Steel or aluminum barrel nut?

TrueBlue711 · February 23, 2018, 01:21 PM

I'm building another AR and the barrel is going to be 24" long and weighs 2.9 lbs. It'll be free floated and I'm curious, will an aluminum barrel nut hold that sucker up just fine? Or should I opt for a steel barrel nut? The steel one will cost an additional $15 and would like to save money where I can. But I won't hesitate getting it if there is a legit concern about holding the barrel in place.

zukiphile · February 23, 2018, 01:53 PM

If you get a better answer than this, take it. I'm not an expert.

I think either will hold the barrel up just as well. I believe the steel nut will allow you to really wrench that nut on very tightly, at the top of ft/lb spec or a bit higher. I believe this because I've buggered up an aluminium one getting it as tight as I wanted.

bfoosh006 · February 23, 2018, 04:53 PM

IMHO... a steel barrel nut is preferred.

I have snapped an aluminum one before... and I really wasn't pushing hard.

Nathan · February 23, 2018, 05:08 PM

Both are fine and both require you be 100% focused on engaging with your tool! I like aluminum for the weight savings.

From a engineered joint perspective, I like aluminum threads to aluminum threads because in the elastic range, they should deform more equally and give a more even load bearing surface....in effect, less point stresses which cause things like cracks.

If you think of a flat sheet of material pushed against a hardened point vs a soft point....the soft point will break down easily spreading the force out, where the hardened point creates an area of high stress and may even pierce the flat sheet.

FrankenMauser · February 23, 2018, 06:13 PM

I don't think it really matters, since the upper receiver is aluminum...

February 23, 2018, 01:21 PM	#1
TrueBlue711 Senior Member Join Date: March 16, 2011 Posts: 489	Steel or aluminum barrel nut? I'm building another AR and the barrel is going to be 24" long and weighs 2.9 lbs. It'll be free floated and I'm curious, will an aluminum barrel nut hold that sucker up just fine? Or should I opt for a steel barrel nut? The steel one will cost an additional $15 and would like to save money where I can. But I won't hesitate getting it if there is a legit concern about holding the barrel in place.

February 23, 2018, 01:53 PM	#2
zukiphile Senior Member Join Date: December 13, 2005 Posts: 4,457	If you get a better answer than this, take it. I'm not an expert. I think either will hold the barrel up just as well. I believe the steel nut will allow you to really wrench that nut on very tightly, at the top of ft/lb spec or a bit higher. I believe this because I've buggered up an aluminium one getting it as tight as I wanted. __________________ http://www.npboards.com/index.php

February 23, 2018, 05:08 PM	#4
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	Both are fine and both require you be 100% focused on engaging with your tool! I like aluminum for the weight savings. From a engineered joint perspective, I like aluminum threads to aluminum threads because in the elastic range, they should deform more equally and give a more even load bearing surface....in effect, less point stresses which cause things like cracks. If you think of a flat sheet of material pushed against a hardened point vs a soft point....the soft point will break down easily spreading the force out, where the hardened point creates an area of high stress and may even pierce the flat sheet. Last edited by Nathan; February 24, 2018 at 08:43 AM.

February 23, 2018, 06:13 PM	#5
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	I don't think it really matters, since the upper receiver is aluminum... __________________ Don't even try it. It's even worse than the internet would lead you to believe.

February 23, 2018, 04:53 PM	#3
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	IMHO... a steel barrel nut is preferred. I have snapped an aluminum one before... and I really wasn't pushing hard.