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what 6mm
- Thread starter Booney
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Trickymissfit
Well-Known Member
if your seeking a great barrel life with very good accuracey the first round to look at it the 6BR. Super efficient with a well designed case. Also well known for shoot far better than it looks on paper. Alot of guys like the Dasher, but I'd go with the 6x47L before I'd even consider the Dasher. The Dasher ain't exactly the greatest case design even though it evolves out of the 6BR. Just takes the 6BR's strong points and creates another problem. The 6XC should be OK, but you can do better as it comes with it's own set of problems. The 6BG is probably better than the 6X47L, but it's not enough to worry about. The 6/250 (XC or whatever somebody lays claim to) can be built out of 22-250 brass and several others. It's problem is that even with standard .243 Winchester brass being used to form the case you end up with too short a neck length. The 6BG is pretty much nothing but a stretched 6BR, but keeps the better neck and shoulder design. The 30 degree shoulder seems to do better with the dreaded doughnut than the 40 degree shoulders do. If you form your cases from .243 brass the case will shrink less, but still be about .330" at the neck.
After you look at these rounds, you move upto the big boys. The first would be the .243 Winchester. Known to be hard on barrels, and dosn't handle 100+ grain bullets as well as we'd like due to the base of the bullet often ending up in the shoulder area. The T.P. point is out at the case lips edge and that means a horrible throat life. But had an enterprising person been smart, and simply reamed the chamber with a 6mm Ackley reamer to a .243AI headspace he'd have one hot momma! Of course the cases would have to be formed out of 6mm Remington brass instead of .243. Barrel life would probably be double. Still kinda inefficient when compaired to the little 6BR. But the .243Ackley is now moved into the slightly overbore condition. No problem if your into the 100 grain bullets, but not so hot with 80 grain bullets or lighter. The 6mm is the next step upwards, and will have a much greater barrel life than the standard .243, but as Ackley said the case is about it for a 6mm bullet without going into overbore. The 6mm Ackley is overbore, but if you use the 105 thru 107 grain bullets it tends to over come most of this. There is the 6mm Vias, and this is a hot number! Nothing much but a 6.5x55 necked down to 6mm and improved. The shoulders are set back about .05". It'll push a 70 grain bullet faster than a Swift can push a 50 grain bullet! Still works far better with the heavier bullets. After this you get into the way overbore stuff that do only slightly better than a 6mm Ackley and eat barrels up
the 6HLS will drive a 107 grain bullet to about 2800fps without too much trouble (maybe even 2875fps). Not all that much slower than the standard .243 even though the case volume is less. The 6BR will drive the same bullet to about 2800fps! The 6BG will do 2975fps on even less powder. The .243 will do about 3000 fps with a very hot max load. (I think the 6BG uses 77% of the powder). The 6mm remington will drive the same bullet to about 3100fps (some say 3150fps). The 6mm Ackley is good for about 100 to 150fps more velocity in a very stiff load.
gary
After you look at these rounds, you move upto the big boys. The first would be the .243 Winchester. Known to be hard on barrels, and dosn't handle 100+ grain bullets as well as we'd like due to the base of the bullet often ending up in the shoulder area. The T.P. point is out at the case lips edge and that means a horrible throat life. But had an enterprising person been smart, and simply reamed the chamber with a 6mm Ackley reamer to a .243AI headspace he'd have one hot momma! Of course the cases would have to be formed out of 6mm Remington brass instead of .243. Barrel life would probably be double. Still kinda inefficient when compaired to the little 6BR. But the .243Ackley is now moved into the slightly overbore condition. No problem if your into the 100 grain bullets, but not so hot with 80 grain bullets or lighter. The 6mm is the next step upwards, and will have a much greater barrel life than the standard .243, but as Ackley said the case is about it for a 6mm bullet without going into overbore. The 6mm Ackley is overbore, but if you use the 105 thru 107 grain bullets it tends to over come most of this. There is the 6mm Vias, and this is a hot number! Nothing much but a 6.5x55 necked down to 6mm and improved. The shoulders are set back about .05". It'll push a 70 grain bullet faster than a Swift can push a 50 grain bullet! Still works far better with the heavier bullets. After this you get into the way overbore stuff that do only slightly better than a 6mm Ackley and eat barrels up
the 6HLS will drive a 107 grain bullet to about 2800fps without too much trouble (maybe even 2875fps). Not all that much slower than the standard .243 even though the case volume is less. The 6BR will drive the same bullet to about 2800fps! The 6BG will do 2975fps on even less powder. The .243 will do about 3000 fps with a very hot max load. (I think the 6BG uses 77% of the powder). The 6mm remington will drive the same bullet to about 3100fps (some say 3150fps). The 6mm Ackley is good for about 100 to 150fps more velocity in a very stiff load.
