The .257 Marksman (25 western)

[WKR]

I wonder how likely it is for Winchester to come out with this round from the factory? Seems like the 257 bore is gaining popularity again and there should be a market for a fast twist 257 magnum.

Doubtful at best. Too overbore and "modern" for a company like Winchester. I'm sure they thought about it when they developed the 6.8 western case but someone talked them out of it.

 

[SloppyJ]

18" Benchmark is born

 

[SloppyJ]

Ill be ready for testing when ADG drops their latest run here shortly. Huge shout out to WKR. Super cool dude that was more than helpful putting all of this together for me. He even gave me all the hard lessons learned getting the brass necked down and some preliminary load data. Stand up guy for sure and did everything he said he would. I appreciate it man. Im still not sure who's more excited about this one, me or him.

She's living in the manners until I order a McMillan mountain tracker LR. Will be topped with a 4x32 NX8. Preece precision chambered the barrel and did a fantastic job.

Weighs 8lbs as shown with mag, Scythe, and cover. The new stock should shave a bit off that.

 

[gerry35]

Ill be ready for testing when ADG drops their latest run here shortly. Huge shout out to WKR. Super cool dude that was more than helpful putting all of this together for me. He even gave me all the hard lessons learned getting the brass necked down and some preliminary load data. Stand up guy for sure and did everything he said he would. I appreciate it man. Im still not sure who's more excited about this one, me or him.

She's living in the manners until I order a McMillan mountain tracker LR. Will be topped with a 4x32 NX8. Preece precision chambered the barrel and did a fantastic job.

Weighs 8lbs as shown with mag, Scythe, and cover. The new stock should shave a bit off that.

Awesome gun SloppyJ, even better that the bolt is on the proper side! Shout out to @WKR for helping another guy out, great to see.

 

[SloppyJ]

Awesome gun SloppyJ, even better that the bolt is on the proper side! Shout out to @WKR for helping another guy out, great to see.

Appreciate it man! Once I finally caved in and got proper left handed rifles I had to transition everything to that. So much nicer to not fight it.

 

[gerry35]

Appreciate it man! Once I finally caved in and got proper left handed rifles I had to transition everything to that. So much nicer to not fight it.

It sure is and safer too. I had a primer blow once on a RH Ruger 77 and got some debris in my left eye. Learned a valuable lesson that day.

Going to watch your load development and see how you do. I have a 6.8 Western but I find the 25's really interesting. The 257 Marksman wildcat is very cool and definitely has my interest.

 

[SloppyJ]

It sure is and safer too. I had a primer blow once on a RH Ruger 77 and got some debris in my left eye. Learned a valuable lesson that day.

Going to watch your load development and see how you do. I have a 6.8 Western but I find the 25's really interesting. The 257 Marksman wildcat is very cool and definitely has my interest.

Get in on it! I happen to know a guy who will hook you up with a reamer!

 

[SloppyJ]

My first time doing any sort of wildcat. Huge thank you to WKR. He helped me out more than he had to and even sold me an extra barrel he had and sent me a few boxes of ADG brass he had coming in on order. Solid guy to say the least.

Step one - Neck down with neck sizing die
Step two - FL size with 25 cal bushing
Step three - Mandrel
Step four - Trim (not needed), chamfer, deburr

Running 21st century neck sizing die and mandrel die. Redding type s FL sizing die and micrometer seating die with short 25cal VLD stem and redding bushings.

Loading up H1000 and Retumbo under some Berger 135s to find pressure and start getting this thing broke in. Updates to follow next weekend.

 

[SloppyJ]

I was able to get out today and run a ladder test on Retumbo and H1000 with the 135 Bergers on my 18" benchmark barrel. Results are below.

On a side note I can confidently say I'm the first person to blow a scythe apart with this cartridge!

I believe i can hit my 3150fps goal around 66gr of Retumbo once the barrel breaks in. 67 was pressure with a stiff bolt lift and 66.5 was pretty spicy as well.

The 66.5 H1000 was when then can blew apart so I doubt it's accurate.

Something went on with the 66 through 67 retumbo loads. Not sure if I recorded it incorrectly or what but I will retest.