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Is that a 75gr A-MAX in the .224x43 SPC? If so, that will be a killer. I've been reading through The Black Rifle again, and one of the main engineers with Army Ordnance felt that the case Remington was using did not have enough capacity to meet the original performance requirements that were advertized (3300fps).
He thought that the .25 Remington would have been a better case to go off of, which is fatter than .222 family cartridges. I still think 5.56 has been a major success in a military capacity, but if I could roll back time and suggest another case, I would be tempted, but I wouldn't want to mess with magazine capacity/space. Anyway, the 75gr A-MAX is a wonderful projectile, with a BC of .435 G1 value. The next one that interests me is the .257 SPC. Something about quarter-bores has always intrigued me, and my grandpa loved the .257 Roberts. I also have experience with .25-06, and it's a very flat-shooting cartridge. I think the .257 SPC will be a great hunting caliber option, especially in light of the South Carolina Game Study statistics. |
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Could you link me up please? This is looking pretty sweet. Quoted:
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Read your post on 68forums. Good stuff. Could you link me up please? This is looking pretty sweet. Been waiting for this announcement for a while now, knew something was in the work but not what. I picked up one of the 6x6.8 barrels a while back and am very happy with it , now the wait begins again 
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Is that a 75gr A-MAX in the .224x43 SPC? If so, that will be a killer. I've been reading through The Black Rifle again, and one of the main engineers with Army Ordnance felt that the case Remington was using did not have enough capacity to meet the original performance requirements that were advertized (3300fps). He thought that the .25 Remington would have been a better case to go off of, which is fatter than .222 family cartridges. I still think 5.56 has been a major success in a military capacity, but if I could roll back time and suggest another case, I would be tempted, but I wouldn't want to mess with magazine capacity/space. Anyway, the 75gr A-MAX is a wonderful projectile, with a BC of .435 G1 value. The next one that interests me is the .257 SPC. Something about quarter-bores has always intrigued me, and my grandpa loved the .257 Roberts. I also have experience with .25-06, and it's a very flat-shooting cartridge. I think the .257 SPC will be a great hunting caliber option, especially in light of the South Carolina Game Study statistics. Good eye. That is a 75 AMAX loaded to magazine length. Greg |
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Good eye. That is a 75 AMAX loaded to magazine length. Greg Any ballparks on velocity? If 23.8gr of 8208XBR pushes it at 2700fps from a 16" AR15 in .223 Wylde, I'm thinking 27.0gr will easily get it past 2900fps without having to push the pressure. That's actually a good 1000yd load at my altitudes. Will 6mm Hagar brass feed through the 6mm SPC BHW chamber? It would be insane if it didn't. 
We really need an AR12.5 guys. It would be best if the industry kept it standardized too, as the AR10 variants are an example of what not to do. Get our maximum COAL up to 2.400" or 2.500", with a common magazine and receiver set design, and take advantage of the new wave of hunting and competition cartridges in the AR family, since a lot of us already know that AR10 is a bit big for maneuverability/weight. |
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The LWRCi six8 is basically capable of that, if, someone would start making steel mags for it. The thinner steel in that magwell will allow much longer COAL than the polymer.
