What do you use to build your upper?

[CastorTroy]

Reaction rod. But I basically only use Surefire muzzle devices with shims, that only get 30ft/lbs and rocksett. I wouldn't use a reaction rod with anything that used a crush washer.

[Wheelhorse]

I believe that if I had an upper/barrel that wouldn't slip together, I would put the upper in an oven at a low setting for an hour or so while the barrel was in a freezer.
This would heat the upper more evenly than a heat gun or hair dryer.
This is the method I use on chainsaw crankshaft bearings and they fall right in.

[Growler]

I wouldn't use a reaction rod with anything that used a crush washer.

Curious as to why?

I’m planning to use a Geissele reaction rod with my first build. I think this will be ideal for tightening the barrel nut as well as the muzzle device. When removing a muzzle device, the torque applied to the barrel extension would be in the same direction as needed to unscrew the barrel from the barrel extension, right? I would imagine the barrel extension torque would be close to 10x the muzzle device torque however. Has anyone ever had a problem unintentionally loosening the barrel extension in this scenario?

[SDW]

I believe that if I had an upper/barrel that wouldn't slip together, I would put the upper in an oven at a low setting for an hour or so while the barrel was in a freezer.
This would heat the upper more evenly than a heat gun or hair dryer.
This is the method I use on chainsaw crankshaft bearings and they fall right in.

Just FYI. BCM's instructions for installing their Alpha handguards are probably being overly cautious, but they say:

"NEVER use an oven to bake or heat parts. It is not a precise way to apply heat, and the oils/solvents/chemicals present can contaminate an oven making it unusable. To warm up cold parts, we recommend use of a hair dryer or heat gun (on LOW). Extremely hot parts are difficult to handle without causing damage."

Probably would apply to installing barrels just as much.

https://www.bravocompanymfg.com/download...ctions.pdf

[Dontask]

Bev.

[bob4432]

I have a couple Aero uppers along with a BCM (plan on picking up more), but for this Grendel build would you use the BCM upper knowing how they machine their uppers - as in the the size if where the barrel extension goes, using just enough heat to tighten the barrel but plan on using a bit of blue Loctite, or go with a one of the Aero Precision uppers and using the shim technique using SS shims till just a little heat is necessary, and of course using a bit if blue Loctite at the end?

Also, FWIW, I plan on using a A1 style (the 30cal version) with probably 2 shims and blue loctite, and just a bit above hand tightening since no timing of a brake of this particular FH are necessary.

Last, I plan on using a SA Clamp on the gas block, using blue Loctite around the barrel, on the Socket Head Screws and also on the gas tube too. Will be using a torque wrench for the gas block and since I am using a ALG rail, that torque will be dictated by their system, and yes I will be using Anti-Seize where applicable.

This not going to be a 'fast shoot' rifle, but one to learn techniques of accurate, repeatable longer range shooting.

Having said that, has anybody found either a BCM or Aero Precision upper to be the base of a more accurate upper, or is it just 'flip a coin' time because they could both be considered pretty much equal? Or what about shimming vs using the known smaller BCM had any difference on the final product?

Thanks in advance,
Bob

[FRB6.5]

I'd measure the inside diameter of each upper and the outside diameter of the barrel extension once you have your barrel and see what combinations of fit you end up with. At times you can run into a barrel extension that is undersized enough to be sloppy in a BCM.

[Sixoeight]

I use the No-Mar upper vise block. It has pins but I don't use them so no stress there. I would not want to use this style without a good beefy vise, but luckily I was gifted an extra that must weigh over 50 lbs.

[Bazinga]

Another vote for the BEV block. Works perfect for my needs.

[Djgrendel]

I use a reaction rod, and have access to liquid nitrogen if needed. Freeze the barrel and insert. Snug barrel nut by hand. After thermal equalization, use a reaction rod and torque the nut.

[centerfire]

Curious as to why?

I’m planning to use a Geissele reaction rod with my first build. I think this will be ideal for tightening the barrel nut as well as the muzzle device. When removing a muzzle device, the torque applied to the barrel extension would be in the same direction as needed to unscrew the barrel from the barrel extension, right? I would imagine the barrel extension torque would be close to 10x the muzzle device torque however. Has anyone ever had a problem unintentionally loosening the barrel extension in this scenario?

Torquing a muzzle device with the barrel mounted on a reaction rod runs the risk of damaging the pin in the barrel extension, damaging the receiver, or changing the index of the barrel in the barrel extension. The propper way to install a muzzle device is with a barrel vice.

[LRRPF52]

For muzzle device work, I always clamp the barrel in the vice.

I don't use much torque though normally on muzzle devices.

[Wargrendeleagle]

For muzzle device work, I always clamp the barrel in the vice.

I don't use much torque though normally on muzzle devices.

Any particular barrel vise? With a short barrel like the 12" GB will there be enough room between gas block and end of barrel? I read on another forum some guys use 2x4s. Which seems crude to me but I'm building a house so no shortage on them.

[SDW]

Any particular barrel vise? With a short barrel like the 12" GB will there be enough room between gas block and end of barrel? I read on another forum some guys use 2x4s. Which seems crude to me but I'm building a house so no shortage on them.

Sounds familiar. I made a clamp for holding my Bilstein shocks for doing rebuilds with something along this line.

Just drill a "barrel sized" hold through about a 6" section of 2x4, in the wide side. Then saw it in half through the middle of the hole and you'd have a nice clamp to throw in a vice. Hmm. Maybe you'd want to do it length ways, come to think of it. To get more contact area on the barrel.

[centerfire]

I made a barrel vise out of 1/4" plate and pieces of lead. It clamps the barrel with bolts and I then set the entire assembly into a large jaw vise. The barrel vise is about 4" long and I could probably twist off the end of the barrel before the barrel slips.