6 mm br improved --- What is it ?

Add me to the list of curious

I also did some searching to find a definition/specs for the 6mm BR Improved and came up short. I hope jim1k isn't doing a Calfee on us.
 
So it this then?

The 6BR-DX

The 6BR-DX is an improved version of the 6mm BR Norma cartridge, with a 40? shoulder and a bit less body taper than a Dasher.

Thanks
 
No it is not. If you read the story about the DX it mentions that the neck is shorter than that of the BR. I believe that that is because the shoulder has been moved forward as well as had its angle increased. The 6BR improved is designed along the lines of the Ackley improved cartridges where the neck shoulder junction is a the same place as the parent case, (although chambers are generally cut about .004 shorter to make a more positive fit with the unfireformed brass). With the DX I believe that you would have to expand to a larger caliber and then neck down to form a false shoulder before fire forming, much the same as is common for the Dasher. On the other hand, the 6BR Imprioved does not require any of that. If your chamber neck ID requires it, turn the neck, load and fire. Another advantage is that with loads that deliver comparable performance, the throat wear is noticeably less than with the Dasher. I believe that this is because of the longer neck. There is something that has been called the turbulence point that speaks to this issue.
 
Boyd and Tim,

Thank you for the clarification-

So does the .272 neck require one to turn the necks or is it a no turn - for me nice to have no turn ....

JR
 
6mm br improved what is it?

While we are on the subject of improved.
What would happen if you just chambered the case .040 deeper Fireform the cases by seating the bullet well into the lands.
would it give the same results as to case capacity thus improved?. I like the standad shoulder angle.
 
GerryM said:
While we are on the subject of improved.
What would happen if you just chambered the case .040 deeper Fireform the cases by seating the bullet well into the lands.
would it give the same results as to case capacity thus improved?. I like the standad shoulder angle.
Click to expand...

Two things, off the top of my head...First, running the reamer in .040 deep will likely yield more volume gain than simply moving the shoulder to a 40° one. Second...your necks will be .040 too short..roughly.
 
mwezell said:
Two things, off the top of my head...First, running the reamer in .040 deep will likely yield more volume gain than simply moving the shoulder to a 40° one. Second...your necks will be .040 too short..roughly.
Click to expand...

really I've stretched br cases .050 and not lost any neck length. but after that you will...
 
geo.ulrich said:
really I've stretched br cases .050 and not lost any neck length. but after that you will...
Click to expand...

Ok smarty britches. Yes, you can stretch it out with fire forming. I was speaking in generalities. I've formed brass with pistol powder and tissue paper, and seen the throat on the brass. That doesn't mean I should have. That brass came from somewhere.

But, your point is valid.
 
6mm br improved what is it?

OK I see what your saying Butt....
explain the Dasher that,s how that case is formed
standard Br case is loaded long then shot forming the case. correct?
 
For the sake of getting beat up on here by people that don't even have one. It will give you a very easy to make case no matter if it is a .266 neck or a no turn. My first reamer was reground from a new JGS Dasher reamer so it stayed a .266 neck and it shoots very well with both Barts 105 and 103's. Fire forming is a easy also, turn down to the shoulder and load and shoot. If you keep the the chamber clean and dry and wipe off the cases with non chlorinated brake cleaner they yield the most uniform case I ever made, they blow out to 1.550- 1.553. A shortened Harrell's D3 works perfect for sizing and a seater from the reamer. The reamer is for a chamber 1.560 long and .460 at the shoulder and .4708 at the .200 line neck is .266 and free bore is .125. With two barrels this the most accurate case I have played with, and with two different powders, easy to tune stays in tune over 40 degrees. Seating depth is a plus it isn't real fussy also, velocity is good with a 26'" Kreiger I was getting 2974 repeatable and ES. was single digits with H4895 and RL-15. So for long range guys 28" will give you 3000, short range that barrel length was on a 13.5 legal heavy gun. I will soon will working with the 12 twist barrel with Barts 80gr. BT. with the .060 free bore reamer but after 8 twist groups it will be hard to beat......... Jim
 
Jim1K - have you shot this 6BR improved in a 1K match ? How did it do over three targets ? With wind or not ?

Thanks for your reply - Always ready to try new stuff.

Thinking I will make one of these and try it out in the west....

Jerry
 
Guys I am done with long range and about everything else, I just can't see good enough to get serious again. Tom Mousel is doing a bang up job with it at 1000. I will tell you this at my range in back I ran five groups in a row from .027 to .150 and three of them were in a 17 mph wind, so I wasn't cherry picking. It was with a Brux and I started with a new Kreiger and it is doing the same so it isn't a fluke. It is competitive from 100 to 1000 yds. not to many calibers can say that, the ppc is king in group and the 30 in score but if the wind blows.... lol. They are not competitive past 300 but the 6br imp. is...... Jim
 
jim1K said:
For the sake of getting beat up on here by people that don't even have one. It will give you a very easy to make case no matter if it is a .266 neck or a no turn. My first reamer was reground from a new JGS Dasher reamer so it stayed a .266 neck and it shoots very well with both Barts 105 and 103's. Fire forming is a easy also, turn down to the shoulder and load and shoot. If you keep the the chamber clean and dry and wipe off the cases with non chlorinated brake cleaner they yield the most uniform case I ever made, they blow out to 1.550- 1.553. A shortened Harrell's D3 works perfect for sizing and a seater from the reamer. The reamer is for a chamber 1.560 long and .460 at the shoulder and .4708 at the .200 line neck is .266 and free bore is .125. With two barrels this the most accurate case I have played with, and with two different powders, easy to tune stays in tune over 40 degrees. Seating depth is a plus it isn't real fussy also, velocity is good with a 26'" Kreiger I was getting 2974 repeatable and ES. was single digits with H4895 and RL-15. So for long range guys 28" will give you 3000, short range that barrel length was on a 13.5 legal heavy gun. I will soon will working with the 12 twist barrel with Barts 80gr. BT. with the .060 free bore reamer but after 8 twist groups it will be hard to beat......... Jim
Click to expand...

I think you're talking in a bit of shorthand because you already have everything in your head. I don't have that knowledge so it seems to me that some dimensions are missing i.e. length from base to shoulder, base to start of neck etc. In other words, what are all the dimensions I would give PTG or JGS to make this reamer from scratch?
 
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