20 ga. Chamber length

[Chad Hefflinger]

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

http://pic20.picturetrail.com:80/VOL1373/6511424/24488932/412969745.jpg

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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[Chad Hefflinger]

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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[Todd Poer]

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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[John Campbell]

More than one factor effects the felt recoil of a gun. Chamber length is one of them. In relation to the cartridge length, of course. If the mouth of a case restricts the passage of the charge into the forcing cone and barrel proper, it will contribute to felt recoil. But not by much.

Other factors include the LOADING. Which, in the case of most commercial ammunition is fairly "stiff." Each firm has its own idea of a good 20-bore load.

Gun weight is another factor. So is stock configuration. Buttstock "plate" or pad. Shooting style, etc.

However, I've fired thousands upon thousands of handloaded 3/4 oz. 20-bore loads in 2 3/4-inch cases/2 1/2 -inch chambers with perfect comfort and results. But that's just me...

[Drew Hause]

Bruce has previously made the point that some factory 20g cases are shorter than 2 3/4"

Estate (Federal) 2 5/8"; Fiocchi 2 11/16"; Nobel Sport 2 3/4"; Winchester 2 5/8"; Winchester Universal 2 9/16"; Remington Gun Club 2 11/16"

http://pic20.picturetrail.com:80/VOL1373/6511424/24488932/410136599.jpg

If the case mouth looks like the one on left, it's a problem in YOUR gun

http://pic20.picturetrail.com:80/VOL1373/6511424/24488932/412969745.jpg

A summary of “Long Shells in Short Chambers”, by Sherman Bell with technical assistance from Tom Armbrust in “Finding Out for Myself” Part V, Double Gun Journal, Winter 2001 is about 1/3 way down here. This was a PRESSURE, not RECOIL study
https://docs.google.com/document/d/1ZIo0y746UsSRZIgRuuxwAbZjSBHitO_EanvwLYc-kGA/edit

[Harold Lee Pickens]

Bruce has demonstrated this with pictures before. Win AA's are not 2 3/4". Put them next to an RST shell and they are just barely longer. This is not the case for all shells as Cheddite shells such as Herters are markedly longer than the AA's. Rem 20's are similar to the AA's, I dont know about Federals.
I shoot factory AA's and Rem thru my Parker 20 fluid steel 20's, but most of the time am shooting 3/4 oz AA reloads and they are really sweet to shoot. I cut down Herters 20's to 2 1/2" and have scaveged RST 20's, so lately have been loading them esp for my older damascus guns such as my Manton 20 hammer gun.

[James L. Martin]

Here are 2 20ga hulls , a Fed top gun at .610 and a new style Win AA at .608 .I load the AA hulls with 7/8 oz for hunting in my 2 1/2 chamber Parkers and LC Smith. The AA hulls with a polywad works great for those full choke guns.

[Chad Hefflinger]

In the picture Drew posted with various spent shells lined up is a good illustration of varying lengths of shell casings. If you were to add another line on the board at 2 3/8", wouldn't that make you pucker just a bit:corn:

[Todd Poer]

[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.

[Drew Hause]

As a victim of a K through post-grad education in the great State of Missouri, this works for me ;)
http://www.omahamarian.org/trap/shotshellenergy.html

35 ft/lbs is more than 1 3/8 oz. 3 3/4 Dr. Eq. (1295 fps) in an 8# gun at 32.6 ft/lbs

And BTW: my aforementioned 2 3/8" chambered 20g had a crack in the wrist that required repair

[Dean Romig]

I should have made the point earlier that the majority of "off the shelf" ammo makers load their shell to the charge necessary to fully cycle the semi-autos out there today, which are primarily inertia operated... but even the gas operated semi-autos require a minimum of pressure to operate properly.





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[Todd Poer]

As a victim of a K through post-grad education in the great State of Missouri, this works for me ;)
http://www.omahamarian.org/trap/shotshellenergy.html

35 ft/lbs is more than 1 3/8 oz. 3 3/4 Dr. Eq. (1295 fps) in an 8# gun at 32.6 ft/lbs

And BTW: my aforementioned 2 3/8" chambered 20g had a crack in the wrist that required repair

I like it. Good stuff. I did not see your free calculator. Btw sorry to hear about the 20 broken at the wrist. Do you know why it broke. I saw a gun with a broken wrist after a fall, not certain I have heard of a broken wrist on a shotgun from just recoil.

