Need help with rare 6.5 Ackley Magnum?

[Bob L.]

My brother in law is working on a rare wildcat and was hoping for any help with start loads, familiarity,etc. This is what we know: The barrel reads 6.5 Ackley Magnum, W.H. Hobaugh (I think that is the spelling?) The die set is from RCBS that also reads 6.5 Ackley Magnum. The case's are 300H&H Magnum. We are not sure if this is similar to the 6.5 Apex magnum. Does anyone have any data on this, or more info, or a recomended start load with 120, 129, 140 grain bullets, or a similar case that we can use as a start load? Trying to be safe on this project.
Thanks
Bob

 

[Long Time Long Ranger]

There are many variations. The one I saw the most before the 8mm rem mag case came out for necking to the now STW was a blown out 300 H&H case with the Ackley shoulder. The guys shooting it could neck and load the full length 300 H&H cartridge and it was ready for fireforming. It was similar to the 6.5-300 wby and the now 6.5 STW. I have the STW and if you used light loads for mine as starters you would be fine if this is the version you have. Good luck with it. Ballistically it can hang with any cartridge out there that will fit on a standard magnum action.

 

[gr8whyt]

Hobaugh was a barrel maker/gunsmith of some reputation in Montana (Philipsburg, I believe) in the 50s - 60s. My brother had post 64 mod 70 30-06 re-chambered to 30-338 Win Mag by Mr Hobaugh. I know that doesn't help with your situation, but the name caught my attention. I had not heard that name in a long time. Good luck with that rifle.

-- gr8whyt

 

[Bob L.]

If this helps here is the measurements on a fired case.
Overall length is 2.485 but it also has a long neck of .400, the body from the base to the shoulder is only 1.908. It is like .130 shorter than a 264 win mag case. Top of the shoulder to the base of case is 2.083.

Thanks
Bob

 

[Bob L.]

I forgot to add, This is a shortened H&H case, it is .360 shorter than a full length H&H case. The case capacity weighed 79 grains of water but that was clear to the top of the neck, and it has a long neck of .400.

 

[backwoods83]

Sounds like a 6.5x257wby imp to me, slightly more effective than a 264wm, but with the neck length it shouldn't be any harder on barrels, use 257wby data up to the 120 grainers as a start then work your way up.

 

[mdkjnk]

Are you still looking for info on this round?

 

[FEENIX]

After nearly 6 years, my WAG is that the OP has since moved on. gun)

 

[just country]

morning, if the 300HH case has been shortened. U could look at the

load for a 6.5 Rem. Mag. depending of the case length and size??

lightbulbgun)