Creating a 180gn load, .338 excalibur

[clyde09]

Howdy Gents,

Bout two years ago I acquired a Ruger No. 1B in .338 win mag reamed out for a .338 Excalibur. A ridiculous amount of power in such a small lightweight package, I love it. Ive managed to get it to shoot 1/2" groups at 100yds and began loading 180gn accubonds to see how fast I could get 'em truckin. I realize the Excalibur was created to move a 200gn projectile at 3500f/s, but the idea of having a 180 moving a few hundred f/s faster is enticing. What Ive noticed going through multiple load manuals, is the other 338 mags have a slight charge increase when loaded with a 180gn compared to the 200gn. I'm sure y'all know the limited amount of data for the Excalibur, exclusively in A-Squares Manual. Due to the lack of information, Ive been loading the 180s with the data for the 200's. I'm gettin about 3615f/s average from them and I'm pretty happy about that. However when you look at Nosler's data for the 338-378, one of their hotter loads accomplishes the same velocity when the 338-378 only moves a 200gn at 3350f/s with a max charge. I know I'm probably treading on thin ice when I ask this, but can anyone give a rough estimate of velocity within the safe rage for a 180 from the Excalibur? Would anyone with a load creator program be willing to exchange a few emails with me concerning this? Ive calculated increase percentages from similar cartridges, attempted to calculate the estimated pressure increase per grain of powder, I suppose my best bet would be to buy a windows computer and run a load creator program.... I was just wondering if there was something I overlooked before I go do that. I'm shooting from a 26" barrel, and Id prefer not to make it over 30" in length. I get that its relatively unsafe, so nailing me to the wall is not necessary.

Thanks

 

[Lefty7mmstw]

Welcome to L R H !

You've already got the big stick, so just tread lightly.... Are you getting decent brass life and easy extraction?? If so, you are likely safe in your loading. If I don't have data for a cartridge/bullet/powder combo, I watch the brass life and extraction more than actual velocity. Wishing for a velocity and getting there safely are two entirely different things.

I ask though, why aren't you looking at bigger, high b.c. pills for that 338? My #1 in 338 win has a lot of trouble getting anything over 250 grains pushed hard enough to do well. I've actually settled on 225's as a best compromise. With the reamed out chamber in your #1, you ought to do very well accuracy wise with the 300 grain pills and have better long range performance to boot.

 

[clyde09]

Thanks for the welcome and the reply,

I've only used A-Square and Quality Cartridge brass (I think Jameson is the only other manufacturer), I typically get upwards of 8 firings before the brass starts to fail, it'll stretch about .005-.007" per firing. Whether it be a factory A-Square load, a minimum charge by data or any load for that matter, its hard to extract. The only time I've experienced easy extraction was after the first firing of Quality Cartridge brass. I polish the brass after resizing, fired brass comes out of the chamber with very small abrasions all the way up to the shoulder, so I assume the chamber is still rough even after attempting to polish it up with a ball hone. I'm also seeing flattened primers from minimum charges, mild charges, and hot charges using Federal magnum match primers, and a safe ogive to lands distance. So I'm pretty dead in the water when it comes to watching for pressure sign.
As for my choice of bullet, I was looking to get some devastation within 600yds, more of a varmint load I suppose, the rifle is awful finicky with any load and anything outside that range I couldn't make a shot on with a clear conscious. I don't think the platform this cartridge is chambered in could fully take advantage of high b.c. projectiles. I will eventually re-barrel the thing, and at that point in time I'm sure I'll play with the heavier slugs.