6BR vs 6CM

[joesr]

Today I got a call from a 6BR shooter that tried the 6CM. He ordered two barrels from me at the same time one in 6CM and one in 6BR.

Both shoot lights out as far as accuracy. However, in wind the 6CM out performed the 6BR by rings on the target. He is sending back the 6BR barrel to be rechambered in 6CM.

His findings are that the 200-15X he shot at Mineral Wells in the past two weeks is one of the highest scores he has ever shot and it was with the 6CM. Out shooting all of the 6.5x284's.

The facts are that the 6CM is as, if not more, accurate than the 6BR and with 300 to 400 feet per second more and better barrel life there is no reason to shoot the 6BR.

Joe Hendricks
Hendricks Shooting Improvements
6CM@comcast.net
724-933-8110

 

[rcw3]

Joe

The 6CM may indeed be a great cartridge but that's some "puffing" there:

1. A 6CM is as accurate as a 6BR; and
2. It has a better barrel life than a 6BR; and
3. It can beat out 6.5 x 284's

If that's what your cartridge can deliver, then it really is a magical cartridge and you deserve whatever success and recognition that comes from it.

Robert Whitley

 

[LESLEY]

RCW3 Im the one who use to shoot a 6br. Im not saying the 6br is bad it is a proven benchrest round.But i shoot prone matches with open sights so i dont have a scope where i can hold off and see the miraige. In br you can shoot your shots a lot faster you shoot for group size. In xcourse we shoot for score with open sights prone with a sling. And i dont see where a br can shoot with a cm in xcourse matches. I love the 6 br and allways will but in prone matches I dont see how it will beat a 6 cm.

 

[LESLEY]

i cant tell you what the numbers are but if you can tell me what the differece is in a 142 mk at 2950 or 3000 and a 6 cm at 3200 with a 115. What is the drop wind drift AND BARREL LIFE please

 

[joesr]

Joe

The 6CM may indeed be a great cartridge but that's some "puffing" there:

1. A 6CM is as accurate as a 6BR; and
2. It has a better barrel life than a 6BR; and
3. It can beat out 6.5 x 284's

If that's what your cartridge can deliver, then it really is a magical cartridge and you deserve whatever success and recognition that comes from it.

Robert Whitley

Robert,

1. I believe the 6CM to be as accurate as the 6BR. Both at long range and at 200 yards. I have, and my customers have seen the results.

2. The 6CM does have better barrel life than the 6BR. I expect 3000 rounds from every barrel and 4000 rounds from most.

This is with shooting the 115 DTAC at 3000 to 3100 fps. Some of my customers report 3200 fps.

3. Beating out the 6.5x284....ballistically the 6.5 is better. But when you look at the accuracy of the 6CM it is the fact that the average 6CM barrel will out perform the average 6.5x284 barrel at long range.

There is no magic in this, it is simple ballistics, physics, metallurgy and luck that has led me to this conclusion.

Joe Hendricks

 

[chrisj]

Joe, I don't doubt that you may get 3000 rds of accurate bbl life with the 6CM.
I have gotten much more than that out of 6BR bbls shooting 105 bullets with around 29-30 grs. of Varget or RL15.
5000 rounds and still shooting easy sub moa. May not win a BR match, but works for position shooting.
I had a 243 on a Tikka one time that was an honest 1/4" to 1/2" 5 shot group rifle @ 200 yards. I have never had another 6mm artridge that shot that good until the 6BR.The only other cartridge taht shot that good was my 6.5Grendel in a bolt gun.

Chris

 

[rcw3]

Joe

I did not say it isn't so, but besting both the 6BR,in accuracy and barrel life) and the 6.5 x 284,in performance) in all those areas is a tall order, and maybe your 6CM is up to it. I can say this, on a windy day at 1000 yards, a 6.5 x 284 would be my choice over a 6mm without question, and the right 7mm with heavy bullets would be my choice over a 6.5 mm. It just seems that no matter how fast you drive the 6mm bullets, they get blown around quite a lot in the last 400 yards of a 1000 yard match. You can run numbers on a program or a wind drift chart, and that may say they're equal, but for me it always seemed like a whole different ball game when your on the firing liine out there on a windy day.

