The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores 10.75x68 Project??Go | New | Find | Notify | Tools | Reply | |
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All this talk about the 10.75x68 has reinfected me about building one! I thought I'd use this post to hopefully start a knowlage base of 10.75x68 info. I have a 1940 mfg FN Mil style action that Steve Button has stoned & polished, put a new bolt handle on, contoured a SMP M1 (30-06 5 down) bottom metal, it is intended to look somewhat Rigby like. Put a Hubber Concepts 2 stage adjustable trigger on it. Didn't surface grind it, all hand stoning, as I wanted to keep the charger hump & use stripper clips (modified). This will be an open sight rifle only. 1 standing & 2 folding with a Lyman M48 peep sight. Steve worked the front sight to sit lower to bore & will do same for rear sight. Since it is an open sight rifle only, it also has more of a Pre-War look with lower sights. We might have to cut off rear standing sight if it gets in the way of peep sight view. We'll decide when it's finished. Steve took an NECG H&H flip night sight & removed the barrel band compleaty recontoured it. Making it more Pre-War looking I think. Since I have this as a starting point... What the heck, let's build a 10.75x68! I'm sending Steve 4 dummy rounds to verify that it will hold 4 down & 1 in chamber. We are sure it will but just making sure! With this mag box I can load to 3.35 COL or there abouts. So can seat a Woodleigh 400gn to crimp in the cannelure. Dave Kiff sent me 3 reamer drawings, CIP, a US version & a cast bullet version. Just got them, plus they look really confusing to me! I think I want the CIP version throated for the longer COL. Getting a LW # 5130 Type E barrel. Ordering it in the standard Contour ie.. not changing the contour, at 26". It is .625 at 26" & Woody said it going up about .012 per inch if shortening the barrel. I will go with 24" or 25" finished barrel. I like longer barrels usually but 24" may look better for this rifle. Decided to have Steve make a solder on under barrel sling base with the large eye like some of the earlier Rigby's. What I want this rifle to be a general purpose gun, 200 yd or less open sights. So not wanting to race with a 404J. Aming for 8.5 lbs. will add wt if needed. If it can go up to 2210-30 FPS that's sweet, if not, 2150 plus is also good. I'm sure it will go fast enough to get the job done as long as I do my part. If this posts a bit jumbled its because I had to use my iPhone to post. Computer is in shop.  If anyone has load data, articles, pics, info or such lets share them. I have some load data I've collected & 2 articles. I'll post pics of the action & front sight as soon as Steve sends them to me. I lost the first one he sent me Duh! Info on reamers & go- no-go gages would be helpful. I may just buy a reamer & gages from Pacfic if needbe. About $200 for a set unless there is options. It's a Mauser thing, you wouldn't understand. | ||
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I think I got my post cleaned up a bit. It's a Mauser thing, you wouldn't understand. | |||
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may I ask what is the difference between the CIP and SAAMI specs? Jim | |||
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Hey Jim, to be honest I'm not sure!  Without my computer I can't print them out to really compare them at the moment. Using iPhone only for the moment. If you would like I can send you the 3 reamer drawings & if you wouldn't mind posting them for everyone to check out. I plan on posting everything I can find about the 10.75x68 here so we can have the info & data in one place if anyone else would like to have it. Hopefully some others will add their info also. If you would like to PM me an email addy I'll send you the reamer drawings. Cheers, Allen It's a Mauser thing, you wouldn't understand. | |||
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Jgrabow6493 posted this info on my 10.75x68 post: I measured a mag box from a K98k 8m/m Mauser and a 1930 Oberndorf Sporter in 10.75x68 Mauser. - Outside Dimensions 8m/m 10.75x68 Front Width: .811 .940 Front Height: 1.100 1.211 Rear Width: 1.003 1.147 Rear Height: 1.300 1.429 - Inside Dimensions Front Width: .700 .854 Rear Width: .875 .930 Jim Matt FISH!! Heed the words of Winston Smith in Orwell's 1984: "Every record has been destroyed or falsified, every book rewritten, every picture has been repainted, every statue and street building has been renamed, every date has been altered. And the process is continuing day by day and minute by minute. History has stopped. Nothing exists except an endless present in which the Party is always right." | |||
