Case capacity of the 6x47 Swiss match and the 6-22-250
- Thread starter JOHN708
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JOHN708
Silver $$ Contributor
Chris, Thanks for your response.
I'm looking to drive 115's at 2900-3000 fps. with 2500 rds barrel life out of a long range gun. From what I've read the 6BRX/Dasher will do that,2950fps) with slightly less powder than the 6-22-250, with possibly slightly better accuracy. If I want more velocity with less barrel life I'll probably be better off with the 6XC. If 6-47sm brass becomes readily available, that may be a better choice.
John
I'm looking to drive 115's at 2900-3000 fps. with 2500 rds barrel life out of a long range gun. From what I've read the 6BRX/Dasher will do that,2950fps) with slightly less powder than the 6-22-250, with possibly slightly better accuracy. If I want more velocity with less barrel life I'll probably be better off with the 6XC. If 6-47sm brass becomes readily available, that may be a better choice.
John
My 6/250 case using Win 250 Savage brass holds 46.6g of water un-fireformed, formed she holds 50.6g of water. The 6XC I have, made on a WIN 22-250 Rem case, fireformed, holds 49.5g of water. This is with a hair of dish soap to break the water tension and the cases were filled to level with not water visable above the case neck. These two cases are so close it is not funny.
6/250 on the left fireformed, 6XC on the right fireformed.
Going to the range today for fireform some 308 Lapua made into 6/250. I'll let you know what these hold after forming too. As for speed, the 6/250 will push 'em well past 3000 fps in a 30" barrel, as will the 6XC.
Update:
So I'm back from the SWF rifle range, it's the next day now.
The 38.3g load of H4350 with 210M's and 105 Lapua bullets with the 308 Lapua cases formed into 6/250's did not show any pressure signs and were going 3070 fps with the 28" 6mm barrel!
Water capacity of the 308 Lapua's fire formed into 6/250 is 48.7g water, 308 URBR brass fire formed into the 6-250 holds 50.3g H2O and WW 250 Sav into 6-250 holds 50.6g of H2O.
6/250 on the left fireformed, 6XC on the right fireformed.
Going to the range today for fireform some 308 Lapua made into 6/250. I'll let you know what these hold after forming too. As for speed, the 6/250 will push 'em well past 3000 fps in a 30" barrel, as will the 6XC.
Update:
So I'm back from the SWF rifle range, it's the next day now.
The 38.3g load of H4350 with 210M's and 105 Lapua bullets with the 308 Lapua cases formed into 6/250's did not show any pressure signs and were going 3070 fps with the 28" 6mm barrel!
Water capacity of the 308 Lapua's fire formed into 6/250 is 48.7g water, 308 URBR brass fire formed into the 6-250 holds 50.3g H2O and WW 250 Sav into 6-250 holds 50.6g of H2O.
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This is from the November Blog Archives. Note this is with pre-production prototype brass. My measurements of H20 capacity, with a spent primer inserted were 46.9-47.0 grains. NOTE: the samples we received had a LARGE flash-hole and large primer pocket.
At Shot Show Lapua told us the production run will almost certainly utilize small flash hole and small primer pocket.
HOT NEWS--6.5x47 Lapua Samples Arrive Today:
A couple dozen sample 6.5x47 cases arrived today via airfreight from Finland. Christmas came early. Powder capacity is 46.9-47.0 grains H20 and the cases have LARGE Primer Pockets. We've only had the samples for a few hours as this is written. The brass looks great--very consistent with extremely well-finished primer pockets and flash holes. We did not have a tubing mic handy, but the neckwall thickness looks very uniform.
We weighed 15 cases. Right out of the box, untrimmed, the 6.5x47 brass proved extremely consistent weight-wise. Weight Extreme Spread was 0.5 grains, with an SD of 1.708 grains. Recorded weights were: 159.3, 159.5, 159.0, 159.4, 159.4, 159.1, 159.3, 159.1, 159.2, 159.1, 159.0, 159.5, 159.4, 159.2. Run-out, measured at the shoulder, was under .001",one-thousandth). On most of the cases, the needle did not move past the half-way point between thousandths markers. Very impressive.
Other 6.5x47 Lapua Characteristics and Measurements:
1. The primer pockets are LARGE, as is the flash-hole.
2. At 1.836" OAL, the case is a bit shorter than a 6XC. The 6.5x47 is .280" longer than a 6mm BR Norma case.
3. The H20 Capacity,with primer in place), is 46.9 grains, based on our actual measurements, filled to over-flow.
4. The shoulder,.451-.452") is slightly narrower than a 6BR case--our Lapua factory-loaded 6BR ammo is just over .457" at the shoulder.
