You are mostly right. The 16" version gets you the same action and ( untapered heavy) barrel as you'd get in the 16" VPT, VPC, Pro Varmint etc. The AT-ONE ( aka the eighty one) does come in a 24" moderately tapered barrel ( Heavier than an American pencil barrel but not as beefy as a untampered 16 or 20" . They are hard to find at the moment but there are still a few floating around. ( Love mine BTW) As far as I know, there are no 20" At-One's state side but that doesn't mean you couldn't swap any barrel in. It's a simple and inexpensive process.
That said, I can tell you ( as others can here if you search) that those stubby barrels shoot very well. If I were to put a can on an At-One, I'd likely pick the shorter version.
Lots of discussion on this model if you search here.

 

Yes, the At-One is basically a Varmint with a stock more conducive to benchrest shooting with its wider/flatter forend. The butt adjustments for LOP and comb height are nice, also.
It is also available with a threaded 24" bbl which is a bit harder to find due to being the more popular offering among bench shooters. Same price.
I bought a 24" last August (for 50/50 Bench) and have been quite impressed after resolving some minor stock fit issues. My other choice was the MTR but, after 6 months of not being able to get one, money was burning a hole in my pocket! I'm now glad it worked out that way.
@tbates66 , what do you plan to use it for?

 

Good question. I've always had several .22s and mostly hunt squirrels and plink a variety of convenient targets. As I've gotten older I spend more time at the range seeking the ever-illusive one-hole groups. I don't compete and likely never will, but have great fun shooting with friends. So, I've become interested in bench style rifles with bag friendly forearms and light triggers; accuracy being the primary goal. Truth is, it gives me an excuse to buy another rifle and track down the scope that works best.
I have an accurate Bergara BXR with an 18" barrel, so I'm not too phobic about short barrels. But, an old dog like me doesn't doesn't warm up to new tricks. A 20" seems about right for me. That being the case, I may try to find a trainer with a 20.5" barrel. I'll keep looking and appreciate everyone's help

 

the "At-One" model. BTW....the name of it is just silly.

No lie.
I have the threaded 24" @1 uncanned and like it.

 

Have you actually held the stock and played around with it? I had a Boyd's AT-One and still have a CZ/Boyd's sitting in the closet, it was not my favorite stock with hard to work button's and wobbly check rest. Don't let that stop you as you may really like it.

 

I’ve bought 3 of the 16” versions and have replaced the stock eventually on all 3

 

I have the 16" version. I wanted the longer barrel but did not want to wait and I am very happy with mine even though I will never put a suppressor on it. I do find the buttons stiff but I don't move them now that they are set for me, so it is no big deal, and I do not need either adjustment to be at its maximum length so my buttstock and cheekpiece are very solid.

 

Just do yourself a favor and get the Varmint Precision Chassis. You'll be glad you did!

 

I've had a NIB 24 incher for about a month now. It still doesn't have a scope on it. I put an Area 419 15 MOA rail on it, and I'm close to a scope. I can't wait to brake it in. I've got a good variety of ammo to play with. Very soon......

 

I admire your patience!

 

I can not complain about my @1 24". It shoots much better than I am capable. I managed a best 243-8X on a USBR target at a local match.
But based on my Begara BMR Carbon accuracy, I would not worry about any premium Rimfire with a shorter barrel.

 

My 457 AT-1 24", 457 Pro Varmint 16.5" and T1X 20" are my go to ARA competition rifles. The AT-1 shoots slightly better than the Pro Varmint and slightly worse than the T1X. But some days just the opposite.
At the ARA Indoor Nationals last fall there were 7 AT-1's, 6 with 24" barrel and 1 16.5" barrel. Kinda tells you something.
And the Boyd's stock on the AT-1 is solid and firm. No looseness with any of the adjustments.

 

The adjustment buttons on mine are overly firm also but, with the pad fully extended is not wobbly for my XLong LOP.

 

Yeah, the buttons on mine are also quite firm and I make sure I'm pushing dead center.

 

I have the 16" and yes my buttons are hard as well. But who cares, I have it set where I want and the gun shoots great. AT the moment my most accurate CZ...but I'm working on that.

 

I picked up a used one with 24" barrel at local gun shop. Shoots lights out at 50yds, and I am finding what it likes at 100yrd, so far Wolf Target Match seems to shoot best. Yes the buttons are a bit fussy but as was mentioned above once it's set it's set.

 

The buttons on these At-Ones are all stiff. They need to be by design as if they were easy, the adjustments would be prone to slippage and /or accidental activation. That's why most companies use a screw down vs spring loaded release/lock system. The advantage to the spring loaded Boyd's system is that a) it is field adjustable without tools and b) leaves no protruding knobs to snag/poke. That said, this system reportedly works fine unless you are a really big/tall guy pushing the limits of adjustment ( in which case some report wobble in the cheek/butt pieces).. Most of my rifle stocks are " set and forget". Once initially set up , it's rare they are messed with on the range anyway.

 

I have a very gingerly used AT-ONE with the 16.5" barrel and it's a shooter although I have more work to do on it's favorite ammo. Sometime over the summer I'll be getting another 457 but haven't decided on which one.

 

I have an AT-One 16.5". Like it a lot, shoots as well as I expected but I'm not a competitor. Never considered the 24", I don't like the longer barrels.

Agreed on the stock adjustment buttons being heavy. I smoothed things out and changed springs, much better now but seldom change the settings.

I'd guess that the name comes from the Boyd's stock. I like the CZ version stock better, a much simpler design.

Jim