Need help, 300 Shannon???

[yorker]

Hey guys,

Picked up a rifle built by Jerry Shannon out of WA years ago, it is a 300 Shannon which is a 300 weatherby with the radius shoulders gone and more like a typical 270 angle or something. If anyone knows anything about this cartridge or someone who does I would love some advice about starting loads to see how it shoots with something like H1000. there is piece of paper that came with the gun that says 78.5 gr of imr 4350???

I do have the specs from c&h for the dies that came with it.

Thanks
Earl

 

[Lefty7mmstw]

Hey guys,

Picked up a rifle built by Jerry Shannon out of WA years ago, it is a 300 Shannon which is a 300 weatherby with the radius shoulders gone and more like a typical 270 angle or something. If anyone knows anything about this cartridge or someone who does I would love some advice about starting loads to see how it shoots with something like H1000. there is piece of paper that came with the gun that says 78.5 gr of imr 4350???

I do have the specs from c&h for the dies that came with it.

Thanks
Earl

How does the case capacity compare with that of the 300 roy?? If it's close, I'd start 10% down from roy data and work into it. The biggest thing you need to worry about here is volume; if you are really close to a book round (as it sounds like you are) starting low and playing cautiously using a chrono should yield good data.
What bullet weight was the 4350 load for???? It would seem to be a rather stout load as hodgdon shows about 73 grain I4350 with a 180 depending on brand. Even the older hodgdon #26 manual only shows another grain using crusher data before the roy had a pressure limit.

 

[yorker]

Thanks for the reply. 180 gr bullet, and yes I thought the same thing.

Tried to attach the schematic so people could see, not sure if it worked.

Earl

 

[Lefty7mmstw]

looks to be around a 30 degree shoulder angle on your round from your numbers hazarding a guess. I'd say roy data would work but you need to take a look at the free-bore too considering the recommended charge. roy's have a good bit, but if they were running the charge weight 4350 you say they were, they had to either have a slow twist barrel or a hell of a throat; possibly both.

In any case, a normal length barrel without an abnormal throat or twist should net around 3200 fps with a 180 if you get a powder like rl22/rl25 or h1000 in it and fill her up well. I'd beg/borrow/steal a chrono and start low in the roy data working to the 3200 fps mark and call it a day. You'll be doing well and still safe.

 

[yorker]

Thanks for the advice,

I will be doing just that probably start with H1000., oh yeah, 1-10 twist

Thanks
Earl

 

[Lefty7mmstw]

Thanks for the advice,

I will be doing just that probably start with H1000., oh yeah, 1-10 twist

Thanks
Earl

you're welcome.


Have a good one Yorker. Should be a fun challenge for you. PM me if you've got ?'s if you want. I work with mil-surp powders a good bit so I'm used to going where there isn't data.