To shoot modern steel loads, you need to make sure the gun is rated for them. The European standard proof was upped a few yrs ago to allow for the high speed steel rounds, which operate at higher levels than any of the lead rounds. They are now apparently supposed to put BAR pressure ratings of the round on an insert, in the box, over there. The new standard is 1370BAR on the proof test. Considering that a hot round in the days of lead was 1330fps, that gives you a picture of what pressures are now with the 1550's and 1625's and 1700fps rounds.
INFORMATION SHEET
CIP REGULATIONS ON
STEEL SHOT AMMUNITION AND SHOTGUN PROOF
This paper summarises the current CIP (Permanent International Commission for the
Proof of Small Arms) regulations relating to steel shot cartridges for 12 and 20 bore
shotguns, and the proof requirements of guns used to fire steel shot ammunition. The
information is based on recent CIP Decisions taken in plenary meetings, with some
explanatory material added.
1. Steel shot cartridges.
1.1 The steel shot must have the following hardness values (Vickers):
Surface VH1 < 110
Core VH1 < 100
1.2 The steel shot load must be provided with a sufficiently strong and direct
acting protective device designed to prevent any abrasion by the shot on the
internal barrel wall
(i.e. plastic or other wad). This protection must be effective for firing at temperatures from - 20ºC to + 50ºC.
1.3 The marking “Steel Shot” must be printed on the cartridge tube. The same
inscription in one of the languages used by the CIP member states may also
be added.
2. Standard 12 bore steel shot cartridges.
These cartridges, if they are to be fired from standard proof shotguns
(ie those proved to 960 bar (transducer) or, previously, 850 bar (crusher))
, or magnum proof shotguns (ie those proved to 1370 bar (transducer) or, previously, 1200 bar (crusher))must not exceed the maximum admissible service pressure of 74 MPa
(new units “megapascals”, in place of the old 740 bar) specified by the CIP and measured by
means of a piezo-electric transducer.
2
2.1 The steel shot diameter must be ≤ 3.25 mm
(i.e. equal to or less than 3.25 mm – which is smaller than English no
.
3).
2.2 The mean velocity, measured at a point 2.50 m from the muzzle, must be 400 m/s (around 1,300 ft/s)This velocity is to be measured using a
cylindrical barrel and the mean value of a series of 10 shots.
2.3 The momentum must be: Mo = mV 12 Ns. (Momentum = mass of shot x its velocity, measured in Newton-seconds (!). It is calculated by multiplying the weight of shot load (in kgs) by the velocity (at 2.5 m) in m/s. So, a 30 g load at 385 m/s has a momentum of 0.030 x 385 = 11.55 Ns i.e. just under the 12.0 Ns limit).
See Endnote.
2.4 Markings to be borne on the basic packaging, in addition to the normal safety
warnings:
- “Beware of ricochets: avoid firing at rigid and hard surfaces”
- “Steel Shot cartridges”. The same inscription in one of the languages used
by the CIP member states may also be added.
3. High Performance 12 bore steel shot cartridges.
These cartridges, whether 12/70 or 12/73 and longer
(i.e. 12 bore cartridges for 70 mm (2 3/4in) or 73 mm chambers), can only
be fired from 12 bore guns specially designed to fire steel shot ammunition and bearing the Steel Shot proof mark (this includes the words “Steel Shot” and a Fleur de Lys ). They must all
observe the maximum admissible service pressure of 105 MPa (1,050 bar (transducer)).
3.1 The mean velocity measured at a point 2.50 m from the muzzle, for any 12/70 or longer cartridge, must be ≤430 m/s
(around 1,400 ft/s). This velocity is to be measured using a cylindrical barreland the mean value of a series of 10 shots.
3.2 For 12/70 cartridges the momentum must be: Mo = mV < 13.5 Ns (see para 2.3 above).
For 12/73 or longer cartridges, the momentum must be: Mo = mV < 15 Ns
(see para 2.3 above)
. See Endnote.
3.3 Where the steel shot diameter exceeds 4 mm (“BB” or larger), only weapons having barrels with a choke less than 0.5 mm (equivalent to halfchoke) are to be used.
There is more to this if you want to read about 20ga and etc;
http://www.chircuprodimpex.ro/produ.../cip-regulations-on-steel-shot-ammunition.pdf