Brass swelling up from cold weather

[Unoboats]

Had a first time for me on this subject. My 6.5x284 loaded in lapua brass would not allow the bolt to close till the bullet warmed up a couple minutes. I understand metals will contract in cold weather, but it never got below 35 degrees last night and the shells were under the bolt in a case. inside my truck.
Need some coaching on this one. been reloading my ammo since 1968 and this is a first for me.
Chip

 

[Tensilon]

That sounds a little odd to me. My background is in biological sciences. I'm not a physicist or an engineer but I believe that generally speaking metals contract when the temperature is reduced and they expand when heated... The only metal I know of that expands when the temperature is reduced is gray cast iron but there may be a few more. Was the rifle in the truck also?
Tens

 

[Mram10us]

OP, how are you resizing your brass? How much headspace are you allowing for?

 

[David Emerson]

New one on me. I live in N Dakota and have hunted at -25 and never experienced what you have. Very close fit and steel contracts faster than brass? Need to talk to a metallurgist I thinks.

 

[Unoboats]

That sounds a little odd to me. My background is in biological sciences. I'm not a physicist or an engineer but I believe that generally speaking metals contract when the temperature is reduced and they expand when heated... The only metal I know of that expands when the temperature is reduced is gray cast iron but there may be a few more. Was the rifle in the truck also?
Tens

You are right and I put that out of context, sorry. saw that after i posted.

 

[cowboy]

Tight head space and moisture turned to frost in chamber??? More than likely it's your rifle - not your brass.

 

[Unoboats]

OP, how are you resizing your brass? How much headspace are you allowing for?

This was brand new Lapua brass, so I did not bump the shoulders back.

 

[Unoboats]

Tight head space and moisture turned to frost in chamber??? More than likely it's your rifle - not your brass.

Well it has been cold to warm and then cold again the past few days hunting. Makes more sense than my brass. It was a match reamer, had two other rifles in the truck that did not do this , both high end production rifles, my reloads in them. The 6.5 is a trued remington action.

 

[Mram10us]

You mention match reamer. Any fitment issues when tested after reloading, or is this the test ?

 

[memtb]

How cold was the rifle? The chamber have been reduced in size due to the cold ambient. Possibly minimal sizing/resizing and/or tight chamber! Or as previously mentioned, frost forming on brass or inside chamber! memtb

 

[Unoboats]

Thanks Cowboy it seems you may have hit on the issue. and my apologies for my implying metals expand in cold when in fact I should have stated contract. My Science background surely escaped me on that comment.

 

[Unoboats]

You mention match reamer. Any fitment issues when tested after reloading, or is this the test ?

It is a tight chamber but so far have had no issues up to this point, Only have 130 grain Swifts moving 2855 at muzzle. so have not experienced pressure signs.

 

[David Emerson]

I know a guy that ruined his barrel that way. Left his rifle in a case in his hunting pickup in the winter and often jack rabbit and fox hunting. Our smith here at that time figured it was frost in the barrel. By spring it would not shoot well anymore

 

[Unoboats]

Thanks guys for all the help, I hope this will be an isolated issue. Checking with my smith today. You all have been a great deal of help.
Chip