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The new 33XC & 37XC cartridges designed by David Tubb
- Thread starter Butler12
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Are you retreading the receiver. All savage 338lm are large shank 1.12 I think
Yes they have a 1.120 tennon and shank . The tennon is only part of the problem 3/4 of the 3plus “ case is in the 1.120 diamiter shank that’s a cartridge having over 135 grains of g20 capacity in a weenie 1.120 shank at least the tenon is supported by the action That’s why I stated re barrel it with a shouldered 1.300 shank and it will be fine
It’s not a large shank it’s a large tennon the shank is the same as the tennon where on a Remington set up your running a larger shank 1.250 to 1.350
less of a problem then the xc run at the same pressures it’s a shorter case with way less h20
Is the 0.585 bolt face consistent with the 33XC? I think it is but let me know if I am wrong. Was thinking of a barrel for my AI AXMC. Not sure if that is possible
Yes it’s the same the xc is a lapua case cylinder Formed from the same cylinder just Shouldered way forward with out cutting of the access case
In my View yes tennon of 1.187 or larger and action O. D. Of 1.450 or larger and a shank of 1.300 and larger
The bolt body also needs to be at least nominally 0.750-inch to handle this 0.585 case-head size. My Surgeon XL action works fine. Maximum tri-axial stress in the barrel steel surrounding the chamber occurs on the inside chamber walls about midway along the case, excluding neck length. Al Harral (VarmintAl.com) has a color fringe image of this produced by his LS-DYNA FEA program for a 243 Winchester chamber in a Remington Model 7.
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There is some reason to believe that in some ways the smaller bolt diamiter being .700 may be stronger then the .750 in the fact that the lugs are closer togather and pressure is applied closer to the lugs due to the column being closer to the diamiter of the lugs less leverage. One other thing to consider Jim is that if a .700 bolt requires a larger diamiter action body to be stronger then the Remington 700 ( 1.350) I.e. locking surface material in action then a .750 bolt would need a Much larger body as well most .750 bolt actions have or use the standard 1.350 body making the action weaker the factory Remington 700
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The size of the "attachment areas" of the bolt lugs to the bolt body is the "shear area" which determines their mechanical shear strength, not the bearing area of their back faces as seems most commonly believed. Examine in detail some of Al Harral's FEA calculated tri-axial von Mises stress color fringe images of Remington-style bolt lugs and seats. The bolt lug stress failure pattern under thrust loading is a shear failure in a roughly diagonal plane angling from the outer rear corner down to the bolt body connection in front. You can see this diagonal peak stress pattern in the fringes on the sides of the loaded bolt lugs. All of the front locking lug designs I have examined and most of their seats in the receiver are super strong. A scaled-up larger action design would be mechanically stronger, all else being equal.
Surface area does displace and the farther apart those surfaces are in relation to equal force will put more stress on attachment area You are correct a larger virsion of the same scaled up will make one stronger. If all is equal scale
Riddle me this James ? (In full respect ). Take for example a defiance action heights , length and width of their lugs are roughly the same Demintions as the Remington 700 in fact just a little smaller. The location of those lugs considering the tennon is the same size and so is the action o.d. How is increasing the bolt diamiter changing the attachment area Or making it larger A smaller radius on the same surface attachment would increase The attachment not decrease it not to mention that increasing the bolt o.d. Would decrease the attachment area and remaining in the action surface locks If the o.d is still 1.350
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It’s ok. I not either. I just wanna sling really big bullets, really far, really fast. Lol
I am sorry, but I am not keeping current on the many new actions developed since I quit building custom rifles 12 years ago. So, I cannot answer your question.
In addition to Al Harral's great website (VarmintAl.com) for rifle engineering studies, I recommend Stuart Otteson's fine book, The Bolt Action (Vol I), which is published by Wolfe. He never completed Volume II to my knowledge.
I developed my own rating parameter for comparing rifle action strengths: bolt-face stiffness in pounds of total bolt thrust per inch of bolt-face setback. For a blueprinted Remington M700 action, with both bolt lugs bearing equally, that stiffness value runs between 2.8 million pounds/inch (dynamically measured) and 4.0 million pounds/inch of setback quasi-statically calculated from elasticity data for the materials. For a factory action, these values are halved because only one of the two lugs is bearing the initial thrust load. This bolt-face setback includes bolt head compression and receiver front-ring stretching, as well as bolt lug and seat compression and flexing. Receiver stretching is greater than most realize because only the front two receiver threads carry almost all of the load for the 16 TPI V-threads. The bolt-lug faces are assumed to be properly lubricated with a thin film of high-pressure grease.
Quasi-static bolt thrust values can be properly calculated from peak chamber pressures after back-figuring an effective piston diameter for each case-head type and size from actual bolt-thrust vs. chamber pressure data. Dynamic bolt-face thrust loads include the impacting of bolt-lugs on their seats and of primer cup and case head on bolt-face during firing as well as any axial effects of radial or tangential stresses. Properly polishing the chamber walls (to a highly polished finish) assures maximal bolt-thrust and minimum brass stretching during the firing cycle. Any liquid between the case and chamber walls during firing will accomplish the same friction-proofing temporarily.
In addition to Al Harral's great website (VarmintAl.com) for rifle engineering studies, I recommend Stuart Otteson's fine book, The Bolt Action (Vol I), which is published by Wolfe. He never completed Volume II to my knowledge.
