AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: Gary Rad on June 08, 2017, 05:19:48 AM
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Hello, I was wondering if anyone could tell me how tight a breech plug should be. Is there a ft. lb. measurement?
Thanks, Gary Rad
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I have never used a torque measurement when installing or otherwise fitting breach plugs. I just make sure that I have nice contact at the plug face [ I use a felt tipped marker to verify that it is seated well] and at the tang barrel interface. If I can't snug it up and have the tang aligned with the barrel flat when using a 10 in handled crecent wrench, I go back to my file.
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It just needs snugged up. When I still shot modern benchrest, most rifles could have the barrels screwed off by hand with no tool or clamp. As long as the rifling is the right direction for the threads, it can't unscrew, only tighten.
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All the Rice bbls I've bought require a 12" wrench plus a 12" pipe to either remove the breechplug or to install it. The end of the plug and the shoulder are colored w/ a Sharpie and if they both show contact w/ the ledge and bbl {it always happens w/ the Rice bbls}, I just leave as is. That's one of the reasons I only use bbls from Rice.....Fred
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I had never thought about the numbers, but the recommended torque for a 5/8" coarse thread is 96 ft-lbs, which is quite a bit to tackle with just a 12" wrench. Think of going after a garden-variety lug nut with a short wrench.
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I'm puzzle about the need for any kind of torque at all. After all, its a PLUG, not a fastener. Near full depth threads, tightened until the breech is sealed, is the optimum system. Torque only put a preload stress on a part that is designed deal with stress only when the gun is discharged. JMO.
Hungry Horse
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I use a 12" wrench, and brass shim to protect the plug. It should be a nice firm lock up to the witness mark stamped on the bottom flat and tang. It doesn't need to be killer tight, which can actually stress the breech threads. As long as the threads are a nice fit, there will be no problem with leakage or loosening.
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Hello, I was wondering if anyone could tell me how tight a breech plug should be. Is there a ft. lb. measurement?
Thanks, Gary Rad
As an old German friend of mine use to say –“Gutenntight” ;D ;) ::)
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You don't have an option on ft. lbs except it must be good and snug and the tang must line up with top flat. Believe me it will not come unscrewed. The plug is about 4 times less likely to come out than the barrel is to blow up.
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I use a 12" wrench, and brass shim to protect the plug. It should be a nice firm lock up to the witness mark stamped on the bottom flat and tang. It doesn't need to be killer tight, which can actually stress the breech threads. As long as the threads are a nice fit, there will be no problem with leakage or loosening.
Do you also put anti-seize on the threads before screwing together?
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That's a good idea if you ever need to remove it -- but don't use too much it can leach out and mess up your barrel finish ;)
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I use PTFE pipe thread tape. Works great.
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While fitting I use moly paste. I have some from years ago for treating barrels. It is no good for that...
IT is good to prevent galling while you fit the plug. I always go in and out, several times to full torque. That irons out the thread fit. Later when you take the plug out it will loosen up less upon putting it back. I use a 14" wrench and a dead blow hammer. I lean on the wrench and give moderate smacks until it stops. I have no idea the torque. I'm not so interested in some torque spec but a good tight fit to the the index. I have a real barrel vice and V-blocks so my barrel will not move. IF you are using a bench vice be careful not to muck up the barrel flats.
Definitely coat the threads with grease. I use cast bullet lube. IF the gaps in the thread fit is filled with grease they can not rust or accumulate fouling.
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Some where between goodenschnuggen and frikkienbroken. Don't forget th roll the r. ;). I use a 12 inch old fashioned adjustable wrench. The jaws have just enough wear to fit the taper on the breech plug tang. I've heard them called a Stilson wrench, they look like a pipe wrench but are not. As far as a tourque spec, my semi educated feel says 20 or 30 ft lbs. it's important the face of the plug and the shoulder snugs up solidly. I've been known to use blue locktite rather than a lube or sealer on the plug threads when I do final assemble, after touch hole liner installation. The blue locktite will not interfere with later dissassembly, if necessary. It does prevent rust and does not interfere with browning if you keep it off the tang joint. Anti seize will migrate and in my experience, does cause later browning and blueing problems
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My questions......why does Rice fit the plug so that a 12" wrench plus a 12" pipe is req'd? Also....do they seat the plug w/ a torque wrench and to how many ft/lbs?
I may be 85 yrs old but am a fairly big guy w/ strong arms and can't seat the Rice plugs w/ only a 12" wrench. Would I prefer a less tight plug, you betcha, but it is what it is......and I won't spend the time to achieve a less tight fit.....Fred
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Breech plugs that are difficult to tighten might be that way because, the threads in the barrel are closer to a hundred percent than most of us are used to. Threads on almost everything we normally deal with don't approach full thread depth. I debreeched a couple of antique barrels that were a much courser thread than we use today, but they had almost full thread contact. Which would make them much stronger than the average thread contact we are all used to. That's my theory.
Hungry Horse
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My questions......why does Rice fit the plug so that a 12" wrench plus a 12" pipe is req'd? Also....do they seat the plug w/ a torque wrench and to how many ft/lbs?
I may be 85 yrs old but am a fairly big guy w/ strong arms and can't seat the Rice plugs w/ only a 12" wrench. Would I prefer a less tight plug, you betcha, but it is what it is......and I won't spend the time to achieve a less tight fit.....Fred
I think what they do is thread the breech to .500" exactly, mill the breechplug to .500" exactly, and screw the whole thing down. The final torque is whatever is necessary to get the plug to line up with a flat. Seems to vary a bit between barrels, in my limited experience.
If I was a longhunter, backwoods settler, Indian, or anyone else who relied on a muzzleloader as a serious survival tool, I'd want a breechplug fitted so that the torque required to remove and replace it was less than than the force required to crush decent hardwood. In the absence of access to specialized gunsmithing tools and a full-sized workbench with a vise, that might make the difference between a fixable and an unfixable problem in the event of a stuck ball.
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When the plugs are really tight, you need a rock-solid vise that will not allow the barrel to spin.
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Tighten the plug till it strips then back off a quarter turn. Other will say back off a half turn YMMV.
To the person who takes this advice seriously it is a joke.
Cheers R
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I have an original J P Gemmer that only requires a 6” wrench to remove and install the breech plug. Makes cleaning easy!
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I don't have any thing to add regarding installing a breech plug. It's all been covered pretty thoroughly by everyone. The one thing I possibly do different is lubing the breech plug. I use axle/bearing grease on the breech plug threads. If the barrel is to be browned, I make sure to clean the area well with lacquer thinner. I have never had a problem with the grease migrating later on.
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Kit Ravenshire liked his finger tight.
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Get one of Rice's breech plug wrenches. These are the best things ever.
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Waksupi...
It just needs snugged up. When I still shot modern benchrest, most rifles could have the barrels screwed off by hand with no tool or clamp. As long as the rifling is the right direction for the threads, it can't unscrew, only tighten.
Never thought of it that way, but the one or two times I had to pull the plug to extract a round it was always tighter.
Whenever I order a barrel I put in the notes to unscrew the plug 1/2 turn because they are put in so tight. Once I can see the mark I can always get 'em back together.