.257 wildcat build

[AZShooter]

Thought you might like to know, there is a new source for 284 win brass. Norma now makes it for Bullets.com. It is supposed to be built to higher standards. It is reported that the primer pockets stay tight longer.

Norma to Make 6mm Dasher and .284 Win Brass for Bullets.com « Daily Bulletin

I have owned the 6mm-284, 25-284 and the original 284 win. IMO the 284 is the only one that might require the use of a long action. In my experience Remington short actions often require some minor alterations to feed the 35 degree shoulder properly. This is not the situation if a SA Ruger M77 tang safety is used. They feed the 284 or its offspring fast or slow with perfection. If a longer magazine is desired there is room to alter the factory mag box. My gunsmith lengthened both of my SA Rugers to 3.1"

As for reamers I talk to PT & G about some details, then sent them a dummy round with instructions on where I wanted the throat. To date I have six reamers that are exactly what I wanted. My friend Dan has eleven. We have had zero issues with PT & G.

 

[Welderboy11972]

Trying to get things together. I think it would be easier for me to make dummy rounds to send to get my reamers. Redding has setting & FL dies for both cal. I'm thinking that the 25/284 FL die will be ok to neck down the 6.5/284 brass. As for the 25/300 saum, would it be best to order redding neck die with the bushings in the 300 saum and put a 257 bushing in it. I don't think the 25/300 saum FL die will neck the 300 saum brass down that far without issues.

I need to start ordering things, and don't want to put my cart in front of my horse.

Thanks AZ shooter, I was just getting ready to order some brass to make dummy rounds.

 

[elkaholic]

Hey guys, I've got a few questions about a 25 cal wildcat build.

I've been reloading for about a year for 3 factory rifles. ( 2 25-06 & 300rum) I feel like I'm ready for my first custom build. I'm a big fan of the quarter bores. I was thinking of a 300 win mag necked down to 25. I was looking around on the net for barrels, brass, dies and so on. I happened across a set of redding 25-300 saum dies at a really good price and that got some wheels turning in my head.

Is a 25-300 saum a good idea or is it just way to over bore?
Would 25- 300 win mag be a better idea?

I did a search and only came up with 2 posts on the 25-300 saum.

Any advice on this would be great, thanks

If you want to buy a reamer, I can set you up with a 25 SS that would likely exceed 3400' with 120's in a true short action and would not be too bad on barrels.....Rich

 

[AZShooter]

You can use a seater die to partially reduce the neck before going with the final FL or bushing die.

Not sure how well a series of bushing dies will work in necking down from 300 to 25. There is a tendency for the case mouth to hang up on the entrance of the bushing. Too bad Redding doesn't offer those bushings with one side tapered.

You could start by running the 300 SAUM brass into the 300 SAUM FL die without the sizer ball. Then try the 25 SAUM seater die ands follow up with your final 25-300 SAUM die. It might work.

I once made a die for making 284 win brass into 6mm-284. I used the 6mm-284 reamer to make a form die then enlarged the neck area with some emery cloth. It worked quite well as the in between step.

 

[Welderboy11972]

AZshooter, could I talk my redding bushing and have it machined out with the taper you talking about. Then I could use it to set the shoulders back, instead of having to FL size everytime.

Look over my rough drawing. It was just a quick sketch of what I'm thinking.

 

[Edd]

If I was building a .257 SAUM, I wouldn't start with 300 SAUM brass. I would start with 6.5-4s brass from GAP. Even 7mm SAUM brass would be a better starting point than the 30 caliber stuff.

If you are going to use Defiance XM actions instead of short actions, you could build something a little less boring than a 25-284 or a 25 SAUM. Something like a 25-7mm Blaser.

 

[Welderboy11972]

If you want to buy a reamer, I can set you up with a 25 SS that would likely exceed 3400' with 120's in a true short action and would not be too bad on barrels.....Rich

25 SS??...I don't know the cal but it might be something that I'm interested in.

Edd, the 7mm saum case are a little different size then the 300 saum. The 7mm being longer. ( I'm thinking it's the necks longer) I don't know if the case body's are the same. Is this something that can be fixed with trimming and fire forming. I looked on GAP site and they are out of stock on their brass.

 

[elkaholic]

25 SS??...I don't know the cal but it might be something that I'm interested in.

Edd, the 7mm saum case are a little different size then the 300 saum. The 7mm being longer. ( I'm thinking it's the necks longer) I don't know if the case body's are the same. Is this something that can be fixed with trimming and fire forming. I looked on GAP site and they are out of stock on their brass.

The SS case is based on the SAUM but is shorter and more efficient. It will outperform the saum and/or gap. We get 3300' with 140's in a 26" barrel. It has a long neck and 40 degree shoulder. I make brass for it out of 7 SAUM which would be easy to neck down to 25. Several of the guys on the forum have built 6.5 SS, and there are also 270, and 7 SS built. The 25 SS would be exactly like this only necked to 25......Rich
View attachment 270 SS_165 Matrix-5-2.pdf

 

[Welderboy11972]

The SS case is based on the SAUM but is shorter and more efficient. It will outperform the saum and/or gap. We get 3300' with 140's in a 26" barrel. It has a long neck and 40 degree shoulder. I make brass for it out of 7 SAUM which would be easy to neck down to 25. Several of the guys on the forum have built 6.5 SS, and there are also 270, and 7 SS built. The 25 SS would be exactly like this only necked to 25......Rich
View attachment 56517

That's almost exactly what I was looking for. Thank you

 

[elkaholic]

That's almost exactly what I was looking for. Thank you

This would be a LOT easier on barrels and probably would be very close to the velocity you would get from a WM necked down.......Rich

 

[Welderboy11972]

This would be a LOT easier on barrels and probably would be very close to the velocity you would get from a WM necked down.......Rich

Thank you again, any information you could give me on this would be greatly appreciated.

 

[Rich Coyle]

The SS case is based on the SAUM but is shorter and more efficient. It will outperform the saum and/or gap. We get 3300' with 140's in a 26" barrel. It has a long neck and 40 degree shoulder. I make brass for it out of 7 SAUM which would be easy to neck down to 25. Several of the guys on the forum have built 6.5 SS, and there are also 270, and 7 SS built. The 25 SS would be exactly like this only necked to 25......Rich
View attachment 56517

What's the case capacity? You are matching .264 Win Mag velocity with a 140 going 3,300 feet per second.

 

[CopperBasin]

The .257 AI is a very efficient option you might consider.

 

[elkaholic]

What's the case capacity? You are matching .264 Win Mag velocity with a 140 going 3,300 feet per second.

Yes it does! Capacity is 71 grains of water depending on case lot......Rich