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I'm talking about the type of takedowns where the barrel is screwed in and out every time like the Mausers and such. After reading many of the threads on this and other forums I have a question about proper thread form. Most of the negative comments on this system is that with V-type threads there is inevitable wear in the system and subsequent sloppiness developing. I know that Mauser selected buttress type threads for their bolt shrouds that were under continuous motion to minimize effects of wear. Buttress threads are also common in breech locking artillery. Square type threads as used on Springfield and US Enfield barrels might be another option. Is there any advantage to these types over V-type in a takedown system? Bob www.rustblue.com | ||
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The Winchester models 97 and model 12 and the FN Model D BAR all use a v thread on the barrel and barrel nut and a square thread on the od of the barrel nut and id of the receiver. The square thread is the one unscrewed to take down the barrel. John Browning invented the system and it has worked for over 100 years. | |||
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Is there a reason why machine leade screws are all "Acme" ? Jim Kobe 10841 Oxborough Ave So Bloomington MN 55437 952.884.6031 Professional member American Custom Gunmakers Guild | |||
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 Because ball screws last longer and are more accurate? Sorry Jim I can't help being an asshole! lol But yes, Acme threads would work very well, except receivers don't come with Acme or trapezoidal style threads. When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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Wouldn't it be great if someone would offer a receiver with ballscrews Jim Kobe 10841 Oxborough Ave So Bloomington MN 55437 952.884.6031 Professional member American Custom Gunmakers Guild | |||
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Acme and square threads are stronger than V threads. And they do not "split the nut" under high loads. Enfields & Springfields have square. | |||
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Yep, throw away the barrel vise and action wrench. | |||
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 The Anschutz Fortner locks up with ball screws Jim. Well sort of. It uses ball bearings for locking lugs. Our local biathlon team uses them and the kids are forever loosing their balls when they clean their guns and I had to order 100 of them to keep them on their slippery-sticks. Of course those silly Bavarian's used 5mm balls which are not something you buy at Home Depot. THOSE BASTARDS ! When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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I have always suspected that if the receiver was split just at the front, sort of like the Sauer 200, but you still wanted to utilize threads, 10 TPI, double lead, Acme threads would be the way to go. It would only take three complete turns to screw it on and the combination of the Acme thread and the double lead would reduce wear to nothing and virtually eliminate the chance of over tightening. The split forward part of the receiver with a crimping bolt would lock the barrel solid on an unthreaded portion of the barrel. But it would mean making a custom receiver. When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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I can think of only 2. The M1 and the M14 are 10 tpi Stub Acme. From what I can google about them, probably not the best application for a takedown. Full depth Acme might be better. | |||
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My 1946 South Bend lathe proves that all threads wear..even Acme. When I build TD's I used banded sights and sight bases. A little wear, simply tighten the barrel and rotate the sights back to battery. Interrupted threads are cute. but an attorney friend pointed out that with ANY mishap, the maker is in a more defensible position leaving full threads | |||
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Good points. My theory is that the threads will not wear enough to cause any problems, in normal use. How often do you need to take it down anyway? From the ones I have done, the only times they get taken down is to show other people how they work. Otherwise, it is once or twice a year, if that. So, if you are worried about wear, then stop taking them apart for no reason other than to see how they work. They will all out last you anyway. | |||
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I'm not sure where I read, or heard it Duane and I'm to damned lazy to work out all of the math just for the sake of curiosity, but it strikes me that the sheer strength of the barrel threads is about double the sheer strength of the locking lugs in a Remington 700. So I suppose in all fairness the interrupted thread is plenty strong. But like your attorney buddy, they have always sort of scared me a bit. Plus as the threads and shoulder wear the barrel would over rotate and the purchase would become less and less. I still have a horrible hankering to do one in a double lead thread. The tightening force of double lead is about half of single lead and each turn of the barrel doubles the advance without compromising any sheer strength. But that would mean making another action and while my (great ideas) level is always at an all time high, my motivational levels are way down around (yeah I gotta try that some day)! Not at all conducive to productivity. Then there is the fact that I would never get my money out of the job and that tends to put a damper on things too. When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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......slightly off topic, but is there any advantage to having small mating tapers at the barrel end of the action and a matching one at the end of the barrel thread ? I hope you can understand my description. Would this help alignment or possibly take a small amount of load off the threads ? Roger | |||
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No, that would accomplish nothing. | |||
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Rod: With a steep thread and LH rifling, the barrel would tend to loosen.....HAR!!...Or....?? | |||
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Just use left hand threads. Then see how long it takes your friends to break it down. | |||
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LOL @ Duane Fortunately for those of us here, Old Billy Leeper is the only one on this forum who shoots ass-backwards barrels and he's getting so old, dotty and blind he probably wouldn't notice if the damned thing screwed off and dropped into the snow anyway. LMAO ROFF  When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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one of the most numerous, if not THE largest percentage of commercial take down actions - the AR7 ... yeah, i know, it's not anything like a hunting rifle, nor particularly accurate - but it works if it had an arisaka paratrooper takedown "wedge" it might be better  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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Martin Hagn showed me one of his take=down Mausers and it had acme threads. Henrickson wishes he still had my visual acuity (brand new lenses in these eyes) and razor-sharp intellect. By shooting left-handed, one can compensate for any barrel-loosening torque. Regards, Bill. | |||
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Congrats on the new lookers, Billy. My old man just got his cataracts fixed. It had gotten to the point that we were scared to ride with him in a vehicle. Actually, I thought I was safe and that you would probably be hibernating. What with winter and all, and spring so far away, I though would have napped right through this entire thread. Obviously, the evil monster that lives in your kitchen has stopped buying that decaffeinated coffee. LOL When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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Far as a quick change, takedown system the West Texas Ordnance Switchlug makes it very easy (no personal experience- just anecdotal evidence). Easier than a barrel but as "almost" no tools (just a small torque driver) or gauges needed. Doesn't rely on thread torque to retain the barrel, uses a locking recoil lug, so no stresses on the threads... A little extra work on pinning the lug and a tapered mating surface for it on the barrel, but looks slick as snot. If I had a reason for needing quick barrel changes in the field, this would be it (700 compatible). | |||
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Locking recoil lug. Post a picture of that. | |||
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I had a couple of customers bring them to me for install Tom. I sort of went: "HO HUM, Yeah OK!" It's basically a recoil lug with a split at the top and a couple of ears with an Allen screw in them to clamp the lug on the barrel. It also has a couple or three locking pins that engage the receiver. You drill the receiver for the pins and then pin the lug to the receiver. Then you screw in the barrel hand tight or strap wrench tight and tighten the Allen screw to lock the split lug on to the barrel so the barrel won't unscrew. You can do exactly the same thing by drilling a pinned recoil lug for a grub screw and just locking it lightly to get the same effect without all of the ugly and protrusion. I wasn't really moved by the device, but I'm kind of an ornery SOB at the best of times. When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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Ok, I see now. thanks. I can think of more elegant ways. | |||
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Yup, those are the ones. If you want the same thing without the ugly, just buy one of the wide recoil lugs with pins and drill and tap a hole to 6x48 right at the very top. With that split ring, when you tighten the screw the tops come together and force the barrel down into the bottom of the recoil lug and locks the barrel. A simple grub screw in the top of a wide lug does exactly the same thing and really does not compromise the strength of the lug at all. When I was a kid. I had the stick. I had the rock. And I had the mud puddle. I am as adept with them today, as I was back then. Lets see today's kids say that about their IPods, IPads and XBoxes in 45 years! Rod Henrickson | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Gunsmithing Thread form for takedown barrels/receivers
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