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Rocketman,

Have you conducted, or do you know of any research concerning Young's Modulus of good Damascus barrels? This would be in reference to the elastisity of steel shot passing through the choke constriction and if the Damascus barrel expands and contracts.

I witnessed steel shot, #2's and smaller, being fired in Damsacus guns with no noticable effects. The chokes of one 12 gauge Parker's Damascus barrels were measured .030" and .035" constriction and minimum barrel thickness of .030". I was so amazed at that Damascus "steel shot special" that I bought it.

The story behind the subject Parker is that the owner thought that the chokes were .015" and .020". Only later when he had access to good barrel thickness and choke gauges did he realize his mistake. Of course, he continued shooting that gun. When I bought it about 150 rounds of high quality steel 4's and 2's had gone throught those chokes. As one might guess the stock is cracked from the recoil of those steel loads.

If I could obtain access to the means to accurately measure the barrel's expansion and contraction this gun might be sacrificed to research.

Respectfully,
Mark

Chuck, I'd really like to see you try that but, I would think you should test it without porting, and then port the barrel for testing, even in varying degrees, testing loads in it all along the way. Might learn even more by doing this. I will donate a 12 ga. Rem. 1100 barrel for the testing.

Don, let me chew on this some today while I harrow some firebreaks in the pine plantations. I'll get back to you tonight. Thanks for replying.

Stan

Chuck,

If you are serious email me.

Pete

Don . . . "increasing velocity requires reducing pressure". Are you speaking in general, or only in the specific case of the changes that take place as a shot column passes through the choke? I ask because, while pressure and velocity are not directly related, more often than not an increase in velocity will be accompanied by an increase in pressure. Or at least that's what you see if you look at a reloading manual.

Larry, while pressure and velocity are not directly related, there are more tight connections between these units, than you could think and plz stop to repeat this sh*t every time.

While I understand the rationale to relate this to Bernoulli's principle, I'm skeptical that it would be applicable in this debate.

I'm looking at the stress/strain issue on the choke as more of a single impact event, where the shot is traveling in a direction and then deflected in another. I suspect the point of highest stress will be somewhere along the cone.

Gas dynamics. The gas pressure will be increasing dramatically just behind shot column and wads, if shot column and wads meet obstacle such as full choke for example and slow down.