What gets a can hotter -- slow fire or auto? Mythbusters.

[rsilvers]

I tested the following comments:

Maybe the semi auto firing at one round per second, which Phil Dater [I believe] has stated here that Doug Olson and later himself found to be more abusive than automatic firing to silencers, is actually less abusive to barrels and that would make a big difference given the durability test involved semi auto fire as well as automatic fire.

(Phil Dater)Doug Olson told me that firing at a rate of 1 round per second accumulated more heat in the suppressor than full auto. Whether you believe him or not is irrelevant. I believe what a man of his experience in the field of experimentation tells me.

(Neil Parker)This is correct. The suppressor gets heated up more gradually and I would believe what Doug Olson has said. The amount of experimentation and R&D that he has done in this field is remarkable, and his track record speaks for itself.

Today's Mythbusters experiment is "What gets a can hotter, semi auto or full auto?"


Results:

[exkc135driver]

Mucho interesting.

Edited to note: dumb questions asked before watching video; watched video; dumb questions deleted.

[markm]

So the FA gets the can slightly hotter a little bit faster.

[rsilvers]

I posted a video.

30 round mags. I originally planned to use two Beta Mags but they proved unreliable.

[CarlosDJackal]

IMHO, this is one of those "DUH!" topics. Why do you suppose most fully-automatic weapons are designed to fire from the open bolt (HINT: It's not for the CDI factor nor is it because the machine gunner wants sand and debris to accumulate in between firing)?

This is also why each of the military weapons systems (to include ones that are no F/A) have a "Sustained Rate of Fire" identified that is different from the "Maximum Rate of Fire".

[markm]

I originally planned to use two Beta Mags but they proved unreliable.

Inconceiveable!

[markm]

IMHO, this is one of those "DUH!" topics. Why do you suppose most fully-automatic weapons are designed to fire from the open bolt (HINT: It's not for the CDI factor nor is it because the machine gunner wants sand and debris to accumulate in between firing)?

The weapon used is closed bolt.

The theory behind the possibility that semi would cause more heat was along the lines of.... Rapid repeating bullets could possibly push hot gases out of the can before the complete heat transfer happened.

In my opinion, the overall heat difference is not significant. When people make claims of this or that can being "full auto rated", it's meaningless.

[Puffy93]

I think this is one of those questions where you are 99% sure but that other 1% still makes preaty much sense.

[SHIVAN]

Do the calculus on the area under each curve. Which one represents more heat imparted to the suppressor? Not peak temp, but more heat imparted to the can as a function of time.

It looks very close to me, with a slight edge in total heat transfer going to the semi...

[rsilvers]

Area under the curve is a function of both heat input and heat output.

It looks like semi has more area under the curve, and I would attribute that to slower cooling due to a lower temp differential between the can and the air. However, I don't know how to prove the exact cause of it.