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Here are the 3 reamer drawings from Allen.    Jim | |||
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This is from Allen.  Jim | |||
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I built a few of them early on, sold two of them on AR sometime back, One a neat English gun and the other a custom FN I built... Basically reloading is walk in the park...I got 2150 FPS with a 400 gr. Woodleigh and 2350 FPS with a 350 gr. Barnes..I tried it on Buffalo with both bullets and it did them in exceptionally well...If you need reloading data email me at ray@atkinsonhunting and I'll send you a good deal of load data.. I gave un the caliber because of hard to find and expensive brass and dies..That has eased up a bit I understand... I will say this for the 10.75x68..It has the same balistics that made the 404 Jefferys famous so it can't be anything but good, and it does all this with a modicum or recoil and muzzle blast..Its a wonderful and overlooked cartridge for buffalo, Lion and even elephant IMO.....It had a bad rep early on simply because of bad bullets which is no longer the case...I used Woodleigh .404 Jefferys bullets in mine and they worked like a charm, so I never saw the need to use the Woodleigh 350 gr. bullets...The 350 gr. Barnes was just as good and penetrated like hell.. Best powders were WW-748, H4198, VV140, VArget, and H335 as best I recall. My buff load was the 400 gr. Woodleigh with 74 grs. of WW748 for an average of 2140 FPS.. and 64 grs of H335 with a foam filler and a 350 Barnes X and I don't recall the velocity but it was around 2300 to 2400 FPS. At the time brass was hard to come by but I happen Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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Hey Allen, 1st, tell Steve that Jim said Hi when you talk to him. 2nd, Call Steve 11/01 and tell him to open the box up to 3.4” internal length – you’ll want this for use with monometal bullets as it will allow you to load to 3.36” without issue – and you should have sufficient meat in the front of the box to handle that length. The action should not require much metal removal as the commercial FN actions were cut for a 3.4” magazine box. 3rd, Go with the 10.75x68 USA reamer schema – you should have a more accurate rifle with the tighter tolerance as well as the shorter freebore length. This schema also has plenty of room to accommodate monometal bullets as well as every current C&C manufacture bullets. 4th, It’s just a little more cost wise than the Huber Concepts, but if you can swing it I’d go with the Blackburn metal trigger – it’ll set very nicely near the rear of the trigger bow and is fully adjustable. I’m using the Blackburn on both of my M98 Mauser FN commercial action builds that Steve has in his possession. 5th, Your rifle will be more ‘lively’ in the hand without punishing the shoulder at about 7.5lbs weight. 6th, I responded to your loading request on the other thread. Good luck! Jim  "Life's hard; it's harder if you're stupid" John Wayne | |||
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Jim Thx! What is the difference between the CIP & US version of the 10.75x68 reamers? Less free bore. Dave mentioned the CIP version has something over 1" I think he said. It's kinda Greek to me trying to figure out the differences! Cheers, Allen PS, I'll tell Steve you said hi! He is a great guy to work with that's for sure & does really nice work! It's a Mauser thing, you wouldn't understand. | |||
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Allen, We’ve had a number of discussions here in the BB Forum recently regarding freebore, leade, throat, etc and they were a headache maker. Basically the thing to remember is that the shorter distance that the ‘caliber diameter of the bullet’ has to travel before it engages the rifling generally equates to enhanced accuracy. And most modern bullet manufacturers recommend a 0.020” through 0.100” bullet jump for their hunting bullets. The CIP specification was established based upon the original 1905 specification for the 10.75x68 Mauser cartridge/chamber and this specification was established when quality and tolerances of