Wildcat idea, 7mm WSSM Improved, Dasher style

[Evan]

So I've been mulling over the idea of a 7mm WSSM Improved Dasher. I was thinking something like a 25 WSSM necked up to 7mm, shoulder blown forward 0.10" and given a 40 degree shoulder. I think this might yield roughly a 55gr charge for a potential 2950fps with the 180gr in a 30" barrel.

Another thought is taking the 7mm SAUM and bumping the shoulder back 0.25" with a 40 degree shoulder. This yields the same end result but you could leave a longer neck; maybe something like 0.35" long to keep the 180 out of the boiler room and potentially extend throat life.

Any thoughts on this? Has anyone tried it?

 

[Kenny474]

I love the idea of the 7mmWSSM improved. I have thought about a 7WSSM since I first saw the WSSM line. I just have zero experience with wildcat development, so in reality I had no idea where to start. It looks good on paper, and it's a very compact powder column, so there is a chance it could work very well.

If you try it and it works well, sign me up. I would love to add one to the gun rack.

 

[oldroper]

Have you read this

http://www.accurateshooter.com/forum/index.php/topic,3556124.0.html

 

[Evan]

old roper, I just read that link you sent me. It is a good read and appears to be about the 7mm RSAUM, which is an excellent choice. I am trying to create a variant with even less boiler room. I do not want 3000+ fps due to barrel life. I only want to reach 2900-2950 with the 180s and then be able to load up some lighter loads for when I'm not shooting way out there. I have heard that the short mags like to run at near max pressure to get good accuracy and avoid problems, so less powder capacity would work nicely.

I'm thinking at first I would try this in a bench rifle to make sure the accuracy was there, and then try it in a tactical rifle. Hopefully the shorter case length would allow the bullets to be seated much further out and still work with the magazines.

 

[dan06]

The biggest drawback for wssm's is the brass is really crappy.....I have a 6.5-.243wssm in an ar-15. It shoots well but you have to sort and anneal to make it shoot. I get about the same balistics as a .260 remington with it.

 

[Kenny474]

I think you will have issues in a tactical rifle, as most are repeaters. You are talking about a really short, fat case with a 40 degree shoulder, not the best for feeding from a magazine.
I still like the idea, but think it will be best for single shot use.

 

[Forum Boss]

I only want to reach 2900-2950 with the 180s and then be able to load up some lighter loads for when I'm not shooting way out there.

What you want is do-able with a .284 Shehane, long barrel, and H4350. I may even be doable with a standard .284, long barrel, and Reloder 17.

If you want the bigger boiler room the RSAUM is worth looking at, now that Norma brass is available.

 

[A mf B]

Working on one now. Went with a 35° shoulder. Calling it the 7mm A.M.F.B Building it in a impact 737 MAG bf with a CRB 1-8 twist Barrel 28 inches. Hornady 243 WSSM brass' 180 eld-m

 

[std7mag]

Working on one now. Went with a 35° shoulder. Calling it the 7mm A.M.F.B Building it in a impact 737 MAG bf with a CRB 1-8 twist Barrel 28 inches. Hornady 243 WSSM brass' 180 eld-m

Dude!!!

That's a 15 and a half year old thread!!!

 

[A mf B]

Dude!!!

That's a 15 and a half year old thread!!!

The future is now......... ?! this is my first attempt at a wildcat just looking for information and looks like it's not a new idea

 

[Mulligan]

The future is now......... ?! this is my first attempt at a wildcat just looking for information and looks like it's not a new idea

Keep us posted as this progresses

CW

 

[A mf B]

Keep us posted as this progresses

CW

Will do. The rifle is at the gunsmith when I get it back I will definitely post results

 

[wilbur300wsm]

Hello, I’ve played with this case quite a bit over the years. I’ve opened it up to 30 cal and built 2 hunting rifles. I kept the shoulder angle untouched. Pushed a 150gr accubond 3,070’ish in a 22” barrel. Latest build is still in the 6mm but I blew the shoulder forward roughly .10” forward and went with the 35* shoulder for better mag feeding. I’m running a 105gr Berger hvld at 3,380fps in an 8tw bartlein 29”. I do feel as you open up in cal dia, you gain efficiency. Dave Kiff cut my reamers and Whidden made my dies. The one pic is the each variant with a 30br for comparison

 

[Evan]

Dude!!!

That's a 15 and a half year old thread!!!

Yikes… time sure flies, but even 15 years later I still think it’s an interesting idea but I never pursued it after starting this thread.

 

[A mf B]

Hello, I’ve played with this case quite a bit over the years. I’ve opened it up to 30 cal and built 2 hunting rifles. I kept the shoulder angle untouched. Pushed a 150gr accubond 3,070’ish in a 22” barrel. Latest build is still in the 6mm but I blew the shoulder forward roughly .10” forward and went with the 35* shoulder for better mag feeding. I’m running a 105gr Berger hvld at 3,380fps in an 8tw bartlein 29”. I do feel as you open up in cal dia, you gain efficiency. Dave Kiff cut my reamers and Whidden made my dies. The one pic is the each variant with a 30br for comparison

Thanks for the share! Now that Hornady is making 243 WSSM brass again I think it'll be a fun project and a cartridge for both PRS and possibly some F class. Won't be the best for Either but why not?

 

[jpjulian]

Where are you finding the Hornady WSSM brass? I've been looking for some .223 WSSM Hornady and can't find it.

 

[wilbur300wsm]

Thanks for the share! Now that Hornady is making 243 WSSM brass again I think it'll be a fun project and a cartridge for both PRS and possibly some F class. Won't be the best for Either but why not?

If you sort your brass by weight it’ll help. Not sure of your reamer spec, but I turn the necks down to a “normal” thickness of .015” wall and annealed then. I had both 30cal and the latest 6mm reamer made so I’d turn the neck.

 

[A mf B]

If you sort your brass by weight it’ll help. Not sure of your reamer spec, but I turn the necks down to a “normal” thickness of .015” wall and annealed then. I had both 30cal and the latest 6mm reamer made so I’d turn the neck.

Just received the K&M neck turning tools so down the rabbit hole I go the reamer neck is .32 straight my loaded round diameter is .3204 at the top and .3245 just before the shoulder.
The neck thickness at the top is .0168 and at the bottom is .0190 so I'm going to try to turn it all to .0160 when I size the brass I did it in two steps with a mandrel .2625 and then .2825 then annealed the brass.

 

[rardoin]

Yikes… time sure flies, but even 15 years later I still think it’s an interesting idea but I never pursued it after starting this thread.

Rich Sherman and friends did what you implied from your old post….pushed the 7 SAUM shoulder back around .100”, cut .075” off the neck, blew out the taper and pushed the shoulder to 40deg and called it a Sherman Short Magnum. Essentially a 6BR magnified to 7mm. It works. In ADG brass, I can push a 180 hybrid up to the mid 2900’s with N555 and not trash brass (B spec reamer/die). However, the sweet spot is around 2910-20fps in my experience. Fully formed, properly head stamped brass is also a plus. Can also get there with the 6.5/7 PRC.

 

[wilbur300wsm]

Just received the K&M neck turning tools so down the rabbit hole I go the reamer neck is .32 straight my loaded round diameter is .3204 at the top and .3245 just before the shoulder.
The neck thickness at the top is .0168 and at the bottom is .0190 so I'm going to try to turn it all to .0160 when I size the brass I did it in two steps with a mandrel .2625 and then .2825 then annealed the brass.

For clarification, are you annealing before you turn the necks? It seems to go a little better if you do.