Robert Whitley

 

[rcw3]

RCW3 Im the one who use to shoot a 6br. Im not saying the 6br is bad it is a proven benchrest round.But i shoot prone matches with open sights so i dont have a scope where i can hold off and see the miraige. In br you can shoot your shots a lot faster you shoot for group size. In xcourse we shoot for score with open sights prone with a sling. And i dont see where a br can shoot with a cm in xcourse matches. I love the 6 br and allways will but in prone matches I dont see how it will beat a 6 cm.

The guy on the National Match Forum who said he witnessed your shooting said he thought you were shooting F Class in a 3 x 500 match. Your posting here suggests you are shooting across the course with open sights and a sling. What's the situation?

Robert Whitley

 

[chrisj]

I must agree with Robert on the theory that heavier bullets in larger calibers seem to shoot better in windy conditions at long-range...ie...more than 600 yards. I've tested in 6mm,6.5mm, 7mm, and 7.62mm cartridges and it seems that the larger bullets GENERALLY shoot better. Most 1000 Yard benchrest shooters who shoot the heavy guns, shoot .30 caliber magnums. And that is what wins Most 1000 YD matches. There must be a reason for that.

Chris

 

[Raptor]

I don't have a dog in this fight and I do think Joe is on to something with his 6CM but, I have to agree that when it comes to real world shooting the heavier bullets out perform the lighter ones hands down.

I live in South Dakota and trust me when I say the wind blows out here. I do a lot of tactical shooting and practice alot from 500 to 1000yds on steel and paper plates. A few years back I had a chance to shoot on a course in Neb. that had steel plates out to 1300yds. I shot my 308, 260 and 6.5x284. The 6.5x284 was the only one that rang the steel 4 out of 6 times @ 1300yds. I shot the 260,Shooting 140s)at it and I may have hit it once but it was all over and I had no consistancy.

I went back down this year and shot it again. I have since sold the 6.5x284 and built a 6XC, hopeing for better barrel life but similar performance. NOT SO... The XC is no 6.5x284 in the real world. At 1300yds it was just like the 260 was a few years ago, it sprayed them all over. High, low, left, right. When I hit it it was luck. I have since switched to my 260 with the 123 Lapuas and decided to give them a go. Much to my surprise I hit the plate 6 out of 9 times and when I missed it was due to wind call.

Now both of these rounds in my guns use the exact same wind and elevation call. The 123s flat out shot the 105s hands down. Maybe the 115 would work bette I don't know but I was disappointed in the performance of the XC at this range. Granted I don't shoot at this range but still the 123s flat out performed the 6MM bullet. I could have swore I was shooting my 6.5x284 again when shooting the 123s in my 260.

 

[joesr]

Raptor,

1300 yards is much longer than I shoot. Mostly I shoot out to 600 yards and from time to time out to 1000 yards. At these distances the 115 performs perfectly.

One note on the 6XC. You have to shoot moly and over 600 yards I would strongly suggest you shoot the 115.

Shooting moly in the 6XC makes an unbelievable difference in velocities. I can not explain why in the 6XC it makes such a difference and with the 243 and the 6CM it dose not seem to make much difference.

However, with the 6XC if you are not shooting moly your velocities are much lower.

The one thing your post demonstrates, but does not address is the combination of velocity and larger bullet weight for a specific caliber. For long range shooting you need to use the biggest bullet available, that is accurate and has a great BC. The key is getting as much velocity as you can out of the bigger bullet without giving up accuracy.

What I have done with the 6CM is allow the 6mm shooter to shoot the 115 at velocities at or beyond 3100 fps with great accuracy,1/4 to 1/2 moa). Also this is with bare bullets.

Everyone has a "pet" cartridge. Also, every shooter should choose the cartridge that performs best for their game and more importantly one that improves upon the part of their game were they are the weakest.

I am a poor prone shooter in comparison to my 200 yard position shooting so I developed the 6CM to improve my 600 yard shooting. Making reading the wind easier and very accurate. This way when I miss the wind or break a shot slightly off center I am not loosing points.

I think that many shooters look for what I was looking for and many shooters will benefit by shooting a cartridge like the 6CM.

Furthermore, the 6XC, 240 NMC and other similarly sized cartridges do about the same on the target, but you have to use faster burning powders and this yielded shorter barrel life.

With the 6CM you have the best of both worlds. Great accuracy with large bullets and your barrel last much longer.

I would think that if you were able to shoot a 6mm cartridge, like the 6XC, with the 115 at 3000 fps or better you would find that is performs as good at the 6.5 x 284 and better than the 260 with the 123.

