Steel shot and half choke

[cromwell7]

I'm looking at using my browning 525 with steel shot.

I've read that the maximum shot size to be used with half choke is 1's which according to some charts I've found is 4.06mm in steel.

I have also read that the max size to use with steel is 4.0mm, will the .06 make a massive difference and cause damage?

The cartridges I have are rc atomic line 36 gram 1's.

[herby]

No

[figgy]

Dont worry after a while the gun will no longer be 1/2 choke the hardness of the steel shot will eventually stretch the choked part of the barrel same as it does to multi chokes it would not stop me using it.

[Kraai]

Rc nr1 is 3.7mm

[cromwell7]

Cheers guys 👍

I've read a few articles over the last year or so about the wrong shot size/cartridge length and or shot material being used and ruining guns.

[figgy]

Cromwell a fair few after market choke makers now state that over a period of time the choke will stretch and if it becomes tight in the gun to throw it away and replace as they are now classed as a consumable part. Carlson extended tubes have a lifetime warranty as the main constriction of the choke is in the extended part of the choke outside the barrel,unless you measured it you would never know it had stretched.

 

Stick to smaller shot sizes and loads in your fixed choke and it should be fine fore years. The price of used multichoked steel shot proofed semi autos is so cheap that its not worth ruining a decent gun. Used Hatsans for less than a thousand game carts.

[neutron619]

The funny thing about the whole topic is that people seem to be intentionally blind to figgy's point.

 

If a car (made of steel) on the motorway veers out of lane and strikes the crash barrier (made of steel) a glancing blow - at a one-degree angle, say - no-one would question that both the barrier and the car will be damaged by the impact. They'd have the police out to clear up the mess and workmen to fix the barrier ASAP, with a 50mph limit on the road until it was done.

 

Scale it down and talk a gun barrel and a smaller piece of metal doing the striking however, and people claim that the potential for damage is merely imaginary in the minds of some worrisome people who should just get out and shoot more.

 

The situation is far more subtle. Even firing lead shot through a choked tube will deform it - just very, very, very slowly.

 

Any angled collision will deposit energy into the objects involved since the direction of at least one of the objects will be changed which involves an energy transfer. If either of the objects are immovable, the energy will be lost through deformation of the immovable object. The degree to which this happens is reduced in proportion to the stiffness of the substance.

 

Theoretically this means steel should deform chokes less than lead (the process of bouncing will be more efficient and less energy absorbed by the barrel wall). However, because the collision occurs in a contained space, the "bounce" simply forces the pellet into another pellet and so on, the net effect of all those collisions being greater pressure on the walls of the choke tube - the only component remaining which can absorb the energy - and so the likelihood of choke deformation is increased.

 

Fundamentally, there's nothing wrong with this - rifle shooters consider barrels to be consumables and there's no reason some wildfowlers couldn't do the same with their (absurdly) tight choke tubes. The trouble is, many of them don't want to accept that subtlety.

 

As it stands, the CIP / SAAMI recommendations are based upon the above. All chokes and barrels will expand with the use of any kind of shot. The rate at which they expand entirely down to the fluidity of the shot column and the angle and velocity of impact of the shot on the walls of the choke tube. It just so happens that lead shot causes this process to occur particularly slowly and steel and other harder shot tends to cause it to occur rather faster.

[motty]

Remember, Neutron, with steel, the pellets should not come into contact with the barrels.

I think the guidance I have read is, no bigger than 4mm steel through full choke.

[cromwell7]

Forgot to mention figgy my 525 is multi choke.

It's interesting to hear your theory neutron,

I wonder if you approached a Manufacturer of chokes/guns with a bulged barrel and explained you followed the guidelines, would they come out

With a similar explanation.

[oldypigeonpopper]

h

 

Forgot to mention figgy my 525 is multi choke.
It's interesting to hear your theory neutron,
I wonder if you approached a Manufacturer of chokes/guns with a bulged barrel and explained you followed the guidelines, would they come out
With a similar explanation.

hello, i presume you mean a browning 525 ? i have one but would never use steel shot, i think figgys suggestion on post 6 is well worth noting. cheers

[BrowningB525]

Forgot to mention figgy my 525 is multi choke.

It's interesting to hear your theory neutron,

I wonder if you approached a Manufacturer of chokes/guns with a bulged barrel and explained you followed the guidelines, would they come out

With a similar explanation.

 

I shoot no 1 and no3 steel through my B525. The standard invector plus chokes say what is and isn't suitable for steel.

[neutron619]

Remember, Neutron, with steel, the pellets should not come into contact with the barrels.

I think the guidance I have read is, no bigger than 4mm steel through full choke.

 

Indeed, though this is true 99%+ of the time, if you take my meaning.

 

It's also still worth remembering that when they're held together by the wad, they're essentially acting as one slightly squashy "slug" which will in fact have a tendency to increase damage - if they're "free-flying", they're more able to deflect off the barrel wall (through the wad) and deliver the energy elsewhere, whereas packed together they will tend to act rather like a Newton's Cradle, where the first pellet in the chain impacts and the last pellet is "bounced". Obviously this is happening in all directions for all the pellets at the same time, which makes the situation rather more complicated!

