6mm Cartridges

[joesr]

There is much talk about on this board, currently, about the 6x47. From what I understand it is the same as the 6XC just slightly shorter. Please correct me if I am wrong.

However, this cartridge has been done over and over and the results are going to be exactly the same.

I understand the frustration with the 6XC as I received a call today confirming my order for brass that was placed nearly 2 years ago.

I am long past the 6XC or similar cartridge phase of my shooting.

If you want to shoot a 22-250 sized case then go for it. However, the larger 243 case based cartridges are superior to these cartridges.

With the 6mmCompetitionMatch the shooter is able to obtain 100's of feet per second more from any of the larger bullets and obtain longer barrel life.

The 6CM is proving to consistently shoot for over 3000 rounds with the same or better accuracy of the smaller cartridges.

The problem with the smaller cases is that you have to shoot faster burning powder to achieve the highest velocities and this kills the barrels.

With the 6CM or similar cartridge you can shoot powders like H1000 to achieve even higher velocities and stress the barrel less.

Most importantly the 6CM is just as accurate it not more than the 6XC or 6x47.

With the 6CM you will still get the accuracy and obtain longer barrel life.

It is hard to believe that a larger case will get you better barrel life and better accuracy, but it is proven.

You can contact me for more information.

Joe Hendricks
6CM@comcast.net

 

[Forum Boss]

There is much talk about on this board, currently, about the 6x47. From what I understand it is the same as the 6XC just slightly shorter. Please correct me if I am wrong.

The 6.5x47 Lapua, is first of all, a 6.5 to start with obviously. It also comes with a small flash hole, small primer pocket and is rated to 63,090 psi.

However, this cartridge has been done over and over and the results are going to be exactly the same.

In terms of exterior dimensions you may be right. But it has NOT been done before as a factory round with small flash hole and a 63,000 psi CIP rating. Darrel Jones was able to push 120s up to 3150+ with this cartridge. That's WAY more velocity than I could get with my Rem .260 which has a bigger case and more capacity. The small flash hole may be part of the secret.

Most importantly the 6CM is just as accurate it not more than the 6XC or 6x47.

I haven't tested a 6CM, so can't comment on that, but it looks like, with the right powder/bullet combination, the 6.5x47 will be VERY accurate--able to shoot in the high ones at 100 yards with boattail bullets.

With the 6CM you will still get the accuracy and obtain longer barrel life.

I think the whole 6CM concept is very intelligent, and it appears to offer enhanced barrel life compared to a conventional .243 or .243 AI.

Where I see the 6.5x47 fitting in is on the 600-yard line and with the tactical shooters.

 

[Cheechako]

Joe

I have to agree with you that the 6mm small to mid-size cartridge discussion is getting tired but there doesn't seem to be an end to it as new shooters come along. Any of them can do a search on any one of several forums and get enough reading to last them a whole shootin season.

I don't think you'll convince any of the older shooters about which way to go. They have already made up their own minds, mostly as a result of actual competition. And, in the end, all that matters to most of us on this Forum is where the bullet meets the paper. I'll leave it to others if they want to argue with you some more but I'll repeat what I've always said in the past - there is accuracy and there is velocity. All of the current crop of 6mm match bullets shoot their best at 3000 fps plus or minus. Any more and accuracy deteriorates. In a good long barrel you can do that very easily with no more than 40 grains of powder in a 50 grain case. If you're willing to sacrifice a little barrel life you can do it with bigger cartridges and if you're willing to fight sticky bolts and short-lived brass you can do it with smaller cartridges and maybe even pick up a little added accuracy in the process. JMHO

Any of the 4 on the right will get the job done.

Now if you want to talk strictly 600 yards, that's a whole nuther discussion.

Ray

 

[joesr]

Ray,

I agree with much you have stated. Many shooters shooting 6mm cartridges have picked there “baby” and they are not going to switch.

Also you are correct that most of the 6mm bullets like a velocity range around 3000 fps. How ever the better bullets also shoot well at velocities over 3000 fps.

You state that if you go over 3000 fps the accuracy deteriorates. I have to assume this is more due to the cartridge being maxed out than the bullet.

I am shooting the 107 Sierra at close to 3200 fps for all of my 200 and 300 yard shooting. It is performing great at this velocity. Off the bench this load shoots under ¼ MOA.

Most importantly the 115 DTAC the way I shoot it is going about 3100 fps and I see no signs of problems with it. In fact the faster I shoot the bullet the better it performs. I am only limited by the case capacity as to how fast and how accurate the bullet shoots.

The biggest myth you believe is that the larger cases results in shorter barrel life. This is absolutely false. There is an optimum case capacity that needs to be coupled with the correct powder so that the shooter can obtain the optimum barrel life. If the case is too small then you have to use powders that are fast burning to obtain the velocity.

However, the results of the better barrel life by shooting the optimum sized case is lost if the shooter has to shoot a cartridge that is not as accurate as the cartridge that inferior for barrel life but has great accuracy.

The best thing about the 6CM is that it is as accurate as any 6mm cartridge we have shot. The 6CM gives more velocity for long range and the barrel life is better than all other 6mm cartridges.

