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One Of Us |
Shown here are the muzzles of a HEYM "Express" 505 and 375. Both of which are specifically contoured to their respective bore diameters. This ensures the correct balance and weight distribution.  | ||
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A jewel in the crown :-) | |||
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| one of us |
new_guy, What are the diameters of those muzzles, and how long are those barrels? This will give us an idea of the proper contours for a .505 Gibbs and a .375 H&H, according to the masters. This would add redeeming social value to your gunporn. Yep, perfect crown for any sporter, especially working big bores.  Rip ... | |||
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One of Us |
how about the 404J contour as well? | |||
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| One Of Us |
Each bore diameter has it's own contour(375, 404, 458, etc...), so the 404 will sit between the 375 and 505 shown above. | |||
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OK guys, new_guy is being evasive, guarding proprietary info, doesn't know and won't admit it, or just doesn't care as long as he gets to pimp his gunporn here, with minimal redeeming social value, so I add some here.  Looks like the rule of thumb for Heym is the same one used by most of us. Contour your barrels as close to 0.125" barrel wall thickness in the grooves, at the muzzle, as possible, for a minimum weight rifle. That is a #3 sporter contour of 0.625" diameter at 24" barrel length for a .375 H&H, etc. Adjust the contour heavier for balance and desired weight. The weight of the stock (& etc., etc.) comes into play there. Rip ... | |||
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Hi, RIP. You know that you're going to have to purchase one of these to get all of the details, right? We satisfied the Mauser cosine rule some time back. http://forums.accuratereloadin...151085242#6151085242 Barrel lengths are all 24" (unless otherwise requested.) Muzzle diameters... would you like all calibers or just the 505? | |||
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Jolly good show then, new_guy. Of course we would want to know the "Heym-Proper" muzzle diameter at 24" length for the Big Five: .375 H&H .416 Rigby .404 Jeffery .450-bore/.458-caliber anything .505 Gibbs We can interpolate anything else, pretty please. Rip ... | |||
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| one of us |
Balistic masturbation once again haunts the hauls of wisdom! The size of the crown/muzzle has little to do with impottant factors other than it varies with length of barrel be it a no. 4 or a no. 5.. About anything one does to a barrel has some effect, some greatly, some not so much and others not at all, but a short heavy barrel will balance about the same as a long med barrel..bottom line is how it effects the shooter, his desires, build, and preferences.. I like a 20" carbine 375 H&H or a 26" 375 H&H and I would use a no. 5 douglas. Some might prefer a no. 4, but not me..Carbines are a trade off, less velocity but not unusuall since they are short and thick they tend to be more accurate if you get lucky..and a 100 FPS means nada in a big bore IMO, in that they both kill. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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I certainly don’t know what is ideal, but I’ll contribute that two original Oberndorf Mauser Type A 9.3x62 barrels in my possession measure .590” just behind the barrel band front site bases (the front of the bases are blended with the crowns). One is from 1939, and the other from 1934. DPCD’s “1930” Oberndorf Type A pattern is a good bit thicker at the muzzle- I think .630” or .650”. 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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Right, and a 10.75mm Oberndorf I measured is .683 muzzle OD. Muzzle diameters actually mean nothing without knowing the contour that is behind them. My 450 Nitro has barrel walls of .090. What does that mean? Nothing. | |||
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I prefer a #3 barrel on a 375, I try to keep the overall weight to about 8.5 lbs with the iron sights and about 9 Lbs with scope..Even a no. 2 barrel works pretty well..No. 4 for a 416 as a rule, but even then a #3 works well for some..My main concern is not to get the rifle I have to pack all day long is not overly heavy, mostly due to my age I suspect.. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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Contours either taper or are straight.Given the muzzle diameter at least one knows that the barrels will not be slimmer than that. | |||
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past time to buy a new crowning reamer | |||
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| One of Us |
I like my Browning Safari 458. Has a pretty thin contour toward the end of the pipe but it swings like a bird gun. If you want it fast handling, I have found few if any better. My particular rifle is extremely accurate. Think I paid about $1,500.00 for it. Control round feed, three position safety. I have quite a few custom built rifles but i just do not know what it is about this gun that is just so right for me. | |||
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Amen! BH63 Hunting buff is better than sex! | |||
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If I remember right, it’s basically an FN with a browning logo. Good stuff all around. I’d love to have one. | |||
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Moderator |
i believe in FAR lighter contour barrels than most -- and I think 0.125 is hugely too heavy past ~20" .. think about the taper -- if 0.125 if fine at 16", it makes a bit heavy at 26" 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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Gosh, but I wish I knew about barrel contours when I bought my pre 64 M70! Nothing to contribute here, but that I have enjoyed reading Atkinson's opening remark - ( best content of the whole thread). Keep up the good work Ray! NRA Life Benefactor Member, DRSS, DWWC, Whittington Center,Android Reloading Ballistics App at http://www.xplat.net/ | |||
