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There seems to be a natural gap in cartridge selection for big bores. We have various 'over .458' bores (.474, .500, .505, .510, .550, .585, .620, .700). We have large diameter case heads deftly fit on to common commercial actions like the Gibbs on a CZ550. We have cartridges whose case capacity is so large that people do not like to load them up to capacity, like the 160+ grain Gibbs. And we have a trend among the last generation to ask what can be done on a .308 length action, as witnessed by the light deer rifles on one hand (243, 257Bob, 6.5Creed, 7-08), and by the B&M series in large calibre (9.3, 416, 458, 470, 500). But where is the 2.2" case built on the Gibbs .635" casehead? It would seem that a 120 grain capacity cartridge line could be built on a very short action. Have we discovered a natural limit where no one wants a 7.5 pound rifle that can match factory 500Jeffrey ballistics? Or is it the wildcat that awaits 2015? It looks like a grown-up benchrest round. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | ||
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Yikes! A Gibbs case head in a short action rifle? Surely the Rigby case head size is as far as I care to go with bolt thrust issues. And that CZ .505 Gibbs bolt face is a mere sliver of retention of the Gibbs rim. With the Gibbs case head, if you get over 55,000 psi you need an action size approaching 50 BMG capable. Like for the high pressure .408 Chey-Tac. That one is not a good idea for a CZ 550 Magnum. That would be difficult to keep light and handy for an .XXX/.505 Gibbs PPC.  | |||
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Another more practical reason is feeding reliability. Extremely short fat cartridges are hard to make feed properly. Try any of the BR series of cartridges sometime. I really like this style of cartridge in a lot of applications, but the DG rifle isn't one of them. There is no need to shave that much weight, the bolt thrust gets bad as mentioned, and a longer, skinnier cartridge just feeds a lot more smoothly and reliably. | |||
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True. And there goes magazine capacity unless more bulk is added in a drop box or banana straight-stack magazine. | |||
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So the 500AccR and 49-10 are our ultimate handy, large carehead rounds? what are boltface thrust limits on the .590 Rigby casehead? +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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I believe the max case head/case body combo for a true short action would be a shortened .500 Jeffery case. That said I believe that max most practical case would be the .338 Lapua/.416 Rigby case shortened...perhaps using the .423 Dakota (Lapua mfg) cases that Grafs has on close out for <$1 per case...hmmm, I just have about 600 of those!  Now back to case length...for a true short action (M70 WSM is an intermediate length action) I would recommend a 55mm case length, rather than the B&M's 57mm case length, as that would give the optimum COAL/case capacity combination with available bullets including the CEB BBW#13s and ESP Raptors. Maybe blow the shoulder out to .571" with 30 degree shoulder angle for maximum case capacity...I'll draw up a few dummy cartridges and post them later today. Definately would need KC Scott's dropped Ruger' floor plate for 3 down. Yep...a 12.7x57mm should slightly exceed the performance of the 50 B&M cartridge which is a  for the concept, Can't think about it! Have to finish my BB Mausers... AhhhhhhhhJim  "Life's hard; it's harder if you're stupid" John Wayne | |||
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With all due respect, what most here really need is "MORE TRIGGER TIME". Get out and shoot whatever floats your boat OFFHAND more.-Rob Never underestimate the power of stupid people in large numbers to do incredibly stupid things- AH (1941)- Harry Reid (aka Smeagle) 2012 Nothing Up my sleeves but never without a plan and never ever without a surprise! | |||
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I wish that I could. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Think Ruger #1 in 577 NE and 18" barrel. Singe shots and doubles are the shortest actions with the longest carts  That or the 12 or 20 gauge Savage bolt actions. The feeding issues with the Gibs case on the WSM action may make you fall out of love quick methinks. The 500 Cyrus may be your answer. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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I am perfectly happy with my .458B&M built on the Winchester Mdl 70 WSM action. I opted for the 20" bbl over the 18" bbl purely as a matter of aesthetics. It shoots the CEB BBW#13 solid 450gr and non-con 420gr to the same POI. It goes over for another Ele in August. Mike ______________ DSC DRSS (again) SCI Life NRA Life Sables Life Mzuri IPHA "To be a Marine is enough." | |||
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If the CZ 550 Magnum action is rated to 3800 bar (55,100 psi) with the Gibbs case head, it ought to be rated to 63,828 psi with the Rigby sized case head. However CZ uses the 550 Magnum action for the .338 Lapua Magnum, which has a CIP max of 4700 bar or about 68,150 psi, very nice brass that it is. The CIP pressure rating for the .505 Gibbs cartridge is only 2700 bar, about 39,150 psi, dating back to olden days' brass. But .408 Chey-Tac pressure spec is 63,800 psi (old reference from a Chey-Tac web site) on the same case head size as the .505 Gibbs. Stout new brass. Engineers and lawyers: The CZ 550 Magnum is probably engineered to handle 50% higher pressure than they recommend for regular use ... But I am sure they would recommend against building a .408 Chey-Tac on a CZ 550 Magnum action. If the CZ can handle .338 LapuaMag at 68,150 psi, according to marketing equations, it ought to be able to go that high with the 49-10, or 12.7x68mm Magnum Tornado, having a .338 Lapua Magnum case head right?  | |||
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500 Cyrus: .500/.416 Rigby Short From another forum, with huge cast lead boolits by Ranger Rick, used in a Savage bolt action: Nice boolitts.  | |||
