6mm- 284 Wildcat

[CJ6]

Then there's the bolt face issue with the 30 RAR. and why not just shorten the 6.5 PRC ?

 

[Louisiana Shooter]

So after a few measuring and calculator sessions the 25MX (25-450 Bushmaster) Seems like a viable Cartridge. After measuring my BlackJacks and allowing 1.3" of room above the base of the neck. Where the XC and the Lapua are both too long for the BlackJacks in order to stay well under 2.8" OAL, if that's your goal. Taking brass from .45 down to .25 or even .244 could prove disastrous and might be better left to a Manufacturer. Now on the hunt for some 450 Bushmaster Brass. Opting for the 6mm Version allows the possibility for a shorter OAL Cartridge if that benefits your application. With slightly more boiler room than the 6mm Creedmoor the 6mm MX could possibly afford far greater accuracy due to it's short Cartridge dimensions. Hypothetically speaking it might offer greater efficiency much like the 300 WSM. If it's too long for your needs then probably 6-30 Remington AR might better fit the bill not that it's available anywhere.

Be sure to take your brass down in steps with some annealing between steps or you will not be able to neck it down without a lot of losses. At one time, someone offered a set of dies with various bushings made for the wildcatter to use in this very way. May try some research on that if it's still available, it would work fantastic for what you are wanting to do. My set has saved me a LOT of brass while experimenting with wildcats.

 

[AckleymanII]

Actually any .284 case, but with baby steps and followed with a
series of internal mandrels and lots of lube, it's not to bad. It's
more then a 10 beer job, I'll tell ya'. I just leave them 7mm and
go play.....

Yeppers, leave it to the 7mm size and go play. I shot out two 6/284's in the late 80's with long Hart barrels, 10T with 85g Sierra bthp, IMR 4831, Winchester brass, 3650 fps.

 

[B23]

All due respect, it seems like you're going through a lot of work to create something that already exists with the 6mm Creedmoor and with the Creedmoor you have your pick of, small or large primer, top shelf brass with Lapua, ADG, and Alpha.

 

[Fuj]

All due respect, it seems like you're going through a lot of work to create something that already exists with the 6mm Creedmoor and with the Creedmoor you have your pick of, small or large primer, top shelf brass with Lapua, ADG, and Alpha.

Not necessarily !! With the 284 case being wider, you can find a
point where it's more efficient. When I developed the SA284, It
was just a matter of shortening a 284 Winchester case to 7/08
length. At being able to use 3 more grains of powder, I easily
hit the upper nodes that a stock 7/08 could not reach using 180
class bullets. Short and fat cases just seem to have higher accuracy
rates, in my opinion. Good point about the small primers though.
What we need in the wild catting business is some brass manufacturers
to make short SP brass on the 284 Winchester platform. The 450
Bushmaster brass looks promising but not sure if the web is strong
enough. Bushmaster brass is only loaded to 38000 psi. May pick some
up to cut apart and test.

 

[RustyPin]

Not necessarily !! With the 284 case being wider, you can find a
point where it's more efficient. When I developed the SA284, It
was just a matter of shortening a 284 Winchester case to 7/08
length. At being able to use 3 more grains of powder, I easily
hit the upper nodes that a stock 7/08 could not reach using 180
class bullets. Short and fat cases just seem to have higher accuracy
rates, in my opinion. Good point about the small primers though.
What we need in the wild catting business is some brass manufacturers
to make short SP brass on the 284 Winchester platform. The 450
Bushmaster brass looks promising but not sure if the web is strong
enough. Bushmaster brass is only loaded to 38000 psi. May pick some
up to cut apart and test.

Yup. A true short action version of the .284 Case. Here is an illustration set up for the Blackjacks. It's slightly longer than the bushmaster though. This would offer plenty of room to chase the lands in a true short action. A shorter 6.5 PRC case would be nice as well.

 

[DaveTooley]

Be sure to take your brass down in steps with some annealing between steps or you will not be able to neck it down without a lot of losses. At one time, someone offered a set of dies with various bushings made for the wildcatter to use in this very way. May try some research on that if it's still available, it would work fantastic for what you are wanting to do. My set has saved me a LOT of brass while experimenting with wildcats.

