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Accuracy International AT-X

Manual states 49 inch pounds on the barrel lock screw. Getting ready to change a barrel, anyone have issues with loosening or barrel exhibiting better accuracy in the higher ranges, 55-65?
I use this technique. Was doing 60, but some engineer-type said 55 for bolt stretch reasons…I’d attempt to explain further but I’d just use all of the wrong words lol.

I think logically his technique below makes sense, but I can’t back anything up with tests.

 
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I’ve had the best luck on my old AT and new AT-XC with 65 in/lbs. I also have flats on all my barrels so I tighten them some with a crescent wrench before torquing the quick lock screw. I’ve found this makes everything very consistent and seem to see slightly better groups.
 
The stock 49 or whatever the nearest fixit stick works for me. My first shot is usually 0.2 mil low and I'm not sure if that's the barrel or suppressor seating or barrel fouling or all the above. My RTZ is consistent so I have seen a need to try any different torque settings.
 
Keep in mind one issue particularly with the bonded AT/AX was bonding agent getting in between the clamp area on the quickloc. Which contributed to people having issues with 49 inch lbs not being enough and inconsistent

The AT/AX/AXMC are all bonded unlike the ATX
 
Does anybody know what freebore and neck diameter the 6BR factory AI barrels are reamed with?
I'd say the fb is around 120 length, as it's bout 15k longer than my 104fb barrel. The fired brass comes out 2725-273. So I'm guessing it's a 274 or slightly smaller neck. This is a 7.25tw 26in Wintac AI house brand barrel. Headspace is a bit long......virgin brass is growing 0.005-0.00055, running 29.7gr Varg with a 105 moving 2800.

Just what I've found with the one AI 6br barrel I have. I have a few other BR barrels that are chambered to go gauge plus 0025, and they're about a thou shorter in headspace VS this particular setup. Could be action headspace variation. I torque my barrel up relatively tight with a 24in crescent then torque the quick change screw to 55"/#.
 
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My impact barrel on my comp gun is a .130 freebore and .274 neck diameter, which has been great for no turn prep on lapua brass. I’ve been at 30.2 gr Varget and was hoping the barrel specs were roughly comparable on the factory AI. That way, I could just keep using the same ammo across both guns.
 
Quick question for all the gents in this forum. I purchased a AT-XC and I am waiting for it to show this summer. I have a small fortune in AW mags, will they work without issue in this chassis? I cannot seem to find any real answer. I am over $1500 in aw mags and would love to not have to start stacking up another form of magazine. Appreciate any insight!
 
Quick question for all the gents in this forum. I purchased a AT-XC and I am waiting for it to show this summer. I have a small fortune in AW mags, will they work without issue in this chassis? I cannot seem to find any real answer. I am over $1500 in aw mags and would love to not have to start stacking up another form of magazine. Appreciate any insight!
They should work fine @Rory_Fritz uses them in his Gen 1 AT-X with no issue and I can't imagine they've changed the design so dramatically since then that they wouldn't work.
 
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Little barrel chop.
1000015175.jpg
 
Can anyone tell me what is the biggest barrel profile I can run in my ATX? I am using the full top rail and internal weights.
Im unsure of the internal weights....however there have been posts here that say you can't run a 1.25 barrel in this chassis. Assuming the internal dimensions are the same between the at-x and the aics at-x chassis, this doesn't hold true. I have a at-x aics chassis with a vudoo in it with a 1.25 barrel and full bridge, you just have to put the bridge on the barrel before placing it into the chassis. The tabs that secure the bridge are too thick to just place the bridge down into the chassis from the top. Then again, if you go this heavy on the barrel, you may not see the need for the internal weights.
 
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I own a very light Hill Country Rifles “Sheep Model” rifle chambered in 6.5 Creedmoor with a Stiller action.

It has a 22” Benchmark #2 barrel and consistently shoots sub 0.25 MOA.

I ‘m interested in putting it in an AT-X chassis and was wondering if it’s as simple as just bolting it in per AI’s instructions, and if so, would it then be able to use AICS box mags without having to add DBM bottom metal?

I apologize in advance if I have posted this in the wrong forum section.

Any advice will be appreciated.
 
I own a very light Hill Country Rifles “Sheep Model” rifle chambered in 6.5 Creedmoor with a Stiller action.

It has a 22” Benchmark #2 barrel and consistently shoots sub 0.25 MOA.

I ‘m interested in putting it in an AT-X chassis and was wondering if it’s as simple as just bolting it in per AI’s instructions, and if so, would it then be able to use AICS box mags without having to add DBM bottom metal?

I apologize in advance if I have posted this in the wrong forum section.

Any advice will be appreciated.
Yes the stiller should drop right into an ATX rem700 Aics chassis. As long the magazine cut is sufficient(like for a hawkins mag box), all aics mags should function.

My question is why put a hunting gun into a chassis that already shoots tiny groups?
 
Yes the stiller should drop right into an ATX rem700 Aics chassis. As long the magazine cut is sufficient(like for a hawkins mag box), all aics mags should function.

My question is why put a hunting gun into a chassis that already shoots tiny groups?
One of my sons recently joined a club with a 1000 yard range and he wants me to accompany him occasionally for some father/son long range shooting. The club also allows night shooting.

I already own appropriate LR scopes and NV gear, however, I only own 2 tactical style rifles in calibers other than .223/5.56. Both are GAP 308 rifles, an older Rock rifle and an early Gap 10 model. Both 308s and are very accurate using factory match ammo, but I believe a 6.5 CM would perform better past 800 yards.

Since I have two almost identical, except for the actions, 6.5CM hunting rifles, I was exploring the possibility of installing one of them in a chassis that would be better suited for LR target shooting and also accommodate the use of an OSTI PVS-22 clip on NVD.

One of the 6.5CMs was originally built by HCR in 260 Rem on a Stiller action and the other started out as an early Dakota 76 in 22-250. Subsequently, both rifles were sent to HCR for re-barreling to 6.5CM. Additionally, the Dakota was also installed in a McMillan Hunter’s Edge stock. They are both tack drivers using factory 143gr. Hornady ELD-X ammo.

Rather long-winded, but that’s why I was looking at the possibility of putting one of the 6.5CMs in a ATX chassis. Since the Stiller is SS and the Dakota is finished in black Cerakote, I would prefer to use the Dakota in a chassis, however, I don’t think it would bolt right in as the action’s footprint may be closer to a M76 than a M700.

Maybe it would be a better idea to start handloading again and develop a hotter load for one of the GAP 308s that would keep bulltet velocity supersonic out to 1000 yards...........

Hill Country Rifles - 6.5 Creedmoor .jpg