AR test conditions...frozen bolt.

[Dubster]

Why would freezing in the reciever cause a KB? As long as there was no buildup in the barrel/chamber area then pressures wouldn't increase, the bolt just wouldn't move, but I think the energy of the round will free the bolt.


Just wear eye protection, you're too valuable a resource to lose around here.

We all know the effects of heat and cold on metal. Wouldn't the low temperature, at least at some point change the internal diameter of the barrel? And could that in turn effect pressures?

Dub

[SixPointEight]

We all know the effects of heat and cold on metal. Wouldn't the low temperature, at least at some point change the internal diameter of the barrel? And could that in turn effect pressures?

Dub

Provided he's using factory ammo, and not reloads at the limit of pressure, I think the thousandths of an inch you're talking about will result in a negligible(in firearms sense) pressure increase.

Tech, you have calipers? measure the barrel, then measure it cold, I'm not predicting a notable difference.

[Jak1]

Carried an M16A2 for three winters in upstate New York. Never had a problem with frozen bolts or firing in VERY cold weather ( compared to Cali ) with blanks or live rounds. I don't know what temperature different lubes freeze at but CLP worked just fine.

[technique]

No Calipers. Gun is not visible now either. There is a good inch or so on top of it.

One of the things that got me thinking was that Addax (piston) sold some of his uppers to Alaskan PD guys. They were (IIRC) having issues with their DIs in those subzero temps....I don't recall the details.

Wonder if the firing pin would freeze?

[pyro3k2]

It's cold enought out side for water to freeze ie snow, but is it truely cold enough outside for the lube to start freezing/clump up? I've taken very basic gun lube (the cheap **** at wally world) out at -19 and still didn't have my bolt freeze or any sign of freezing after 20minute proling exposure.

[tomd1584]

In the name of science, it must be done.

My hats off to you, sir!





btw, whats snow?

[aplinker]

So if mortaring can clear it up...do you think if it was frozen and then just fired, ya think it would just cycle fine through the whole 20?

Yes... and, even if it didn't cycle the 1st one all that would happen is you'd wait for the heat to melt it, then mortar or rack, and go.

Now, in EXTREME cold, it might not heat enough to melt, so you'll need to mortar, maybe a few times.

It's firing on a closed bolt anyways. Nothing is really different or unsafe.

I say this with ZIP experience - but I know people who have been in extreme cold (not anything we see in CA) and what they've said about it. CA is nice and cozy. I've been lucky enough not to need a rifle in anywhere nasty/different I've traveled.

[aplinker]

You realize that, if snow is on top of the gun, you've now insulated it at 32F?

You want it exposed, if possible, if you want it COLD.

You need to be a good deal below zero for this to make a real difference.

[technique]

Yes, not much I can do about it though. Still snowing.
There really isn't anything I can put it under to stop that.
I did pull it out and set it back on top.

I noticed something when I did this. You know when it rains and the parking lots and streets get that oily rainbow effect? That's whats running out of the gun. So, bye bye lube.

[The DRis]

Not all your lube will leave.

[Richie Caketown]

You are brave testing out your ACog as well

[djleisure]

This is a beautiful thing. Looking forward to the outcome. Thanks for posting this up!

[pacrimguru]

good luck with the test. i think everything will run as it should.

on a side note, i flipped the finger thing upside down on the afg and indeed it does feel better. thanks for the tip!

[ar15barrels]

I predict absolutely nothing is going to happen.
You are going to pick the gun up out of the snow and every round is going to feed/fire/eject just like before.
It's not cold ENOUGH to cause a problem with the lube.

[technique]

Pac,

Awesome.

Randall,

I don't think so either. But since I have done the good ol' dirt test, might as well do some snow too.