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Who the heck says 0.125" barrel wall thickness in the grooves is good at 16" barrel length? I say 0.125" is good at 24" length. Keep tapering down after that. Therefore, 0.120" wall thickness in the grooves at 25" length, 0.115" at 26" length. That is a Douglas no.3 sporter contour in a .375 H&H barrel: 0.625" muzzle diameter at 24" length. With that I built a 6.75-pound .375 H&H. It could shoot 0.75-MOA for 3 shots. Desirable is a compromise between strong enough (not to bulge or split) and stiff enough (for group sizes smaller than your hat) versus weight. In the antiques and double rifles the pressures were lower and accuracy not as important as balance and daintiness, for that special pinky finger erector. The first .450 NE was a double rifle of John Rigby. The fifth set of barrels they tried in proof was the right combination of slimness and steel alloy. The first four failed, bulged or split. Meanwhile Jackman Jeffery became the first Nitro Express creator by building a Farquharson .400 S. Jeffery (.450/.400 NE 3") with one barrel of greater wall thickness. His first try at proof survived, even with a lesser strength steel like they had been building the NFBPE rifles with, before the full Nitro Express. I think 0.125" at 24" length is a good rule of thumb for any caliber. SAFE BET. Continue to taper between 16" and 26" by about 0.010"-diameter per inch of barrel length: For a .375 H&H: 16" barrel length: 0.705" diameter 22" barrel length: 0.645" diameter 23" barrel length: 0.635" diameter 24" barrel length: 0.625" diameter 25" barrel length: 0.615" diameter 26" barrel length: 0.605" diameter CZ uses a muzzle diameter of about 0.670" at 25" length for .375, .416, and .458 calibers. That is almost perfect by ".125-Rule-of-Thumb" for the .416 Rigby: .416" + .125" + .125" - .010" = 0.656", round to 0.660" at 25" length. That is heavy for a .375 H&H of same contour. That CZ contour is a little light for a .458 WIN by .125-ROT: .458 " + .125" + .125" - .010 = 0.698", round to 0.700" diameter at 25" length. That is about the minimum contour that Shilen will make for a .458-caliber rifle barrel, their light varmint contour. The CZ .458 WIN barrel is actually 0.459" in groove diameter, so if it is 0.670" diameter at 25" length, the wall thickness at the muzzle is: (0.670" - 0.459")/2 = 0.1055" The SIGARMS, Prechtl-actioned Magnum M98 .450 Dakota has about the same barrel wall thickness in the grooves at same 25" barrel length: 0.1055" I have found accuracy to be excellent with that sort of .458-caliber barrel. If you twist my arm, I might agree to a 0.1105"-Rule-of-Thumb, but no thinner, for barrel wall thickness at 24" length. 0.1105"-ROT. Therefore 16" barrel minimum thickness in the grooves, at the 16" muzzle = 0.1505" Check my arithmetic. That would be based on empirical evidence with modern steels. Rip ... | |||
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First Pearl:
Second Pearl:
 Apparently, Elvis (new_guy) has left the room. Rip ... | |||
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No offense intended (and in that regard I hope to distance myself from some of the above posters), but the .375 and .505 both look too light to me. Heavier is better for several reasons. Better (i.e., steadier) hang, less sensitivity to vibration, less muzzle jump and less recoil are a few. Plus, the extra weight builds upper body strength. Mike Wilderness is my cathedral, and hunting is my prayer. | |||
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In case anyone is still wondering about those numbers, despite the figures trotted out, I've found that info like that can sometimes be extrapolated from measuring pictures on the page. It just so happened that on the screen I'm using, calibres more or less line up with mm, suggesting the muzzles' wall thicknesses approximate 2/10ths inch for the .505 and 3/20ths on the .375; the o/s diameter of the .505 is about 9/10ths inch and the .375 nudges 7/10ths. The muzzles on double rifles are more slender than that, of course - each stiffens the other and weight needs to be kept down. The o/s diameter of Heym's 88PH in .450/.400, for instance, is less than 6/10ths inch. Thinking of Julian Hatcher's turning down a Springfield barrel over the chamber to 1/16ths thickness, I can't see lower db pressures being much to do with it. | |||
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I don't think accuracy matters as much with some of the thin barrels. Just gotta be sexy and survive proof. Since Elvis ain't talking, and sambarman338 is a little too imprecise for me, the picture of the Heym .505 Gibbs and .375 H&H says to my eyeballs: O.D. .505 Gibbs = 0.850" wall thickness in grooves at muzzle = 0.1725" O.D. .375 H&H = 0.650" wall thickness in grooves at muzzle = 0.1375" Those are none too light. Looks about right. I prefer to work out at the gym and carry a light rifle. Using a rifle as a dumbbell is, well, just dumb. Looking at some old barrel profiles, Lilja tapers by 0.007" diameter per inch of length in the terminal, constant taper part of the barrel, and his no.3 sporter is 0.630" at 27". At 24" it would be 0.651" diameter. Very Heymish, my guess. A Douglas no.3 sporter is lighter, 0.625" at 24" and tapers a little faster. I consider that the minimum weight for a .375 H&H, perfect for balancing the lightest of synthetic stocks. The Heym is a bit heavier. No doubt perfect for balancing a slim walnut stock. All the crap about muzzle diameter being meaningless is too funny. Of course the cylindrical knoxform for threading and transition into a taper by myriad forms is going to affect strength and weight and stiffness and balance!  Rip ... | |||
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Hell RIP, sometimes I miss the proper key, I don't reread posts, that's a waste of time..  As a matter of fact just give me a no 3 Douglas measure and I can live with that at 20 or 26..I used to like long tubes in a no. 4 but my young muscle turned to marshmellow melt about a year ago, today I probably should use a No. 1 Douglas in a .375 with a muzzle brake..  Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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