6BR verses 6 Creedmore
- Thread starter dreever
- Start date
B Nettesheim
Gold $$ Contributor
One is on the cover of magazines one is not
Well the 6br doesn't shoot farther than 600yds, right? Just falls right outta the sky. Thats why the dasher was created 
Less wind drift and more energy. The difference in wind drift at 1000Y with a 5mph wind coming from 3 oclock is approx 9", favoring the 6 Creed.
Let's look at it the other way. The BR get's about double the barrel life, uses approx 10 grains less powder and has less recoil.
A good point ........... but I've read many times that shooters said the same of the .30-06 when 308 win first appeared. ......... and there were initially many sceptics too over the PPCs when they were introduced in short-range BR, only now the records were held by the .222 Rem and the 6X47mm (ie the 6-222Mag version).
It's not that I necessarily disagree with you, but would just point out it's a mite early to know if the 6mm Creedmoor will turn out to be one of those game-changing designs that come along every generation or so. I know several people who are trying it out in mid-range F-Open this year as a replacement for shot-out BR, Dasher and 6.5X47L barrels. Last year there were none, it is that new. They may all go back to those cartridges in a season or two .... or they might not.
Oh dear, you must be a bit torn up here Grimstod. On the one hand you hate anything with the Creedmoor name in it. On the other hand, you worship anything with the word Lapua in it. .......... and why are people looking at 6mm Creedmoor? Well because it is in the same capacity / performance bracket as the 6mm Long Dasher and 6-6.5X47 Lapua AI, 6XC and suchlike but as a factory round ... and the clinching factor is 6.5 Creedmoor Lapua manufactured small primer brass that becomes 6mm with a single pass through the smaller version's sizing die. Throw in some new very high BC heavier bullets such as the 110gn SMK that the larger case can handle better, likewise being better able to handle 115s than the smaller sixes .....
Sweet nightmares, my friend!
Grimstod
Machinist, Designer, and Shooter.
Does it give you nightmares? You brought it up. And no I Do not hate the 6mm Creedmoor. I actually think it is superior to the 6.5 parrent case.
I suspect some others on this thread have taken it with disrespect
(to the 300 Win Mag and by negative association hence to the 6mm Creedmoor). I lean towards an interpretation about this referring to case capacity and charge size between cartridge designs of a common calibre, hence an apples and oranges comparison as between .222 Rem, .30-06 and .50BMG despite the three having very similar relative dimensions but in very different scales.To those who might see the .300 Win Mag as somehow inferior to the 308 perhaps they ought to do a little digging into the history of their sport and discover how many competition records it held in its day. The .300 belted magnums ruled at Camp Perry for decades in any calibre sling shooting and the Wimbledon Cup, from Ben Comfort in 1935 with the .300 H&H Magnum, then in the late 1950s / early 60s the .30-338 Win Mag wildcat before Winchester introduced the .300 WM as the last of its quartet of what were then called 'short magnums' when it took over this role until the 6.5-284, etc, etc appeared in the 1980s or even 90s. The 300WM has won a lot of 1,000 yard BR Matches over the years and no doubt held world records too for periods. A better modern comparison would be between the 308 and .300 Rem SAUM.
On the other side of this ledger, perhaps people should ask themselves just how would 308 Win use be holding up today if it weren't the ICFRA mandated cartridge (alongside 223 Rem) for Fullbore / Target and Palma Rifle, Match Rifle and the FTR division of F-Class. I can remember the hot 'sniper' competitions of not so many years ago ... all 308 Win, but that was the sole cartridge allowed in the rules. Then the smaller 6.5s started being allowed in some jurisdictions, and in no time at all 308 Win is no more, no more ....
or as Quint sang in 'Jaws': 'Farewell and adieu'
No ... it certainly doesn't give me nightmares. I don't use it and doubt if I ever will .... but I'm watching with interest to see how it works out on the ranges as I would any interesting new development.
....... and if the people I know adopting it for the 2018 season who are very serious and accomplished competitors indeed were to read your summation of 6mm Creedmoor users
The only thing the 6CM has is a bunch of noobs that want to be tacticool.
....... they might feel a bit aggrieved and insulted, but I think they're more likely to laugh and move on.
