doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Lengthening 2 9/16" chambers

Agree 100%. I too thought the notion of a plastic case adding much more than an iota of wall strength very far-fetched.
JR

If you cannot work out that the earth is flat, how can you work this out ?
O.M

You are right. The earth is an oblate spheroid. I apologize.
Your analysis of the strength of a plastic shot shell is not germane. At 10 BAR it probably would blow out the primer or swell up and split. Inside a gun chamber it will act very differently. An early sign of excessive pressure is a flattened primer. Meaning that the normal primer was retaining it's shape under, let's say 800 BAR. That same primer it it weren't backed up by the breech face would blow out to hell and gone. The same analogy will hold for the case. The only way to test exactly how much hoop strength a case provides is to get two identical single barrel shotguns. Using a standard case in one increase the charge until you get a dimencial change. Now in the other gun, using similar cases but having 1/3 of their circumference removed lengthwise follow the same procedure. I believe there would a significant difference in results. Do you say the difference would only amount to 10 BAR?

I think it would be zero.

The case is ironed by pressure to the chamber walls.

It can't add any hoop strength before the chamber yields because of it's elasticity.

A brass case flows under pressure, you can't tell me it adds any strength to the system.

Yours is the first assertion of this alleged phenomoneon I can recall.

The first assertion is true, so what?
The second, steel is also elastic, so what?
The third, where to begin. Because brass flows under pressure it can't add any strength to the system, really? Do you really think that?
Let's put all that aside for a bit and look at what will happen in two identical pressure vessels in the following test. One is subjected to increasing but time limited pressure spikes until distortion. The other is subjected to the last pressure on the first before distortion and is held at that pressure. Over time the second vessel will distort too. How quickly this happens depends on the material involved. What revelance does this have to the matter at hand? Only to illustrate the difficulty in testing the effects of pressure in different contexts. Submarines are designed to withstand a pressure from the outside that would blow them apart if applied from the inside. But enough. I can see that nothing I might say would convince you. And rightly so too. If I don't back it up with proof-- well.
By the way, can you prove th Earth is an oblate spheroid?

Sure. But it requires a very accurate scale and a good bit of inconvenient and difficult travel.

My Fox Sterlingworth with lengthened chambers AND cones would weigh more at the pole (pick one) than at the equator.

Gravity is inversely proportional to distance you see.

Before we part agreeing to disagree, consider this:

Do you suppose an inner tube ads any strength to the tire?

Hmmm. Going back to the years I worked in a service station and repaired bunches of tires: You can certainly run on a tire with holes if it has an inner tube. But I don't think I'd want to count on the integrity of a shotgun with holes in the chamber walls, counting on the hulls to keep me safe.

What kind of strength? Schwinn actually sold, back in the day, inner tubes that were "thorn resistant".

They were slightly harder to poke a hole in. And less flexible, making the bicycle more work to ride.

It could be argued that the tire/tube assembly, when so equipped was, "stronger" than with the standard tube, could it not?

Best,
Ted

Yes, but wood cracking at rear of side plates is common problem. It maybe more common than found in old Ithaca 37. Most used field grade LCS guns have them to greater or lesser extent. Looks like JMC has that covered by using light game loads. Don't see much reason to ream out chambers because it isn't going to provide anything in return for effort required to do it.

If by strength you mean resistance to internal pressure, then of course, if the inner tube wall is uniform and all else being equal, the tire with the tube will withstand more pressure. That's pretty basic engineering. I beginning to think that you are more interested in appearing clever than in the underlying subject of pressure. Furthermore the subject of gravity is far more complex than you seem to think and you could certainly not determine the shape of the planet by your method. Gravity varies all over the surface of the Earth, lots of research on this by the US Navy. This is my absolute last post on this thread. Having worked for the Navy on nuclear subs I'll bet I spent a hell of a lot more time thinking about pressure than you seem to have done. The End.