Burnt Guns

SWAT magazine had several write-ups on the restoration of burnt out guns. One of the writers had a house fire where his guns were destroyed. Some were not even recognizable but he managed to get them restored. There was a Kimber 1911, an AR15 and some inherited firearms.

regards,
 
I think these burnt rifles are fixed beyond repair now.
Broken1.jpg


The chamber of the .222 has now expanded to a half inch, and failed at 5:00.
Broken2.jpg


The reciever of the #1 is broken, expanded and bent.
Broken3.jpg
 
Good man! Excellent - now we need the details.... there must be a story to tell...

It makes me want to go out and blow up an old beater.....
 
Look out Boomer, and the rest of you guys that want to reuse 'fire treated' guns. Let us assemble the info with the engineering data:
1) Melted aluminum, therefor minimum temperature was 1220F(melt point of Al alloys); and probably in the 1500F range easy.

2) These temps are beyond what is employed for tempering the quenching portion of the steel heat treatment process; and beyond steel's critical transformation temp of 1330F which is attained during a full anneal.

3) Tensile yield strength of AISI 4140 chrome moly steel in the annealed condition is 60,000 psi which is the working pressure range of many rifle rounds. Production quench and temper yield strength for rifle barrels and actions is in the range of 120,000 to 140,000 psi; 4140 steel can be heat treated to a yield strength of 220,000 psi, but in this condition it is far too hard and BRITTLE for impact loading as in firearms applications.

So, the house fire guns will be in a near annealed heat treat state, which will contain the pressure of an undetermined number of firings. What is occuring at the inner chamber wall (where the stresses are greatest) of each shot will be a certain amount of yielding of the steel, which will produce cracking at the inner chamber wall. These cracks will propogate through the remaining material with each sucsessive shot until a catostrophic burst occurs.
 
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And lets not even get into the dimensional changes that steel undergoes when being heat treated (or heat un-treated).

Anyone who would restore a gun thats been in a fire is A) stupid or B) really freakin' rich. Essentially it'd have to be remanufactured.

Steel also loses its carbon content when heated significantly in a environment containing oxygen (like air). The higher temperatures the worse the carbon loss. Carbon is what makes iron into steel. As the content drops so does the strength and ability of the steel to take a heat treat.

In otherwords playing with burnt guns is playing with fire. Sooner or later you're going to get burned.
 
From looking at the side pic of the Ruger and seeing the rust present in fracture it appears that this crack was caused during the fire, or the rust wouldn't be there. Did U use standard loads to disassemble the rifles or a compressed charge of Bullseye? Thanks for posting pics, it's a great way to show what can happen with burnt guns.
 
ckid said:
From looking at the side pic of the Ruger and seeing the rust present in fracture it appears that this crack was caused during the fire, or the rust wouldn't be there. Did U use standard loads to disassemble the rifles or a compressed charge of Bullseye? Thanks for posting pics, it's a great way to show what can happen with burnt guns.
Click to expand...

The powder I used to disassemble these guns is about 5 times faster than Bullseye.:cool: The rust appeared very quickly after the "disassembly" was completed. The pieces where driven down into the snow and I just let it melt off and did nothing to prevent the rust from occuring.
 
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