Barrel wobble

[Recondo]

Newbie here, just got my new grendel rifle. The barrel seems to wobble a lot inside the hand guard though all screws are tight. Is this normal? I paid extra to have it lapped? Any advice from the senior builders is greatly appreciated.

[grayfox]

Not a senior builder but I've built a few. In a word, no, not normal.
1. What barrel is it?
2. What upper?
3. What barrel nut are you using?
4. You have a torque wrench with crow's foot/proper adapter right?


Barrel should be not just snug but torqued (the barrel nut that is) to spec into the upper receiver, many guys even bed it with some loctite (I'm doing that now in mine, loctite blue for me -- never rocksett!!!!!) tighten, torque to 35, loosen, tighten, torque, loosen, tighten, torque. IIRC the spec is 35 to less than 80. Barrel should seat flat and firmly inside the upper and pin is aligned in its slot.
There are lots more experienced builders on here, but I hope this gives you some things to think about.

[BCHunter]

Definitely not normal.
Is the wobble in the barrel to upper fit?

Or upper to lower fit?

First case take hand guard off and check the barrel nut is torqued on.

Second case is more common, and depending on lower may have a screw to tighten upper to lower fit. Or get an acuqa wedge to take out the tolerance slop.

[Tex Nomex]

If it's barrel movement inside your hand guard, it's a loose barrel or loose hand guard.
Remove the hand guard and see if the barrel moves in relation to the upper receiver.
If it's tight, then it's just a hand guard issue.
DO NOT fire this weapon until you sort this out.

[bj139]

Take the upper off the lower and grab the barrel in one hand and the receiver in the other and twist and bend the unit.
If there is no movement it is just the handguard. If there is movement, you need to remove the handguard and tighten the barrel nut.

[Klem]

I've been fooled before by handguards that flex because they are long and tubular. It deceives you into thinking the barrel is flexing but it's really the handguard around it. You need to clarify whether it is the barrel flexing or the handguard. Then figure out if the culprit is done-up properly. It may just be a light-weight flexible handguard and everything is fine.

[Recondo]

Thanks for all the good advice, I will check it out tomorrow and post back

[Recondo]

[grayfox]

Very glad you discovered this before the ammo did!!!
Receipt inspections - definitely mandatory!
Stay safe brother.

[NugginFutz]

Very glad you discovered this before the ammo did!!!
Receipt inspections - definitely mandatory!
Stay safe brother.

Couldn't agree more. I inspected the chamber on a new rifle I'd purchased, and couldn't see light through the bore. Ran a patch and out of the muzzle popped the long end of a chamber flag that had been snipped off, apparently by letting the bolt slam home with the flag still in place.

Could have gotten ugly.

[cwlongshot]

Manufactuer told me to remove handguard and test barrel nut. It was so loose I could move it with my fingers. He wants me to ship it back for repairs, I asked him to send a call tag. I don’t want to name the company but this is inexcusable. Moral of the story : always inspect your firearms before firing, new or not. Will post to let you all know how this ends. Thanks for your help.

Glad you found it.

Bottom line we are ultimately responsible for ourselves... Something forgotten in this sue happy world. Good on retailer to make this right as its obviously there error. Hopefully he will expedite it back to you

Good luck,
CW

[Lastrites]

I understand why you may not want to mention the company by name but think of the flip side of making others aware of a potentially dangerous situation who may have also purchased the same from that vendor and are not savvy enough to see or know that a critical step was missed. While you are helping that vendor hide his mistake you are hindering a situation that could end very badly for someone else.

No manufacture/vendor is without fault, things can happen over time that they may have no control over but skipping the torquing of a barrel nut shouldn't be taken lightly.

[Kswhitetails]

It only ends badly for the person who fails to check their weapon properly before they begin to use it. The need to know the maker at this point is curiosity at best. I applaud the maker for fixing the issue before much customer blame/flaming.

[bj139]

The way the AR15 is designed I don't think this is a safety issue.
Unless the bolt lugs are rotated, the firing pin will not hit the primer.
If the barrel was pulled out slightly you would just have a failure to fire.
I have fired several AR15s with hand tight barrel nuts with no problem.
I would just tighten the barrel nut rather than mess around with shipping.

[Recondo]

I decided not to name them after thinking maybe they had a young gunsmith in training that assured his boss all was good. The overall quality of the build looks top notch also. Although it never should have happened , I got what I felt was a sincere apology and it’s being rectified . There was accountability and so they got forgiveness. Maybe we all need more of both.