With all the talk about the pro’s and con’s of the various barrel change systems that are out there, is there any functional differences between the older torqued on AI barrels and the newer quickloc ones? I’m assuming AI has it pretty much debugged.
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Quickloc AI vs Torqued Barrel
- Thread starter Afkirby
- Start date
Some people have reported a wandering POI with the Quickloc when torqued at the factory specs, and said it went away when they increased the torque on the screw to 55-65 in-lb.
I haven't seen that problem myself, but it's hard to argue against a regularly torqued barrel via barrel vise and action wrench for simplicity and consistency with no worries about it moving or loosening up. While it's not said explicitly anywhere you can torque a barrel into an AI quickloc action... I've done it to compare group sizes to the barrel being hand tight + 50 in-lb on the Quickloc screw compared to 75 ft-lb on the barrel with a barrel vise and action wrench and then snugging the quickloc screw to 50 in-lb. I did not notice any difference in group size or a wandering POI between the two methods as the barrel warmed or after tapping the barrel with a rubber mallet between shots.
So for now I'm sticking with hand tight on the barrel (or a little past hand tight using a stubby open end wrench wrench on the barrel flats or with a strap wrench) plus 50 in-lb on the Quickloc screw. If anything ever acts odd in the future I'll just go back to torquing the barrel to 75ft-lbs (AW & AE spec is 100 ft-lb, same thread diameter and pitch as the AT and AX308, I decided to do a little less because of the H-cut relieved threads for the quickloc) and then tightening the quickloc screw to 50 in-lb.
I haven't seen that problem myself, but it's hard to argue against a regularly torqued barrel via barrel vise and action wrench for simplicity and consistency with no worries about it moving or loosening up. While it's not said explicitly anywhere you can torque a barrel into an AI quickloc action... I've done it to compare group sizes to the barrel being hand tight + 50 in-lb on the Quickloc screw compared to 75 ft-lb on the barrel with a barrel vise and action wrench and then snugging the quickloc screw to 50 in-lb. I did not notice any difference in group size or a wandering POI between the two methods as the barrel warmed or after tapping the barrel with a rubber mallet between shots.
So for now I'm sticking with hand tight on the barrel (or a little past hand tight using a stubby open end wrench wrench on the barrel flats or with a strap wrench) plus 50 in-lb on the Quickloc screw. If anything ever acts odd in the future I'll just go back to torquing the barrel to 75ft-lbs (AW & AE spec is 100 ft-lb, same thread diameter and pitch as the AT and AX308, I decided to do a little less because of the H-cut relieved threads for the quickloc) and then tightening the quickloc screw to 50 in-lb.
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I use a Borka torque wrench (made for the AI quicklok barrel @ 49 inch/lb) to screw-in the quicklok screw on my AT, after hand-tightening the barrel on - haven't had any problems with it.
I've used a barrel vise on the 3 AE's I owned, that of course is the recommended method and works well.
That said, if I'm reading your statement correctly, I'm not sure it's a good idea to torque an A/T or A/X barrel to 100ft/lbs in the somewhat loose clamshell design, then tighten to 49 in/lbs. I would think that might put an undue strain on the clamshell threads.
I use the Borka torque wrench as well.
Yeah, a barrel vise/action wrench/torque wrench install would be ill-advised in a post-‘14 AI. The manual specifically states to thread the barrel in until flush (no gap) with the action face (basically a firm hand-tight), then torque the QL bolt to 49inlbs. I would be far more likely to experiment with an increase in torque to the QL bolt, but I think you’d be asking for trouble by torqueing a barrel to 100ftlbs before using the QL bolt...
With all the pre fit barrels being made by different companies has anyone seen that tolerances may be different? Wondering if it is from these different pre fits that are loose.
I've measured about 10 AI actions now and while admittedly that isn't a large sample, all of them (AE/AW/AT/AX308) were within a 0.002" window (+/- 0.001) for the receiver face to bolt face dimension. That's more than good enough for spinning up prefit barrels provided the gunsmith has the appropriate thread gauges to verify the tenon threads as well as a tool to measure the dimension from the barrel shoulder to the back of the headspace gauge (Dave Tooley showed his neat solution, which was a calibrated sleeve with a built in thimble micrometer to measure the actual barrel shoulder to back of headspace gauge dimension.)
That’s was my thought...maybe some of the barrels that are coming loose were done by a gunsmith that got them “close enough.” That’s the first thing that came to mind on why some shooters are having issues with a barrel coming loose.
Who has barrels coming loose? Nowhere did the op say ai barrels are coming loose. I have done literally hundreds of barrel swaps now on my ai and don't know how the barrel could come loose if you screw it on and tighten the quickloc screw.
If you look through other threads you’ll see where some guys are saying they keep coming loose tho. I don’t think it’s an AI problem tho.
I have 4 barrels for my AIAT from various sources.. I torque them all with a 5nm (45in.lb) torque wrench made for mountain bike seats and handlebars. It is a single T handle type torque wrench. Being 4mm it conveniently fits ARC rings, the barrel lock screw and the stock adjustment screws. I have never had a barrel come loose or any funny POI shifts even set to only 45 inch pounds.
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