Could be better
Very well made. This thing is backwards though. If it had flats on the body of the tool it could be locked into the vise and you could work on the upper easily. As it is now, you lock your barrel nut wrench in the vise and push this thing into it and simultaneously push and apply a breaker bar to the tool. This was pretty difficult to do with my BRN 10 because that barrel had well over 80ft lbs applied to it and was pretty hard to get removed from the upper. Good tool but the Botach KleyZion one is a lot better because it has flats to lock it securely into a vise.
Stout tool
It holds the barrel well when barreling a receiver and avoids putting a lot force - stress on the receiver. Having found no other tool to hold an AR10 upper, this works well. However the one con is that it should have two flat sides to allow it to be secured in a vise. Presently you have to secure a breaker bar or ratchet in a vise and then attach the tool and then slip the barreled receiver over the tool. This is cumbersome. It would be much more user friendly with a couple of flat side to be held directly in a vise. If it had the flat sides it would get five stars. Otherwise its stout and can be adapted to do the job.
Works excellent
Would give it 5 stars if it had flats on the sides to lock it in a vise. Not a problem to put your own flats in it if needed however.
Economical alternative!
Please check out the great Brownell's tutorial on Youtube to find out how to use this. In practice, you place your upper, with barrel and barrel nut affixed hand-tight, muzzle-down through a crows foot or armorer's wrench that hat been locked horizontally in your bench vise. This fixes the barrel nut and when you place this device in your barrel extension, the splines lock against the barrel extension, just as your bolt would. Now, when you attach your 1/2" drive torque wrench to the tool, your twisting rotates the barrel against the barrel nut, with no forces transferred to your upper itself. If you want to use it upright, similarly to the more expensive options from Geiselle and Kley-Zion, you can. Since there are no flats on this tool, it will rotate in your vise when you apply torque. What you can do is get a breaker bar (also called a flex handle) with flat faces at the end that will clamp in your bench vise. With the 1/2 driver of the breaker bar protruding above the vise but locked upright by the vise jaws, and the breaker bar braced against the body of your vise to limit sidelong rotation, you can now place the end of the Extension Torque tool on the 1/2 driver without fear of it twisting as you work. Careful not to apply only downward and rotation force so the tool does not come up off of the driver. I hope these tips are useful to you! Using both approaches, I was able to attach a BA 20" barrel to my new Aero Precision LR 308 upper and also time a VG6 Gamma 762 Muzzle Brake perfectly. Just a pleased customer wanting to share my positive experience and tips to save you a bit of money versus the alternatives. I paid full boat for the tool and have not been compensated in any way for this review.
The only way to work on your barrel
Like everyone said, this is much cheaper than the Geissele and works great. I too wish it have vise flats instead of being completely round, but I also wish it was 2 inches longer. I know adding light will increase the price, but it will be worth it to allow more room to do more than adding a barrel nut. I used mine to install a flash suppressor. It was just barely long enough for the vise to hold securely and for me to have enough room to work. Overall, I would buy this over the $200 Geissele anyway.
Must Have Tool...Needs flats ground
Must have tool for AR work. I would have given it five stars if it had flats on it like the Geisselle tool. As it comes, it will spin in the vise. I took the grinder to it (don't bother milling it, as it is harder than woodpecker lips) and now it is perfect. Brownell's, please change this one thing and you will have a hands down winner. Way cheaper than the aforementioned tool as well. Safest way to torque your barrel nut. I don't use the clamshells anymore now that I have this.