I found a recoil calculator that was on a rifle webpage and then had to to convert ounces to grains and drams to grains. I think I came out about the same as yours but I also played with 2 3/4 drams of powder for a 1 ounce load and foot pounds went up. As follows is exercise I went thru. Will put same variables in the link you provided to see if its different. Lots of variables to consider to get different outcomes.


Okay. I found a shooters recoil formula. Calculator is setup for rifles but it should calculate out the same. Had to convert grains to drams and ounces of powder and shot. I ounce of shot is 437.5 grains and 2.5 drams of powder is 68.36 grains of powder. Looking at Bruce's table for my 16 Gauge I used a 7lb weight for the gun. With these inputs it calculates out at 32.85 foot lbs for the federal load.

Since I/we don't know how much powder is used in the RST loads then its hard to calculate the differences. But its an interesting point. If the charges are all the same just put in 1200 fps for the RST loads and keep then recoil energy goes up to 34.4 lbs. Then the recoil energy is less for the Federals by 2 lbs, thereabout. That is only about 4.5% difference and maybe negligible due to certain vagaries.

For giggles went and calculated what an 8 pound 12 gauge would produce at 1200 fps, 3.5 drams 1 1/8 ounce load. That recoil is 45 lbs. That is a 28% increase. If gun frame is about the same on a 12 to 16 gauge Parker and assuming wood is about same thickness, that is about 10 or more extra pounds being exerted on the stock. That might be the difference in whether old american walnut splitting out, or not.

http://www.shooterscalculator.com/recoil-calculator.php

[Todd Poer]

Hey Drew;

Maybe missing something. I just put in the variables you mentioned in the calculator you linked to. Sorry could't resist since you are from the "Show me" state. I put in 1.375 ounces of shot, 1295 fps, 8 lb gun, 33 grains for the wad just showed up in calculator, then put in 102.5393 grains of powder which is equivalent to 3.75 drams of powder. I came up with 67.4 foot pounds of recoil energy, not 32.6 lbs.

I could be wrong but 1 dram of powder is suppose to equal 27.344 grains of powder. That maybe the variable that is messing up. 3.75 times 27.34 equals 102.5393

Also my original calculator based on rifles did not account for wad weight, which might add to recoil a tiny bit.

[Frank Cronin]

I think your issue is the table is for smokeless which is measured by weight. BP is by volume.

27 grains is equal to 1 dram of black powder.

102 grains of smokeless in a shell you can pretty much expect a grenade to go off.

[Drew Hause]

Alliant 12g Reloading Guide
http://www.alliantpowder.com/reloaders/RecipeList.aspx?gauge=12&gtypeid=3

1 1/8 oz. at 1200 fps in Winchester AA case, Win 209 primer & WAA wad
Unique 21 gr = 9,100 psi
Green Dot 19.5 gr = 9,300 psi
e3 17 gr = 10,450 psi
Red Dot 18 gr = 10,400 psi

[Todd Poer]

Hmm, Btw Drew really just kidding on show me state. I think Missouri is cool. Especially some of the Indian artifacts that come out that place. Very cool. Maybe your time in the field you have found some cool arrowheads yourself.

Okay my conversion does not distinguish between the substance whether it is black powder or smokeless powder. It is 1 dram of something is equal to 27 thereabout grains of something. Now if there is a contingency that says this shell uses smokeless powder that is equivalent to x drams of black powder please let me know what that conversion is. Otherwise a dram of something is still just 27 grains of something.

Just went and found a box of shells. It says 2 1/2 dr. eq. I stand corrected. So in these off the shelf loads how do you know how much grains of powder do they actually use or how many grains. What your saying is that when using smokeless powder you can get by by using 80% less than black powder. Is that about right. I think your calculator just said use 18 grains as an average. Which I guess backs up what you were saying.

My head hurts. This is all as confusing as the tax code and Chinese stereo instructions.

[Drew Hause]

Here you go Todd
http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=455407

[Todd Poer]

Thanks Drew. That all makes sense for something about 100 years ago. Why they don't just say what they use and how much of it in today's standards is mystifying. Maybe the Gubmint should do something about it. Just kidding.