I know it sounds too good to be true and that is why the list of shooters shooting the 6CM is growing slowly.

But the list of shooters shooting the 6CM is growing and it will continue to grow.

The proof is on the paper and on the paper over time.

Joe Hendricks
6CM@comcast.net

 

[Cheechako]

Joe

I have never seen a 6CM, as far as I know. From what I have gleaned from your posts I am guessing that it is a long neck 243W, possibly one of the SMC shapes, or something along those lines? How about a description or a photo?

If you say it shoots better than any of the other 6mms I have to take your word that it does so in your rifle. But I am skeptical, I admit. I have always held the opinion that accuracy is the product of a good barrel and a good bullet fired at the optimum velocity for that particular bullet. I do believe that when you exceed that velocity, accuracy suffers, not because the cartridge is maxed out but because the bullet is. I,and many shooters I know) first pick a bullet that I want to shoot and then I build a case, barrel, and rifle around it. That's why there are times when the really long barrels can be a handicap instead of an advantage. VLDs are good examples. It's a long way from CF rifles but the 38 wadcutters are probably the best examples - super accurate to 50 yards but not much better than a rock beyond that.

As far as barrel wear is concerned, I am somewhat of a maverick. I look at a barrel as an expendable. There are 5 - primer, powder, case, bullet, and barrel. Some are expended faster than others but none of them last forever. Trying to extend barrel life at the expense of accuracy is foolish. I suppose my Benchrest background is showing but barrel life is the least of my concerns. I want a barrel that wins, even if it means a life of 800 rounds. One that can't win but lasts 5000 rounds is for losers. Otherwise I'd be shooting a 30-06. 20 years ago I probably would have agreed with you. If you found a good barrel you would nurture it and do anything to make it last. Nowadays there are many good barrels available and changing them is as easy as changing your shorts. I have had BR barrels that I shot less than 200 rounds but none that have lasted over 1500. I doubt if any combination of case shape, powder charge, or bullet would made them last longer.

I have known competitive shooters who have tried your approach. Bigger case, slower powder, less pressure, etc. None that I know of still do that. Maybe there are guys shooting a 6CM at the matches I go to but if so they are keeping it a secret. I collect comp cartridges so I try to snoop around to keep track of what guys are using and I've never seen one, with that moniker anyway. Maybe they are calling it something else?

BTW, I am also skeptical of your claim of sub 1/4 MOA accuracy. I shoot 100, 200, 300, 600, and 1000 yard Benchrest. All of my rifles will shoot sub 1/4 MOA groups on occasion but only the 100 yard rifles can do it consistently. I'd kill for a sub 1/4 MOA long range rifle.

As I said, I'd sure like to see one of those 6 CM cartridges. So would a lot of other guys, I'm sure. If you've posted a photo somewhere I must have missed it. In my competition cartridge collection I have, probably, close to fifty 6mm cartridges. I'd bet you a beer that one of them is a spitting image of the CM.

Ray

 

[Cochran]

I dont have an opinion either way on the 6CM but I tend to believe Joe is right that optimum velocity is a product of the case/bullet/powder not just the bullet, assuming good barrels. Everyone always says the optimum velocity for 107s is about 3000 fps. Yet I've gotten great groups with them at 2500 fps. in a 6BR with a slow lot of Varget as well as 3200 fps in a 243 based case. The same thing holds true for 142s that are supposed to shoot best at 2950 fps. Seen great groups out of a .260 at 2650 fps and a 6.5-06AI at 3200 fps+.
I dont know much about short range BR but I believe the trend over the last few years has been to run thier little 68s hotter. I wonder if there was a time when conventional wisdom was to run them at 3000 fps. Seems like most are running around 3400 now.

Jeff

 

[Bobs243Ackley]

For those of you who would like to see a picture of the 6CM, it has been posted here before. It is in this thread on page 2, all the way at the bottom on the second page. It is the cartridge in between the .243 Win., & the 6XC.

Cordially,
Bob Blaine

 

[joesr]

First off let me state that I never said the 6CM was more accurate than any other 6mm cartridge just that it is as accurate as any other 6mm cartridge I have shot.

Furthermore, to date it is the best shooting cartridge I have ever shot. The reason I state that is several fold. First, it is very accurate and consistently I am getting groups off the bench at 200 yards, with my Tubb rifle,which is a very bad gun to shoot off the bench) and with iron sights are 1/2.

Today I installed a new barrel on my 2nd Tubb rifle and took it to the range. My current number one barrel has 2500 rounds through it and I wanted to have a good backup just in case.

However, and this is the best part, both guns shot the same load with the same accuracy. Both barrels came in way under 1" in mid day heat with some wind. It was not he best testing conditions, but it was all I had to work with.

Remember I am testing with iron sights. Further more in both rifles, the one with 2500 rounds and the new one, I shot the same seating depth.

I don't know if this cartridge is going to carry over to bechrest. To me it looks like it has the accuracy potential for long range benchrest, by the bench rest shooters are going to have to prove it.

One thing I know for a fact that shooting this cartridge for across the course or for NRA long range, it really does work.