 

It's interesting to hear your theory neutron,

I wonder if you approached a Manufacturer of chokes/guns with a bulged barrel and explained you followed the guidelines, would they come out

With a similar explanation.

 

Forgive me for sounding arrogant, but it's not a theory - it's clearly shown by physics and mathematics.

 

If there is a choke in the barrel, it means that the choke surface is at a non-zero angle relative to the barrel axis. The tighter the choke, the bigger the angle.

 

If the pellets travel along the axis of the barrel then when they meet the choke, they will exert a force upon it equal to the total force of impact multiplied by the sine of the angle of incidence. The tighter the choke, the bigger the sine of the angle and the higher the impact energy / force.

 

If an impact occurs - whether it's pellet behind wad or pellet alone - there will be an energy transfer of some kind. (Fundamentally, this is what makes choke work.)

 

The result of that energy transfer will be either to deflect or deform the pellet or the barrel with the loss of heat as an inefficiency.

 

The materials of which the pellet and barrel are made determine whether the pellets and barrel are more likely to be deformed or deflected - it's a question of the properties of the material, namely it's rigidity / elasticity. The quantity of heat lost in the action will also determine how much energy is "left" to effect this deflection / deformation.

 

Softer pellets and harder barrels will make pellet deformation more likely. I imagine there is also a greater loss of heat. This is the case with lead shot.

 

Hard pellets and hard barrels are more difficult to call, but heat loss is likely to be lower and the deformation of pellet / barrel much more closely matched.

 

Two thoughts to leave you with:

 

One - if pellets were formed from barrel steel, we'd see guns ruined in a few shots. The fact that "steel shot" is actually more brittle soft iron prevents this.

 

Two - imagine the reverse position, of shooting steel pellets through lead barrels. Again, we'd see guns ruined in a few shots.

 

In both of the common scenarios, lead through steel and soft iron through steel, the rate of deformation is accepted to be slow enough that the gun's life is not severely endangered. It doesn't mean that deformation isn't occurring - only that it's slow enough not to seriously affect performance or leave the manufacturers liable for guns damaged by something other than ordinary wear and tear.

 

The guidelines are issued to protect against the extreme scenarios - fine English guns with paper thin, soft steel barrel walls, firing massive, soft iron shot through tight chokes. Here, the size of pellet makes the relative hardness of the pellets within the wad high enough (i.e. they are not very squishy) that the relative hardnesses of the barrel and pellet make it more likely that a barrel deformation will occur.

 

I don't know if the manufacturers would issue the same explanation, but this is the science behind the guidelines, or as near as damnit.

Edited November 13, 2016 by neutron619

[Old farrier]

 

Indeed, though this is true 99%+ of the time, if you take my meaning.

 

It's also still worth remembering that when they're held together by the wad, they're essentially acting as one slightly squashy "slug" which will in fact have a tendency to increase damage - if they're "free-flying", they're more able to deflect off the barrel wall (through the wad) and deliver the energy elsewhere, whereas packed together they will tend to act rather like a Newton's Cradle, where the first pellet in the chain impacts and the last pellet is "bounced". Obviously this is happening in all directions for all the pellets at the same time, which makes the situation rather more complicated!

 

 

Forgive me for sounding arrogant, but it's not a theory - it's clearly shown by physics and mathematics.

 

If there is a choke in the barrel, it means that the choke surface is at a non-zero angle relative to the barrel axis. The tighter the choke, the bigger the angle.

 

If the pellets travel along the axis of the barrel then when they meet the choke, they will exert a force upon it equal to the total force of impact multiplied by the sine of the angle of incidence. The tighter the choke, the bigger the sine of the angle and the higher the impact energy / force.

 

If an impact occurs - whether it's pellet behind wad or pellet alone - there will be an energy transfer of some kind. (Fundamentally, this is what makes choke work.)

 

The result of that energy transfer will be either to deflect or deform the pellet or the barrel with the loss of heat as an inefficiency.

 

The materials of which the pellet and barrel are made determine whether the pellets and barrel are more likely to be deformed or deflected - it's a question of the properties of the material, namely it's rigidity / elasticity. The quantity of heat lost in the action will also determine how much energy is "left" to effect this deflection / deformation.

 

Softer pellets and harder barrels will make pellet deformation more likely. I imagine there is also a greater loss of heat. This is the case with lead shot.

 

Hard pellets and hard barrels are more difficult to call, but heat loss is likely to be lower and the deformation of pellet / barrel much more closely matched.

 

Two thoughts to leave you with:

 

One - if pellets were formed from barrel steel, we'd see guns ruined in a few shots. The fact that "steel shot" is actually more brittle soft iron prevents this.

 

Two - imagine the reverse position, of shooting steel pellets through lead barrels. Again, we'd see guns ruined in a few shots.

 

In both of the common scenarios, lead through steel and soft iron through steel, the rate of deformation is accepted to be slow enough that the gun's life is not severely endangered. It doesn't mean that deformation isn't occurring - only that it's slow enough not to seriously affect performance or leave the manufacturers liable for guns damaged by something other than ordinary wear and tear.

