Wildcatting the 6.5 rpm

[surfr716]

So after my first antelope hunt I'm absolutely hooked, so much so I've decided to build a new rifle for the task. While my 6.5 PRC is plenty up to knocking down a speed goat ive always had a soft spot for the quarter bore.

My original plan was to build a 257 weatherby but I hate magnum belts so I started looking at more modern cases with similar powder capacity. My first thought was to neck down the 7 prc and go but my buddy and I got to talking and after looking at case capacity it's within 1.5 gr. Of h2o of the big weatherby case and fits standard actions and bolt faces. So now we're looking at having prg build us a 25x6.5 rpm reamer. I also debated the 25-06 ai but I really don't have much love for fireforming brass if it can be avoided.

My question is has anyone experimented with similar or for that matter wildcatting this cartridge at all? My plan is to run the 115-134 gr projectiles in the 25. Any feedback is welcome

 

[A382DWDZQ]

I think I’d go with something that has a better chance of long term brass availability. There’s some other big 25s that have been done, 257 Banshee, that didn’t really take off, so it would be worth researching why and what could improve on that work that was already done. I think there probably are some opportunities that didn’t previously exist with powder and bullets.

 

[Nbowlin]

I have been pondering that exact same thing for quite awhile. Impatience got the better of me and I ended up with a 25 sherman reamer. A slightly improved 280 ackley. 24" 134 @ 3300fps. They should be pretty similar with the rpm having a bit more room in it.

 

[eLightfoot]

Pretty sure a guy on long range hunting (swampy) has or was building this exact wildcat. Problem is weatherby brass, it’s soft and way overpriced. I’m thinking a 25-6.5prc improved is worthy

 

[Nbowlin]

adg or peterson makes rpm brass. cant recall which but one of them does

 

[sndmn11]

Peterson

 

[surfr716]

Pretty sure a guy on long range hunting (swampy) has or was building this exact wildcat. Problem is weatherby brass, it’s soft and way overpriced. I’m thinking a 25-6.5prc improved is worthy

The 6.5 just doesn't have the capacity I'm looking for. Thought about using the 7 prc as the parent but even it's behind the rpm. My other thought was WSM brass, powder capacity is within spitting distance of the 257 weatherby and in a short action case having a long action donor it made sense to use it. Ill order up enough Peterson brass to last the barrel life and go from there I reckon.

 

[surfr716]

Buddy made up a dummy round, using a 131, to send in to ptg. Looks pretty promising as a modernized 257 weatherby

 

[Nbowlin]

The 6.5 just doesn't have the capacity I'm looking for. Thought about using the 7 prc as the parent but even it's behind the rpm. My other thought was WSM brass, powder capacity is within spitting distance of the 257 weatherby and in a short action case having a long action donor it made sense to use it. Ill order up enough Peterson brass to last the barrel life and go from there I reckon.

fwiw Ive done 4 6.5 7wsm's and they are 5-600 and out on the barrels. I would venture necking down would only hasten this problem, but I will continue doing it cause its impressive and i like it. I did a 25 saum on a 22" barrel and a walmart safe 3100 with the any of the three 131, 134, 135 was achieved. Much easier than the 25 cal varient of the 6.5 sherman (280 ackley brass based).

 

[HingleMcCringleberry]

A 6mm rpm is intriguing. Wonder how much faster it would be over a creedmoor?

 

[AZ_Hunter]

I know this thread is old, but any updates on this? I was having the exact same thought 25-6.5RPM for the same reason: 257Bee in modern case with std bolt face.

 

[surfr716]

My buddy ended up getting the reamer made but hasn't done anything with it. I wound up building a 25x7prc, I liked the brass availability and 3350 with a 133 is plenty fast for me. Haven't shot any animals with it yet but I'm liking the groups so far.