Thanks for the kind words at the beginning of your post.

Joe Hendricks
6CM@comcast.net

 

[LESLEY]

the match was a 3x500 and no i didnt shoot f class the guy next to me Kent lucus did and the gun i was shooting was his gun brand new. The first 2 relays i was fire forming his brass and i shot a 197 and a 194 the last relay i shot brass that was allready fire formed and that is when i shot the 200 with 15

 

[joesr]

RCW3 Im the one who use to shoot a 6br. Im not saying the 6br is bad it is a proven benchrest round.But i shoot prone matches with open sights so i dont have a scope where i can hold off and see the miraige. In br you can shoot your shots a lot faster you shoot for group size. In xcourse we shoot for score with open sights prone with a sling. And i dont see where a br can shoot with a cm in xcourse matches. I love the 6 br and allways will but in prone matches I dont see how it will beat a 6 cm.

The guy on the National Match Forum who said he witnessed your shooting said he thought you were shooting F Class in a 3 x 500 match. Your posting here suggests you are shooting across the course with open sights and a sling. What's the situation?

Robert Whitley

Robert,

You need to understand that my world ends at 600 yards. I should have stated that in my post.

However, all of these arguments are a factor of velocity. You can not argue that for long range shooting velocity is very important.

When you run the 6.5 142 at 2950 fps and compare it to the 115 at 3100 you find that the 6mm bullet drops 31.53 inches less than the 6.5 bullet. Also in a 10 MPH cross wind the wind drift of the 115 is 5.09" less.

Lets say you are able to shoot the 142 at 3050...the 115 drops 8.62" more and drifts 1.21" more than the 115.

The 115 has a BC of .580 to .570 so I used an average of .575. This is according to SSI earlier this year.

The bottom line is that at the worst the 115 at 3100 is equal to the 6.5x284. From my experience the 6CM is more accurate than my 6.5x284's so that gives the 6mm some advantage.

For long range shooting velocity rules. The 6mm 115, 6.5 142, 7mm 180, 30 cal 240 are all great bullets. It is all a matter of how fast you can shoot the bullet and shoot it accurately and safely.

But velocity does not win matches. What wins matches is the ability to shoot your gun.

So for an XTC shooter if you can shoot your gun across the course and then take it back to 1000 yards and have it out perform the specialized guns you are ahead of all the other shooters because you know you gun intimately, you shoot it every day.

I simply stand by my previous claims that the 6CM is as accurate as the 6BR, has longer barrel life than the popular 6mm cartridges,shooting larger bullets at maximum velocities) and will out perform the popular cartridges,6.5x284) at long range.

Joe Hendricks
Hendricks Shooting Improvements
6CM@comcast.net
724-622-0747

 

[Raptor]

Joe,
Thanks for the tip on the moly but I don't care for moly so I will always take mine "Naked".,HA)

I have only shot 20 115s through my 6XC to see if they would even shoot with my 1-8 twist and I shot them at 600yds. They shot about as well as the 105s but no better. However to be fair I didn't shoot enough of them to say one way or the other. But I do go back to what I was saying that I think the 139 or the 142s in a 6.5x284 will do better at 1000yds in the real world than the 115s will even though the 115s may look better on paper.

In "MY" experience I have found that the heavier the bullet the better it shoots at long range when your talking similar velocities such as my 6xc with the 105s and the 123s in the 260 or your 6CM with the 115s and the 6.5x284 with the 139s or 142s.
I will take the heavier bullet everyday of the week.

This is not knocking your 6CM with the 115s just that I have to think the 139 or 142 is going to be hard to beat in the real world conditions at l000yds. I shoot in the wind a lot out here or I wouldn't be able to shoot. I believe you were talking less than .25moa wind difference on paper between the bullets but I have not found this to be true in my experience at the longer ranges. I won't argue that you would not see any noticable difference to 600yds but past that I think is where you start to notice the heavier bullets stay on course better esp at the 1000yd mark.

I hope you don't take this as a slight on your fine caliber because I have not had the pleasure of shooting one. This has just been my experience with the guns I have in 6.5 and 6MM keep up the good work!!

 

[olympian]

I have been following these posts on the 6CM and it is quite interesting reading. In looking at loading data for the .243 Winchester, I have noticed Hodgdon's Retumbo as being a rather promising slow-burning, single-base powder, but I have not seen much about the use of Retumbo in the 6CM. Am I overlooking something about the combination of the 6CM, the 105-115gr bullets, and Retumbo?