Oh well, I am just going to put gas in it and drive it.

Later. I have showed my ignorance enough for 1 day. Btw did you know that 3.75 drams of black powder makes a boom when it blows up.

[Drew Hause]

This probably did also :shock:

Hatcher's Notebook, 1966
https://books.google.com/books?id=yESNUKSg5aMC&pg=PA184&lpg
“E.C.” blank powder burns with extreme speed…to give a sharp report when it is not heavily confined. An enthusiast once got hold of some of this powder, being familiar with “E.C.” shotgun powder…and loaded a bunch of shells. To try out his new load he got out his fine Lefever gun, and put up a target in the shooting gallery to get the pattern. There was a terrific detonation, and a big piece was blown out the side of the barrel near the breech, flew across the room and buried itself in a wood bench.

[Todd Poer]

This is confusing and has me wondering, again. I guess the calculators make allowances for modern powders but they don't actually tell you which allowance for which powder. They just use the black powder equivalency, on some. Unless the calculators have fine print to allow for modern powder in weight then should it really make a difference if black powder yields are the standard? I can see if reloading you need to convert the drams of black powder to the right modern powder weight due to its efficiency. However aren't the yields suppose to be the same based on the properties of black powder.

So if say I have a load that is suppose to be 3 drams of black powder equivalent then 1 dram is suppose be 27 grains of explosive yield for black powder times 3. So if black powder equivalency is the standard then that is all is necessary to use the calculators. They are not reloading to black powder coefficient calculators, telling you how much to drop it down to modern loads equivalency or are they. Hence I understand when using Drew's link to a calculator they already make the allowance and plop 18 grains in unless you change it yourself. Others don't.

However, I strongly agree that when reloading the black powder conversion to smokeless powders you need to account for it and then about 6 to 7 grains of modern smokeless powder is equal to the standard and reference black powder equivalent of 1 dram of black powder. Whether is 6 to 7 grains actually used for modern powder it is suppose to produce the same result as 27 grains of black powder, Right?

Anyway this is much harder than it needs to be just to figure out recoil but obviously you need to know which variables to use and how each are defined. I have a feeling there is a violent agreement in there somewhere. Its an apples to oranges comparing to apples discussion.

[Michael Moffa]

Unreformed engineer here but when I did these calculations about a decade ago a 1oz load at 1200fps was 16 pounds force. (this was my standard Clays load for skeet and sporting clays). When I started to shoot International skeet, I made up some 1 1/8 oz loads at 1550 fps for second shot at stations 3, 4 and 5. These forced out at 35 lbs of free recoil. You had to be a man to pull the trigger a second time. I only used three of these shells per round.

[Chad Hefflinger]

I received my flat of 2 1/2" RST's today, I will see how these pattern and shoot. I also got my letter today on this gun and it matches to the gun completely, it even states the chokes as I measured them... cylinder/full:)

[Todd Poer]

Unreformed engineer here but when I did these calculations about a decade ago a 1oz load at 1200fps was 16 pounds force. (this was my standard Clays load for skeet and sporting clays). When I started to shoot International skeet, I made up some 1 1/8 oz loads at 1550 fps for second shot at stations 3, 4 and 5. These forced out at 35 lbs of free recoil. You had to be a man to pull the trigger a second time. I only used three of these shells per round.

I have been playing around with these recoil calculators that are free online. Most of the time for shotgun loads they say how many drams and not grains. However not certain if they use dram equivalent to black powder but I suspect they are using maybe modern powder weights/grains. Very confusing since modern powders you use less of it but boxes of shells are marked for black powder equivalency and you don't know how much or what type powder off the shelf loads are using. At least I can't find out. Active reloaders set it straight for me some. I think 35 lbs is probably about right on heavy loads. I think Drew and other are right but its dang confusing.

