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Re caution, especially with older guns . . . I recently acquired an Ithaca Flues Grade 4E 20ga with some unusual features. 24" barrels with a swamped rib and 2 3/4" chambers. I requested a factory letter from the Cody Museum. Barrel length matches the letter. I was hoping that if the gun left the factory with 2 3/4" chambers (sold in Feb 1920) the chamber length would have been noted. 2 1/2" chambers would have been standard on an Ithaca 20 back then. Neither the gun nor the letter is marked 2 3/4", which it measures. Factory chokes are noted as 2 and 4 (F/M) and they measure within those ranges for a 20ga. It's easy to load up light 20ga reloads, but I am somewhat hesitant to do that in modern 2 3/4" hulls. Even though the Claybuster 3/4 oz wads make it easy to load 3/4 oz. I'm thinking about the gun mostly for grouse and woodcock hunting. So far, I've shot it only with RST 2 1/2" shells (including spreaders) which is one way to deal with the tight chokes. It could well be all original, longer chambers and all, making me hesitant to tamper with it.

Comments?

I don't know of such a chart and it would vary from one manufacturer to another. And even between batches to a degree. I would just run them over a chronograph, starting at about 80% of what you are using now.

What are the wall thicknesses ahead of the chamber? That would seem to be critical to know given that you at least suspect the chamber may have been lengthened.

I know from experience when using Swiss powder that 3f has more velocity than 1 or 2f. But because I am using the same grain amount their is a little more recoil. Pressure for black powder isn't an issue as a 10 gauge is only in the 4500 to 5000 psi range. Goex and Elephant powder from my testing has the slowest velocity and also produces the most visible smoke. Old Eynsford and Swiss burn the cleanest and produce the most velocity if that is what you are after.

I have a one pound can of DuPont FG, FFG, FFFG, and FFFFG I ended up with from an estate sale. Been using the FG only so far just because I read it has the lowest pressure rating out of all of them…whether it’s true or not?

I can't entirely agree with that statement. Obviously, you don't reload .410s, if you feel that way.

That's something I need to have done. Right now it's strictly a guessing game on whether Ithaca lengthened the chambers at the buyer's request or whether they were lengthened later on. A whole lot of that happened, as I think we all know, when 2 3/4" became the standard chamber length. And clearly sometimes happened when it shouldn't have.

The terms "Flues" and "2 3/4" chambers" hardly ever go together. Get out your wall thickness gauges.

You’re correct Stan. I don’t load .410 but I do 28 gauge, and there is a substantial savings.

I reload because you can’t buy the ammo. Haven’t seen any black powder 10 gauge ammo since I’ve been on the planet. Same with modern 2 1/2 10 gauge loads. Cooked one up the other day that turned out pretty good actually had cooked up four of them. Three out of 4 loads did halfway decent at 45 yards. I had 151, 159, and 142 hits in a 10” circle at 45 yards. Load was 2.5 oz of buffered of lead #5’s with a BPI tuff wad and 45 grains of lil gun. I experimented with wad slits. The winner imo was 4 slits to the 4th ring down. That was the most even pattern with 151 hits. I loaded up some of the same plastic wads cut short in my old Damascus SXS. The patterned horribly. No plastic fowling and the wads never opened up or looked like they sealed in the bore. I cant get any of the modern manufacturers #5 turkey ammo to shoot this tight. The old federal long discontinued red box NWTF turkey ammo was about the best I could get. Federal roll crimps their current line and left the hulls to long. They won’t cycle in my gun. Winchester #5’s are the only available option in factory loads now…And the only way I can get them is ordering them online and paying shipping by that time. I’m better off to handle it. It’s cheaper and produces patterns with 4 to 5 times the hit count at the same distances. The patterns below are all with the same 45 grains of little gun at 45 yards the top pattern I cut my plastic wads down to the fifth ring the middle pattern I cut down to the fourth ring they both were four slits. I tried one more cut shallow to the third ring down. It backed out the primer and my pattern hit high. I didn’t post that picture because it obviously wasn’t a safe load. It’s amazing how were slits in the same shot cup with the exact same powder charge produced higher pressures I learned something new the other day with that one. The bottom target was with only two slits all the way down to the base of the wad.


I made shot cup cushions out of Felpro cork gaskets. They all stayed inside the shot cups except for the two pedal so I would assume that was a success also with not having any shot still sticking inside of them. This is my first try with a buffered load and cushion shot cups. Like I said, my Damascus try was a complete failure. The patterns were horrible and blew out at 25 yards except for one loaded with one and 5/8 ounce of buffered number six. I ended up with 10 less pellet count versus a non-shot cup load and no buffer. I tried the same load at 40 yards and didn’t even hit the target. The non-shot cup and non-buffer load I would put 18 to 19 pellets on a turkey head at 40 yards. I think my next plan of action is for the Damascus is to take my non-shot cup original original load and just add buffer into it and see if it evens up the patterns or not

Here are my 3.5” loads and recovered 3.5” load wads/shot cups at 45 YARD…










The most even pattern imo…







Here are the shot cups recovered from my Damascus loads. They didn’t even blow the seals out around the bottom, going down the barrels and only two opened up one pedal. I’m guessing they probably snagged going down the barrel? I would say they’re too heavy of a shot cup for that old gun. Either that or the load just doesn’t have enough pressure to blow them open and peel them back, or the barrel inside diameters are too big and not producing a tight seal around the shot cup as it’s going down the bores if I had to guess. The plastic shot cups do look like they have just a little 1/8th of an inch or so of a dirty ring “scrub” towards the base of each of the shot cups where they probably touched the inside of the barrels when going through them. So imo very little contact. It explains why I had zero plastic fowling in my barrels. I wonder if a softer target wad would expand a lot better when firing, get better contact going down the barrel, and intern produce better groups?

You can see where I drew the blue arrow marks. It looks like just that small little ring came in contact with the barrels when going down them. The 2 shot cups on each end of the photo below were the only ones that had a pedal open up. The insides of the old barrels have pits, hills, and valleys so if a pedal could have grabbed along the way causing it to open.



I can save these shot cups were all laying right at the base of my 25 yard target so they had enough energy to get there and either drop right at the base of it or bounce off and fall on the ground within a foot or two of the target.

My 3 1/2 inch loads. I found most of them probably 35 to 40 yards out straight in line with my 45 yard targets.