303.27

[6878mm]

Has anybody got a load for a 303.27
Different weight projectiles I realise use different weights of powder

[bladeracer]

Has anybody got a load for a 303.27
Different weight projectiles I realise use different weights of powder

I've never even seen a .303-270, but happened to be discussing the .303 wildcats with a mate last week.

ADI do list some of their old data still, but not with AR2206H. ADI state that you can use AR2206H for any AR2206 load data though.
Note the warning to knock 2gn off these numbers in an SMLE. So 33gn with a 100gn bullet, or 31gn with a 130gn bullet. They don't list data for the 150gn but I would start with 29gn or 30gn.

ADI 303-270 100gn.jpg (97.2 KiB) Viewed 820 times

ADI 303-270 130gn.jpg (78.64 KiB) Viewed 820 times

ADI 303-270 150gn.jpg (52.54 KiB) Viewed 820 times

[Blr243]

Not as common as the 303 25 But I think the 270 makes more sense from an easy necking down point of view. I have one or two 303 270 cases. I think I found them in an old toolbox somebody gave me. I had a 30322 Rifle once. Piece of garbage not an easy thing for someone relatively New to reloading

[6878mm]

I have got some W760 powder, I was hoping some of that would turn up in the loading data

[bladeracer]

I have got some W760 powder, I was hoping some of that would turn up in the loading data

Maybe if you can find some really old manuals there might be some data.
I'm not a fan of the Winchester ball powders.
AR2206H is readily available while you try to ferret out some Winchester data though.
W760 has a similar burn rate to AR2209 so it can certainly be used, though probably better suited to the heavier bullets. No idea where you would start with charge weights though.
When I was trying to make W748 work in the .303 a member here sent me data from Hornady's online system, but it doesn't list W760 with 150gn or 174gn bullets. It's possible they might have data for it, but you might have to pay for the subscription service. Not sure Hornady will even know about the .303 wildcats though.

It might well be worth emailing Nick Harvey as he must have worked on load data for it back in the day.

If it were me I'd measure the case capacity with water, compare it to .303, and adjust the .303 data to suit.
For example, for .303 with 125gn jacketed bullets ADI list 41gn to 45gn of AR2206H.
Compare that to their .303-270 data of 31gn of AR2206H you're looking at around 70% of the .303 data (it seems like very light data to me though).
If you can find W760 data for .303 I would load a .303-270 with a 70% charge and shoot it across the chronograph to see where it stands, then work up or down from there. My experience with W748 in .303 though is that I would use magnum primers to get it to burn. Or even better, use AR2206H instead. AR2206H is also a very safe choice when you have to experiment to find your own load data for an obscure cartridge, you can start very low and work up to where you want to be. Try 20gn behind a 130gn bullet if you're apprehensive, it'll probably make around 1500fps, then increase it until the case starts stretching (assuming you're using an SMLE). If you want your brass to last I would drop back a bit from there. If you want more velocity you can keep pushing it but monitor the brass very closely as the SMLE action is rear-locking, the locking lugs are at the rear of the magazine which allows the entire bolt to compress. At some point lifting the bolt handle will get more difficult, so I would drop back a couple grains below this point.