I know about heavy loads and getting the snot kicked out of me. I have a Browning BPS pump that I use for Turkey's. It has a 3.5 inch load I use, or it uses me. Feel like your loading a roman candle in your gun, and when it goes off your getting all of it in that gun. No recoil reduction. Testing patterns I shot about five rounds. The first two where surprising, shots 3-5 were just punishment. It paid off though. I took a really nice gobbler at 60 yards with that gun. Actually thought he was at 40 but it was in a pasture with a little roll to the hill and its really hard to judge distance in open ground like that, but when stepped it off it was 60 and it dropped in his tracks. If I thought he was at 60 would have let him go, still probably more luck than skill, but he was a big old bird and gobbled in front of us for an hour on other side of the field. He got as close as he was coming and strutted for 10 minutes back and forth daring our jake and hen setup to come to him. He was a crafty one and was about to walk off.

Big game for the Tigers tomorrow. Its do or don't time. Auburn has a history of being one of the most dangerous underdog teams in the country. If your an SEC football fan that is a must watch game. I predicted Auburn would beat Georgia a few weeks ago. Its really a pick um game.

[Bruce Day]

I’ve missed the discussion.
Just follow the Parker service load tables in TPS and the recommended loads from Parker. It’s not rocket science.
12ga
11/8 oz at 3dre or 1180to 1200fps

16ga
1 oz at 2 1/2 to 2 3/4 Dre at 1180 to 1200fps

20ga
7/8 oz at 2 1/4 Dre at 1200 FPS

Lots of cartridges are available. Cartridge length issues between 2 1/2” and 2 3/4” are much ado about nothing.

I’ve been off the last couple days chasing wild pheasants with a 16ga C beater and Bert. We’ve been limiting out. Temps today were high of 30 and winds 25 to 30. I’ve been using cheap Herters shells bought at Cabelas, the shame of it all.

Another day on the northern plains , then down to the central plains for more pheasant and quail then in a few weeks off to the southern plains for quail. I’ll live dangerously and stuff Remington 20 ga shells from Cabelas in the old Parker D 20 ga.

[Chad Hefflinger]

Bruce,
Based on 2 3/4" shells in a 2 3/8" chambered 20 gauge not being an issue, would you or others also say a 3" shell with 1 1/8 oz and 3 dre load would be acceptable to shoot in a 2 3/4" Parker with 2 5/8" chambers?

[Bruce Day]

No. Wall thickness.

Why would I shoot a load that far exceeds the published service load max and exceeds what Parker recommended ? I urge people to take the effort to find out what Parker said.

[Chad Hefflinger]

Ok, now I'm confused. The load I referenced, 1 1/8 @ 3 dre is what was referenced in an earlier post as recommended service load. The only difference in my question was about using this same load in a shell that is 3/8" longer than the actual chamber length. This is basically what we were discussing with using a 2 3/4" shell in a 2 3/8" chamber. Why would one far exceed the published service load and one be much ado about nothing? I'm not busting anyone's chops here, I'm just trying to understand

[Bruce Day]

The 1 1/8 3 load is 12 ga not 20. I know of no Parker recommendation and think it unwise to shoot that load in a 20 ga.

Parker regularly recommended that load as it’s patterning load in its 2 5/8” chamber length 12s.

[Brian Dudley]

Here is something that i have often wondered about parker 20g chamber lengths. As we know, a many of them are 2-1/2” and that is what this thread is about.

Take 12g as an example. Parker bored their chambers at 2-5/8” for intended shell length of 2-3/4”. The 1/8” shorter chamber was intended to provide a better gas seal at the forcing cone and result in better shot penetration. 12g hang tags state specifically “chambers: 2-5/8”... Use: 2-3/4” shells”.

Now, what was the period length for commercially available 20g shells? 2-5/8” or 2-3/4”. The above short chambering in parker 12g guns would suggest that if they followed suit in 20g, then the intended shell for a 2-1/2” chamber would be 2-5/8”. The same 1/8” difference. 1/4” seems like too much difference.

Does anyone have an example of a 20g hang tag showing chamber length and the intended shell length?

[Chad Hefflinger]

I would think if the chambers actually measured 2 1/2", they may have been intended for 2 5/8" shells. The chambers in the 20 ga I was discussing are actually 2 3/8", and I would think were truly intended to be used with 2 1/2" shells following the 1/8" shorter theory. The difference here is not 1/4" but rather 3/8" and why I asked about using a 3" shell with 1 1/8 oz 3 dre load in a 12 ga with 2 5/8" chambers (3/8" shell to chamber length difference)

[Todd Poer]

Hey Bruce nice picks and glad to hear someone is tearing them up.

