Invar barrel

[Webphut]

I use to work in R&D at a national lab and once in a while a project with rapidly changing temperatures were experienced, we opted to use Invar 36. While It is a bear to machine, it is great in terms of Coefficient of Thermal Expansion. In other words it does not move around as much as carbon or stainless steel when it changes temperature . Has anyone had a barrel made with Invar 36? If so, may you please fill me in on it performance and accuracy when shooting steady long durations. Such as shooting varmints. I have googled this with no results, so I thought I would ask before emailing a barrel company for a quote looking like an idiot.

[RobertMW]

Wow. I highly doubt it. There is no reason to worry about the thermal expansion of the barrel, as long as the barrel is made from a properly treated blank.

The whole point of using the invar is to eliminate stresses caused by thermal growth strain. A properly treated barrel will have little to no differential strain caused by heating - that it will expand uniformly. And since any barrel being used for real accuracy will be free floated, it won't deflect off anything as it expands.

And even though invar will hold up better than stainless, it will cost a whole lot more for the material, and a whole lot more for the machining.

So, if an INVAR barrel ends up being several times the cost of a stainless or carbon steel barrel, without making up for it by lasting at least as many times longer, or having impossibly better accuracy (the world reccord group is already miniscule,) there is no reason to do it.

[Webphut]

Yeah ok. Thank you. I figured that, but was just curious. The question actually sparked because I am having fits with my 223 Kimber of Oregon classic. It is fine if I let it cool down and shoot , but when shooting squirrels, I got lost in the heat of the moment and bullet don't hit the target. Was concise rating a bull barrel to eliminate the problem, but got off onto la la land dreaming and was just wondering. Thank you.

[ar15barrels]

Thermal wander of your zero has to do with the barrel walls being inconsistent in thickness.
A better quality barrel will have a straighter bore and therefore less differentiation in barrel wall thickness.
The more thickness variation you have in the barrel wall, the more the barrel will deflect as it heats up.