243 Improved cases

[Rtheurer]

OK Fellas I know I saw a 243 Improved Case on this site with a 6BR shoulder and something like .320 NK length. For the life of me I cant find it again. I was thinking about this case for awhile & would like to take a closer look at it. Any info would be great. My intent for it will to be a Long range prone gun, shooting 115 DTAC hopefully around 3000FPS. Any help on this case would be appreciated.

RussT

 

[Cheechako]

Russ

It's called the Super BR. The 40 degree version is the 6mm LSI. Neck length is closer to .350" Usually made from Lapua 243 brass. You'll find cartridges along these same lines at just about every case length from 1.5 to 2.2 inches. This area of wildcatting has just about run its course thanks to the new Lapua and Swiss 47mm cases.

Ray

 

[Cheechako]

Maybe this was the photo? The Super BR isn't shown here but many of the others are.

Ray

 

[jadams]

Russ:
Ray will be saying " not another .243 Improved " !

A couple of years ago I requested from Dave Kiff of Pacific Tool that he make me a reamer based on the 6mmBR. Norma print using the full lenght .243 Lapua case. We call it the .243BR-K. , The K is for Kiff )
I chose to keep the shoulder angle at 30º so that it would use std. 6BR. neck/shoulder dies also the std. 6BR. seating dies. It does require a custom full length sizing die though. Hornady Mfg. has the specs. on file and can supply the full length die for use with bushings., Lonnie at Hornady )
The reamer is a no turn at .274". My barrel is a 30" Kreiger 1 in 8.5". I use 44.0 gns. plus of Re-22 to load a 105 Bergers between about 3150 to 3265 depending on the load. If I didn't have both a new .22 Dasher and a new .22 x 47 lapua to play with
it would be my 600 yard gun of choice
, I supplyed samples to your moderator about a year ago )
John

 

[Cheechako]

Russ:
Ray will be saying " not another .243 Improved " !
John

John - Not me. I'll never say that. I'm a certifiable wildcatter who thinks the more the better. What I meant was that there aren't many wildcats left that can be based on the 243 case but I expect to see the Lapua and Swiss 47mm brass wildcatted a lot. Looks like you've already started.

Ray

 

[Rtheurer]

John & Ray

Thank you Very much for the info. 243BR-k is very intresting. Tell me a little aobut case forming proccess & what you have experienced with loading for this case. I was thinking this is the way i would like to go. Here is what im looking for

1. use of 243 Lapua Brass
2. longer neck than 243 winchester
3. use of mostly available dies.,not reinventing the wheel)
4. 32 to 35 deg shoulder
5. hopefully longer Barrel life than the 6.5X284 that Im currently using with the same performance.

This is a tall order I think, If you all could tell me if im heading in the right direction or your thoughts on what im trying to accomplish I would like appreciate any thing you could shed some light on for me.

Alex Sitman has a order for a prone stock & I will be picking my Stiller Predator action today. Barrel should be here in a month or so. I like the fact that Dave Kiff has a print made & Hornady has the print for a sizing die.

Thanks again this really helps you guys are the best.

Sincerly Russ T

 

[ROCKJAG4]

OOPS. ISN'T THE 243BR-K THE SAME AS THE "243 MIDDLESTAT THAT WAS DEVELOPED WAY BACK WHEN..FER SHURE IT IS ..FULL LENGTH 243 CASE WITH A 30 DEGREE SHOLDER.NOTHING IS NEW.JUST REBORN...

 

[Cheechako]

Rock

Are you sure you're not thinking of the 22/243 Middledtead? That's the 243 necked down with a 30 degree shoulder pushed back to create a longer neck.

OTOH, the 240 Page is the original Super BR. Page took some Arsenal brass,7.62x51) necked it down to .243, and pushed a 30 degree shoulder back creating a longer neck. This was before the 308 W and 243 W were introduced.

But, as you say, "Nothing is new."

Ray

 

[Raptor]

Rtheurer,
Isn't this the same case Robert came up with, the 6MMSuperX?? You use a 6XC die and a .120 shim under the die and run a 243 case into it and you now have a 243 case with the 6BR or 6XC neck and shoulder.

I have one an it shoots great!!! Like you, I wanted a longer neck on a 243 with a 30 degree shoulder. I feel this gives you better throat and barrel life. I had a 6XC but I wanted to use the slower powders for better barrel life and the BR and XC cases are just a tad small for the slower powders.

When Robert came up with the 243 case and a longer neck and a 30 degree shoulder it was a dream come true. I just use a .120 shim under my 6XC die and run the case into it with some imperal sizing wax and I have a case. Just that easy.

Fire forming the case is nice because the gun shoots just as well as when your using a formed case. I am using H1000 and it shoots just great for me. I am really happy that it likes the H1000 load because its really a slow burning powder and fills the case up nicely.

N160, 560, H4831,H4350 also shoot well in this case. You can push them faster than I am but I like how its shooting and will be using if for a tactical rifle and @ 3000+ fps with the 105s it does all I need it to do. Its shoots 3 shot groups at 400yds from .75 to 1.7" and thats shooting off the hood of my pick up with sand bags.

 

[Rtheurer]

Raptor:

If you take a peek at the Date you will notice I asked this back in 2006. Since then I have chambered the 6mm Super X and have tested just about every powder and bullet Combo known to man. I have the spread sheets to prove it. In my Data book for load development I have 5 full sheet of Data. I have shot a few sling matches at 1000 yards with it and a few 600 yard prone matches as well. the last two matches at 600 yards yeided a 198-14X and a 200- 10X with 105 Berger VLD's and N560.

You might have to ask Robert but I think I was one of the first to take on this superX project after I had contacted him via Email. Robert, again thank you for a great design I sure have been enjoying it.

I have been burning High BTU temp powders in this Barrel for a test to see how fast it will shoot out in a worst case sceneario. Im at around 900 with out looking at my log book, and should be around 1000 after the Long Range Regional this weekend.

115 Bergers, 105 VLD Bergers, 105 Amax and a bunch of others shoot really well.


Hope you have as much fun as I have over the last year or soo.

RussT

 

[Rtheurer]

Raptor:

If you want some real low temp powder try N165. It is not as hot as H1000. Just because it is slow buring, does not mean the BTU's are any less.

N165 might not shoot real well in your barrel. It did not in mine, but then again H 1000 did not give me any real startling Velocity or ES's.

RussT

 

[Raptor]

Rtheurer,
I would love to see your data would it be possible to send it to me??? My son just had his rifle rechambered to one too. He had a 6-250 that he was having problems with sticky extraction. He shoots highpower and tactical matches.

He is going to a big sniper match in Maryland in June and is going to take the SuperX. I think its a mistake since he's only had the gun a month now. He's going to rely on my data!! Thanks!!