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How much steel is required to rebore a 30 cal to .358 or 9.3? Wall thickness is what I guess I'm asking? J E S has lots of info but doesn't give a minimum thickness after boring. I'm just contemplating a rebore on one of the economy guns like the Ruger American. I like the tang safety on my rifles. TIA | ||
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I had Jes rebore a Rem 721 3006 to a 9.3x62 for me. It turned out great and shoots extremely well. The barrel wall is thinner of course but not overly thin and I don't think there is a Real rule of thumb. Cal30 If it cant be Grown it has to be Mined! Devoted member of Newmont mining company Underground Mine rescue team. Carlin East,Deep Star ,Leeville,Deep Post ,Chukar and now Exodus Where next? Pete Bajo to train newbies on long hole stoping and proper blasting techniques. Back to Exodus mine again learning teaching and operating autonomous loaders in the underground. Bringing everyday life to most individuals 8' at a time! | |||
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In speaking to Jesse at JES Reboring prior to doing my 375 Whelen, he said he likes to have at least .200 over bore size. So a .375 would need to be .575 or larger. Just add .200 to the bore diameter you'd like to end up with and that will give you the minimum barrel diameter you'll need. Mart "...I advise the gun. While this gives a moderate exercise to the body, it gives boldness, enterprize, and independance to the mind. Games played with the ball and others of that nature, are too violent for the body and stamp no character on the mind. Let your gun therefore be the constant companion of your walks." Thomas Jefferson | |||
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Thanks, Mart. Precisely what I was wondering. I have a Savage 111 in 9.3X62 done by JES. But I was wondering what I have to watch for in looking at rifles not sold in the desired caliber. Maybe I can get a Ruger American bored to .358 Winchester. But I'm still wanting a drop box magazine so I can use a ten round mag or a five rounder if I wish. Looks like some more 'smithing will be in my future. | |||
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When I talked to Dan Pederson about a rebore, he thought my .600 30 06 was pushing it to go to 9.3. Suppose it depends on the builder. | |||
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Cliff LaBounty required .10 a side. | |||
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I believe my addition and decimal placement are sound. Please explain. And for future reference please type your reply outside the quote. "...I advise the gun. While this gives a moderate exercise to the body, it gives boldness, enterprize, and independance to the mind. Games played with the ball and others of that nature, are too violent for the body and stamp no character on the mind. Let your gun therefore be the constant companion of your walks." Thomas Jefferson | |||
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I agree. Common advice I have adhered to is to have at least 0.125" wall diameter in the grooves, AT THE MUZZLE, and bigger everywhere else. Example 1: For a .375 with groove diameter of .375", that is to have a 24" barrel length, the barrel diameter at the muzzle/crown should = .375" + .125" + .125" = .625" OR LARGER. Example 2: For a 9.3x62 with grove diameter of .366", that is to have a 22" barrel length, the barrel diameter at the muzzle/crown should = .366" + .125" + .125" = 0.616" OR LARGER. I have never had a problem with inaccurate/whippy barrel when I stick to that standard. Nor have I ever had a barrel peel back from the muzzle like a banana. Not even adequate barrel wall thickness at the muzzle will prevent that, if one forgets to remove the bore-sighter from the muzzle before firing: http://www.worldaffairsboard.c...77-split-barrel.html    | |||
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If that bore sight is lead-free it might be legal to hunt with in California.  In the 1980's I had a very good visit with Cliff LaBounty at his shop and I remember him telling me that nearly any standard sporting rifle could be opened up two calibers. For example, .270-.284-.308 or .243-.257-.264 or.338-.358-.375. He also said that heavy barrels could be opened up more and that light barrels might not be able to go up two calibers. We were discussing opening my .22 Varminter (.22-250) to .35 Whelen and he said the barrel was plenty heavy to go that big but would require more than one rebore operation to get there. . | |||
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What I'm saying is simply that I did not have to have my .30-06s bored out to .500 + as you stated. He bored them all to a .338-06. This is .03 larger than the standard .30-06, not .200, but .03 for the .338. | |||