Going back to the original question, if you take the Lapua small primer 6.5 Creedmoor case and neck it down to 6mm to get to the 6mm version (and I assume maybe the Peterson Cartridge Co. SR primed version of same too, but I can't comment never having seen one on this side of the Atlantic) the Creedmoor is really just a lengthened case version of the BR.
Case water capacity increases from around 38gn to around 54gn or 40%. The internal ballistics rule of thumb is that if everything else is equal (bullet, barrel length, peak pressure, powder characteristics other than burning rates which will be different if optimal) then the MV % increase = the case capacity increase divided by four. In this example 40 over 4 = 10% performance improvement. So if the 6BR gives a 105gn bullet say 2,800 fps MV in a particular barrel length at peak loading, then the Creedmoor should be able to get another 280 fps making it 3,080 fps MV.
Both cartridges use identical case-head and web set-ups, both have 30-degree shoulder angles, both have adequately long necks (the 6BR longer than necessary for good performance hence the success of the Dasher whose fireforming reduces the parent case's neck-length considerably). I can't comment on case taper off the top, but doubt if they're that much different.
It adds another way-step in what is a range of competition 6mm cartridges, old and new.
At the bottom of the case-capacity ladder you have the trio of wildcats based on the 222 Rem 'family', the largest of them the 6X47mm (6mm-222 Rem Magnum) in its day the short-range BR cartridge to beat.
Then there is the 6PPC with around 33gn water capacity.
The 6BR and its improved versions at 37gn up to around 41gn water capacity for the Dasher
6mm International at around 44gn capacity (the 250 Savage case necked down with other changes) and a steeper shoulder angle than the BR and Creedmoor at nearly 35-deg in the Harvey Donaldson version. This was touted as a possible alternative to the BR in some disciplines such as CISM 3-position shooting and nearly adopted by the US Army team many moons ago.
6mm Swiss Match and 6-6.5X47mm Lapua wildcat - very similar designs but the older 6SM uses large primer brass and is therefore inferior to the Lapua case based version. The 6SM was highly developed in Europe for 300 metre shooting, but probably never attained the widespread use or popularity of the BR which has been king for many years in Europe in the important 3-position ISSF 3-position 300 metre discipline. Around 46gn water capacity for the Swiss Match and 1.5-2gn more for the Lapua based case version. The latter has been 'improved' through fireforming on occasions too as per the 6BR to Dasher for another couple of grains capacity and is usually called the 'Long Dasher'. There are proponents of the 6-6.5X47L in mid and long-range BR and it was thought for a while it would seriously challenge the Dasher. Although taking more than a few records, it hasn't dislodged the Dasher though and seems to be losing ground these days.
That brings us to the Tubb 6XC, 6mm Creedmoor, Whitley 6mm SLR (a reformed 243 Win), 243 Win, and 6mm Rem in ascending size order with around 50gn water capacity up to 54gn. The XC, 243, SLR, and 6mm Rem use large primers as does the Creedmoor in factory Hornady form (but most people using it for precision shooting will reform 6.5CM small primer brass as mentioned). The XC, SLR, and Creedmoor have long, or long enough, necks allied to 30-deg shoulder angles and are efficient modern designs. SR primer case-head brass will be stronger and take higher pressures for longer than the others though. All feed well from magazines. the 6mm Rem has an improved wildcat version called the 6mm Crusader - a very capable mid/long-range F-Class cartridge (while the barrel lasts which isn't that long in full-pressure loadings). There are many who look down on the 243 with its relatively short neck and 20-degree shoulders, but John Whidden keeps winning long-range sling shooting matches and championships with it. (I do prefer the Robert Whitley's 'SLR' variation though where a pass through the sizer die bumps the shoulder back to produce the XC's longer neck and 30-degree shoulders.)
Then finally, although I'm sure I'll have missed something, there is the 6-284, a necked down 284 Win or 6.5-284 Norma case and a one-time favourite of long-range precision shooters. Superb ballistics but a barrel burner. A very strong and efficient rebated-rim case design with 35-deg shoulders.
All of these cartridges have been or are still being used in competition in original factory or improved wildcat forms. With fast-twist barrels and heavy bullets everything from 6mmBR up is 1,000 yard capable.
