If the Valor has the qc option. Can you still do full tenon shouldered barrel for it? Or does every barrel have to be cut for the quick change option.
Gunsmithing Curtis Valor question. Need a little help before buying
- Thread starter LC 6.5 Shooter
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I've seen this question a few times. The full thread bbls will work with the QC Valor/Zeus. You can also torque the QC bbls if you want, but unnecessary. You just lose a few threads in the action since the QC doesn't have full threads, which isn't a huge deal and doesn't affect anything if torqued sufficiently. I once bought a QC action with a QC bbl torqued, which I thought was stupid as hell, but it was fine.
The full length tenon is technically 0.002”-0.004” shorter to allow for the additional inward travel under full torque (if I recall correctly). Prints are available on the Curtis site when I checked months ago.
You can run both barrels in a QC, however the locking Allen’s will need to be removed or stick out.
My QC was chambered with a full torque, shouldered barrel.
You can run both barrels in a QC, however the locking Allen’s will need to be removed or stick out.
My QC was chambered with a full torque, shouldered barrel.
On QC actions such as the Valor or Zeus, the first (from the action face/lug side) ~0.30" of female threads are milled away so that when a QC style barrel tenon is machined, the flat section of the tenon will provide a suitable surface for the two set screws to engage. If you install a fully threaded tenon, the threads in that 0.30" section are floating in air since the male threads have no female threads to engage. In that sense, you can use either style on a QC action.
However, while the QC action's two set screws don't actually hold the hand tightened barrel in place, they do add a degree of additional force on top of that generated when you properly hand tighten the barrel. If you use a fully threaded barrel tenon, the set screws will dig into the crest of the tenon threads, possibly/probably damaging both the set screws and tenon threads. If you don't use the set screws, you do lose that "extra" level of resistance to loosening of the barrel. Your call on whether to use set screws, many have tested (sometimes unintentionally), and properly hand tightened, the barrel doesn't loosen under normal shooting conditions.
There is however another difference between a QC machined barrel and a full thread barrel - that is the amount of case head protrusion/stick out. Due to the phenomenon known as "thread crush", the tenon will "stretch" slightly (about 0.002" at 100 ft-lbs). This means, if your barrel tenon has been machined to the tenon print (Note: I believe the Curtis tenon print has the spec flipped - it lists a shorter case head protrusion for hand tightened and longer for a torqued barrel) a fully threaded barrel tenon that is NOT torqued, will have 0.002" greater headspace than a QC machined barrel. This difference is strictly derived from the depth the chamber is cut - it has nothing to do with the tenon threads.
Does that create an issue? In my opinion, no. SAAMI provides a 0.010" range between Go and No-Go (headspace) gauges, so if the barrel is in the middle of that range, 0.002" won't matter. Even if you were 0.002" out of spec, it would just mean cases sized for that rifle might not fit another rifle within the SAAMI spec range.
However, while the QC action's two set screws don't actually hold the hand tightened barrel in place, they do add a degree of additional force on top of that generated when you properly hand tighten the barrel. If you use a fully threaded barrel tenon, the set screws will dig into the crest of the tenon threads, possibly/probably damaging both the set screws and tenon threads. If you don't use the set screws, you do lose that "extra" level of resistance to loosening of the barrel. Your call on whether to use set screws, many have tested (sometimes unintentionally), and properly hand tightened, the barrel doesn't loosen under normal shooting conditions.
There is however another difference between a QC machined barrel and a full thread barrel - that is the amount of case head protrusion/stick out. Due to the phenomenon known as "thread crush", the tenon will "stretch" slightly (about 0.002" at 100 ft-lbs). This means, if your barrel tenon has been machined to the tenon print (Note: I believe the Curtis tenon print has the spec flipped - it lists a shorter case head protrusion for hand tightened and longer for a torqued barrel) a fully threaded barrel tenon that is NOT torqued, will have 0.002" greater headspace than a QC machined barrel. This difference is strictly derived from the depth the chamber is cut - it has nothing to do with the tenon threads.
Does that create an issue? In my opinion, no. SAAMI provides a 0.010" range between Go and No-Go (headspace) gauges, so if the barrel is in the middle of that range, 0.002" won't matter. Even if you were 0.002" out of spec, it would just mean cases sized for that rifle might not fit another rifle within the SAAMI spec range.
