Cold temp & cartridge size

[baddad06]

OK has this happened to anyone else. I live in Northern IL and left my range bag in the trunk all morning. I went to the range that afternoon and was loading 357 mag cartridges into the cylinder and they wouldn't seat flush. About 1/2 of the 50 I tried to load in the cylinder sat up about 1/8 of an inch. I had resized all prior to loading and ran them through the Lee FCD to apply a medium crimp. I had also brought my EMP 40 so I ended up just shooting it. The rounds for The 40 fired chambered perfectly with no failures.

When I returned home I was going to run the 357's through my FCD again. Before I did I tried to Load them in the cylinder again and poof they all seated flush! Could the cold have caused the cartridge to swell or the cylinder to shrink? I was using my Windicator 357 mag.

Thoughts

 

[Mike Kerr]

I can only give you non scientific answers. Cold temperatures impact steel such as your cylinder differently from brass in your cartridge. I learned several winters ago not to try to reload in my unheated garage when the temperatures were under about 40f especially when they dipped to about 25f. Every setting, drop, measurement, fit etc. was different. Cases got stuck in the die much easier than in warm weather, everything was different. So maybe you were experiencing similar reactions at the range?

 

[Blue68f100]

They will definitely shrink some but at a different rate. Brass shrinks less so there could be a problem. Provided I entered the number right.

coeffecient of expansion
http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

Brass is 10.4
Steel 6.7

Calculator
http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.html

 

[transtech]

357's won't seat:
You've been shooting a lot of 38 Specials, probably lead bullets, in your 357 chambers & they left a .100" ring @ the end of the cartridge part of the chambers, this ring made up of carbon fouling & lead residue left @ the mouths of the 38 brass in the space that would have been taken up by the longer 357 brass. Cure: vigorously brush the chambers of your cylinder with a .40 caliber brush to get the ring out, the after that only shoot 357's in your 357 chambers.

 

[mahansm]

Coefficient of thermal expansion is a number to express how much a substance will expand with increasing temperature. As temperature decreases, the substances contract at the the relative speeds given by the CTE. Since brass has a higher CTE than steel, the brass will shrink more than the steel. The clearance between the cylinder wall and the cartridge brass should increase as temperature goes down. CTE for lead in the units you used is 15.1, so the lead will not cause the cartridge case to swell as temperatures decrease.

 

[243winxb]

I am thinking a bulge from over crimping.

 

[rcmodel]

Temperature had nothing at all to do with it.

See posts #4 and #6 for the correct, and only remotely possible answers.

rc

 

[Reloadron]

The temperature change was not enough to matter. I also agree with either post #4 or post #6 as the problem.

Just out of curiosity when I read this thread I placed two .357 Magnum factory cartridges in my freezer at -20.0 F. Prior to freezing them the neck OD was 0.37550" @ 68.7 F. Following over an hour at -20.0 F. the same diameter measurement was 0.37540". Rest assured they don't shrink enough to matter.

While this little science experiment was interesting I was not curious enough to shove one of my 357 revolvers in the freezer to note any change in cylinder diameter measurements. Condensate quickly formed on my victim 357 cartridges and I wanted to spare one of my revolvers that fate.

Ron

 

[baddad06]

I am familiar with the 38 ring and clean my guns after every use. I also have learned the hard way on how to properly crimp. I am convinced it was temp related only because when the pistol and ammo both were at room temp I had no issues with seating. Thanks for your input. As always you guys provide valuable insight.

 

[OYE]

I am convinced it was temp related only because when the pistol and ammo both were at room temp I had no issues with seating.

I absolutely agree. I've had several .357 revolvers shrink to the point that they fit loosely in the holster and you couldn't even begin to get a cartridge in the cylinder. All due to cold temperatures !!!!!!! Science be d-------ed. OYE

 

[rcmodel]

My .45's become .44's here in the bitter Kansas cold.

Happens every year.

But only when the wind is in the north.

rc

 

[Toprudder]

The cold always turns my "magnum" into a "special".

 

[41 Mag]

The cold always turns my "magnum" into a "special".

You just need to find you a "hotter primer"......of course you have to be really careful, the switch might be costly.

baddad06,

Your loaded rounds might be on the wide side at the crimp,( guessing here), and with a little shrinkage of your cylinder due to the temp, and possibly haveing slightly tigher bores in it, this "could" explain your issue. Only way to tell is to measure the offending cases, compare to otheres which might fit. You can repeat the temp by leaving your revolver in the truck as before and checking other rounds as necessary.

I personally have never had this issue, and do not see how even if the ammo was cold and shrunk, how this would be an issue in not dropping into the chambers of the cylinder. Now if the revolver was cold, and the ammo really warm like when sitting in the sun, possibly, but still never had that issue either. Usually when things get a bit sticky the first place I start checking is the crimp or the area just behind it where the case sometimes bulges due to a long case or too much crimp.

 

[oldpapps]

I've been wearing glasses since I was 12 years old. And you say so what.
When I was playing in uncles year round summer camp, at one time I was stationed in central Montana, Judith Mountains. It got cold there! Being young and dumb, I went out hunting late one afternoon, must have been all of 3:30 or so, the sun went down around 5 or so and no hunting after dark.
Now to the point. Didn't think I would ever get to it did you?
My GI glasses at the time were glass in plastic frames. They got cold, very, very cold just like me. The glass shrunk more than the plastic and the glass lenses just fell out. Different materials react at differing rates and amounts to temperature changes.

Now to your fail to seat problem.
I don't remember seeing an arctic blast of 30 or 40 degree below zero weather rushing in yesterday. If metal shrinking was the cause, your loads must have been right on the edge to begin with. More likely, cold, thickened oils/greases in the cylinder was the culprit.
SOP in the far north is to park rifles out side, more to lessen sweat rust than shrinking metal. And those hearty people don't report weapons failing to chamber because of the cold.

But then, anything is possible.