BR case
- Thread starter Northman
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Forum Boss
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Well, there are a lot of factors. The two most important things are probably the small flash hole design and the consistency of the brass. As to the latter, we've sectioned brass from various manufacturers, and we can say that the Lapua brass is normally very very good, and the flash hole area is very consistent case to case. Weight is very consistent also.
To give you an idea. I weighed 40 loaded 6BR cases recently. These were charged with Norma 203B, weighed to the tenth of a grain, as well as I could with a PACT scale. I triple checked each charge. I trimmed the cases to length, but didn't touch the flashholes or primer pockets. Get this. With bullets and primers in place, about 1/4 of the loaded rounds weighed exactly the same down to 0.1 grain. Another were within 0.3 grain or so, high or low.
The BR case also has a shoulder angle that has proven to be very accurate in the 6PPC case. And the small primer pocket seems to deal with high pressures better than a large primer pocket. I know I can push my Lapua 6BR cases to higher pressures than even Lapua .243 brass.
Relatively high pressures combined with near 100% load density gives consistent combustion and low ES and SD.
Factor all these things together, and it's hard to beat the 6BR case as a parent for both larger and smaller wildcats.
We have asked Lapua to bring out a version with about 5gr more capacity, retaining the long neck. This would be like a Long-necked Dasher, and would let you shoot the 115gr DTAC bullet, or the 123gr Scenar in a 6.5BR.
To give you an idea. I weighed 40 loaded 6BR cases recently. These were charged with Norma 203B, weighed to the tenth of a grain, as well as I could with a PACT scale. I triple checked each charge. I trimmed the cases to length, but didn't touch the flashholes or primer pockets. Get this. With bullets and primers in place, about 1/4 of the loaded rounds weighed exactly the same down to 0.1 grain. Another were within 0.3 grain or so, high or low.
The BR case also has a shoulder angle that has proven to be very accurate in the 6PPC case. And the small primer pocket seems to deal with high pressures better than a large primer pocket. I know I can push my Lapua 6BR cases to higher pressures than even Lapua .243 brass.
Relatively high pressures combined with near 100% load density gives consistent combustion and low ES and SD.
Factor all these things together, and it's hard to beat the 6BR case as a parent for both larger and smaller wildcats.
We have asked Lapua to bring out a version with about 5gr more capacity, retaining the long neck. This would be like a Long-necked Dasher, and would let you shoot the 115gr DTAC bullet, or the 123gr Scenar in a 6.5BR.
Ok. Thanks for the reply. A question then.. if this case is so efficient, why has nobody,don't know if it has been attempted) made a larger case? You said you were trying to get laupa to make it take 5 grains more powder. But what if someone would try to make it larger? Say X% bigger, so it would both take more powder, and be able to shot heavier bullets..
If you could get it up into the 140-170 grain bullets of the 6,5 or 7mm, and increase powder, you would get a outstanding cartridge.
I'm a very new beginner here, so I'm just asking. Am I the only one thinking about this? Or..
If you could get it up into the 140-170 grain bullets of the 6,5 or 7mm, and increase powder, you would get a outstanding cartridge.
I'm a very new beginner here, so I'm just asking. Am I the only one thinking about this? Or..
Forum Boss
Administrator
As to the larger case here are a couple things to consider.
Out to 600m or so, against paper, it's not clear that you will have any advantage by going to a heavier bullet.
For across the course competition, David Tubb has come up with a new design, the 6XC, basically a 6-250. But, the brass isn't as consistent, and you burn quite a bit more powder. Cases this size and larger also appear to need a large primer, so you loose that advantage of the 6BR case.
RUAG has come out with a larger BR style case--the 6x47 Swiss Match. Thus far however, at least in 300m competition, it has not proven superior to the 6BR.
The closest thing to what you may be describing is something like the 6x44 wildcat, which was used by Joel Kendrick to set a number of 600-yard world records. There is a full write-up of the 6x44 on this site. The negatives are that case-forming is extremely time-consuming.
As for pushing a 140-grainer, many, many different cases have been tried. The problem is that these bullets have a long bearing surface so you need a good deal more powder to drive them. Though it is not ideal, the 6.5-284 is probably the accuracy king for long distance in the 6.5 caliber ... at least so far.
Coming full circle, once you move into heavier bullets, with bigger cases, and more powder, you start to sacrifice many of the advantages of the 6BR, namely low recoil, efficiency, ease of load development.
I should know. I campaigned a Rem 260,6.5-08) for 3 years. It would drive a 123gr Scenar about 2950 fps or a 139gr Scenar about 2840. Out to 600 the 6BR has proven more accurate, much more consistent, easier to tune, and it gives up very little ballistically. There are fewer brass issues with the 6BR, you get much less recoil, barrel life is longer, and it's less costly to load because you use 15 grains less powder.
