doublegunshop.com - home Forums Thread Like Summary - Shell length 2.5” or 63.5-65-67mm.

If you have short chambered gun, 2 1/2” finding proper length shells can be an issue. Looking at some British shell boxes and CIP rules, they say safe for guns chambered for 2 1/2” or 65mm and the shells are 65 or 67mm. 2 3/4” chambers use up to 70 mm. 2 1/2” converts to 63.5mm. But they consider 65 and 67mm as still, ok which tells me a few mm is less important than chamber pressures. Sounds reasonable.

Measuring a large number of Remington 20 gauge hulls most came up with an average just over 2 9/16 “ = 2.5625” = 65.1mm. Weird because we consider them to be 2 3/4”=2.75=69.8mm. Might just be one lot but it is about four thousand, so not just a short box. My Remington 20’s were closer to 2 1/2” than 2 3/4”. A few were 2 3/4” but most nearer 2 9/16”. Winchester AA were closer to 2 3/4”. Length can be different from lot to lot and some of my hulls are old. But as a group the Remingtons measured under 67mm. I just need to sort the longer ones out.

So I’ve decided to use hulls which have an overall length under 67mm and have built a simple gauge for go or no go. Once measurements are confirmed I intend to just keep my pressures down to the 8,00-9,000psi levels for 20 gauge loads. In the end, this eliminates trimming hulls, eliminate special wads and simplified reloading. Have not decided to trim all hulls down to 67mm but I might.

Next I am going to look at a 12 gauge hulls and see if Fiocchi, B&P, Remington, Federal or AA has a similar hull as a starting point. If not, I’ll just trim one group down to 67mm and load as normal.it would be nice to just reload instead of making so many special trips, special shells, wads and adjustments. And I think getting things to fit into a 67 mm shell might be a lot easier than finding things to fit into a 2 1/2”= 63.5mm shell. Going from 70 to 67 has got to be easier than going from 70 to 63.5mm.

STFU Ed.

campero, I love it. Never thought of using candle wax. But I think it would be a little tricky on the floor of a gun show with a gun I have not yet bought.

I'll post a photo of my solution, though it has a few more coats of finish to go and it needs to be cut from the stock yet. Marks are for 2", 2.5", 2.75" and 3". The shoulder is 3.5".

The idea for this came from a photo texted to me, by another member here. Many thanks for that.

Crude, but it works for me

Gauge by FGP1154, on Flickr

To know the exact measurement of the chambers in a quick and easy way, without tools, there is a way that I imagine many of you know.

We need a stick, a wax candle and a ruler. We will make the measurement in one of the two chambers, if the shotgun is SxS or O/Y. First of all, we will make a block with newspaper and we will put it in the barrel at a distance of about 10 cm from the extractor. This will act as a stop for the wax.

The first thing to do is to place the barrel vertically with the breeches facing upwards. Tape both barrels, leaving a gap in which to test. Optionally, the inside of the barrel can be lightly oiled.



Fill the barrel with wax.


Wait for it to cool and solidify.


Cut it so that it is level.



With the help of a stick and through the front barrel, we will remove the wax candle with small blows.

Measure the length of the chamber.


This is the chamber length of my W&C Scott & Son, that surprise me with 70 mm!

PD: Sorry for my bad english and regards!

Brent, your solution is great and very usefull but hard to do for all gauges. Mine is easy and it show how is the chamber and the first part of barrel, but as you said is not for do in a gun show.

Regards!

Ed you really area a moron aren’t you? Have you every looked up what factory pressures are? They all run high enough to operate a dirty, semi auto. Even the 3/4 ounce loads are running 9,500 to 11,900 psi. Saying light loads, or low brass shells is a completely dumb thing to do. It is pressure, not the pay load, not the velocity, not how tall the brass is. By your logic the old Active loads ought to be best because they had the very least brass height you possible could have, none. Payload and velocity might be important to recoil but have zero effect on pressure. Please block me and stop responding to my post. You are becoming a waste of keyboard clicks. You bring nothing to any post that I can see. Go back to whatever board you came from, assuming they will have you.