6.5-300 WTHBY.

[magshooter]

Does anyone here have any experience with the 6.5-300 WTHBY. or 6.5 WWH I have read the articles in Wilcat cartrige book and P.O. Ackley book, and am aware of the questionable reloading data available, just wondering if anyone here had actualy dealt with it 1st hand Thanks....Sarge

 

[ballpowder]

While not exactly the same cartridge I have and love a 6.5 STW. It has a different shoulder and only holds one grain more powder. My rifle is a lightweight and is a little picky. I have tried a few powders and bullet combos now and have much more planned.
It depends if you can live with single shot or need mag length. The best load I have right now is 86gr WC872 and a 140gr AMAX. RL25 works great with 120gr bullets and Retumbo is my goto with 130-140gr hunting bullets. I have yet to try US869 though I am sitting on a pound.
H50bmg has been trouble with any load that is compressed and even some that are not. I believe I'm dealing with powder bridging at the neck and pressures shoot way out of control. When I pull the bullets the powder has to be dug out with an ice pick.
My latest experiments are with 107gr Sierra matchkings. About 75-76 grs H4831 shoots good and I plan to work up from 78gr of h1000 next.
Also IMR7828 is a good one but to get both accuracy and velocity of WC872 primer pockets are junk in two uses so I selved it for now.
I hope some other users jump in.

Tim

 

[magshooter]

Great reply, I forgot about the 6.5 Westerner I should have included that in my initial thread since they are so alike.
Mag length is more important than FPS in this rifle as I plan on hunting with it.
What powder gave best velocity?
What powder gave best accuracy.
What about barrel life?

Thanks....Sarge

 

[ballpowder]

Sarge I really haven't do too much chronographing just because in the begining I usually just focus on best groups and primer looks/case extraction. Some loads I have clocked are as follows:
120gr TTXS & 75.5gr RL 25= 3620fps accuracy at 75grs
129gr Interbond & 88grs WC872=3555fps
129gr Interbond & 74grs IMR7828=3499fps Too Hot
123gr Sierramatchking & 73grs H4831=3375fps Very mild
Like I said I've tested other powders and other bullets w/o chrono. I'm guessing that the Retumbo and WC872 loads with 140gr bullets top out around 3400fps safely and reliably.
Now accuracy Retumbo knocks out 1/2" to 5/8" groups at times and the WC872 has gave me two in the 3's but other wise good solid 3/4" to an 1" over the spectrum and that really is impressive for a #1 contour barrel dont you think? The RL25 load with the Barnes bullet is a 5/8" hunting load too. So far I have 147 rounds on the barrel. Cleans up nice, we'll see how long it lasts. Tim

 

[ChrisNZ]

...So far I have 147 rounds on the barrel...

I suspect you may well have used up 1/4 of your barrel life already. That's a heap of powder down a small hole..

Keep us updated

Chris-NZ

 

[magshooter]

Good stuff Tim, that is some vital info.
That is a good shootin barrel even if it were a magnum contour.
Who makes the barrel and what twist is it , who was the riflesmith.
I built a 7STW in 1990 , I used a MK X action and a Douglas barrel 1-10 twist 26'' mag contour , it shot like a house on fire I shot plenty of deer with it and shot 63 ground hogs with it one year I finaly burnt it up around 2005 and even then it would hold 1 1/4 that was after a couple thousand rounds , almost no brass loss. I had it rebarreled to 7mm Ultra and enjoy it 1/2 as mutch. I missed the 7STW so mutch I went out and got a NIB Mod. 70 7STW. Thanks for the information if you do any further load development please pass it on, thanks.....Sarge