6mm Super X

[Rtheurer]

This Question will most likely be answered by Robert but here we go anyway.

Can the 115 Berger be shot in a 30" Barrel with a 1:8.004 twist barrel. And if so are you able to get to 3000 Fps or 3100FPS with any pressure. Was there any accuracy with your set up at this speed? What powder did you have best results with.

Have you tried or used the 105 class bullets in this case.

I have some 95 grain Berger's that Should be shot up also. This would be a nice no wind light recoil load that should shoot very well with this case I would think.

Rifle is at the gunsmiths house right now. Its been a long wait as other projects got pushed to the front and this one put on the back burner.

Thanks in Advance Mr Whitley and who ever else has info on this most gorgeous little case.

RussT

 

[rcw3]

Russ

I had no problems running the Berger 115's in the 3000 fps range with the 6mm Super X. I did not try to run them up higher, although I believe you could with that cartridge. In truth, I was running them in a 7.5 twist barrel. I think 3100 fps will be flaunting bullet failure with the Berger 115's so I won't go there.

Usually about 43.5 - 44.5 gr of H4831SC with a Russian Primer will get you there, usually with the ES around 20 and the SD in single digits.

Robert Whitley

 

[Raptor]

Robert,
I ordered a reamer from Pacific for your 243SuperX and would be intrested in hearing about some of your loads esp with the 107s.

I have a 1-8 26" Kreiger that is now a XC and I may rechamber it for now. I would also be intrested if you do have a run of dies made. My son will also be using this in HP and tactiacl matches. Thank you for all your advice and help with this. I think you have a wonderful idea with this round. Its easy to form and should be easier on throats. Thanks again!!!

 

[Rtheurer]

Im right in the middle of working up loads.

Im working on 105 Berger VLD's 115 Berger VLD's 107 Sierra Match kings and soon to come the 105 AMAX. Also sent some 95 Grain Berger VLD's down range for break in. My throat is a little long for those bullets.

So far a mild loading of N160 and 107's have shot in .353 and 115 Bergers have shot a .313 with 4831SC

Barrel is a 1:8.04 Satern Palma Countour 5 grove.

Ill keep you posted. Alot of groups in the .6 region.

RT

 

[Rtheurer]

Big D

Good to hear from ya again. I was going to leave the DTac alone for now and consentrate on the Berger's Of course I had some 107's on hand that I used for barrel break in and fireforming the brass. The little Amax I purchased on a wim. I nad them shooting good at 3000fps+ this morning. So far My best groups have been .318 .357 and a .353 The last one being with the Sierra 107's. They were seconds I picked up from the factory on the way down here in january. They shoot good at 100 yards anyway. the other two groups were with the Berger 115 VLD. Alot of groups have been in the .6 region. Im on my second firing of all my cases so things will only get alot better. I had a Nast Doughnut on every case, and have since got rid of it with the expander mandrel and another clean up with the neck turner.
Im going to shoot it at 600 yards on Sunday. Should eat out the XRing.

RT

 

[mod70]

Robert Whitley,
Are the donuts normal for the 6 super X on the first firing after forming?

 

[rcw3]

I use Winchester brass and I do get a donut after reforming the case, however, with Winchester brass the donut is not very big. If you have the reamer design I set up that has the .130" free bore and the one and a half degree throat angle, the bearing surface of all the bullets like the DTAC 115, the Berger 115, Berger 108, Sierra 107, Berger 105 VLD are all ahead of the donut and the donut does not seem present any issues with concentricity or accuracy,although you will feel it if you are pulling an expander ball back through it after running it up into the resize die,i.e. a 6XC sizing die held off the shell holder .120"). If you neck turn, the donut becomes a non issue.

I have a couple different barrels, one that's chambered with a neck turned brass type neck,.274" neck with various brass turned to .2715" or .272") and a "no neck turn" chamber that has a .276" neck). Honestly they both shoot great. The DTAC 115's are a tricky bullet to get to shoot well, not because of anything to do with the cartridge. I found the Berger 115's were a lot easier to get to shoot and shoot well.

Attached is my favorite version of the neck turn version of the Super X reamer.

Robert Whitley

 

[Rtheurer]

Shot the SuperX today for the first time at 600 yards. I shot two strings of 20 shots with two sighters each. 115's loaded with a mild but accurate load of R25. And 105 VLD's with N560 cci Br4 primers. Both loads shot exactly the same. It was a 6:00 fishtail today so I really had to be on top of things.

Elevation was excellent and well within the Xring Minus one shot on both loadings.

Im going back to check out the R22 loading that I tested last week. i think this with the 115 bergerVld is going to be what Im looking for when i Hit the Long line. Pressure signs are non existant for both of my loads I shot today. they are a little slower then what I was hoping for though.

Robert:
i'm running the 274 neck reamer and turned brass to 272 after its first firing I ran the case in the expander mandrel and cleaned up the doughnut with the neck turner. Very consistent necks now.

 

[gunor]

6mm Super X

What are you doing for dies?

Thanks

 

[Rtheurer]

I used a set of Forster 6XC dies on the initial sizing. The Forster does not have bushings so Now I have ordered and recieved a set of 6BR Neck dies and bushings. I still use the 6XC for seating bullets.

When the Base of the cases start to get Thicker on down the road I will run them into my 6mm remington die. My Bench rest buddy who is using this case at 1000 yard Bench matches does this right now with great success.