Also, there is enough material that it might be possible to actually machine enough away inside to allow a steel mag that will go to 2.45-2.55. At that point, we're talking the talk and walking the walk. Possibilities will open up for new wildcats and possibly some future off the shelf stuff. LWRCi is not making it proprietary, they are allowing any company to make the lowers and uppers to match according to their specs. So it should be easy to stay common on all parts. |
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Any ballparks on velocity? If 23.8gr of 8208XBR pushes it at 2700fps from a 16" AR15 in .223 Wylde, I'm thinking 27.0gr will easily get it past 2900fps without having to push the pressure. That's actually a good 1000yd load at my altitudes. Will 6mm Hagar brass feed through the 6mm SPC BHW chamber? We really need an AR12.5 guys. It would be best if the industry kept it standardized too, as the AR10 variants are an example of what not to do. Get our maximum COAL up to 2.400" or 2.500", with a common magazine and receiver set design, and take advantage of the new wave of hunting and competition cartridges in the AR family, since a lot of us already know that AR10 is a bit big for maneuverability/weight. Quoted:
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Good eye. That is a 75 AMAX loaded to magazine length. Greg Any ballparks on velocity? If 23.8gr of 8208XBR pushes it at 2700fps from a 16" AR15 in .223 Wylde, I'm thinking 27.0gr will easily get it past 2900fps without having to push the pressure. That's actually a good 1000yd load at my altitudes. Will 6mm Hagar brass feed through the 6mm SPC BHW chamber? We really need an AR12.5 guys. It would be best if the industry kept it standardized too, as the AR10 variants are an example of what not to do. Get our maximum COAL up to 2.400" or 2.500", with a common magazine and receiver set design, and take advantage of the new wave of hunting and competition cartridges in the AR family, since a lot of us already know that AR10 is a bit big for maneuverability/weight. No you can't stick a Hagar in it. It is a normal 6.8 chamber. Loading data is coming along. It has only made four trips to the desert in the last week. Like you said we need a bigger lower to handle cases with the longer bullets. The Hagar offers some extra but not enough for the virtual unobtainium brass. IMHO. Obviously the Hagar could be chambered up by BHW but it was felt the 6X6.8 they are building now would get it done. Loading long and heavy bullets at single shot length gives up nothing to the Hagar in real application. H4895 is churning up some good numbers. 8208 and CFE will get shot too. Greg |
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The LWRCi six8 is basically capable of that, if, someone would start making steel mags for it. The thinner steel in that magwell will allow much longer COAL than the polymer. Also, there is enough material that it might be possible to actually machine enough away inside to allow a steel mag that will go to 2.45-2.55. All of that would be absolutely fabulous...if they would work. But, I see a couple of possible flies in the proverbial ointment for a receiver design originally optimized for 2.26" cartridges: a. Cartridge OAL too long for reliable feeding with the receiver interior dimensions? b. Cartridge OAL too long to reliably eject unfired rounds through the ejection port? |
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I just looked at the case dimensions of the Hagar, and realized that it is as long as a .223 Rem case, meaning that it is longer than the 6.8 case. I see why it would make sense to stay with the 6.8 case over the Hagar now.
With the "AR12.5" concept, the main engineering questions that need to be answered are: * What families of cartridges would such a receiver set accommodate? * What implications does this have on the Bolt and carrier group? * If a larger bolt is used, as should be, what does this mean for the barrel extension, hoop strength, and upper receiver? How do you increase receiver barrel nut thread OD, while keeping compatibility with existing AR15 handguard options? It looks like the .30 RAR has addressed all of these questions with the upper receiver group. The AR15 really needed to be redesigned once it was re-chambered in .223 Remington, and probably chambered in a slightly larger case with the capacity to achieve the 3300fps original SCHV design goals. If that had happened though, the AR15 would have died a quick death, and never seen the light of day as a military rifle. The unintended benefits of staying with what they had led to the success of the design, and longer barrel life. Stanc: All of that would be absolutely fabulous...if they would work. But, I see a couple of possible flies in the proverbial ointment for a receiver design originally optimized for 2.26" cartridges:
a. Cartridge OAL too long for reliable feeding with the receiver interior dimensions? b. Cartridge OAL too long to reliably eject unfired rounds through the ejection port? The magazine feed lip angle is probably the biggest factor in getting cases to orient correctly into the chamber, followed by the feed ramp(s). That will have to be addressed by each magazine specific to a certain case design, with case taper, shoulder length, and shoulder angle having contributing input into a reliable magazine. The existing AR15 ejection port length is more than long enough, even for .308-based cartridges, but needs to be widened for fatter cartridges if they go larger than a Russian short/PPC/Grendel case. It's plenty fine for the .30 Remington-based cartridges, but definitely needs to be opened for the .473" and WSSM-based wildcats. As the AR15 becomes more and more the 21st Century's Mauser action, this trend of chambering it in more cartridges suitable for hunting and long-range competition will demand that the Stoner design evolve to be a little larger, while not jumping up to the AR10. If anyone doubts the marketability of an intermediate sized AR15, look at D-Tech and his 1-year wait for WSSM-based AR15's, which use a larger upper receiver, a WSSM-specific magazine, a huge bolt and I think different carrier, while still being limited to the AR15 lower's COAL constraints-the main handicap of the system, which was built around the .222 Remington in 1957. |
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Marty of Teppo Jutsu did the .30-6.8, the .30 HRT years ago along with a similarly spectacular .338 Spectre, best done of the 10mm magnum brass but can be done on 6.8 too if you don't mind trimming and reaming. My 30 HRTs will push a 110 gr to 2800 fps out of a 24 inch barrel, 2600+ out of a 16. The 5.56 x 42 or 43 were done by quite a few people and I am building one as I type, still waiting on the blank from BHW for that one. ARP did that in a 42 mm case instead of 43 mm so you can seat those long 80 gr. bullets and not be past the full diameter portion of the bullet when seated to magazine length. That does make it a little short on the 50-65 gr. bullets though. At 95% of the .22-250, that's quite a potent round.