Magazine feed aside, they all have pros and cons. As a general rule, the smaller the case and powder charge to bore size, the easier it is to shoot, the less stress put on the action and barrel and therefore the opportunity to attain very high precision increases. The larger cased versions give higher MVs and therefore with any given bullet weight less wind drift, also often allow the cartridge to work better with heavier bullets (115s for 6mm instead of 105-108s). This can be particularly important to prone shooters with their longer courses of fire and targets pulled for every shot allowing far more time for the wind to change compared to a fast 5-round BR string. As more powder is burned, efficiency drops as does barrel life, heat and recoil increase, and while it may not be impossible to get as good precision as in the smaller cartridges, it definitely becomes harder. So as always it is swings and roundabouts - gain on one, lose on the other; put crudely precision v external ballistics.
So putting PRS and other 'tactical' type shooting to one side with their need for snap shooting, low recoil, flat trajectories, high-cap magazines giving flawless operation etc, the 6mm Creedmoor will generally give higher scores than the 6BR / Dasher in mid-range F-Class and other such disciplines if the wind is blowing all over the place, but not necessarily so in calmer conditions. At long ranges, it will outperform the BR (but in its turn be at a disadvantage to 6.5s and sevens) in such matches in all but the gentlest of conditions.
In BR, as a rule, things are reversed unless the conditions are horrible as the BR's inherent outstanding precision beats almost anything if the shooter can avoid suffering a wind change mid string.
You couldn't pay me to chamber a 6 Creedmoor.
Meanwhile, you couldn't stop me from chambering another 6BR
Which is your favorite so far, 6x47, 6 Dasher, 6BRA, 6BR?
Kevin sure does good with his Dasher but a while back he sent me the 6BRA links. Is your group, over there Colorado way, changing over to BRA ???
I'm shooting 6x47 still because the barrel is doing well but I might switch over this summer to something smaller.
MarkS
Silver $$ Contributor
At one time it took a big 30 Cal. to shoot long range. Now 6mm are Kicking Ass everywhere. I have set between 30 cal's on 1000yds benchrest line and beat both of them. That was back in 2000' not many of us were shooting 6mm then, not the case now. I have had a 6XC, to get more speed, and it did not make the cut in 600 yds benchrest, it would 3" groups all day, but at the time it took 2" or less. I had the XC chamber cut off and a chambered a 6 BRX, groups dropped to 2" and less. When the 6.5 x 47L came out a 5 of my friends tried the 6mm x 47L, same as the 6XC, they could not run with the 6BR, 6BRX, 6brdx, or Dasher.
The key to the 6BR and IMP's is the Lapua brass. IMO Lapua 6BR and 220 Rus is the best brass made. As far as accuracy I am staying with my 6BR and 6BRX.
I would like to see how the 6 Creedmoor would do at 600 and 1000 benchrest it should be the top round coming up for PRS and F Class type matches.
Mark Schronce
The key to the 6BR and IMP's is the Lapua brass. IMO Lapua 6BR and 220 Rus is the best brass made. As far as accuracy I am staying with my 6BR and 6BRX.
I would like to see how the 6 Creedmoor would do at 600 and 1000 benchrest it should be the top round coming up for PRS and F Class type matches.
Mark Schronce
I had the same experience with the XC, good enough for F, but not BR. Your comments on brass are interesting Mark. I know no end of people who were seduced by the Norma Dasher chamber and brass thanks to the long neck and getting rid of the need to fireform basic 6BR. I can't decide if they made a mistake yet, but it certainly doesn't seem to have proven to be the proverbial answer to the maiden's prayer so far. For my first Dasher, I've stuck with the traditional Lapua brass / fireform route.
I think with you that the 6mm Creedmoor will turn out to be an excellent F-Class cartridge especially for those who like to shoot sixes and nothing but sixes. BR? As you say, it'll likely prove another 6-6.5X47L - good enough to win on occasions in the right hands, but not good enough to win consistently.
Still, like the 224 Valkyrie and other innovations, it's always fascinating to see something new and watch how it works out in practice. And as they say, nothing ventured ... nothing gained. If nobody tried anything we'd still be shooting .30-06 and 303 if not .45-70 and .450/577 'Short Boxer'.
You got that right, man!
........... especially with 'mandatory' 173gn RNFMJ and RNSPs out front!
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