20 ga. Chamber length

[Heff]

I have been reading through post with the search engine on various chamber lengths and gauges. Based on what I have been reading, the consensus seems to be that chambers were roughly 1/8" shorter than the desired shell to help seal pressures with the old fiber wads (2 5/8 for 2 3/4 and 2 7/8 for 3" in 12 ga)
Does this mean a 20 ga intended to shoot 2 1/2" shells would have 2 3/8" chambers? If so, can 2 3/4" shells be safely used in this configuration or should 2 1/2" be used?
I recently purchased a 20 ga made in 1911 that by my measurements with a machinist scale check out to be 2 3/8" chamber length to the front of the forcing cone.

[Robert Brooks]

A lot of 20 gauges Foxes did indeed have 2 3/8 inch chambers i have fires a lot of field 2 3/4 inch shells in mine until I started buying 2 1/2 inch shells.Bobby

[Drew Hause]

Chad: I had a 1924 20g Trojan with 2 3/8" chambers, and foolishly tried 2 3/4" 7/8 oz. skeet loads. Recoil was brutal, and if I'd been smarter would have checked the end of the shells for feathering caused by entering the forcing cones

67mm shell left - 65mm right



Please don't lengthen the chambers; end of the chamber wall thickness may be inadequate

[Dean Romig]

I've had that same experience, especially with a 20 gauge VH.





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[Heff]

Thanks guys, I ordered a flat of various 2 1/2" shells from RST yesterday.

[Bruce Day]

RST cartridges are fine but so are Remingtons, Winchesters, and Federals. I have Parker 20s ranging from A to D grades in both Damascus and fluid steel and that’s what I use.

[Dean Romig]

Bruce, can you buy 2 1/2" shells in those brands?





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[Southpaw]

I swear its crazy and confusing. These guns are marked 2 1/2 inch chamber and 2 3/4 chamber but aren't. Its like going to a lumber yard and buying a 2 by 4. Even that is not actually a 2 by 4. Rounding I just guess is the American Way.

[Dean Romig]

I asked the previous question because I have fired 2 3/4" shells in various 20 ga. Parkers, knowing that doing so would probably do no immediate harm to the gun but they smacked me hard enough to know I didn't want to shoot them in other than a hunting situation and never at clays. But I have to wonder, if they clobbered me that hard what effect would they have on the gun over time??





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[Southpaw]

[QUOTE=Dean Romig;228140]I asked the previous question because I have fired 2 3/4" shells in various 20 ga. Parkers, knowing that doing so would probably do no immediate harm to the gun but they smacked me hard enough to know I didn't want to shoot them in other than a hunting situation and never at clays. But I have to wonder, if they clobbered me that hard what effect would they have on he gun over time??

I remember years ago reading at how this specialty gun maker never made any sxs over a 16 gauge for an upland gun. Just said that in his opinion the if you a build a gun to gauge frame specific then a 12 gauge is to heavy to carry and long term kick is two big with the loads especially the way a sidelock or boxlock interfaces. I know there will be a lot of disagreement and argument against it but that was his opinion.

I do know that with Parker's if you get different frame sizes say a 1 frame on a 12 gauge then if wood is made to fit then you could get stock issues down the road (wood becoming brittle, oil soaked, etc) and too small around wrist.

Bruce opened my eyes the other day and I went and found a recoil calculator. For instance on my 16 gauge 1 frame gun and about 7lb gun weight for a 1 ounce load and 2.5 drams of powder the recoil was about 35 lbs. For giggles I did same typical calculation for a 12 gauge using an 1 1/8 ounce load with 2.75 drams of powder and the recoil calculated out at 45 lbs. If that is the same case for a 1 frame gun on a 12 gauge then that 10 extra pounds of recoil could have a cumulative effect, maybe. I think most Parker 12 gauges are on the 1 1/2 frame so wood might be beefer and gun weighs more but I dare say that the recoil will still be around 45 maybe to 50 lbs depending on loads. I think that is the critical part about the protecting the stock and old wood.

I just think there are more problems with the nature of the loads for 12 gauge systems in old Parkers. It rears its ugly head if a 16 gauge is loaded up to perform like a 12 gauge. I think 20 gauge say on a 1 frame has plenty of hedge. But I am no expert but sure would like to hear from one.