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Old September 6, 2011, 09:32 AM   #1
300magman
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30.06 Brass Temp After Firing - 1 round hot & the next cold

This is my first time loading for a bottleneck cartridge, I am using H4350 in a 30.06 with 180gr bullets and working up a load (starting near book minimum)

Anyway, I am getting an odd temperature variance in the brass. I eject each piece into my hand to inspect it, immediately after firing, and I am noticing that one piece may come out at atmospheric temperature and then the next may come out searing hot. How could this be?



As a second question, how strong is the action on a 15-20 year old Remington Model 7600 (in general) Should I be worried about approaching book max loads if there are no pressure signs on the brass or primers?

And will a hot load stick the brass in the chamber the same as it does on a bolt action, or would it simply blow the slide action open farther than usual (it usually just unlocks and cracks open slightly)
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Old September 6, 2011, 10:03 AM   #2
brickeyee
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How many rounds have you fired i the action?

The steel heats up and can no longer remove as much heat from the brass quickly.

Why wold you even care what the brass temperature is?
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Old September 6, 2011, 03:38 PM   #3
Unclenick
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Brickyee,

Sounds like that's his question: is there a reason to care about this observed inconsistency? I'd say not unless the recoil and point of impact both drop dramatically when the subsequently cold ejecting shot goes off. That would indicate improper ignition.


300magman,

Once you start shooting, the gun warms up as Brickyee said. At that point how hot the case gets depends both on how long you let it sit in the chamber before firing and on how quickly you extract it afterward. Letting a round sit in a hot chamber for a long time before firing heats first the case and primer, then the powder. The result from both the heated primer and powder raises pressure and velocity, so it's not considered a good practice.

In really hot guns, like you get from sustained full auto fire and if the weapon fires from a closed bolt, occasionally a chambered round that is allowed to sit may "cook off", meaning it fires spontaneously from the heat. I've never seen that happen in guns heated only by target shooting rapid fire rates, but letting a round sit in a hot target rifle chamber is still called letting it "cook". The resulting increase in pressure and velocity can put your shots high at long ranges.
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Old September 6, 2011, 08:38 PM   #4
300magman
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Thanks for the input Unclenick, it really seems like it should be common sence, but its not really something that jumps out at a shooter and I will try to keep that in mind when I start to shoot matches.
As for my current question, I will have to pay more attention to how long each round is chambered before firing and the like, to see if indeed it is a hot chamber heating the brass.
But if I recall, I was firing pretty quickly after chambering...and I can't remember if it was only the first round in each string that ejected cold brass or not....but if that is the case, then all is explained and I should have realized what the cause was but I was probably too focused on looking for pressure signs and concentrating on feeling any changes in ejection effort.
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Old September 6, 2011, 09:17 PM   #5
Jim243
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Quote:
I eject each piece into my hand to inspect it, immediately after firing

Strange, it takes me two hands to jack my Rem 7600, I supose it could be done, but why? Let the case cool on the bench and then check it.

Quote:
(it usually just unlocks and cracks open slightly
More likely your holding the slide too tight when the rifle goes off and pulling the slide on recoil, I do that on some shotguns with mag loads.

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