Reply with quote #1
So this guy thats behind the whole ".243 CM" fan fare appears to have disapeered.
Having said that, I'm looking for imformation on how to get more barrel life out of .243 and it's variations of cartridges.
Ive heard of "special cleaning regimine" but do not know what those are...
As well as using slow & "cool" butning powders, but do not know those either. Any information would be appreciated.
Reply with quote #2
Lately, there has been talk about how even when using moderate velocities, there are techniques to get literally twice as much barrel life out of known "barrel burner" cartridges/loads. I'm looking into those techniques.
I'm loading/shooting for 1000 yard competitions: 100 grain bullets minimum....
I agree with what you say and thanks for your input!
Reply with quote #3
Joe hasn't disappeared. He has just decided to concentrate more of his efforts to his business and shooting as to promote his 6CM from what he has told me. I still shoot my 6CM and love it. I only have about 1000 rounds thru mine rite now and it still shoots great. Shooting H1000 and 115 DTACs. I'm sure if you want information on the 6CM either Joe or a 6CM shooter will answer you.
Reply with quote #4
I have not disappeared.
I simply don’t read this board much.
However, to answer your question:
Getting more barrel life out of a 243 sized case, be it the 243 Win, 6CM, or 6AI is easy.
The first question one asks them self is what am I giving up to get the barrel life. The answer is nothing. Velocities are off the charts and in now way is accuracy less.
The secrete is only the slow burning, single based powders. We have been seeing these results for over 15 years from most barrels.
So what powders? H1000 is my favorite and N165 is close behind for the 243 and 6CM. For the 243 AI Retumbo and N170 will probably work well, but I don’t have any experience with this cartridge.
I don’t coat my bullets, so Bergers or other J4 jacketed bullets don’t work as they blow up. Sierra 107’s and DTAC 115’s are the only bullets I use currently. Having to coat a bullet with molly or something else just so it doesn’t blow up is problematic as eventually even the coated bullet will fail.
On barrels I only use cut rifled barrels. Kreiger and Bartlein 4 grove barrels are the only ones that have passed the test currently. I don’t know why other barrels don’t work. However, the problem with other barrels is fouling. Not copper fouling, but carbon fouling. Even other 4 grove barrels have proven to foul with carbon to the point that they are unshootable.
Cleaning….it is simple and I’m changing my opinion on why and how the cleaning I initially prescribed works. I use a mixture of Shooters Choice and Kroil for daily cleanings. Then every 200 to 400 rounds I JB the throat of the bore aggressively. Initially, I thought I was smoothing out the steel in the throat, however now I believe I am removing hard carbon deposits. Regardless of why or how this works, it works to extend barrel life.
With the 6CM I have seen over 3000 rounds from every barrel before it gives up ½ MOA accuracy. In fact, different from the 6XC or 243 Win, I have never had a barrel loose accuracy. With the 6CM I am pulling barrels just because of the round count and not because of any perceived degradation in accuracy. My barrels are being pulled based on the time of year and where I am in my shooting schedule. Pulling the barrels has nothing to do with performance issues. I have pushed one of the barrels to 4132 rounds and that barrel shot a 200-10X at 600 yards on its last adventure at Perry.
The key is the slow burning single based powders. It not only works with the 6mm cartridges, but also works with the 6.5 284.
However, this recipe does not work with the 6XC or simular undersized cartridges, as they don’t have enough case capacity for the powders. Furthermore, the 6XC and simular cartridges require coating the bullets simply to get competitive velocities. In my opinion, while the 6XC and other cartridges like the 6BR can achieve good velocities the cartridge is being pushed too hard and requires too fast of a powder to achieve acceptable barrel life.
Accuracy from a 6mm is easy. Barrel life is very important to the competitive shooter, as the shooter is spending more time practicing and shooting matches and less time developing loads for a new barrel.
On that note I will state that ever-single 6CM barrel, I have had, has, after 400 rounds, settled into the best load being 49.3 gr of H1000.
One final thing is that I jump all of my bullets 40 to 50 thousands of 1 inch. And I never change the seating depth during the barrel’s life.
Reply with quote #5
I shoot a 6mm superX, a design from Robert Whitley. It is simply a 243 with a 30 deg. shoulder and a slightly longer neck. I followed Joe and Roberts advice, and use the same powders the Joe has already mentioned and the throat has moved a total of .005 in just under 1,000 rounds. I also shoot either 115 gr. DTAC or JLK bullets at around 3,000 fps with great accuracy and no failure to arrive issues. The throat gets some attention with J-B's every 200-250 rounds as Joe mentioned also. I don't know if it smoothes the throat area or removes the carbon, but it gives me piece of mind. On the subject of barrels, I shoot the 6mmSX cartridge in both a button rifled Broughton and a cut rifled Kreiger with no appreciable differances between the two. Other than that, it's simply load and shoot.
I hope this helps,
Reply with quote #6
please can you give a newcomer a detail description how you use the J-B for the throat. Your technique ( patch ? ).