I developed my own rating parameter for comparing rifle action strengths: bolt-face stiffness in pounds of total bolt thrust per inch of bolt-face setback. For a blueprinted Remington M700 action, with both bolt lugs bearing equally, that stiffness value runs between 2.8 million pounds/inch (dynamically measured) and 4.0 million pounds/inch of setback quasi-statically calculated from elasticity data for the materials. For a factory action, these values are halved because only one of the two lugs is bearing the initial thrust load. This bolt-face setback includes bolt head compression and receiver front-ring stretching, as well as bolt lug and seat compression and flexing. Receiver stretching is greater than most realize because only the front two receiver threads carry almost all of the load for the 16 TPI V-threads. The bolt-lug faces are assumed to be properly lubricated with a thin film of high-pressure grease.
Quasi-static bolt thrust values can be properly calculated from peak chamber pressures after back-figuring an effective piston diameter for each case-head type and size from actual bolt-thrust vs. chamber pressure data. Dynamic bolt-face thrust loads include the impacting of bolt-lugs on their seats and of primer cup and case head on bolt-face during firing as well as any axial effects of radial or tangential stresses. Properly polishing the chamber walls (to a highly polished finish) assures maximal bolt-thrust and minimum brass stretching during the firing cycle. Any liquid between the case and chamber walls during firing will accomplish the same friction-proofing temporarily.
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I think most of us that recommend a .750" diameter two lug bolt know that to it means a larger diameter barrel tenon comes with that. Also
It will work fine.
Some of the manufactors don’t offer larger tenons with their . 750 bolts only the standard 1.065 16 tpi and some 18 tpi Lugs in many cases are the same size as a standard 700 footprint on the . 750 bolt . And if your going to have a larger bolt you need a larger .o.d. Body if not now the locks in the action are too small and have to little surface. The .700 bolt leaving aprox .050 around face should not be any ones concern. If it’s un safe then no one should ever be shooting Mauser Crf action
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There's no reason to go .750" unless the lug OD diameter gets larger. Because bolt race ways are either EDM'd or broached the tenon diameter has to increase. No way around it. Increasing diameters proportionally increase lug surface area as well as shear strength.
With that being said in 40 years I know of one bolt that the lugs sheared off. We suspect questionable after market heat treatment was involved.
With that being said in 40 years I know of one bolt that the lugs sheared off. We suspect questionable after market heat treatment was involved.
Correct the defiance .750 bolt have 700 lugs and tenon . Makes no sense to me .
Correct me if I'm wrong....So, it would seem that the best popular actions/rifle for the 33XC or 37XC builds would be Surgeon, Stiller or AIMC due to tenon/barrel thread vs lug size?
Of course any of these will need to be single fed and live round extraction would require pulling the bolt. But can you still feed these super long rounds at 4.4'' COAL without an issue in these mentioned actions or will some minor surgery be required?
Of course any of these will need to be single fed and live round extraction would require pulling the bolt. But can you still feed these super long rounds at 4.4'' COAL without an issue in these mentioned actions or will some minor surgery be required?
You can do it. But it not really a good choice.
Smallish barrel shank with small bolt lugs will probably pressure out early.
The Desert Tech rifles work great too and give the option of making barrels in other cals with no non portable tools needed for barrel changes....just a seekonk torque driver. My DT SRS in 33XC works very well and will extract and eject fired and unfired rounds. No need to pull the bolt. I think most of the others will do the same? Single feed for all due to the length of the round though. It won't fit magazines.
Frank
Frank
I built my first 33XC on a Savage action and don't seem to be having any of the speculated problems. That's the third .585 case head barrel for that action. I have another Savage action that's working it's way through it's second 338 lapua based wildcat.
I rebarreled a 338 RPR in 300 Norma and it runs into pressure about 30 fps later than a buddies Surgeon XL. There are a likely bunch of reasons for that don't involve the action.
I need another rifle to test solids in the 33XC and have another 338 RPR on the way. It's the fastest way I have to get a usable ELR rifle up for testing. The 1:7 barrel is already here. Everything on the RPR is heavier than the Savages I'm not having any problems with.
The tenon under the bolt in the Savage is only 0.458". There are thousands, if not tens of thousands, of those rifles out there. Where are the failure reports? The service history doesn't really support the .700/.750 theories.
I rebarreled a 338 RPR in 300 Norma and it runs into pressure about 30 fps later than a buddies Surgeon XL. There are a likely bunch of reasons for that don't involve the action.
I need another rifle to test solids in the 33XC and have another 338 RPR on the way. It's the fastest way I have to get a usable ELR rifle up for testing. The 1:7 barrel is already here. Everything on the RPR is heavier than the Savages I'm not having any problems with.
The tenon under the bolt in the Savage is only 0.458". There are thousands, if not tens of thousands, of those rifles out there. Where are the failure reports? The service history doesn't really support the .700/.750 theories.
Sids01,
The scenerio you are querying about has to do with what is called "factor of safety". And although your example(s) might pass your muster qualification, what is not presented is the diminshed structural integrity of the total package, with it's decreasing safety factor as we move in this direction.
I am involved in shotgun sports, steam engineering, and other ventures, and believe me, shit does happen.
The scenerio you are querying about has to do with what is called "factor of safety". And although your example(s) might pass your muster qualification, what is not presented is the diminshed structural integrity of the total package, with it's decreasing safety factor as we move in this direction.
I am involved in shotgun sports, steam engineering, and other ventures, and believe me, shit does happen.
Hi,
Same teams that said the Remington triggers were not a safety issue right up until the point of the recall??
Sincerely,
Theis
Wanted to throw this out there....any new or slightly used 33XC competition ELR builds out there that anyone is selling or aware of? I searched SH and found one build that had sold. If not in 33XC, I might consider picking up a .338 LM build. PM me if anyone is aware of anything. Thanks!
Sooo I just bought a Savage elite precision in 338 lapua, and was planning to rechamber soon with a 37xc, is my action strong enough for the 37xc?
