Bringing my 300 Wea Mag out of mothballs

A/1-61

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Jul 30, 2023
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Massachusetts
In a recent post, I related my desire to rebarrel my 7 mm STW. After much deliberation, I decided not to change the barrel contour but to put a new diamond fluted bull barrel on my Remington action, shortening it to 24 in, with a twist of 1-8 and adding a muzzle brake, holes on sides and top only. Presently, My STW is at Hart Barrels getting that work done. Hopefully 8 to 9 months which leaves me no time to test my existing load or work up a new one for the fall hunting season.
Therefore, I have decided to take my 300 weatherby mag out of mothballs and it is now my winter project for my Utah hunt this year. I bought it in 1986 and used it out west, during 3 yearly hunts over the next 10 years into the mid-90s and it has been rarely taken to the range and not hunted with since then. I don't believe I have put 200 rounds through it. I have just ordered a Timney trigger for it and expect it next week, my first. I have always used Jewells.
My question now, revolves around working up a load for long range, out to a thousand yards. The last few years I have been kind of stuck on Hornady bullets, and I am leaning towards a 200 grain eld /x, but the 212 grain is also interesting. I am completely up in the air on powder. In the '80s I used mainly H,4831 and Sierra 200 grain bullets with decent results and briefly, 7828 with no good success. My goal is somewhere around 2900 to 3,000 FPS , maybe slightly less.

Does anyone have any input on a tried and true load they may have used?
 
I think the 212 or 220 eldx should be worth a try, or similarly heavy bergers, Nosler AB or ABLR, or slightly lighter monos if so inclined. Unless using a mono, I think any .30 mag should usually stick with above 200 grain bullets. Of course recoil could be a factor and of course barrel pickiness could be another.

I get over 2900 with 212 eldx out of my 300wm, so you ought to be able to do a bit better than that. I've used Retumbo, H1000, and IMR4350 with good velocity in my win mag. I couldn't get my hands on RL22, 23, or 26, so those would be other options to try. Plenty of ways to skin a cat these days with the challenges of finding a lot of these things.
 
In my "modern" Weatherby's 300, One Japanese like yours and one US, I have only used 200 AB and Partition with RL22. I had goo luck, but I dont have the velocities. I have not gone heavier, didnt need to at the time.
 
In my "modern" Weatherby's 300, One Japanese like yours and one US, I have only used 200 AB and Partition with RL22. I had goo luck, but I dont have the velocities. I have not gone heavier, didnt need to at the time.
There's a lot of freebore on weatherbys creating a long jump. I used to load back in the 80s to just barely fit in the magazine for better accuracy 3.573. You can go longer but then you have a single shot rifle.
 
Update: I've tried several powders in my 300 Wea over the past few weeks. H4831 was a bust. Terrible groups and pressure signs under 2800 fps. I went looking for Retumbo but could only find an 8lb canister for $440. A lot of dough to spend on an untested result. So I tried H1000. I had good results with loads between 80.5 and 81.5 with a node at 81 grns - 1/2 moa group with 3008 fps velocity. Pressure signs showed up at 82. I think I've found my load. Thanks for the input.
 
Update: I've tried several powders in my 300 Wea over the past few weeks. H4831 was a bust. Terrible groups and pressure signs under 2800 fps. I went looking for Retumbo but could only find an 8lb canister for $440. A lot of dough to spend on an untested result. So I tried H1000. I had good results with loads between 80.5 and 81.5 with a node at 81 grns - 1/2 moa group with 3008 fps velocity. Pressure signs showed up at 82. I think I've found my load. Thanks for the input.
And btw, I'm using a 212 ELD X
 
What about this…just for fun?
IMG_0497.jpeg
 
What about this…just for fun?
View attachment 549472
A word of caution when using Barnes data. Note that the O.A.L. for both TSX and TTSX is the same, yet the TTSX is much longer. Might end up with a locked up bolt. I tried to talk to Barnes about it, they insist they are right. Experience tells me they are NOT!
 
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