doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com CIP, London, Birmingham Proof Marks for Steel Shot

I recently came across an article quick referencing the use of Steel Shot in CIP/UK proof shotguns. In my opinion, a good simple guide to share.

https://cip-london-birmingham-proof-houses-barrel-proof-equivalency-table-for-use-with-steel-shot

I believe the fluer de lis mark is used by all signatories of the European proof act, not just England, to designate proof for high performance steel.

Something I find interesting is that they are admitting using standard steel loads in older guns will often lead to bulged barrels, even in guns with minimal choke in the tube.

No big deal, I guess.

Best,
Ted

I don't know anything about the Standard Steel shot ammunition as it's not available here in North America. It looks like the Europeans are using the CIP over the S mark as well as the Fleur de Lys stamp.

Advice on Steel Shot

I have never used any steel shot in my shotguns to date. The North American steel shot ammunition appears to be too hot for use in light game guns. As LeFusil and Dr. Drew had pointed out to me in an earlier post re: using steel shot through an improved modified choke, was not to, that the recoil alone from high pressure steel loads would very likely damage either the stock and/or the action.

So was just wondering about The British Standard Steel ammunition.

I have a few guns I can use steel in. One, a Spanish boxlock has a cylinder and improved cylinder choke in the right and left barrels, and shouldn’t be harmed, but, in truth, I’m old enough to realize I don’t care if it is harmed or not, it will keep me legal where I need to be. The others are modern repeaters.

I pretty much hunt where lead is OK. Don’t pursue ducks, geese, or doves, so, thus far, I’m OK

Best,
Ted

I've shot enough American steel loads through my old BSS to shoot it off face on the right barrel, which always fires first. I shimmed the hook and keep using it. Before starting the left choke was opened to match the right, at .018". Never a sign of any damage. Going off face was just a combination of heavy loads being fired through it for a long time, not the fact that they were steel shot loads.

The duck hunting author, Worth Matthewson, from the Pacific Northwest, wrote in one of his books that he shot off the shelf steel loads for years in an old LC Smith. He took it to a gunsmith for some issue and learned that the chokes were full and full. There was no apparent damage to the gun.

I am careful about not using steel in really tight chokes, but have no qualms about up to .018".

several other bss shooters report no issues with steel shot, so long as chokes are no tighter than mod...

what about the turkish made guns?

any issues with steel shot?

My understanding is in-order to get the killing performance using steel shot, it requires faster hotter loads.

And what about the pressures? I'm wondering about the chamber pressures for the 1954 London & Birmingham Proof or Re-proof British shotguns?

I had a look in Vic Ventures ‘Gun Craft’, Rules of Proof, pg. 207. In his book, he has a chart from the Birmingham Proof House re: 1925/1954 rules of proof which states, for 12 Gauge, 2 1/2 inch, 3 tons per square inch = 8,943 psi, for 2 3/4 inch = 9,686 psi.

From what I researched online, the CIP “Standard Steel” ammunition pressure limit is 10,733 psi, and the CIP “High Performance Steel” pressure limit is 15,229 psi. So doesn’t the CIP “Standard Steel” ammunition pressure even exceed the 1954 London & Birmingham Rules of Proof? And U.S. SAAMI's specification for 12 gauge, 2 3/4 inch, has a chamber pressure limit of 11,500 psi?

I don’t know, maybe I’m missing something.

No, I think you have got it about right.
I have fired maybe 100 standard steel shot cartridges, mostly 2.5" ones, and they feel just a shade hotter that the usual one ounce loads that I use in my Webley.

However I am sure that it is a bad idea to fire ANY steel loading through more than half choke, i.e. 0.020" of constriction. Others here have fired some of the Superior Steel loads and not enjoyed the experience. I am stocking up on Bismuth as and when...

HB