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A funny thing happened to me last week. I have been carrying my 45 acp in the car. The car sits in an uncovered parking lot at work all day. I had the windows up and the temperature is getting up to 102-4°F. quite a bit hotter in the car. The gun was loaded with Federal Hydroshock HP's. I took the gun in the house and took the magazine out as I rotate mags weekly. I noticed that on 2 bullets the casing had expanded (presumably from the heat) and the bullets had partially fell into the casing. Anyone ever had this happen? The bullets are a few years old.
 

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I've not had that happen to me, but it may be because your ammo is pretty old and the heat/cold has been affecting it. I rotate my carry ammo every six months, shooting what I have been carrying an replacing with fresh rounds.
 

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Do you leave the gun with a round chambered? If so, do you stick the chambered round back in the magazine and re-chamber it? If you do the bullet setback may be caused by this. You should be able to re-chamber a round quite a few times before this happens though. I would not shoot a setback round either.
 

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Jmark said:
Do you leave the gun with a round chambered? If so, do you stick the chambered round back in the magazine and re-chamber it? If you do the bullet setback may be caused by this. You should be able to re-chamber a round quite a few times before this happens though. I would not shoot a setback round either.
If you did, you wouldn't like the result.

:lol:
 

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Setback

The problem with setback is you don't know the round has set back until you unload it. If you have a gun that sets the bullet back regularly it can do it the first time you load a round.

With low pressure loads I have fired rounds (.45 ACP) I have fired round with a heavy setback back before I knew better.

I hear .40 S&W have a real issue with this because of the high pressures and unsuported case head that are common in this round.
 

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mc30707 said:
A funny thing happened to me last week. I have been carrying my 45 acp in the car. The car sits in an uncovered parking lot at work all day. I had the windows up and the temperature is getting up to 102-4°F. quite a bit hotter in the car. The gun was loaded with Federal Hydroshock HP's. I took the gun in the house and took the magazine out as I rotate mags weekly. I noticed that on 2 bullets the casing had expanded (presumably from the heat) and the bullets had partially fell into the casing. Anyone ever had this happen? The bullets are a few years old.
This behavior in materials is common. You experienced what we call in the engineering profession: CTE mismatch. CTE = coefficient of thermal expansion. Different materials expand & contract at different rates as a function of temperature. In this case the brass casing expanded sufficiently to allow the crimp on the bullets to lessen to the point where they could move around.
 

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Re: Setback

ber950 said:
The problem with setback is you don't know the round has set back until you unload it. If you have a gun that sets the bullet back regularly it can do it the first time you load a round.

With low pressure loads I have fired rounds (.45 ACP) I have fired round with a heavy setback back before I knew better.

I hear .40 S&W have a real issue with this because of the high pressures and unsuported case head that are common in this round.
Ever since the other thread regarding setback, I've paid close attention to rounds that I've unchambered. I haven't noticed any setback by just holding it beside a never-before-chambered round. My kids (mostly my oldest son) often ask to see our guns (The XD40SC is a favorite... must be the stainless slide) and I'm wondering if I should start marking the rounds that come out of the chamber.

Are S&W .40 rounds really more prone to setback than others?
 

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mc30707 said:
but I seldom carry with a round in the chamber
If you are not comfortable with a round in the chamber you should consider a revolver. Don't assume you will have two hand or the time to chamber a round.
 
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