C&C bullet construction left much to be desired. The norm during this timeframe was a chamber specification having zero leade specification and a very shallow throat angle. The 10.75x68 USA specification, with its .410” leade (basically 96.9% of caliber) and .4238” Parallel-Sided Leade, was established to better reflect the quality to today’s bullets regardless of whether the bullet is C&C or monometal construction. I have specified a .211” leade (basically 50% of caliber) and .424” Parallel-Sided Leade, for my .423/338 Lapua Magnum (aka: 10.74x69 Magnum, aka: 42-10). Personally, were I building a modern 10.75x68 chambered rifle, I’d have the 10.75x68 USA specification modified with a .211” leade specification and be very happy with the results. I would also be using a 3.4” internal length magazine at a minimum though better yet a 3.530” internal magazine length to take full benefit of the case capacity with modern monometal bullets. With the 3.530” magazine length the handloaded 10.75x68 can approach the factory loaded 404 Jeffery cartridges (at least the Jeffery's original 2150fps-2300fps loadings). I hope this helps. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Allen you have a PM. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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I’ve moved my posts in response to Allen regarding the cartridge and rifle from the Terminal Bullet Performance thread to this thread so that the discussion can take place in a single location… So here goes:
Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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load it to 3.40 or so and avoid a ton of feeding issues and MONEY for custom bottom metal... load it to crimp on the groove of 404 bullets, 2150 aint much to ask from it.. opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Well, as to why a 10.75x68... I'm not very smart! Lol! Actually I'm a traditionalist & love the nostalgia. I figure if I use a US version of chamber it is just a matter of tightening up the chamber & having a longer COL, still basically a 10.75x68. I can get 4 down & 1 in the chamber, my preference. I have never been interested in any of the monometal bullets at all. Prefering the traditional bullets such as Woodleighs. But... these #13 NonCon bullets offer a level of performance that just can't be ignored! With the 325 & 350 gn .423 #13s it really optimizes the 10.75 for shooting anything from any reasonable angle. Makes a nice light carry around gun that can handle any sized critter. And I get to have my Nostalgia! Jim, I just talked to Steve, he said 4 down in the 1M BM is no problem. But the front of the box tapers a little bit to much & it may not close with the 5th one in the chamber. He's working on that. On the plus side, I can have a 3.34 COL, with a bit of filing on the front of the box. So the COL is now good, just have to figure out the front sides of the box. The cartridge shoulder is further forward & of course wider than the 06'. Allen It's a Mauser thing, you wouldn't understand. | |||
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technically, since the american case will NOT fit in a mauser made type A or B chamber, it is not a 10,75x68 .. just my opinion... opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Ah...Jeffe? The American case chamber has the exact chamber dimensions as the CIP specification from the case head through the case mouth. The only difference is the leade and throat area. So...how the heck can an American case not fit in the CIP chamber. Or for that matter the cast chamber? Unless you're saying that neither the Mauser type A or type B chamber meet CIP specifications? And if that's the case then zero commercially loaded 10.75x68 Mauser ammunition manufactured in Europe would fit the type A or type B chambers. