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Old February 7, 2013, 08:40 AM   #45
HiBC
Senior Member
 
Join Date: November 13, 2006
Posts: 3,564
AR15,

Back at post 13 Wyosmith made a similar suggestion.

IMO,its still not too late to do that.

I already shared my opinion,and its just an opinion.I truly hope I am wrong.Time will tell.

For myself,as I work on barrel threads,shanks,chambers,etc....All the stuff where you get one chance,and no sympathy,I work to one standard,you do it right,or you don't do it.

That thing might get sold,down the road 5 years,and 4000 rds later,that stress riser at the sharp inside corner where he turned the shank down,right where the muzzle end of his sleeve mates up,is pretty much a notch.All of the vibration and flex of that barrel will be focused there because everything else is far more rigid.

Over time,that line will,IMO,work harden,fatigue,and fail.If a hand is on the forend,there will be trauma to the inside of the forearm or wrist,right about where folks commiting suicide cut themselves.

I hope its not some kid having fun rolling cans.

To get an idea of what I'm trying to predict,there were some Ruger Redhawks that had a mystery problem with the barrels blowing off at the front of the frame.

I bet the guys with the calculators at Ruger said something lie "Well,that wasn't supposed to happen,I ran the numbers..."

OP,do you have access to Parametric Technology's Pro_Engineer 3d Modeling software?

You could probably build a model of that in Assembly mode,then apply finite element analysis to your model,and watch the colors show you the stress

The trick is getting all the forces acting together,without forgetting any.

Like,the area under the bullet times chamber pressure going toward the muzzle,plus the area of the case at the bolt face times chamber pressure pushing the opposite way.

Short of accelometers,it would be sort of hard to figure out the side loads on that joint,the mass of the barrel trying to hold still while the breech block forces the gun to the rear,but then due to drop in the stock that translates to accelerating the barrel sideways via the joint in question.

I imagine that all works kind of like a pneumatic impact hammer...Doesnt seem like much holding the handle...

I dunno,really.I'm just a seat of the pants shop guy.


Another way to model it,sort of,get a piece of 1/2 in water pipe about 4 ft long.At center,use a pipe cutter to go only about 1/3 the way through.

Still; real strong.

Now,grab the pipe in the middle,and just shake it,hard,a thousand cycles.

This thread shows a pic of one of the Ruger "oops" failures on a Redhawk.This happened to a number of guns

http://thefiringline.com/forums/show...barrel+failure

Last edited by HiBC; February 7, 2013 at 09:03 AM.
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