I'm looking at possibly getting a 2 1/2" 12 gauge shotgun and I'm wondering about what would be involved in reloading for it. I can get some British loads shipped to start with but, long term I would need to find something more affordable along with shot sized for something other than quail or clay.

MEC reloader can be shimmed to work on that shell length. What about wads and shotcups? Anything else really different to be aware of?

I'm looking at 7/8ths or 1-ounce loads with lead shot sized up to BB at modest velocities (i.e. absolutely not over 1200FPS).

TIA,
Sid

MEC sells a Short Kit just for that purpose. Seems like the shorter shells will be perfect for your reduced loads.

I have a Short Kit, but I rarely use it anymore. I load for older 16 gauge Auto-5’s and need 1 ounce at 1200 FPS to ensure they cycle. Instead I use an overshot card and fold crimp it into place. That way the shorter shell has the same usable volume as the longer one.

PW also sells a shorter sizing die for their 375C model presses. I have used it and they do a great job on the shorter shells.

For your Auto-5, why don't you use standard length shells instead of a fold with an overshot card with a shorter hull?

For good ammunition available easily in the US, try these two sources.

http://www.rstshells.com/store/m/2-12-Gauge.aspx

https://polywad.com/

Reloading 2 1/2" 12 gauge shotshells is very common.

Data is available in the 5th Edition Lyman Shotshell Manual and online from Hodgdon.

MEC offers a Short Kit, for their single stage machines, which allows for reloading 2 1/2" shells with minimal adjustments.

Wads are available from many sources and are not as special as you might think. Shotcups are rare and only NOS. Not sure there would be any advantage over regular one piece wads. You can also use card and fiber wads.

If you want to roll crimp your loads, that opens up even more useful data, as any 2 3/4" load that is fold crimped can be used in a 2 1/2" roll crimped load.

65mm 12 gauge has the same cip specs as 70mm.

Because, prior to WWII, 16 gauge Auto-5’s had 65mm chambers. What’s more, converting to 70mm entails a lot of modifications that ruin their collector value.

Reloading 2 3/4” shells with 7/8 ounce loads at less than 1200 FPS will work just fine in a sxs.
That scenario will be 500-700 psi less than a standard 12 gauge shell, enough to be quite safe.
The 2 3/4” shell in a 2 1/2” chamber only adds about 500 psi.
Damascus barrels change the game a bit more.
Also, RST has quality products.

Ummm, firing a 2.75" shell with folded crimp in a 2.5" chamber unfolds the last quarter-inch of the hull into the forcing cone of the shotgun. At the very least, my experience shows this will lead to much higher chamber pressures and difficulty extracting the fired case.

Be careful with this recommendation. garrisonjoe

garrisonjoe,

No that is in fact true.

In 12 gauge, shooting a 1/4" longer shell than the chamber increases chamber pressure approximately 500 PSI, even with some fairly hot steel loads.

I have experimented with it first hand. Tom Armbrust has mentioned it in some articles in double gun journal..

The reason being, a 1/4" longer hull does open up in the forcing cone, but forcing cones are at least .410" plus in length longer than the chamber. A 2 1/2" chamber is supposed to be minimum of 2.500" but can be longer. My point is that the hull is not long enough to impede the shot/wad to any great degree. The same thing happens with 3" hull in a 2 3/4" chamber.

I am not advocating this practice, it just happened to be something that has been experimented with.

I'm relying on a rapidly degrading memory for the following, and will cheerfully entertain informed disagreement.

I recall that Tom Armbrust and Sherman Bell explored the too-long shell problem in the "Finding Out for Myself" series. With plastic hulls, shooting 2¾-inch shells in a 2½-inch chamber resulted in an insignificant rise in pressure. The plastic was relatively thin and could be somewhat compressed when the shell was fired. So, the extra hull length did not greatly reduce the effective diameter of the forcing cone.

However, with a paper shell, the mouth of the hull extending into the forcing cone was not readily compressed, and pressures then rose significantly.

I hope somebody can confirm this.
--Bob

Regardless of the pressure, an unmodified short chambered auto or pump may have issues getting the unfolded shell out of the ejection port. I know the Winchester Model 12 short chambered early guns won't eject the full length shell.

I load 2 1/2" 16 ga. shells on a MEC 8567 with a minor modifications.
The Grabbers have enough adjustment so no short kit is needed. I did have to modify the wad guide though.

Jim

One of my old 12 gauge guns has a 2 1/2" chamber. I really wanted to shoot it so I bought an antique roll crimper off Ebay, and a hull trimmer and a pile of overshot cards from BP. They measure and work perfectly with my 2 3/4 loads just roll crimped instead of folded.