When I started this project, I did it for myself only. However, it works so well that I wanted to tell everyone. I love the debates and talking about he pluses and minuses of the cartridge.

I was asked to post a picture of the cartridge that I have done before. However, possibly better is the explanation of what the cartridge looks like. It is a 243 Win case with a 31 degree shoulder. When I changed the shoulder angle I split the difference between the neck and body. Therefore, the resulting case has a longer neck than the parent 243 Win and more case capacity. Also, by doing this fire forming is made much easier because a part of the chamber makes contact with unfired formed brass.

It would be nice if more people would shoot the 6CM, however that was never my goal. My goal was to put this information out there and then over time see the results.

The results of the 6CM are not just the cartridge. The accuracy results are the cartridge, but the barrel life is the powder choice and cleaning regiment.

I am having the best shooting year of my life. Partially because I am shooting this cartridge and winning more matches than ever before with the highest scores I have shot, but mostly because of the debate and discussion about the cartridge.

Joe Hendricks

 

[Cheechako]

For those of you who would like to see a picture of the 6CM, it has been posted here before. It is in this thread on page 2, all the way at the bottom on the second page. It is the cartridge in between the .243 Win., & the 6XC.

Cordially,
Bob Blaine

Bob

Where????

Ray

 

[KLENCHBLAIZE]

[QUOTE=joesr) If you want to shoot a 22-250 sized case then go for it. However, the larger 243 case based cartridges are superior to these cartridges.QUOTE

Shooting a 250-3000 sized case, in simulated field position competition where the cartridge must develop UK deer-legal muzzle energy, was exactly why I chose to base my .25 Wildcat on the 6X47SM. I don't like recoil and and the less the better. It never occurred to me there would be a demand for this case in the US as for many years it was completely ignored! And anyway, why did the 6mm Ackley wildcat, based on the Savage case, not simply lead to better quality brass being produced if this was, as is strongly suggested, the Holy Grail of 6mm case capacity?

The interest then must simply be down to the quality and consistency of brass that Ruag produce - still superior to Lapua by the way!

Cheers

 

[Bobs243Ackley]

Thanks for the assist gunamonth! You are correct since the posting moved from my response.

Cordially,
Bob Blaine

 

[Cheechako]

OK, found the photo. I have to say I'm embarrassed. Here I've been saying that I have never seen a 6CM and yet I posted several times on the thread that had the photo. Can I plead old age??

Joe, I'm not here to tell you that your cartrdige is not everything that you say it is. I'm sure it shoots great in your rifles otherwise you wouldn't be bragging on it the way you do. I have done my share of wildcats and they are like my children and I'm proud of every one, although they are just like kids in that not all of them turned out the way I had hoped.

I tend to get long-winded on these forums but my real point is/was that there's not much new when it comes to competition wildcats. Especially the mid-sized 6mms. I try to keep a collection of comp cartridges and I have more 6mms than any other caliber.

Any way, i told you I probably had a spittin image of the 6CM in my collection and it didn't take long to find it. Here's a photo I just took with the same three cartridges as your photo. You might have to jump back and forth to compare them but, as you can see, it's hard to tell the difference.

Keep on wildcatting.

Ray

 

[joesr]

I don't have time tonight, but the pictures are not of a 6CM.

However, the difference is not only the case but what you shoot out of it and maintaining the velocity goals.

Both of the cases are shorter than the parent 243 and that is one of the mistakes all of the 6mm wildcat shooters are making.

It may be a few days, but I'll get another picture on here.

The pictured cartridges are the same as what everyone is trying to recreate, a shorter 243 or a longer 22-250-6mm.

The 6CM is something different. I've explained it before and still....no one gets it.

Joe H

 

[Cheechako]

Joe

Now I'm confused again. The photo I posted is not a 6CM. I never said it was. I was showing a cartridge from my collection that was near identical to the photo on the other thread that you posted on 9-05-05 that you said was a 6CM. My point was that the 6CM has been done before. This is all getting very confusing. Did the photo you posted on 9-05-05 show a 6CM??? Here it is.

http://www.websitetoolbox.com/tool/post/6mmbr/vpost?id=619810&trail=8

The photo I posted showed a 243 on the left. the cartridge in the middle is exactly the same length as the 243.

This has been going on for so long that I've forgotten what the hell we were arguing, errr, discussing.

Ray

 

[joesr]

Ray,

I don't think we are arguing. A good discussion with inteligent points and counter points is very enjoyable.

Here is a picture of the 6mmCompetiton Match and the 243 Winchester.

 

[JERRYHM]

Joe and Ray,

I will be BR testing the 6CM at 100 yards across the chronograph tomorrow. Monday 8-7-06 1000 yard BR testing.

Jerry

 

[TonyZ]

Guys, i think that Henry Childs has done a very similar concept cartridge to what we have here. The difference being that his has something like a .500" long neck with a 30,??) degree shoulder. I believe that he is getting really good accuracy and terrific barrel life. I have also been told that he has a heap of data with various pills and powders with this case through testing on his own range setup.
Tony Z.