doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2 3/4" in a 2 1/2" Chamber

The chambers of my 1922 20g Parker were closer to 2 3/8", and the recoil was WICKED with 2 3/4" AA 7/8 oz. target loads (the ONE shot I took!) No doubt the case mouth was extending into the forcing cone.

Thanks revdocdrew,

Now, to keep my metric sanity, 2 3/8 is 2,375 is 60,33 mm.

IF those AA target loads really do have 70 mm hulls, well, then, 9,67 mm of extra hull would sure give some extra recoil, at least in my personal experience. More extra recoil than I got the one time I fired some true 70 mm hulled-ammo in true 65 mm chambers.

My personal standard, as appreantly is yours, is that if a few mm longer hull gives distinctly more recoil than hull same lenght as actual chamber lenght (same loads in hull), THEN that longer hull is raising the chamber pressure, which increases both muzzle velocity and recoil. MAYBE the increase in pressure still results in pressure the old gun can handle for thousands of rounds, MAYBE. I personally will stick to hull lenghts same as chamber lenghts (in the actual 65 and 67 and 70 mm chambers), or to the use of 67 mm hulls in 65 mm chambers of my old guns. I might even be willing to use lower pressure 70 mm-hulled loads in 67 mm chambers, BUT, I have done no testing in my old doubles.

Niklas

Juan Carlos,

I do want to make a quick distinction. I was referring to the 16ga reloading group that Russ Gray founded and is email and Yahoo based. 16ga.com is a different animal and the two groups while having alot of overlap in membership are NOT the same.

I am registered at 16ga.com but didn't find anything there that the 16ga reloading group and this site didn't already offer.

Best regards,

Niklas;
I have wondered many times about that 2½"/65mm my self, since is as you pointed out not an exact conversion. On page 254 of Greener's 9th edition he shows a drawing of "The 12-Bore Cartridge Chamber". Along with dias ranging from .813" down to .798" at approx ½" increments I suppose he shows the length as "2½" or 2 9/16" Long" + an .074" rim c'bore. This would give an overall depth of from 2.574" to 2.636" (65.4mm/2 9/16") to (67mm/2 5/8").

Mike, sorry for the mix up. There was another poster there who is also "one of us",
and he was one of the exceptions.

The mentioning of my "16ga.com" episode was just to make a point and not really a
complaint.

JC(AL)

2-piper,

One can make a strong case that cartridge names often give only approximate information about the dimensions of the bullets, amount of powder and case lenght. One can suspect there is some of that imprecision in dimensions and specifics for shotshells. Actual chamber lenghts, hull lenghts, shotsizes, shot weights, etc. being some of the specifics that seem to often diverge from nominal.

Is there not some saying in English that "Consistency is hallmark of constrained intellects." ?

Niklas

Well friends:

Once again we have a demonstration that the simple answer is not alwasy the right answer, and even the right answer SOMETIMES does not make a hill of beans worth of difference.

Thats where judgement, based on knowledge and experience, becomes relevant.

Just thoughts ...

Regards

GKT

The European switchover to sillimeters and the early misguided efforts to slowly switch over and "blending" systems may have contributed to this?

[quote=... Thats where judgement, based on knowledge and experience, becomes relevant. [/quote]

Or even better, getting real data.

JC,
there are quite a few of us who left that 16 guage.com,I dare say you are in good company! Of course with the exception my friend Drew and couple of others ,untill they are able to clean it up and remove at least one poster we ain't missing much.
Don't feel bad there is a long list of "left the 16 gauge board"
we could start our own group in fact.
Best,
Dave