's the 15th Edition Winchester manual, one of the few sources I found for it.
They seem to prefer the W760 for the heavy bullets, but W748 is what he has access to at the moment. Hopefully he can get enough to last a few years and maybe powder supply will have righted itself by the time he needs to find more of it.

[bladeracer]

Can somebody that uses this stuff confirm that this is what W748 is supposed to look like?

20220629_162304b.jpg (247.52 KiB) Viewed 1481 times

20220629_162257b.jpg (257.11 KiB) Viewed 1481 times

Compared to the AR2206H I'm used to the ball powder looks like extremely fast pistol powder, as if from a .22LR cartridge - is this the right stuff?
I Googled pics and it does seem to look right but it'd be nice to confirm it with somebody who actually uses it.

[northdude]

Yep that is what it looks like. I use it in my 6.5 grendel

[bladeracer]

Yep that is what it looks like. I use it in my 6.5 grendel

Much appreciated!
Just about to go up and shoot some test loads through the chrono.

[northdude]

Im getting good speeds and accuracy in the grendel

[northdude]

How did it go

[bladeracer]

How did it go

Less than ideal
First two were fine, but velocity was 150fps less than expected.
Shot three barely made it out of the case mouth
The primer fired but the powder "melted" rather than burned, and turned into a turd of powder.
I'm hoping it was merely a glitch so we're trying some hotter ones to get the velocity up and see if they work.
He bought five bottles of W748 so it'd be bloody nice to get it to work.
It might be that magnum primers would light it up better, but primer choices nowadays are extremely limited.

I'm not liking the powder though, it barely half fills the case. I don't think it's possible to double-charge it without some overflow, but there might be so little overflow as to not be noticed. I'll have to check the case capacity next time.

It might be that we need to use a filler to keep the powder down on the primer, but that would be annoying.