I’m looking to work up a good load to shoot regularly in a nice little Ithaca Flues 20 bore I recently came into. I’ve read that turn of the century standard loads of 2 1/2 drams resulted in equivalent chamber pressures of 9000 psi for bulk and 11,000 psi for dense smokeless powder.

Looking at Hodgdon’s reloading tables show that the loads listed for 7/8 ounce payloads all range between the 9000 and 11000 psi range or higher and I cannot fing any load data for a 3/4 ounce load.

Not wanting to abuse this sweet little Flues, does anyone have any suggestions or documented pet loads they would be willing to share?

Dave Myrick

Dave, I shoot 2.5" low pressure RST shells in mine. Some Flues 20's have burst the frames shooting high pressure shells. I don't remember the chamber length in my Flues 20, but several of my light American 20ga guns do have the short chambers. RST or PolyWad vintager type shells kill birds just fine for me...Geo

I no longer reload, so others who do will provide some effective load data for low pressure.

I'd stick to the RSTs. In 20 gauge, very are very mild.

I appreciate that advice but prefer to load my own.

I use the lightest Alliant published 3/4 oz load using 20/28 powder, with # 8 Shot my bushing actually throws 11/16 oz. recoil is very mild. Guns are choked tight 11/16 is all the shot they need for clay targets.

I have hunted preserve Quail with the same loads. It’s about the largest bird that load is suitable for. Larger or longer birds I use a different gauge gun.

Pressure is important in most vintage lightweight SXS guns cracking the stock is what you want to avoid.

Boats.

PM sent

Back in the early 1960's I shot a 20 gauge Flues quite a bit. Chambers had been lengthened to 2 3/4" & not knowing any better at the time I shot it mostly with off the shelf 2½DE-1oz shot loads. It took them all in stride. "IF" I were using it today I would limit it to the 2¼DE-7/8oz loads.

This was a fairly late Flues with a 6lb weight. Some earlier Flues' are around 5½lb & may have thinner side walls in the frame which is where they crack.

Keep in mind "Pressure" bursts barrels, "Recoil" cracks frames & stocks. For the Flues you do not want Heavy nor Fast shot loads, its not really so much about the pressure.

I am not at my home computer right now. On it I have several loads which are Flues safe. All loads are tested or from known sources. I will pm them to you this evening. One I use for hunting is AA 7/8 ounce at 7k. For clay target I use a 3/4 ounce load that is even lighter. Best thing to do is pick one, load six shells up and send them out for pressure testing. A very cheap thing to do for total peace of mind.

Have you checked the chambers to see if they are still 2 1/2”? If they are don’t alter them. Nothing makes a gun stronger by removing metal at key stress points.

Look here
http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=421067

And here
http://www.hodgdonreloading.com/data/shotgun

And here
http://www.alliantpowder.com/reloaders/RecipeList.aspx?gauge=20&gtypeid=3

I use a AA hull, Win 209 primer, Claybuster 3/4oz wad and 15 grains of 20/28 powder. Works fabulous and very pleasant to shoot. An excellent load with higher pressure is 14 grains of Green Dot. If you want to use a straight wall hull the SG-20L or M wads work great. Let us know what you do.
Regards,
Jeff

Lots of parts in a 20ga Flues to batter to pieces with heavy loads.
3/4 oz, 1100 fps, and as low a pressure as you can get to burn.

They are struck very thin right by where your hand will rest, to get the low barrel weight. And of course the stocks are very lithe as well.

You are on the right track with your request.

It's hard to find the recipe's they require primarily because most loads listed need to actuate an auto loader.

Do realize that when we speak of "Pressure" here we are talking "Max" chamber pressure. Push a given load to the same velocity with shells have respectively 7k & 9K psi. The 7K load will beyond all doubt have as much or more pressure out there where you hand is. The pressure curve will be different but if the same results are obtained the same work has to be done.

Light shot loads with low velocities are certainly appropriate for the Flues. As long as it has adequate wall over the chamber area don't be concerned about any pressure up to at least 9K. When we trade off to lower chamber pressure we compensate for it slightly for the rest of the barrel. Generally speaking this is not of great concern, but there is a reason that shotgun barrels are made so much "Thicker" in the chamber area.

With the advent of smokeless powders gunmakers began Beefing up the breech area of their barrels, they didn't beef up the rest of the barrel. Black powder burned slower than the early smokeless & thus had lower chamber pressure but higher barrel pressure. Believe it or not, but the gunmakers actually knew what they were doing.

I have two 20 gauge Ithaca Flues guns that I bought for parts. Both have split barrels out at the forend region. What ClapoerZapper says about the barrels being struck very thin is absolutely correct. Knowing that, I stay with low pressure loads in my two intact 20 ga. Flues guns.

That said, one buddy's younger brother used to shoot 3" magnum loads in his Dad's 20 ga. Flues without blowing up the gun. I thought that was crazy when we were in high school. But I consider him very lucky knowing what I know now.

Thanks everyone for the advice. I do know about the pressure curves for smokeless and black powders being different. I also know the relationship between chamber pressure and barrel integrity as well as payload and felt recoil. I do not see the need to hurl shot at velocities faster than 1200 FPS as they do not retain it and doing so puts undue stress on both the shooter and the gun.