5. The neck is SHORTER than on a 6BR case, measuring about .275" compared to .322" for a 6BR. The neck is still long enough to get a long, VLD-style bullet up out of the doughnut area.
At Shot Show Lapua told us the production run will almost certainly utilize small flash hole and small primer pocket.
HOT NEWS--6.5x47 Lapua Samples Arrive Today:
A couple dozen sample 6.5x47 cases arrived today via airfreight from Finland. Christmas came early. Powder capacity is 46.9-47.0 grains H20 and the cases have LARGE Primer Pockets. We've only had the samples for a few hours as this is written. The brass looks great--very consistent with extremely well-finished primer pockets and flash holes. We did not have a tubing mic handy, but the neckwall thickness looks very uniform.
We weighed 15 cases. Right out of the box, untrimmed, the 6.5x47 brass proved extremely consistent weight-wise. Weight Extreme Spread was 0.5 grains, with an SD of 1.708 grains. Recorded weights were: 159.3, 159.5, 159.0, 159.4, 159.4, 159.1, 159.3, 159.1, 159.2, 159.1, 159.0, 159.5, 159.4, 159.2. Run-out, measured at the shoulder, was under .001",one-thousandth). On most of the cases, the needle did not move past the half-way point between thousandths markers. Very impressive.
Other 6.5x47 Lapua Characteristics and Measurements:
1. The primer pockets are LARGE, as is the flash-hole.
2. At 1.836" OAL, the case is a bit shorter than a 6XC. The 6.5x47 is .280" longer than a 6mm BR Norma case.
3. The H20 Capacity,with primer in place), is 46.9 grains, based on our actual measurements, filled to over-flow.
4. The shoulder,.451-.452") is slightly narrower than a 6BR case--our Lapua factory-loaded 6BR ammo is just over .457" at the shoulder.
5. The neck is SHORTER than on a 6BR case, measuring about .275" compared to .322" for a 6BR. The neck is still long enough to get a long, VLD-style bullet up out of the doughnut area.
JOHN708
Silver $$ Contributor
Some final thoughts on 6mm case capacity.
I obtained some 6-22-250 brass to check volumes for myself. H2O capacity wasn't 44gr. but 45.6,10 trial avg.) Capacity increased over the 22-250 by 1.6 grs. secondary to case mouth expansion. Max. capacity at the neck shoulder junction was around 38 gr. of H4350.
If the 6.5x47sm max. case capacity in H2O is 47 gr. My guess is it would be about 45.5 grs. necked down. I'm not sure either case has the capacity to drive 155's much past 2950 fps.
I've concluded that it you want increased barrel life and are willing to settle for 2900-2950fps with a 115, the 6Dasher/BRX is the way to go. The 6x47sm and the 6-22-250 are essentially the same cartridge. Neither seem to be as efficient as the 6br improved. I believe the 6br improved probably holds a slight accuracy edge over either cartridge.
If you need increased speed with the 115's the 6XC seems to be the way to go. A proven winner on the range, with enough case capacity to tune the 115 for optimum accuracy in the 3000fps velocity range.
I'd like to thank everyone who responded to my 6mm ballistic questions. You were all very helpful in narrowing down my cartridge decisions.
John
I obtained some 6-22-250 brass to check volumes for myself. H2O capacity wasn't 44gr. but 45.6,10 trial avg.) Capacity increased over the 22-250 by 1.6 grs. secondary to case mouth expansion. Max. capacity at the neck shoulder junction was around 38 gr. of H4350.
If the 6.5x47sm max. case capacity in H2O is 47 gr. My guess is it would be about 45.5 grs. necked down. I'm not sure either case has the capacity to drive 155's much past 2950 fps.
I've concluded that it you want increased barrel life and are willing to settle for 2900-2950fps with a 115, the 6Dasher/BRX is the way to go. The 6x47sm and the 6-22-250 are essentially the same cartridge. Neither seem to be as efficient as the 6br improved. I believe the 6br improved probably holds a slight accuracy edge over either cartridge.
If you need increased speed with the 115's the 6XC seems to be the way to go. A proven winner on the range, with enough case capacity to tune the 115 for optimum accuracy in the 3000fps velocity range.
I'd like to thank everyone who responded to my 6mm ballistic questions. You were all very helpful in narrowing down my cartridge decisions.
John
Old thread but interesting info. My 6 22/250 hasn't met expectations. I know seating depth was an early culprit. Now I suspect it needs more powder. Running 31.5 Varget and 107's. A lot of vertical and odd off call shots. I'm moving toward a 6 BR and thinking 600 maybe x course occaisonally. Question is with 2000 rounds should I set back and rechamber this barrel or wait a season and rebarrel to 6 BR? Mainly not sure what the life expectancy of the 6-250 is but have seen 5000 6 BR's. 28" barrel. Tired of tinkering.
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