 

[mkeeler3]

the match was a 3x500 and no i didnt shoot f class the guy next to me Kent lucus did and the gun i was shooting was his gun brand new. The first 2 relays i was fire forming his brass and i shot a 197 and a 194 the last relay i shot brass that was allready fire formed and that is when i shot the 200 with 15

OK…..I am confused. I shot the 3x500 Sunday at Ft. Wolters with Lesley. In, fact I was squadded on his point and pulled his target. The match was shot on the new 500 yard highpower target not on any F class targets. All shooters, F class and iron sight shooters alike shot on the same target. He is indicating he shot with a sling and irons. Since I did not actually see him shoot I cannot verify that. HOWEVER, correct me if I am wrong Lesley but didn’t you win the F class category? All the iron sight shooters were on one relay which is the relay you shot on and the iron sight/match rifle shooters shot on the second relay. It was very windy that day, even for TX and Lesley shot great and I was very impressed with the elevation his gun was holding. But, my score was a few points below Lesley’s yet I won the match rifle class shooting a Palma rifle? Of course, I could be wrong and please understand I am not trying to start anything with my post, just simply stating what I know.

Mike Keeler

 

[LESLEY]

i shot tactical kent wasthe only f class shooter there. I didnt say i shot with a sling. I usally do but we needed to see how kents gun would shoot and fire form some more of his brass. I did state that i thought the 6cm was a better round for shooting prone with.

 

[LESLEY]

it has less drop and less wind drif at 600 than a 6.5 with a 142 . I also so think the barrel life is going to be above 3000 but it will take me a couple of months to know that

 

[joesr]

Joe,
Thanks for the tip on the moly but I don't care for moly so I will always take mine "Naked".,HA)

I have only shot 20 115s through my 6XC to see if they would even shoot with my 1-8 twist and I shot them at 600yds. They shot about as well as the 105s but no better. However to be fair I didn't shoot enough of them to say one way or the other. But I do go back to what I was saying that I think the 139 or the 142s in a 6.5x284 will do better at 1000yds in the real world than the 115s will even though the 115s may look better on paper.

In "MY" experience I have found that the heavier the bullet the better it shoots at long range when your talking similar velocities such as my 6xc with the 105s and the 123s in the 260 or your 6CM with the 115s and the 6.5x284 with the 139s or 142s.
I will take the heavier bullet everyday of the week.

This is not knocking your 6CM with the 115s just that I have to think the 139 or 142 is going to be hard to beat in the real world conditions at l000yds. I shoot in the wind a lot out here or I wouldn't be able to shoot. I believe you were talking less than .25moa wind difference on paper between the bullets but I have not found this to be true in my experience at the longer ranges. I won't argue that you would not see any noticable difference to 600yds but past that I think is where you start to notice the heavier bullets stay on course better esp at the 1000yd mark.

I hope you don't take this as a slight on your fine caliber because I have not had the pleasure of shooting one. This has just been my experience with the guns I have in 6.5 and 6MM keep up the good work!!

I would never take any intelligent conversation as a "slight". I enjoy everyone's opinion and I lean much from all of this.

I do think there are two factors you are overlooking in your conclusion. First is velocity. The second is recoil.

Velocity factors big time into what we are doing with the 6cm as we are able to shoot the 115 at velocities as high as 3200 fps. ,Now...this is a hot load and I personally don't shoot mine that fast. But that is not to say that you can not shoot the 115 at 3200 safely.)

The recoil difference does not really play in the contest between the 6.5x284 and the 6CM, but if you really want to carry your argument to the next level the 240 gr 30 cal bullet is much better on paper and probably on target than anything we are talking about.

It is all about shootablity.

Joe Hendricks

 

[joesr]

I have been following these posts on the 6CM and it is quite interesting reading. In looking at loading data for the .243 Winchester, I have noticed Hodgdon's Retumbo as being a rather promising slow-burning, single-base powder, but I have not seen much about the use of Retumbo in the 6CM. Am I overlooking something about the combination of the 6CM, the 105-115gr bullets, and Retumbo?

You are not overlooking anything. We simply have not had the time to spend on testing this powder.

The brief amount of time I have spent with this powder has shown that the velocity results are very similar to H1000.

At this point I have no further information.

Joe Hendricks