257 RPM

[huntinfool18]

I finally got a scope on my 257 and put a few rounds down range. I did a really quick pressure test a couple weeks ago with staball hd powder and 134eld. Took it up to 71grs and 3370fps. For this trip i didn't do anything special loaded 69gr of staball hd with a 134 at the lands no other load work done.
First 3 shots with a scope on are the black target on once fired brass, average 3255fps
After letting the barrel cool and a couple clicks on the scope I fired 1 shot to confirm zero then dialed up 1moa and set the rifle aside while I shot my 7 mag. Next 3shots in the square. Had to let the rifle cool and take a pic. Couldn't leave well enough alone so I fired 2 more. Of course I had to mess it up. It was all me. I'm sure it would have been in the group as well. Gun went off right when a gust of wind came up. This was virgin brass with the same load as above. 69gr staball hd and a 134 at the lands. Was only 5 fps slower then the once fired brass at 3250fps. Pretty impressed with the rifle so far.

 

[FEENIX]

I finally got a scope on my 257 and put a few rounds down range. I did a really quick pressure test a couple weeks ago with staball hd powder and 134eld. Took it up to 71grs and 3370fps. For this trip i didn't do anything special loaded 69gr of staball hd with a 134 at the lands no other load work done.
First 3 shots with a scope on are the black target on once fired brass, average 3255fps
After letting the barrel cool and a couple clicks on the scope I fired 1 shot to confirm zero then dialed up 1moa and set the rifle aside while I shot my 7 mag. Next 3shots in the square. Had to let the rifle cool and take a pic. Couldn't leave well enough alone so I fired 2 more. Of course I had to mess it up. It was all me. I'm sure it would have been in the group as well. Gun went off right when a gust of wind came up. This was virgin brass with the same load as above. 69gr staball hd and a 134 at the lands. Was only 5 fps slower then the once fired brass at 3250fps. Pretty impressed with the rifle so far.

Cool! Rifle specs?

 

[huntinfool18]

Defiance classic, 26" helix 6 barrel, 7twist. McMillan game stalker. Trigger tech. Vortex pst gen 2 3-15 for now.

 

[FEENIX]

Defiance classic, 26" helix 6 barrel, 7twist. McMillan game stalker. Trigger tech. Vortex pst gen 2 3-15 for now.

Sweet!

 

[MagnumManiac]

Nice build, love 25 cal.

Cheers.

 

[RYEWSKY25284]

I finally got a scope on my 257 and put a few rounds down range. I did a really quick pressure test a couple weeks ago with staball hd powder and 134eld. Took it up to 71grs and 3370fps. For this trip i didn't do anything special loaded 69gr of staball hd with a 134 at the lands no other load work done.
First 3 shots with a scope on are the black target on once fired brass, average 3255fps
After letting the barrel cool and a couple clicks on the scope I fired 1 shot to confirm zero then dialed up 1moa and set the rifle aside while I shot my 7 mag. Next 3shots in the square. Had to let the rifle cool and take a pic. Couldn't leave well enough alone so I fired 2 more. Of course I had to mess it up. It was all me. I'm sure it would have been in the group as well. Gun went off right when a gust of wind came up. This was virgin brass with the same load as above. 69gr staball hd and a 134 at the lands. Was only 5 fps slower then the once fired brass at 3250fps. Pretty impressed with the rifle so far.

Gotta love them quarter bores.

 

[huntinfool18]

For you numbers nerds, that's 1800fps and 1000ft lbs energy at 1400yds.
And to think I was going to sell this barrel a few weeks ago

 

[K.E.C. Darkside]

Very Nice, I like any Wildcat.
Everything looks real good.

 

[FEENIX]

For you numbers nerds, that's 1800fps and 1000ft lbs energy at 1400yds.
And to think I was going to sell this barrel a few weeks ago

At my altitude (3300'), with your info, 3250 FPS G7=.325, I was calculating:
1400Y = 1631 FPS/792 FT-LBS. I must be doing something wrong. It is still no slouch, though.

I considered building a .25 cal wildcat out of the RPM in 2021, but I could not secure enough brass then, so I abandoned it and went with the .257 WBY instead.

My .257 WBY propels the 145 Black Hole (G7=.371) at 3090 FPS out of a 22" barrel during my powder pressure test with more room to spare. 1400Y = 1684 FPS/913 FT-LBS.