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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I have heard that Afor. Except it ain't true. Different datum length saami to cip. A round Fired in a saami spec chamber then resized with saami spec dies will not fit in a cip chamber. Ain't the first time that this has happened. Cip cases fit all day in saami chamber. opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Jeffe, I understand what you’re saying. And I’m not saying what you have stated is not true. Heck I don’t even own a 10.75x68 Mauser caliber rifle. I keyed the CIP specifications taken from the above posted CIP cartridge/chamber specification sheet into QuickDESIGN. I saved the SAE (metric unit) file and then used the QD function to the SAE units into English units and resaved the English (inch unit) file. Here are the differences between the CIP 10.75x68 chamber specifications in inch measurements to the PT&G’ 10.75x68 USA chamber specifications – only the differences are noted: Chamber Lengths: L3: Length to Neck Chamfer – CIP: 2.689” – PT&G’ USA: 2.688” (USA = -.001”) /53: First Body Diameter – CIP (Added): .495” – PT&G’ USA: .4953” (USA = +.0003”) Chamber Neck: H1: Diameter at Shoulder-Neck Intersection – CIP: .4543” – PT&G’ USA: .454” (USA = -.0003”) And I’ll throw out one final difference: Throat Dimension: /81: Length to Bore Diameter – CIP: 3.8701” – PT&G’ USA: 3.3182” (USA = -.5519”) So looking at this information there is zero reason that brass fired in either of these two chamber specification, and reloaded using reloading dies cut for these specifications, shouldn’t fit within either chamber. Now regarding the Datum Length; Datum Length is a SAAMI specification and CIP does not have a relating specification. And as SAAMI has not approved and issued chamber/cartridge specification for the 10.75x68 Mauser cartridges (only the CIP specification exists) I’m unsure as to what “SAAMI specification” finish chamber reamer that you might refer to. If the “SAAMI specification” finish chamber reamer that you refer to is the PT&G’ 10.75x68 USA finish chamber reamer then you very likely have a problem chamber with your rifle – meaning the reamer was run deeper in the barrel than it should have been run… Hopefully your SAAMI specification finish chamber reamer wasn’t cut based upon the CIP maxi-cartridge specifications because if you’ll re-look at the CIP cartridge/chamber specification sheet you’ll notice that the L1 and L2 lengths for the cartridge are longer than the L1 and L2 lengths for the chamber. Factory ammunition will always use cases that are manufactured to dimensions that are less than the minimum chamber dimensions. Anyway, it’s an interesting situation… Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Hey Jim, would u mind doing the same thing on the US version & the cast bullit version? I'm sure the case is the same but how does it differ in the lead, throat ect... Thx, Allen It's a Mauser thing, you wouldn't understand. | |||
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Allen, I have an Oberndorf type-A in 10.75x68, do let me know if you need any measurements since you're building your rifle on the pre-war styles. My rifle has a banded front ramp, 1 standing 4 folding express sights on a island base and a banded swivel base. All matching numbers too Do post pictures as the build progresses.Cheers! Zubin One shot..meat! Two shots...maybe...Three shots...heap shit! - Old Indian adage | |||
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As requested: Chamber Lengths: L3: Length to Neck Chamfer – PT&G’ USA: 2.688” – PT&G’ Cast: 2.689” (USA = -.001”) /53: First Body Diameter – PT&G’ USA: .4953” – PT&G’ Cast (Added): .495” (USA = +.0003”) Chamber Neck: H1: Diameter at Shoulder-Neck Intersection – PT&G’ USA: .454” – PT&G’ Cast: .4543” (USA = -.0003”) H2: Diameter at Neck Chamber – PT&G’ USA: .454” – PT&G’ Cast: .454” (same) Throat Dimension: G1: Throat/Freebore Start Diameter – PT&G’ USA: .4238” – PT&G’ Cast: .425” (USA = -.0012”) h: Neck Chamfer Height – PT&G’ USA: .014” – PT&G’ Cast: .0145” (USA = -.0005”) s: Length of Freebore + Neck Chamber– PT&G’ USA: .424” – PT&G’ Cast: .4935” (USA = -.0695”) /72B: Throat Angle– PT&G’ USA: 1º30’ – PT&G’ Cast: 45’ (USA = +45’) /81: Length to Bore Diameter – PT&G’ USA: 3.3182” – PT&G’ Cast: 3.6393” (USA = -.3211”) Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Jeffe, what is your thoughts about going this route? Use CIP spec's on the chamber part of the reamer and have the lead, throat ect... made more along the lines of the US reamer specs. Just in case. If I understand things correctly the lead, free bore or throat is rather long on the CIP reamer. I do want to chamber it for a COL of 3.40" since that will fit my mag box. This area is completely out of my knowledge area! Dave Kiff said some of the throat, lead or free bore or something was real long on the CIP spec reamer. Didn't catch (understand) what he was referring to Input? Allen It's a Mauser thing, you wouldn't understand. | |||
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