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70mm cart in 3" chamber ?


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I've recently bought a third Baikal O/U multi-choke with a 3" chamber rather that the 2 3/4" of my earlier ones. I tend to use Eley HV Pigeon/Fibre which are rated at 70mm length. Will there be any noticeable difference in performance due to the wad not seating in the bore quite so soon ?

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14 minutes ago, Velocette said:

I've recently bought a third Baikal O/U multi-choke with a 3" chamber rather that the 2 3/4" of my earlier ones. I tend to use Eley HV Pigeon/Fibre which are rated at 70mm length. Will there be any noticeable difference in performance due to the wad not seating in the bore quite so soon ?

 

Not that would be noticible at normal ranges but at extreme range the degredation of the pattern may result in more injured birds and you may get 45 yards instead of 50 yards.

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I had a 3" Powell for some years. I used both 70mm cartridges through it and standard 67.5mm and 65mm cartridges through it. Yes, in theory, there's that small gap between the end of the case and the leed or forcing cone. But in practical terms it'll make no difference at all.

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1 hour ago, enfieldspares said:

The only "shells" I wouldn't use and I also don't use them in any 2 1/2" (65mm) chambered gun would be 2" shells and with them I think you may get gas blow past the wad in that circumstance.

My father died in 2001. My oppo is still using the genuine 2" ( not 2.2" or some fancy metric figure) crimp closed ones which Father would have loaded at least some 5 years before his death as cripple stoppers without any problem.

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Thanks for the comments. I was out today with the 3" gun on some barley stubble on a slow flight line and managed to drop the first eight without a miss ! though things did go downhill a little later on. I took some pattern boards out with me and a tried half a dozen shots at 40yds with each barrel at 3/8 and 7/8 Baikal chokes and it looked fine. I'll do a more thorough patterning later.

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1 hour ago, wymberley said:

My father died in 2001. My oppo is still using the genuine 2" ( not 2.2" or some fancy metric figure) crimp closed ones which Father would have loaded at least some 5 years before his death as cripple stoppers without any problem.

That's interesting as I'd have thought that the gap between the case mouth at 2" and the beginning of the forcing cone at 3" of a traditional long case gun or the 3.5" of a "modern magnum" would at 1.5" be such that the main driving wad in a traditional "Two Inch" case wouldn't be long enough to "carry" the gap between case mouth and chamber end to form a seal and that you'd get leakage of the propellant gases around it. My fear then being that there'd not be enough force now left to clear the wad from the barrel. Very interesting. So it'd appear that in a 2 1/2" gun you might just get away with it from your friend's actual practical results. Very interesting. The value of a first hand account.

Edited by enfieldspares
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12 hours ago, enfieldspares said:

That's interesting as I'd have thought that the gap between the case mouth at 2" and the beginning of the forcing cone at 3" of a traditional long case gun or the 3.5" of a "modern magnum" would at 1.5" be such that the main driving wad in a traditional "Two Inch" case wouldn't be long enough to "carry" the gap between case mouth and chamber end to form a seal and that you'd get leakage of the propellant gases around it. My fear then being that there'd not be enough force now left to clear the wad from the barrel. Very interesting. So it'd appear that in a 2 1/2" gun you might just get away with it from your friend's actual practical results. Very interesting. The value of a first hand account.

I'm pretty sure that Oppo's 325 is 2&3/4". Once went home for the weekend without a gun so took Father's little Patstone and a couple of his cartrudges for a walk. I figured 20 yards was good enough to at least slow it down for a coup de grace if needs be in case trying to get closer put it to flight so I let fly. The fox dropped dead to shot with one in the back of the head. At least it enjoyed its last meal - it was still eating it - a pigeon -  which I suppose is why it wasn't really paying attention  to what was going on behind.

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34 minutes ago, London Best said:

I am pretty sure Enfieldspares was referring to 2”” 12 bores, not 2” .410.

I was indeed. The "Two Inch" 12 bore is an odd thing. I think that the "Two Inch" was probably not suitable for the "dram equivalent" aka "bulk powders" or "volume powders" also known as "42 grain powders" that followed on the heels of blackpowder such as Amberite?

It is I think quite recent and didn't exist AFAIK in the days of blackpowder. I think it was only the arrival of what would be known as "33 grain powders" so more bang for less volume of powder that made it possible to make such a cartridge? As I've seen references to the "Two Inch" as "the Twentieth Century Gun"?

Even so with these denser powders Burrard, and he may be the same writer (?), said that it struggled to get a good pressure (and so give a reasonable velocity) and of course that would have been however with the powders that were then available when he was writing.

I wonder how many here have heard of the "other" 12 bore that also was once popular? The "chamberless" of "Heath" gun?

 

Edited by enfieldspares
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Wasn’t it Lancaster who first introduced 2”” as his Pigmy cartridge, I think around the 1890’s? I may have the details wrong. But the idea was a failure, probably for the reasons you have given. It was then re-invented as the Two Inch about 1930? May have been 1920’s?  Can’t just recall offhand.

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