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I do believe that you have the wrong end of something here Dwright.  It's pretty clear - .2" added to groove (calibre) diameter = minimum muzzle diameter. IE .375 + .200 = .575 minimum diameter to rebore to .375 . This also assumes a reasonable tapering up as the barrel runs rearward. The poster's math is fine, as is his placement of the decimal point !! Some machinists may like a bit than .2 dia to work with, but more is not necessary, unless the owner would like extra for looks or for balance.No where has it been suggested that a rebore must take out everything except for the last .2 of muzzle diameter. Its encouraging to see so many replies demonstrating an understanding that large bore barrels don't have to be have the dimensions of a truck axle.  | |||
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Dwright, Perhaps I didn't explain it well enough but I was not referring to boring the barrel out to .500. I meant that the barrel outside diameter needs to be at least .200 larger than whatever caliber to which you are reboring. With that in mind a 338 would need at least a .538 outside diameter, 9.3 would need a .566, .375 a .575 and a 400 Whelen would need a .611 outside barrel diameter. Like I said, just add .200 to the desired bore diameter to come up with the minimum outside barrel diameter (measured at the muzzle). Mart "...I advise the gun. While this gives a moderate exercise to the body, it gives boldness, enterprize, and independance to the mind. Games played with the ball and others of that nature, are too violent for the body and stamp no character on the mind. Let your gun therefore be the constant companion of your walks." Thomas Jefferson | |||
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RIP: That's why I stopped considering a rebore and started thinking rebarrel. I just don't have the time for shit to go wrong... | |||
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Mart, To split hairs, IMHO, 2 cents worth, your formula is only good for low pressure double rifles, with two barrels soldered side-by-side to a rib to give some added stiffness to the barrels. Bullet diameter plus .200 is too small for the muzzle diameter of a high-pressure, single-barrel rifle. Too whippy-flexible and not strong enough regarding splitting. My formula, by your method, is minimum of bullet diameter plus .250" for a featherweight muzzle. But even then, accuracy will not be as good without special bedding tricks like forend tip up-pressure, instead of free-floating. Bullet diameter plus .300" is always better unless you are trying to build a featherweight, and of course the more the merrier if extra muzzle weight is desired for balance. Never a Blaser Shooter, Rip Riflecrank Internationale Permanente, DRSS, SSSS, BASS, LASS, SLSS ****************************************************** Self Appointed Poobah of C.R.I.P. | |||
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RIP, Not my formula. That was what Jesse at JES Reboring advised and once again it was to be considered a minimum required amount of metal. I've no issue with it being more than .200. My rebored Sedgley 375 Whelen has a muzzle diameter of .645, well over the .575 required for a .375 and is plenty light. Shoots well though. Mart "...I advise the gun. While this gives a moderate exercise to the body, it gives boldness, enterprize, and independance to the mind. Games played with the ball and others of that nature, are too violent for the body and stamp no character on the mind. Let your gun therefore be the constant companion of your walks." Thomas Jefferson | |||
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Fair enough, I was reading your comment incorrectly, as I was referring to the inside dim. | |||
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On all my custom barrels, I go with .250 plus the caliber as a minimum, at the muzzle. Life Member- NRA & SCI | |||
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PhilR are you having the rebore done or doing it yourself? | |||
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I'm not doing a rebore, just responding to your question about wall thickness. Life Member- NRA & SCI | |||
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Wayne York's minimum muzzle diameter for up to .375" cal is .550". He's done several rebores for me, but none that pushed his limit. Jesse at JES has done several for me also, a .376 Steyr on a .650" muzzle, a 9.3x62 on a .640" muzzle, and a 50-140 on a .792" muzzle, all H&R single shots. He did a 50-140 for a friend on his .650" muzzle H&R also. I have to say Jesse does fine work for an excellent price and his turn around time is really fast. http://www.35caliber.com/2.html http://www.oregunsmithingllc.c...ing-MuzzleBrake.html | |||