First I cut them to 2 1/2" with the trimmer. I use my MEC 650 for all the stages except crimping. I then put them in a reloading block and add the overshot cards. A little gun oil around the outside rim of each hull helps. Into the roll crimper for about ten turns of the knob they go. It takes a little while one at a time and is definately a labor of love. They come out great. When my wads get here I am going to try my first paper hulls.

Sid,

This isn't exactly what you're looking for but it might give you some ideas.

I load 2 1/2" 12 gauge loads for my Holland and Holland hammer gun that has 2 1/2" chambers. The gun with steel barrels is Nitro proofed for 1 1/8 ounce loads but I don't shoot anything that heavy. Mostly 1/2 ounce #8's lead.

For my 1/2 ounce loads, I use 12 gauge 2 1/2" RST hulls (which I believe are Cheddites), Cheddite 209 primers, Claybuster CB6100-12 wads, 15.5 grains of Alliant Extra Light powder. I put a 0.140" thick card wad in the bottom of the shot cup. I do trim about 1/8" off the shot petals of the CB wads but it may not be necessary. Nice crimps.

I had Tom Armbrust test them for me.

Average speed is around 1373 fps and the pressure averages 4600 psi. Some powder residue is left in the barrel.

I loaded the same recipe but used 14.5 grains of XL powder and speed and pressure just a little lower.

For 3/4 ounce loads, I don't need the 0.140" card wad but use the same powder charge - 15.5 grains of XL. They shoot fine.

I have been shooting these for a couple years and are very satisfying.

By the way, I use a MEC Sizemaster to load these and made a cheap and simple 1/4" thick spacer to use in the pre-crimp and final crimp stations as pictured below.

Not exactly what you're looking for but it might give you some ideas.

Good luck and I hope this helps.

Jolly

there is something similar with the CIP, if i recolect, that the minimum chamber length for 12/65mm is 67mm total chamber length. this is die to the cip +2mm model. we have 67mm and 65mm hulls and both are 2.5" but are called 12/65mm and 12/67mm.

all this means is that for a chamber to be stamped 65mm, it needs to be a minimum 12/67mm
even with high performance 1050bar it has the same chamber dimensions.
this 67/65 mm conundrum comes up all the time in english game loads, and what is a true english loading. but its all the same specs really, same pressure limits for both 12/65mm,12/67mm, and 12/70mm. i even think there was a 12/73mm at one point. i think i have seen specs. i`ve seen weird specs for 20gauge too, 20/89mm thats 3.5" 12gauge. but there are no shells or guns made. but it is there.

Hodgdon has 2 1/2 inch 12 G load data on their site. I load short 10 12 16 & 20 on PW 375 machines & used to on Mecs. They go about it different, either one produces good results.

Having said that 12 G AA hulls measure “About” 2 9/16 . For strong SxS guns like steel barrel Parker’s I use AA’s without trimming to 2 1/2. On the other hand 16 G twist steel Hammer Parker load short using fired 2 1/2 inch RST = Cheddite hulls & Hodgdons on line data. It’s a choice you have to make for yourself considering the gun and pressure. My loads all very mild. Two short 2 7/8 inch 10 G SxS guns load up to 1 1/4 #6 and subject to testing would not be concerned with BB & 1 3/8 oz. No doubt large shot up to 1 1/8 oz possible in short 12.

Back to 12 easier to start with 2 1/2 but trimming down from longer is a viable option. Trimmed Federal Remington or Winchester hull lot better shell than Cheddites.

Bass

Jolly Bill,

No question you have a great idea that works perfectly.

Precision Reloading makes 12 ga. spacer bushings for the same purpose, for those that would rather not make their own. A bit easier to use than installing a MEC Shortkit and less expensive also.

Years ago I made one in 16 gauge.

Dogchaser/Mark,

That is one slick looking and functioning accessory. Very well done.

It must be nice to be clever and skilled!

I checked Precision Reloading and they only have those conversion bushings in 12 gauge and nothing to reduce 2 3/4" to 2 1/2".

All the best and thanks for showing that to us.

Jolly

Jolly Bill,

I can't take credit for it.

The original owner of Precision Reloading, came up with the idea. I made the spacers as we had a small machine shop area to produce all the accessories that we sold.

As far as inventive ideas go.....I am about as clever as a rock.

I had previous experience as a machinist once upon a time.

Precision forgot to print that 600 Jr's and Sizemasters will reload 2 1/2" shells with the same bushing for 3" to 2 3/4". Just be sure the machine is setup for 2 3/4" shells.

I have my 12 and 16ga Mec's set up with short sell kits, it was just the plate and alot cheaper than the kit with the shell holder they sell now. I leave mine set up for 2 1/2" and load 2 1/2" even for my 2 3/4" guns. The only 2 3/4 in stuff I load are coyote loads for my 12ga combo guns and I roll crimp them.