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Abet with a .535" rebated rim. I personally have no issue with a rebated rim but others may deem this to be an issue. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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And if a Gibbs case had a Rigby rebated rim? That would be .045" the Rifle in the 500Cyrus is here: http://50caliberforum.proboard...ion=print&thread=449 +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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@RIP, 416Tanzan, ther´s a "short" Round based on a .505 (.408) Case. Made in Austria, 55mm 2,16" Case length, 30° Shoulder, but, .338 Caliber...so, not a real "Big Bore". It´s named ".338 Little David" Max.Pressure allowed 4400bar ???psi. Best 2RECON | |||
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That would be 63816 psi according to a conversion calculator. Does the .338 Little David have a full diameter rim or is it rebatted? Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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and what is its H2O case capacity? +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Tan, I dummied one up in QD and the H20 case capacity is aproximately 116grs for a .510/.338 Little David. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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 A web search for the .338 Little David returned the Davy Crockett bazooka that fires an M-338 atomic bomb round. Davy ... M338 ... close! Have loaded up another 50 rounds of 12.7x68mm Magnum Tornado ammo, will take a day off tomorrow and go have some fun. Will add some load data to www.ammoguide soon.  | |||
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Have fun That bazooka might be a tad unsporting but I'd love to see it in action. 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Bazooka was one of the ideas that got squashed... Can't imagine why... seems it's ballistic range was insufficient to put the ground crew firing it out of harms way so it never saw the light of day. There's one at the Aberdeen museum in MD. | |||
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I've "blue pilled" a CZ550 magnum action (3X) to 85KPSI and dimensionally checked the action before and after. No change within experimental error. This had to be done, since the top load in the .600OK will do close to 65KPSI. They are very well made and strong actions.-Rob Never underestimate the power of stupid people in large numbers to do incredibly stupid things- AH (1941)- Harry Reid (aka Smeagle) 2012 Nothing Up my sleeves but never without a plan and never ever without a surprise! | |||
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[/QUOTE]That would be 63816 psi according to a conversion calculator. Does the .338 Little David have a full diameter rim or is it rebatted?[/QUOTE] Hi Jim, no other changes. Plain 408Chey-Tac Case necked down in 3-4 Steps to hold .338cal Bullets. Have send a picture to RIP. Just looks like "the mother of all PPC´s".... Best 2RECON | |||
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RIP is good on sharing pix. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Courtesy of 2RECON, .338 Little David, flanked by .308 WCF and .338 Lapua Magnum:  | |||
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Ok…I believe I understand the concept behind the Little David…they’re doing a one-up on the .338 Norma Magnum which had done a one-up on the .338 Lapua Magnum. “What If” Comparison using QL Barrel Length: 26” – Pmax: <63000 – Vihtavuori N560 Powder Bullet: 300gr Sierra HPBT LR MK 9300 G7 Litz – Bullet Length: 1.736” – Bullet Seating Depth: 0.529” .338 Lapua Magnum: – Gross Case Capacity: 108grs water – Net Case Capacity: 92.085grs water – Case Length: 2.724” – COAL: 3.681” – Charge Wt: 82.65gr – Filling/L.R.: 95.3 – Muzzle Velocity: 2690 fps – PMax: 62978 psi .338 Norma Magnum: – Gross Case Capacity: 111grs water – Net Case Capacity: 95.079grs water – Case Length: 2.490” – COAL: 3.447” – Charge Wt: 87.39gr – Filling/L.R.: 92.4 – Muzzle Velocity: 2724 fps – PMax: 62979 psi .338 Little David: – Gross Case Capacity: 104.73grs water – Net Case Capacity: 88.80grs water – Case Length: 2.160” – COAL: 3.117” – Charge Wt: 78.75gr – Filling/L.R.: 97.1 – Muzzle Velocity: 2682 fps – PMax: 62979 psi So…would the .338 Little David be a viable alternative to the .338 Lapua Magnum? Their performance appears virtually identical so yes it appears so. Obviously all three cartridges could have been optimized slightly more…but I don’t own any of the specified bullets so can’t measure the optimum bullet seating depth so I just compared all three cartridges with the Lapua’s seating depth. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Capo, the Sierra bullet chosen is on the long side and not reliable for hunting because of core-cup separation and a thin jacket, despite its over .700 BC. A better bullet choice for hunting, especially for shorter cartridges would be the 225 grain .338" TTSX at 1.56" length and a respectible BC of .514. I can hunt with that, since I don't think beyond 400 yards. Barnes also has higher BC bullets in .338" like the new .338 cal 280gr LRX(TTSX), SecDens .350(!), BC of .667(!)  ,and with a length of 1.863” (that's long for a short magazine!). +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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 Yep...but the Sierra seems to be the bullet of choice for long range sniping...which is the original design intent of all three cartridges.Using the 280gr TTSX bullets would require magnum length, long length and standard length actions respectively to optimize the cartridges. Regardless of course...the Little David does require a larger diameter bolt than the Lapua and Norma Magnum cartridges to overcome bolt thrust. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Are bolts so weak? The ratio between the area of the Gibbs bolt face and the Rigby bolt is only 16%. .635x.635/.590x.590 = 1.16. Even comparison with the 30-06 type bolt face is only 80%. .635x.635/.473x.473 = 1.80. And those case heads both land on a solid steel face that transfers to the lugs. Finally, all the aggregate momentum and energy is sent against the bolt. If we have bolts that handle 9000 ft lbs., what's the problem with generating 7000 ftlbs. in a shortstack on the same bolt? +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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No I don’t believe that modern bolts are weak and I likely misspoke with my statement. I do believe though that a .750” diameter bolt would be safer than a .700” diameter bolt in the long run when subjected to repeated 63K psi loads fired from a 408 CheyTec case head diameter cartridge. Though I can’t prove it and perhaps I’m wrong...which I'll readily admit. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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