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The magazine feed lip angle is probably the biggest factor in getting cases to orient correctly into the chamber, followed by the feed ramp(s). That will have to be addressed by each magazine specific to a certain case design, with case taper, shoulder length, and shoulder angle having contributing input into a reliable magazine. Quoted:
The magazine feed lip angle is probably the biggest factor in getting cases to orient correctly into the chamber, followed by the feed ramp(s). That will have to be addressed by each magazine specific to a certain case design, with case taper, shoulder length, and shoulder angle having contributing input into a reliable magazine. Thanks. That sounds reasonable. The existing AR15 ejection port length is more than long enough, even for .308-based cartridges... Hmm. So is there no difference in ejection port length between the AR10 and AR15? 
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Very interesting, although I can't say that it answers my question. |
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COL's for the 6x6.8 round in the Savage Bbl. ? Mine has not arrived yet. I would start at 2.260 if I didn't have a tool. Same reamer as the AR so of course each bullet will vary depending on if you want to jump the bullet or jam the lands. Plus each production run of bullets may well vary as much as 0.010 in overall length. The only consistent way to set up a proper lenght is to use an ogive measurement hence the problematic usage of a COL. Greg |
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Mine has not arrived yet. I would start at 2.260 if I didn't have a tool. Same reamer as the AR so of course each bullet will vary depending on if you want to jump the bullet or jam the lands. Plus each production run of bullets may well vary as much as 0.010 in overall length. The only consistent way to set up a proper lenght is to use an ogive measurement hence the problematic usage of a COL. Greg Quoted:
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COL's for the 6x6.8 round in the Savage Bbl. ? Mine has not arrived yet. I would start at 2.260 if I didn't have a tool. Same reamer as the AR so of course each bullet will vary depending on if you want to jump the bullet or jam the lands. Plus each production run of bullets may well vary as much as 0.010 in overall length. The only consistent way to set up a proper lenght is to use an ogive measurement hence the problematic usage of a COL. Greg Is a reamer/chamber print available yet ? |
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Is a reamer/chamber print available yet ? Quoted:
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COL's for the 6x6.8 round in the Savage Bbl. ? Mine has not arrived yet. I would start at 2.260 if I didn't have a tool. Same reamer as the AR so of course each bullet will vary depending on if you want to jump the bullet or jam the lands. Plus each production run of bullets may well vary as much as 0.010 in overall length. The only consistent way to set up a proper lenght is to use an ogive measurement hence the problematic usage of a COL. Greg Is a reamer/chamber print available yet ? I would request that from Carl. Perhaps he can accommodate you. Greg |
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I would request that from Carl. Perhaps he can accommodate you. Greg Quoted:
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COL's for the 6x6.8 round in the Savage Bbl. ? Mine has not arrived yet. I would start at 2.260 if I didn't have a tool. Same reamer as the AR so of course each bullet will vary depending on if you want to jump the bullet or jam the lands. Plus each production run of bullets may well vary as much as 0.010 in overall length. The only consistent way to set up a proper lenght is to use an ogive measurement hence the problematic usage of a COL. Greg Is a reamer/chamber print available yet ? I would request that from Carl. Perhaps he can accommodate you. Greg Good enough, thanks. |
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Greg
My name is Adam Pini and i work for the rifle company LWRCi. Dude im digging that 22-6.8spc. I have a spare 6.8 remington 700 action hanging around. I wanted to get some more input on that round. What kind of velocity are you getting etc. Since my company sells so many 6.8 rifles i have tons of brass and wanted to try something like that but with the bullets loaded longer in a bolt action. |
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