Im only on my 2nd firing of 150 Lapua cases. So Have not needed to full length size yet.

Maybee Robert has somthing brewed up with one of the Manufactures of dies??

RT

 

[rcw3]

gunor

For the 6mm Super X you use 6XC dies held off the shellholder .120". The .120" at the base of the case that does not get re-sized has never presented an issue, and some of my cases are up around 8 firings. Robert

 

[rcw3]

Take a look at today's Daily Bulletin,Nov 16, 2007), a guy has a "243 BR-K" which is almost identical to my 6mm Super X. If I didn't know better I would swear the guy just copied the Super X with a few minor modifications.

Download the reamer design I have earlier on this thread, print it out and you will see how close dimensions are. He went with a little tighter neck but otherwise I am sure you can use his loads in the 6mm Super X as the case capacities have to be almost isentical.

Robert Whitley

Later add on:
I have just been informed his reamer has an earlier date than mine, but I never knew of his cartridge when I made mine up or I might have just used his set up. He made his off the 6BR, I made mine off the 6XC because those were the reloading dies I had at the time.

 

[dab4902]

There seems to be a number of similar designs. I have a reamer from Pacific Tool called the 6mm TBR,Tall Bench Rest) that is also similar. My print is dated 2/20/06. Is it like the US patient office? Who ever gets there first wins. I have not had a chance to shoot the round due to a problem getting the stock built.
David

 

[DukeDuke]

This Question will most likely be answered by Robert but here we go anyway.

Can the 115 Berger be shot in a 30" Barrel with a 1:8.004 twist barrel. And if so are you able to get to 3000 Fps or 3100FPS with any pressure. Was there any accuracy with your set up at this speed? What powder did you have best results with.

Have you tried or used the 105 class bullets in this case.

I have some 95 grain Berger's that Should be shot up also. This would be a nice no wind light recoil load that should shoot very well with this case I would think.

Rifle is at the gunsmiths house right now. Its been a long wait as other projects got pushed to the front and this one put on the back burner.

Thanks in Advance Mr Whitley and who ever else has info on this most gorgeous little case.

RussT

Were the 115s VLD stable in your 1-8 twist? Just curious, the box says 1-7. Thanks.

 

[rcw3]

By the way attached is a picture with a 6XC,left) a 6mm Super x,center) and a 243 Win,right).

On the question on barrel twist stabilizing the 115 Bergers, I would never go tighter than 1:7.5" twist. A 1:8" twist will stabilize them but it's right on the edge, and maybe in the wrong conditions, temperature, altitude, etc. you may have a problem with 1:8" twist. Correspondingly, I have had pressure problems with 1:7" twist barrels and the 115's,right there as far as being too much twist - pressures can spike fast with too tight a twist).

Robert Whitley

 

[rcw3]

dmoran

It first happened when I was looking to shoot 115 gr bullets from a 6mm/22-250. I obtained a Krieger 1:7" twist barrel, and what I noticed shooting even 105-107 gr bullets is I could not get the loads up anywhere near what I normally shoot and pressures would spike,flat primers, sticky bolt lift, etc.). I dismissed it as an anomaly, but then another shooter I know bought a Hart 1:7" twist barrel and had the same problem. He ultimately got so fed up with the barrel, he took it off his action with a pipe wrench and I ultimately got it to play with. I re-chambered it to 243 Win and fitted it to another rifle I had and low and behold, I had the same problem,2800 fps with 107 Sierras was about all it would do without pressure issues,flat primers sticky bolt lift, etc.) If you did a 60 second 10 round rapid fire sequence,like we do in highpower shooting) with what is normally a milder load,2800 fps with 107 Sierras), by the end of the 10 rounds the bolt lift would be very hard and the primers would be flat as a can be).

I then heard through a gunsmith I work with that he put a 1:7" barrel on a rifle for a customer for highpower and that the customer also had the identical pressure problems with that barrel. Personally I think a 1:7" twist barrel is right there as far as being too fast a twist for a 6mm, and nowdays I won't buy a 6mm that's faster than a 1:7.5" twist. I know some people on these forums say they have had 7 twist barrels and they use them with no problems, but I will certainly never buy another - too close to or over the "red line" in my opinion. 115 gr 6mm bullets are about as big as you can effectively go with a 6mm, and a 1:7" twist is at or close to the point of no return, the point where pressures can jump up in geometric proportion,out of proportion to the faster twist).

Robert Whitley

 

[rcw3]

dmoran

If you are going to parse words, I did not use the words "pressure spike" and at this point I am a bit annoyed I spent the time responding to your inquiry. Good luck with your fast twist barrels.

Robert Whitley

 

[rcw3]

Robert --

I see the EDIT feature option was used to change "Pressure Spikes" to "Pressure can Spike" and for total illumination of others. .....
-- fastidious indeed !!!!

Donovan Moran

Sorry Donovan that's incorrect.

Have a nice day.

Robert

 

[DukeDuke]

By the way attached is a picture with a 6XC,left) a 6mm Super x,center) and a 243 Win,right).

On the question on barrel twist stabilizing the 115 Bergers, I would never go tighter than 1:7.5" twist. A 1:8" twist will stabilize them but it's right on the edge, and maybe in the wrong conditions, temperature, altitude, etc. you may have a problem with 1:8" twist. Correspondingly, I have had pressure problems with 1:7" twist barrels and the 115's,right there as far as being too much twist - pressures can spike fast with too tight a twist).

Robert Whitley

Thank you Robert!