Any loading data for a 6-300WSM aka 6WSM?

[Idaho CTD]

I was bored and had a reamer from years ago so I built one this weekend. I barely got to shoot it before dark last night to get it on paper at 25yds. I loaded 60 to 64grs of H5010 in 1 grain increments and then loaded 5 at 65 and 5 at 66grs. The first shot was 60grs and it was pretty mild so I jumped right to 65grs. Then I shot a 3 shot group at 25yds with 65grs just because I could barely see the target at 25yds and I knew it would be pointless to try 100yds. It shot in the .1's which was no small feat since I could barely tell where the crosshairs were. It was too dark to get a reading from the chronograph also. Hopefully I'll get another chance tomorrow to see what this load is doing. Any help on loading data would be helpful.

 

[BK7saum]

Re: Any loading data for a 6-300WSM aka 6WSM?

I'd like to see the chrono on data for this one. What bullet are you loading? 105s or 115s. For the lighter weights, I'm not sure you'd see much advantage over a 6-284, even with a longer barrel

 

[Idaho CTD]

Re: Any loading data for a 6-300WSM aka 6WSM?

It's a 29" long 8" twist 1.25" straight barrel with one of my 5 port muzzle brakes. So it kicks like a .22. It's also got a 1 1/2oz Jewell trigger and a Leupold VX3 LR 6.5x20x40 and a single shot Remington short action. I loaded 105 Amax's in it because tipped bullets (Nosler BT's and AB's as well) tend to hold up better to extreme RPM's and velocity better than match bullets.

I'm sure it won't be greatly faster than a 6-284 (the land of diminishing returns thing) but it should be a bit faster. It should come close to a 6mm Mach 4 or .240 Incinerator. Once I get the loads worked out I'm going to water jug test a few bullets. I may end up shooting 90gr AB's or Barnes TSX's just so they stay together. I have a antelope hunt in WY next month I'd like to take it along for.

 

[BK7saum]

Re: Any loading data for a 6-300WSM aka 6WSM?

Sounds like it'll be a laser. My cousin at one time wanted to build a .240 Incinerator. He planned on having an .243 encore barrel reamed, but I don't think he ever did.

I really like the 105 amax's in my 6x47L. They are only running about 2950, but they are plenty accurate. I got enough to burn out my barrel a couple times over when they were sold as blems for $10 a box. I tried 105 bergers and 88 FB Bergers, but the amax's shot as good or better. Plus I've had better luck with the amax's on game.

Good luck with your antelope hunt. Three of us are hunting speed goats in Wyoming this year as well.

 

[Idaho CTD]

Re: Any loading data for a 6-300WSM aka 6WSM?

I did shoot it this morning. I shot a 3 shot group with 65grs of H5010 and it was about 5/8" and 3275fps. Then I did a latter test with 60-66grs of Retumbo. 60-63grs (4 shots) went into just over 1/2" and 61-63grs went into 3/8". The velocity was 3274 to 3378 for the 4 shots. 64grs jumped 100fps to 3476 and went an inch or so higher. 65grs went 3482 and 66grs went 3580. So 64grs is probably the max I'd want to shoot but I would lean towards 63grs just for the sake of accuracy. The dilemma is weather or not it is worth keeping. I have 2 .243AI's. One is a rechambered factory barrel that will shoot 5 shots under 1/2" and the other is a 30" Bartlein that shoots 5 in 1/4". The Bartlein will shoot 105's at 3300fps with 10-15grs less powder. So if I shot where I think the accuracy will be (63grs) the velocity is only around 75fps faster than my .243AI.