Is the 6BR perfect? No. We think something like a 6mm Dasher with a long neck would be better for shoting long-range with heavy bullets. But it performs awfully well as it is, and in the 30BR format, nothing can touch it in BR score shooting.
Out to 600m or so, against paper, it's not clear that you will have any advantage by going to a heavier bullet.
For across the course competition, David Tubb has come up with a new design, the 6XC, basically a 6-250. But, the brass isn't as consistent, and you burn quite a bit more powder. Cases this size and larger also appear to need a large primer, so you loose that advantage of the 6BR case.
RUAG has come out with a larger BR style case--the 6x47 Swiss Match. Thus far however, at least in 300m competition, it has not proven superior to the 6BR.
The closest thing to what you may be describing is something like the 6x44 wildcat, which was used by Joel Kendrick to set a number of 600-yard world records. There is a full write-up of the 6x44 on this site. The negatives are that case-forming is extremely time-consuming.
As for pushing a 140-grainer, many, many different cases have been tried. The problem is that these bullets have a long bearing surface so you need a good deal more powder to drive them. Though it is not ideal, the 6.5-284 is probably the accuracy king for long distance in the 6.5 caliber ... at least so far.
Coming full circle, once you move into heavier bullets, with bigger cases, and more powder, you start to sacrifice many of the advantages of the 6BR, namely low recoil, efficiency, ease of load development.
I should know. I campaigned a Rem 260,6.5-08) for 3 years. It would drive a 123gr Scenar about 2950 fps or a 139gr Scenar about 2840. Out to 600 the 6BR has proven more accurate, much more consistent, easier to tune, and it gives up very little ballistically. There are fewer brass issues with the 6BR, you get much less recoil, barrel life is longer, and it's less costly to load because you use 15 grains less powder.
Is the 6BR perfect? No. We think something like a 6mm Dasher with a long neck would be better for shoting long-range with heavy bullets. But it performs awfully well as it is, and in the 30BR format, nothing can touch it in BR score shooting.
OK, I won't keep you waiting. I "designed" this cartridge about 4 years ago for the exact same reasons talked about above. It uses the old Rem Basic BR Brass with the small primer pocket. Push the shoulder back with several dies, trim, and fireform. I would say the Rem brass is maybe not quite as good as the Lapua but it is a lot better than a lot of guys give it credit for. I shot the Sierra 107 SMK and the Berger 105 VLD. Loads were not much different than what are used in the Dasher, I think I may have gone about one grain higher because I was able to seat the bullets way out, gaining a little more capacity. Bottom line was that I was able to get similar velocities with a little less pressure and about the same accuracy. Do I still use it? No. IMHO the 6BR is a great 600 yard cartridge without any changes. Again IMHO when you get out to 1000 yards the small 6mm cartridges such as the BR and its improved versions can only compete with the mid-size such as the 6XC, 6x250, 6 HLS, etc by really pounding the brass. So why try and make a great 600 yard cartridge into a 1000 yard cartridge? This is especially true now that the 115 DTAC is proving to be a good bullet. You simply need more powder and a 45 to 50 grain H2O case is about right. For the guy who can only afford one rifle the Dasher may be the best compromise out there but at 1000 yards it is still just that, a compromise.
Ray
Ray
Well, the round I was thinking about, was supposed to be used for paper, and to hunt the large game, I need atleast 140grains, with 2000ft/lbs at 100yards. So, I figur, if I can get that from both a very accurate paper puncher, and a hunting round it would be all good.
Right now, the 6BR is good for the hunting I usually do,bambi
), but since I can't buy rifles to the right and left of me, I want the best of both worlds. Increasing the case by say 30%, just blowing all the measurments, I would imagin you would get an exellent round, without all the troubles from the magnums?
Remember, this is all just fantasy, but could it be possible? Sounds very familiar like the WSM and RSAUM's..
Feel free to kill the dream :cry: hehe..
For the moment I'm thinking about the 280Rem or 6.5-06, but don't have enough information on them to really set things in motion an build them.
Right now, the 6BR is good for the hunting I usually do,bambi
), but since I can't buy rifles to the right and left of me, I want the best of both worlds. Increasing the case by say 30%, just blowing all the measurments, I would imagin you would get an exellent round, without all the troubles from the magnums?Remember, this is all just fantasy, but could it be possible? Sounds very familiar like the WSM and RSAUM's..
Feel free to kill the dream :cry: hehe..
For the moment I'm thinking about the 280Rem or 6.5-06, but don't have enough information on them to really set things in motion an build them.
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