doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Lengthing chambers and safety limits

THe rule of 96 is only valid for 12 or 16 ga. guns, if then. If you apply it to .410 bore guns with a 1/2 oz charge, you get 3 lbs, and other gauges give similar impractical weights.

Come to think of it the French got around the 96 rule with their Darne and with using swamped ribs. But the 96 rule is still a good one and I'll abide by it. The idea of taking a 2 1/2 20ga in to a magnum to me is ludicrous. It was a sweet little gun the way it was built. I would expect the same person who would lengthen the chamber of a 2 1/2 20ga would wax ad nauseum about the virtues of a 28ga.

410 not likely to fall under the 96 rule as it is, as you said, a bore and not a gage.

The rule was designed to suggest MINIMUM weights for comfortable shooting of a gun that fits you.

May I suggest that it was not the ribs that helped Darne guns but the type of closure. The Darne breech block closure eliminates headspace and thus recoil.

Regards,

No, pooch, I'm not a small-gauge guy. I have a Elsie 20 which is perfect for grouse for me but there's a time and place when my 20 SKB Model 500 o/u three-inch is also perfect, too. The time is as an older man. The place is slugging it all day in the muck for geese over tollers. A light gun is no burden although I've no desire for a 28 or .410.

Let me try this again. I follow the rule of 96 faithfully in restoring an old shotgun. My goal is to get back to where the gun was initially designed and believe an attempt to exceed that design limit will be my undoing.

Headspace is controlled by the depth of the rim seat versus the rim thickness of the shell. Either a break open or sliding breech gun can have normal or excessive head space. My 16ga Halifax which is basically an R type Darne which does not have the obturator discs except in the highest grade of the R series weighs in @ 2oz under 6Lb. This puts it those 2 oz shy of the 96 rule for an ounce of shot.
As I understand it the "Rule" was designed for full loads of black powder. It has been suggested when using smokeles, which has a lighter powder charge weight when loading to the same velocity the Rule can be altered to 90.
The fact that .410 is not a gauge has nothing at all to do with it. A normally loaded 2�" .410 could be fired comfortably from a 3Lb gun. It might not handle good but recoil would not be excesssive.
Altering the velocity of a load also of course alters the "Rule" as to appropriate shot weight. A 2 3/4 - 1� load would normally have less recoil than a 3� - 1 1/8 load from a 6 3/4lb gun based on the 96 rule for the 1 1/8oz shot because of its much lower velocity.
Burrard acrually had a much better rule than the 96, he recommended for sustained shooting, as in British driven shooting, to keep the recoil "Velocity" of the gun below 16FPS. While not an absolute A very close figure for this is obtained by multiplying the total ejecta weight (shot, wads & powder all converted to Lbs) by the muzzle velocity & then dividing by the guns weight. If this proves to be uncomfortable then just work to a lower figure than 16. This 16 rule will actually work out real close to the 96 rule for a given shot weight propelled at close to 1300 FPS.
As Smallbore said the "Only" thing the 96 rule applies to is Recoil & what is comfortable for one person may well be murderous to another.

I have said this before in at least one other thread. I don't understand the reluctance to establishing a US proof house - let me emphasize on a voluntary basis, i.e. not by government dictation.

There are so many safety issues that can be resolve by "proof testing."

Seems to me it would be a good "business opportunity."

A voluntary basis is the 'camel's nose under the tent.'