gary
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liltank
Well-Known Member
Gary, whats the 6BG... parent case, etc?
Trickymissfit
Well-Known Member
cases are usually formed out of .243 brass. The shoulder length is about 1.45" (I don't have the blue prints in front of me right now). The shoulder angle is 30 degrees, and the neck length is .35". Pretty much uses a full .243 case to form the case. Round is head spaced off a standard .300 savage headspace gauge, and I think the over all length is right at 2.04". Even with case shrinkage figured in, your gonna have a .32" or greater neck length to help you. Kiff has the reamer prints and head space gauge. The idea of using the .243 brass is that there is less movement of the brass during fire forming. Kinda like a Dasher on seroids with a much better neck design
gary
Trickymissfit
Well-Known Member
another nice thing about the 6BG is that it just dosn't need a 26" barrel. A 24" barrel will work nicely.
gary
liltank
Well-Known Member
See, that is what I'm trying to decide. I wanted to go 6BR. But then I got to thinking the Dasher would give me the same accuracy potential as the BR with a little more horsepower. I am thinking of using the 105 Berger Hunting or the 105 A-max. I am mainly going to use this for a high volume of fire rifle for varminting and try my hand at F-open. I want something that will get me to 1000 with good accuracy, but not burn the barrel out in the first season of usage. That is where I figured the Dasher and highly considering the straight 6-250 Rem. I figured neither are really that overbore and should sustain a barrel life of 5-7000rnds. Am I on the right track? What kind of barrel life would I expect from the BG? I am also considering the possibilities of using the 115's.
blipelt
Well-Known Member
The fact is barrel life and caliber depends on what you plan to do. Hunting rifle doesn't really matter what you use.
Calibers are regional and bias. Fact is I am favorable to a 6Dasher since one of the best benchshooters in the country lives here and was the first to use one. Information and help is easy to get. I know the history of the caliber, characteristics, and all the National Titles this little caliber has won since 2003.
Brent
Calibers are regional and bias. Fact is I am favorable to a 6Dasher since one of the best benchshooters in the country lives here and was the first to use one. Information and help is easy to get. I know the history of the caliber, characteristics, and all the National Titles this little caliber has won since 2003.
