doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Center of Balance (CoB) on 16/20 Fox

I recently purchased a three barrel set Fox Sterlingworth circa 1933 16/20 combo.

The gun is restocked with high grade wood which is not hollowed out at all. Further it seems more thickly shaped than other Fox 16s I have owned and seen.

Two of three barrels (16&20) were likely made with the gun, (based on serial numbers on flats and on extractors matching. The third set is serial numbered to the gun with no sign of being overstamped etc.

All barrels balance on the hinge pin in the same spot exactly despite the gun weighing 6lb 13.9oz / 6lb 9.7oz / 6lb 13.5oz with the different barrels (16/16/20). All the barrels weigh out as 3 weight barrels for their length.

Is it reasonable to assume the gun should balance ahead of the hinge pin and I should lighten the stock by drilling out some wood?

I would shoot it for awhile before I did that.

I am under the impression that balancing on the hinge pin is generally considered a good thing for a bird gun. I think GT Garwood/Gough Thomas rated a gun as lively if the balance was within 3" to 4" of the front trigger.

Parker collectors also seem to hold guns that "balance on the hingepin" in high esteem.

You're putting to much importance of where the gun balances. Shoot the gun and if you like it leave it alone. If not, then do something to correct it.

+1 on what the other 2 posters said. Since the length of action differs significantly from one maker to another I think referencing the balance point as the distance from the front trigger makes much more sense than using the hinge pin as a reference as the trigger is what determines the position of the shooting hand.

Also, intended use & personal preference on how a gun should feel is the most important part.

That said, Michael McIntosh once wrote something like "the lighter the gun the more weight forward it should be" & that concept seems to work well for me.

+1 for Brittany Man. The four factor of handling (weight, center of gravity/balance, unmounted swing effort, and mounted swing effort) are all personal preference. Think of them as you would stock measurements - there is no optimal LOP, for example.

AM, if GT said that about balance, then he mis-spoke for sure. And he for sure knew better. He did moment of inertia back in the 1960's, so he knew that balance has nothing to do with lively. Trust me, a 10 lb gun with a 3" balance and umnounted swing effort of 3.0 is not lively; unless you are maybe a professional athlete.

McInntosh probably didn't know any better.

DDA

Well, actually, after he measured the MOI of many British game guns, he said those with the center of balance within that range tended to be lively.

He didn't say that center of balance was the cause of the guns being lively. More of an indicator.

OK. But he should have known better than to try to use balance as an indicator of swing effort (MOI). It is actually a better indicator of weight which is a better indicator of swing effort. Thus we get far afield from the "question." It is far better to say, "This gun weighs X pounds, balances Y inches in front of the trigger, and I find it lively/numb/wand/club/2X4/etc." GT expended a lot of effort explaining gun handling to shooters who had little inclination to understand.

DDA

The MOI Garwood measured and reported was the MOI around the center of balance. That is, the gun was rotated around the center of balance to measure the MOIs he reported. Garwood's MOI measured the rotational inertia of a gun about that gun's center of gravity. Had Garwood measured the MOI about the buttplate that would also give an MOI number but different than the one about the COB.

But in the context he said it in, after he had measured and tabulated the values you list of many British game guns, he noted that those with the balance in that range felt "lively". Not that the COB made it so, just that COB in that range tended to coincide with guns he deemed lively.

I believe I understand both Garwood's writings and the physics behind his MOI measurements. I believe I expended the necessary effort.

I think my original post is accurate. I think it is a reasonable answer to the question that was asked.

Both GT Garwood and Michael McIntosh knew more about double guns, their balance and shooting qualities the you could imagine on your most thoughtful day.
You would do yourself a service to spell his name correctly to of respect for your betters.
I'll bet you still need your whirly gig to tell you what Mac or GT could tell you a few minutes after picking up any gun.

Hi Steven:

GT Garwood and DDA have both measured the MOI of many shotguns. In my opinion the practice has produced interesting data and interesting facts about shotguns.

I think DDA was scolding me for not making a more complete explanation of COG and MOI for the original poster. I don't think he was disputing GT Garwood's shotgun knowledge.

I think you read his comment on McIntosh correctly and as he meant it.