Neil Jones made a set. They do make it easy. Pre RUM I formed a lot of 404 brass down to 7MM. I never annealed and never lost a case.
I shoot a 6MM -.100"-284. Love the round but in hindsight why not make 243 AI.

 

[AckleymanII]

For hot rods:

240 Weatherby with short freebore
6/284 CIP reamer with .050 freebore max for 87g and under bullet weights
6 Rem AI- zero to .030 freebore for 75g bullets and under
243 AI, zero freebore to .030 freebore for 75g bullets and under

6 BRX with .030 freebore for 75g bullets and under is a Magic Mac Daddy! Easy to tune, pick a powder and bullet!

I shot out a few barrels with custom 26", 12T 243 Win with zero freebore. No flies on a 80g Sierra Blitz BT at 3400 shooting tiny groups at 200 yards with IMR 4064 and Fed 210's.

 

[Fuj]

I've posted these before but here's the straight 284. my SA284
and my 284-ELF That is still in the works but has attended it's
first UBR match. Note that the ELF is about the same length
as a 6GT. I have no plans for it other then staying 7mm. Currently
I'm at 2930 fps with a 130 SMK. It shoot's to 1/4 MOA with best
being .206". Needs more tuning.

 

[B23]

but in hindsight why not make 243 AI.

And this was kind of my thinking, certainly wasn't trying to poo poo anyone's idea or creation.

For me, with there already being so many different parent cases out there to choose from that not only have the best brass available, large and small primer, but would require far less brass prep/forming, unless you just had a need to put your own stamp on something I struggle to see the point.

 

[Gabe22BR]

And this was kind of my thinking, certainly wasn't trying to poo poo anyone's idea or creation.

For me, with there already being so many different parent cases out there to choose from that not only have the best brass available, large and small primer, but would require far less brass prep/forming, unless you just had a need to put your own stamp on something I struggle to see the point.

They getting back to 6.5x47L & 6 Br variations… since the 284 has the same capacity as the 30-06… lol.

 

[B23]

It almost sounds like something that'll be nearly the same as Tubb's 6XC

 

[DaveTooley]

Everyone has their own idea of how to skin a cat. When there was only Winchester 284 brass we used 7.5X55 for a similar wildcat. Pre RUM we used RWS 404 brass to make 7,30&338's. I have a lot of reamers in the "lets try this pile" It's been my experience that capacity and brass quality are the key. Shape not that important unless the design is extreme and causes problems down stream.

 

[RustyPin]

It's all in the details, the 25mx illustration allows even the 195 7mm to be used in most short actions. Thanks for the interest. Brass ordered, now to figure out which dies to use sizing it down. Any bets on how far that neck stretches the oal?

 

[ktm571]

View attachment 1341762

A bit late joining this thread. I've been testing with a 284 case shortened to b

View attachment 1341762

A bit late joining this thread. I've also been testing with a 284 case shortened to benchrest proportions in 6mm. I call it 6 BRW (Benchrest Wide). I have a 3-step reforming die set instead of pushing the shoulder back in multiple steps in a std die. Have reformed 450 Bushmasters as well - gives you the small primer option.

 

[Fuj]

A bit late joining this thread. I've been testing with a 284 case shortened to b

A bit late joining this thread. I've also been testing with a 284 case shortened to benchrest proportions in 6mm. I call it 6 BRW (Benchrest Wide). I have a 3-step reforming die set instead of pushing the shoulder back in multiple steps in a std die. Have reformed 450 Bushmasters as well - gives you the small primer option.

Hmmmnn !! You would'nt happen to be at any of the Anderson Creek
shoot's ?? One of the guy's has a 6mm / 284 BR in the works. There is
also a person at Ridgway shooting something similar. I'll have to check
further on that this weekend.....The 284 is just a great case to work with,
with out pushing the edge to needing a magnum bolt face.

 

[alf]

 

[ktm571]

Hmmmnn !! You would'nt happen to be at any of the Anderson Creek
shoot's ?? One of the guy's has a 6mm / 284 BR in the works. There is
also a person at Ridgway shooting something similar. I'll have to check
further on that this weekend.....The 284 is just a great case to work with,
with out pushing the edge to needing a magnum bolt face.

No. That's me at Ridgway on Bucky's benc.h. See you Sunday.

 

[CJ6]

What's the specs on that Al ?

 

[alf]