Brent
Trickymissfit
Well-Known Member
punching paper wether formal or informal is a form of target shooting. Big cases just don't do as well as some of the smaller ones. But the ideal prize is a case that's sized right and yet has the needed umph to take you to the yardage your shooting at. A thousand yards is pretty much the limit for a 6mm bullet, and honestly the 6.5 will do you a better job. (or a 7mm) The 6/250 is a nice little round, but it looks like the throat's gone at around the 1200 to 1400 shot mark. The improved version is slightly better, but nearly as much as must of us shooters would have hoped it'd be. The Ackley version is pretty good, but would be much better reamed with a 6mm Ackley reamer instead of the 6/250AI reamer. They have the same shoulder diameters and the same taper per inch, but the 6mm Ackley has a much better neck length. Unlike the .243AI or the 6/250AI. You ream it with the 6mm Remington improved reamer, and headspace it off a .250AI gauge. The 6BG works exactly the sameway, but uses a .300 Savage headspace gauge. That round fits nicely between the Dasher and the 6/250 improved, but with a .35" neck length. The 6SLR is really nothing much but a 6mm HLS improved that has another .010" added to the shoulder. That round has been done several other times with a 1.56" shoulder and a slightly different neck length, and also with the 40 degree shoulder as well. Great round by the way! The 6mm SLR necked upto 6.5 would be an even better round in my book
Right now there seems to be an interesting resurgence into the 6.5x57 improved case design. There are several out there with only minor differences. One uses plain jane necked up .257 Roberts cases with a 30 degree shoulder and the standard Ackley tapers (Kiff has the reamer prints on file). But others prefered the 40 degree ackley version. This seems to be a serious 1000 yard round that fits nicely between the .260 Remington and the 6.5-06. Dies are easy to come by as all you need is a .257 Ackley bushing die and you open up the seater to fit the 6.5 neck diameter. Recoil will be somewhat stiffer than the smaller 6mm cases, but you get .55 and up B/C's, verses .50 for a 105 Amax (the 107 Sierra being slightly higher)
gary
Trickymissfit
Well-Known Member
a lot of guys are using the Dasher, and a lot of guys are having problems with the Dasher as well. Fire forming cases seems to be a problem with a lot of folks. Some guys are seeing a lot of neck splits too. The 6BG would flat smoke a Dasher seven days a week with less trouble forming cases. But on the otherhand the Dasher starts out using better brass, but as I said before creates other issues. If you used Lapua .243 brass to form the cases I see no advantage but a longer barrel life.
gary
CB11WYO
Well-Known Member
I've got a 6x47 and a 6AI but I would really recommend the 6x47.
I'm using a 30" Lilja so 39 gr H4350 will make 95 gr Match Kings go 3100 fps (as good or better than many standard 243 Winchesters, to my knowledge).
As long as it's built right it's a super accurate and efficient round. (see attached picture)
As for deer and antelope it will do that too. I've killed antelope from 450 to 825 yds with it (at 800+ it's running out of energy so ya gotta hit 'em good
).
And it's extremely pleasant to shoot.
Best of Luck,
I'm using a 30" Lilja so 39 gr H4350 will make 95 gr Match Kings go 3100 fps (as good or better than many standard 243 Winchesters, to my knowledge).
As long as it's built right it's a super accurate and efficient round. (see attached picture)
As for deer and antelope it will do that too. I've killed antelope from 450 to 825 yds with it (at 800+ it's running out of energy so ya gotta hit 'em good
).And it's extremely pleasant to shoot.
Best of Luck,
Attachments
Hunter2678
Well-Known Member
All good info here..I myself love the little plain ol 6br. Any perceived shortcomings IMO can be overcome with nothing but a bit more practice, and thats something that the 6br can give you at an affordable level. I know some guys that I shoot with use the 6x47 for our 1000 yds matches and they definitely have more horsepower than my br does however they all seem to have more issues @ 850+ yds with vertical than I do. Just something to think about. Having said that if I ever build another 6 it will be a 6x47 hands down. Great brass, still good barrel life, great bullets & relatively low recoil to get you to 1000 yds .
Trickymissfit
Well-Known Member
I made an error in my post, and got to thinking about it awhile ago. The data in the Hornaday manual for the .300 Savage is incorrect! It should have a 1.55" shoulder length, and the 6BG has an over all length of 2.040" max. There was actually two different 6BG's. The first one has the same taper perinch as the .300 Savage, and the second one has the same taper as the .243 and 6BR per inch. Personally I'd rather have the .010" taper per inch that Ackley used, but with the 30 degree shoulder. All Bob did was to simply fix the short commings of the .243 Winchester, and yet still use their brass.
gary
gary
blipelt
Well-Known Member
Gary I can't say I had any problems with the 600 brass I fireformed last year. I split 4! But then again like I posted before help is close and experience well no one else compares. I look forward to seeing the 6 BG in Calf. next month at the benchrest and F-Bench Nationals. I am sure if it is good as you say some will be shooting it. Guess we will see what comes out on top.
Brent
Brent
Booney
Well-Known Member
hey cb what about the 6-47 do you like better over the 6AI ?