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Looking down the bore of my 9.3 (originally 30-06) it is quite slick.I appreciate precise metal and wood work. This bore is "pretty" to me. | |||
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Yep Rip - That's my minimun, too! 0.125" barrel wall thickness at the muzzle and larger back down to the action. I had a new light weight 458WM that was only 0.100" at muzzle - Had the barrel cut back to get to that 0.125". ________ Ray | |||
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My factory Ruger 77 RS 35 Whelen measures .560" at the muzzle. The pre-war JP Sauer Cliff LaBounty rebored to 35 Whelen for me measures .556" at the muzzle. | |||
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let's say you have a 26" modern steel barrel for 300 win mag. could you trim it back to say 23 or 24 inches to have enough meat on it to make it a 9.3 or 375 wth a rebore? | |||
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There sure are a lot of those beautiful old German guild guns and some nice English rifles out there with half oct/half round and full rib barrels that mic .600 and even .550 at the crown..Never have seen one that split or blew up..  Are we Paranoid??? Have any of these guys done any testing, if they have I have never heard or read about it, it's probably conjuncture on their part I'm guessing???..It would certainly make an interesting study. Also think about how thin some double rifle barrels are at the muzzle for all calibers!! I have owned some that were very thin, and never a problem..JES stated in the post above that he "likes" to have at least .200 thickness and that makes a 375 .575 at the muzzle, thats pretty thin btw.. I'm not saying one way or the other as I'm not sure, but I believe we get ahead of ourselves in some of these conversations, when we don't really KNOW one way or the other.. I do know that pressure gets less the further down the barrel you go, and thats got to make a difference.. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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When we talk about minimum muzzle thickness we mean what is required to prevent excess hoop stress opening up the barrel. It is no surprise that old low pressure double rifles had thin muzzles since the muzzle pressures with these old cartridges were very low. Most large bore cartridges will naturally have lower muzzle pressures due to their expansion ratios....the .378 Weatherby 'may' be an exception. I doubt that any of the reboring companies have destruction-tested any barrels to see what the minimum muzzle thickness would be. And why would they? The steel with which a barrel is made will also determine its strength. And barrel length also matters, as the shorter a barrel is the higher the muzzle pressure will be. There can be no "destruction tested" rule of thumb with so many variables. Anecdotal evidence from reliable sources is probably as good as anything here. . | |||
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Remember too that minimum barrel thickness, usually at muzzle, for firing purposes may well be much different than that needed to rebore and rifle a barrel. Most barrels are drilled, then rifled, then contoured making a much more stable piece to machine (rifle) on.  Aut vincere aut mori | |||
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I recently had a Ruger Mark II in 7mm Remington Magnum rebored and rechambered to .358 Norma Magnum. The muzzle diameter is .560", so I barely made it under the requirement of .100" wall thickness. The rifle shoots fine, but it hardly takes any shots before the barrel is too hot to touch. Not a factor in the hunting field, but I like to practice instinctive shooting with reduced loads and that includes rapid fire bolt manipulation. I think I may have a solution to the problem, but I won't know for a couple more days. | |||
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I have had Norman Johnson with High Plains rebore about 3 8x57's (.232) to 9.3x62s (3.66) two were Brno mod 21'S and one a half oct/half round full rib Mauser. All three shot fantastic groups. I have one now that shoots one hole and its a half round/half oct. 9.3x62. I had one done about 15 years ago and its a small ring G33-40 Mauser with a rebored 8x57 to 9.3x62 full half oct whippy barrel and its been shot at least 3000 rounds by its present owner. I really don't know of any actual testing that's been done, and if so there would be a hell of a lot of varibles involved, such as half oct which is much thicker than the half round portion of the barrel, and the pressure on the round is less than that of the oct. and that would change the scenario I suspect. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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