Home Forums Hunting & Shooting Combination Guns and Drillings 12 ga. over 25/35 drilling

Mule Deer,

Fwiw, after reading your original post, I called C.E. Harris (who has forgotten more about firearms & loading than most of us here will ever know) & asked him about 2 3/4" shells in 65mm chambers.
His comment was, "Well, he may get away with that & he may well lose some fingers, too. Bad plan, in my opinion, as most of those old Euro barrels are thin & many of them are unsafe with any modern shells."

Reference: the fellow who lost his left hand to an exploding shotgun barrel, I'm going by what the ER doc said that caused the injury.

As for me, I'll be cautious & have all antique firearms CAREFULLY inspected by a competent smith before firing them.
(Fyi, I started collecting hammer combination guns of various sorts in 1969.)

Note: I have a "reissued for WWI" 1888 Commission Rifle that has the "S-marked chamber". Nonetheless, it was NOT re-bored to the standard 7.9x57mm (.323 bore) size. = It shoots .320 PBCB using 10 grains of Red Dot @ 1400FPS beautifully.

just my OPINION, tex

Sherman Bell's "Finding Out For Myself" Part V was a study of shooting longer shells in a short chamber and he did find an increase, note as "insignificant" 10% or less but an increase. I would suspect difference in forcing cone length and bore diameter would also be a factor. I have 12ga shotguns with bores that run from .710 to .732 and forcing cones that go from almost shoulders to fairly long tapers

I think the statement "2 3/4" with the appropriate pressure" is the big issue here. The factory 2 1/2" loads I shoot (B&P High Pheasant) run in the 6000psi 1 oz and 7000 for the 1 1/16. Finding modern 2 3/4" ammo with that low of pressure would be quite a problem as most 2 3/4" ammo is a quite a bit higher pressure to run modern gas operated Semi-auto's reliably.

I still think that if the gun has 2 1/2" chambers, that's what should be shot in them.

The myth began with Major Sir Gerald Burrard, one of the top shotgun writers of his era. In the second of his set of books on THE MODERN SHOTGUN, published in 1931, Burrard states that it’s “distinctly dangerous to fire 2-3/4 inch 12-bore cartridges in a gun chambered for the ordinary 2-1/2 inch cases.” Yet he provides no other proof other than that statement.

Later on another famous British shotgun writer, Gough Thomas, took on this myth. He wrote about it in magazines, and later in GOUGH THMOAS’S GUN BOOK, published in 194. Since he has a lot more to say than Burrard, I’ll extract the pertinent parts:

“But in the particular case cited by Burrard, the main danger arises, not from the constriction when the cartridge is fired, but from the fact that the longer-cased cartridges he had in mind invariably carried heavier loads, and heavier loads…of necessity involve higher pressures. It is, in fact, pressure that causes the danger: no gun was ever burst by a cartridge case….To satisfy myself on this point, I arranged some years ago for a test to be carried out.”

In the test, Eley 2-3/4” ammo was fired in both 2-1/2” chambered and 2-3/4” chambered barrels. Thomas provides a table showing the results, and in both barrels the pressure and velocity results are practically identical.

But Burrard’s untested myth lives on today, as evidenced by this thread. This isn’t unheard of, because once faulty information becomes established by a popular “authority” it’s extremely difficult to dislodge. I even known people in the American ammo business who were surprised when they ran the same basic tests, with results identical to Gough Thomas’s. The most recent test one I heard about was performed by Winchester Ammunition used an old 2.59” chambered 16-gauge Sauer—in which 2-3/4” ammo produced the same industry pressure and velocity specs as it did when shot in 2-3/4” chambers.

The reason pressures don’t rise is a 2-1/2” or 2.59” chamber’s forcing cone is long enough to contain the unfolded crimp of a 2-3/4” shotgun shell. Thus the wads and shot are NOT constricted inside the actual bore by the case. Yet despite plenty of pressure-tested proof going back more than half a century, this myth continues to march on.

I know little or nothing about Mr. Gough Thomas & his published works but neither do I consider him to be THE EXPERT on shotguns or anything else, absent PROOF from neutral/independent sources of the truthfulness of the published data.
Mr. Charles E. Harris, otoh, is a well-known EXPERT on firearms, ammo reloading, cast bullets & other related subjects. AND he too is a published author, with a near-worldwide reputation.