I think in continuation of the discussion where you were enlightening me with the TPS info, we were trying to just to get recoil comparisons to what is actually happen. Btw those charts are awesome. I have another brand sxs 28 gauge that is my brush gun and those choke killing diameter charts you have are helpful.

My point was that just the way sxs guns are made, if you get above 16 gauge the cumulative or maybe one time of too heavy a load can create stock issues on older Parkers and maybe even all older guns using more brittle American walnut. Say if you have a 1 Frame 16 gauge and a 1 frame 12 gauge, inherent with 12 gauge loads your recoil pounds go up and hence you can just have more wear tear issues on the same sized stock. Again almost every field grade 12 gauge Parker I have seen littered across gun shops have some issues with stocks. 16's obviously can if you get loads approaching 12 gauge. I think most 12 gauges are in the 1 1/2 frame but..

I was putting say the same dram equivalent of black powder to grains and coming up with some pretty high numbers in the calculators. The calculators require a grains used of powder. A box of shotgun shells, if you can find them will say dram equivalent. But more and more they don't even say that, they just put a velocity number. I think the calculators are thinking you are using the modern powder grains instead of black powder grains and it produces maybe conflicting results.

BTW Heff, Bruce referenced this chart below from another thread where he was talking about a 16 gauge loads as recommended by Parker. Slide your eyes down and 20 gauge info is there as well.
http://parkerguns.org/forums/attachment.php?attachmentid=58150&stc=1&thumb=1&d=1509914603

[Todd Poer]

Btw Bruce really like this chart and talking about the different velocities. Man I like those 28 gauge numbers. You get less shot, but what you got, get's there faster than all normal loads.

[Bruce Day]

Todd, you should get and read Parkers The Small Bore Shot Gun.

As for me, I’m off to hunt pheasants.

[Brian Dudley]

Todd,
You are just seeing the junk Parkers sitting in gun shops with stock issues and they are sitting there for a reason.
And... the most common frame size for 12g Parkers is by far the 2 frame.

[Drew Hause]

Brian: Up until about WWI the standard 20g load in the U.S. was 2 1/2" with 7/8 oz. shot and 2 1/4 Dr. Eq. Bulk or Dense Smokeless powder at 1155 fps; 7/8 oz. with 2 1/2 Dr. Eq. at 1210 fps thereafter.
It was not until 1923 that the new Super-X and Nitro Express 2 3/4" 20g shells had 2 3/4 Dr. Eq. of progressive burning powder and 1 ounce of shot.
I don't know when Parker begin boring longer 20g chambers; Hunter Arms did not until 1936.

However, Edwin Hedderly, editor of Western Field magazine promoted small bore shotguns for duck hunting and received some fabulous Parkers in exchange for ads; including a 32" 20g A1 Special ordered April 26, 1912.
The Widgeon Duck Club in central California obtained 10 special order, 3" chamber 20g Parkers. Researcher has an early Peters Cartridge Co. 3" 20g shell loaded with 2 1⁄2 Dr. Eq. "E.C." and 7⁄8 ounce of No. 4 chilled shot.

Forest & Stream, February 27, 1909
“Small-bore Guns and Loads”
https://books.google.com/books?id=nEkcAQAAMAAJ&pg=PA337&dq

T.H. Grant, Forest & Stream, December 1915
https://books.google.com/books?id=lRMcAQAAMAAJ&pg=PA711&lpg

Edwin Hedderly, Western Field editor after July 1910
Arms & The Man 1915
https://books.google.com/books?id=BX07AQAAMAAJ&pg=PA158&lpg
Recreation 1917
https://books.google.com/books?id=4uVQAAAAYAAJ&pg=PA97&lpg
Outdoor Recreation 1919
https://books.google.com/books?id=BX07AQAAMAAJ&pg=PA158&lpg

[Brian Dudley]

Thank you drew.

[Bruce Day]

Heading south to the red dirt plains to hunt quail in a couple weeks with Bert and the new pup. Nothing better than to get them on real birds at 17 weeks old, that can make a bird dog.

I’ll grab the old D 20ga and boxes of Win, Fed, Rem and RST 7/8 oz shells so I don’t have to stop at the local hardware stores. Anybody see any birds here?