That is why I am looking for proven loads from documented sources. Yes I could work up some loads that are equivalent to those in use when the gun was new but I want to preserve it as well as enjoy it, hence the low pressure and reduced payload request.

Dave

This image was posted on the PGCA site; a 20g Flues which was the sad victim of "inexpert" chamber lengthening, with a crack between the chamber and forcing cone



If the chambers are no longer 2 1/2" please have the wall thickness at the end of the (new) chamber carefully measured by someone with the interest, expertise and equipment to properly do so.

The chambers of my Flues are 2 3/4”. It also has fluid steel barrels. I’ve been told that by the serial number, the gun was made with the longer chambers. I’ve no way to verify this however. Never the less, it has been shot by the previous owner with factory RIO 2 3/4” 7/8 ounce factory loads with no ill effects as of yet. I have measured the bore diameter, thickness, chamber length and choke diameters and all appear to be within tolerances.

If the chambers were lengthened from 2 1/2” to 2 3/4” is there any benefit to shooting the shorter shell in the longer chamber?

Again, I am well aware of the potential for disaster with shooting modern “full power” loads in vintage shotguns, hence my questions. I want to develop a reduced payload, low pressure load that patterns well and will allow me enjoy shooting this little gem.

Thanks again for all of the replies and the advice.

Dave Myrick

You may have been informed incorrectly. Courtesy of David Noreen

The last Flues period catalogue (1925) states "Unless otherwise ordered Ithaca 28 Gauge and 20 Gauge guns are chambered for the standard 2 1/2 inch shell..."

Beginning with the first NID catalogue in 1926 they state -- "Unless otherwise ordered Ithaca .410 Cal. and 20 Gauge guns are chambered for the standard 2 1/2 inch shell..."

Beginning with the 1927 catalogue the sentence is changed to --"Unless otherwise ordered Ithaca .410 Cal. guns are chambered for the standard 2 1/2 inch shell, 16 Gauge for 2 9/16 inch, 20 and 12 Gauge for 2 3/4 inch and 10 Gauge for the standard 2 7/8 inch shell."

What, exactly, is the wall thickness at the end of the chambers?

Thank you for that information. I don’t have that measurement with me at the moment here at the office. I will forward it along once I get home tonight.

Assuming it is still safe to shoot, does it make a difference shooting 2 1/2” shells?

Dave Myrick

My experience was that 3/4 oz of appropriate size shot at 1100 fps will whack a South Dakota rooster out of the sky at modest distance. ymmv.

I don’t trim 2 3/4 inch hulls for my 20s do shorten 16 & 10 G hulls. It’s gun specific. 2 3/4 in a 20 with short chambers increases pressure, not a lot and within what I consider safe in my gun.

If you go short best path is a MEC 600 with the short kit. Trim or buy short hulls

Boats

As Miller pointed out, weight is an important consideration. I've weighed several Flues 20's that are a bit over 6 pounds. On the other hand, there are others that weigh in that 5 1/2# range. And as best I can recall from research a former poster here had done, the issue with those very light Flues 20's often was not with the barrel, but rather the receiver. They had a tendency to crack right where the standing breech meets the water table.

Definitely a good idea to take careful measurements of any
Flues 20 that now has 2 3/4" chambers. More critical, again, on the lighter ones--because they had thinner barrel walls to produce that light weight. And removing an extra 1/4" to lengthen the chamber could be a very big deal.

If chambers have already been lengthened to 2 3/4", then reloading those hulls to low pressure should work every bit as well as shooting 2 1/2" shells at the same pressure. The longer hull won't give you an additional pressure increase, as it will (although that increase may not be more than a few hundred psi) if fired in a 2 1/2" chamber.

Ithaca introduced the Flues model around 1908. Smokeless powder had been available for at least a decade & a half by then. No doubt Ithaca considered the fact that the Flues guns would be shot with Smokeless when they made them. Standard 20 gauge load of the day was 2 drams or equivalent of powder with 3/4 or 7/8 oz of shot. Later a "Heavy Field" load was offered with 2½ dram equivalent powder & an ounce of shot. With "Progressive" powders in the 1920's an "Express" load was offered with 2 3/4 DE & 1oz shot. No doubt these heavier loads cracked a few Flues frames & split some stocks. This was not however due to the increased "Max Chamber Pressure" of these loads but due to the increased payload of a heavier shot charge at a higher velocity. Same thing that makes it "Kick" harder. That Harder Kick puts more strain on the action as well as the stock.

Barrel bursts have not traditionally been a problem with the Flues to the best of my knowledge. When "ANY" shot barrel does burst down around the forward hand then it probably didn't matter a lot which load was being fired. It could have been a flaw in the steel or could have been some sort of obstruction. A through investigation would need to be done to determine the actual cause.

I've never been one to take a chance so I only shoot shells of the proper length and operating pressure that was deemed safe at the time the gun was manufactured. In 20 gauge I load 2 1/2" 3/4 oz loads using Unique powder and wads from Ballistic Products and both Win AA and Fiocchi hulls. You can easily do it on any MEC press. I happen to have a an old Lee Load-All that my parents gave me about forty years ago. By removing a little bit of material from the bottom of the crimp die it works perfectly for loading all of my 2 1/2" 20 gauge shells.

Try the low recoil low noise Winchester AA in 20. Man are they nice to shoot at clays, quail and dove