 

The guidelines are issued to protect against the extreme scenarios - fine English guns with paper thin, soft steel barrel walls, firing massive, soft iron shot through tight chokes. Here, the size of pellet makes the relative hardness of the pellets within the wad high enough (i.e. they are not very squishy) that the relative hardnesses of the barrel and pellet make it more likely that a barrel deformation will occur.

 

I don't know if the manufacturers would issue the same explanation, but this is the science behind the guidelines, or as near as damnit.

 

Appreciate the science

 

What do you recommend we should shoot the steel through

Or should we use something totally different

 

All the best

Of

[motty]

Not sure I follow all of that, Neutron. I'm fairly certain that I read that hevishot is made from a material harder than barrel steel.

[neutron619]

What do you recommend we should shoot the steel through

Or should we use something totally different

 

Well I think we carry on doing what we're doing and appreciate that if we shoot - for example - high performance BBB steel through full chokes in a thin walled SxS - that our gun isn't going to last as long undamaged as it might if we'd used soft lead #6.

 

I'm not arguing that people shouldn't decide to use HP steel cartridges in "ordinary" guns or that they kill themselves doing it or anything like that. I'm simply saying that they should expect that the gun will wear out faster if they do.

 

I suspect that the guidance from CIP which is pushed by BASC and others is not based on the horror stories of scored or properly blown up barrels, but rather something more boring like an expected time before the gun is rendered out of proof. I'd be interested to know what the criteria were, though we're probably looking back to secret meetings 30+ years to find out.

 

My guess is that someone with a laser micrometer probably put 10,000 cartridges through a test gun or three and measured the expansion at the choke caused by using steel shot. They probably then looked up what the proof house says about bore diameter variation and how much is allowed before the gun is out of proof and divided one measurement by the other to find the number of rounds required to achieve that. My guess is that they found the expansion was an order of magnitude or two greater than that caused by lead in the worst cases, hence the constant warnings on (particularly) HP steel cartridge boxes about not using them in XYZ guns.

 

To return to a real world example, take the Browning A5 and the 100,000 round guarantee they offer with it. Now, is that the mean time before mechanical failure, or is that the number of lead cartridges to put it out of proof? I suspect the former, by some margin. I imagine that because lead is far softer than steel, the number of cartridges one has to fire through a full choke to expand it noticeably is probably more than most people fire in a lifetime. It wouldn't surprise me if it were millions or tens of millions or more. In the case of steel, I'd expect that number to be maybe tens to hundreds of thousands for light chokes and small shot, and probably hundreds to thousands for the "terror" choke brigade with their buckshot-sized steel pellets and 0.060" constrictions.

 

The measurement most relevant here is the Young's modulus, which is an approximate guide to a material's deform-ability / elasticity. For lead, it's about 15GPa and for soft iron, about 210GPa. It's not an exact measurement of hardness (though the Mohs scale is much less scientific and not at all quantitative), but it's a pretty good guide. You could reasonably argue however, that soft iron is about 14 times harder (or at least, 14 times harder to permanently deform) than lead. The number that makes all of this much more interesting still is that even high strength steel - the kind used in barrels, for example - has a Young's modulus of about 200 - it's actually less robust than the shot being fired through it, which explains the need for a completely enclosing wad and the stories of early cartridges creating score marks in the choke area.

 

Again, I emphasize - I'm not saying that the damage is something that Joe Bloggs is going to notice. The number of steel shells I fire in the average year is probably in double figures - I could put them through full choke and be fine, I'm sure. The trouble is, there are folk who will regularly shoot a lot of extremely fast shells, filled with very large shot, through chokes that are 50% tighter than a traditional full choke, if not more. These are the ones who are going to end up with expanded muzzles and potentially, problems.

 

Final thought. Wildfowlers like extended chokes, which saves some of the trouble. I can't change the fact that shot (or wad and shot) are going to impact on the choke area, but I can make the way that happens better for my gun. If I have a 2" choke with a 0.010" constriction and can safely put XYZ cartridge through it, then an 8" choke with a 0.040" constriction should also be fine for that cartridge because the angle of incidence relative to the barrel axis is identical - the latter choke just goes on a lot longer. That means a 12" choke for our 0.060" wildfowling choke ought also to be well within acceptable limits. The trouble though, is that people don't cut 12" chokes in normal guns - they cut a 0.060" constriction in a tube 2" long, which means that rather than the force of impact being the sine of angle X, it's actually the sine of angle 6X - i.e. it hits the choke 6 times harder.

[motty]

Neutron, give your brain a rest. I think you are looking into this FAR too deeply.

[Old farrier]

Far too deep

My take on it ........ for what it's worth 😊

Internal choke tube follow the manufacturer reccomendations

 

Fixed choke in a older gun

Any stretch caused by a big load in a tight could stretch the choke possibly causing a bulge the barrel

 

External aftermarket choke tubes are designed to stretch and return to the starting size they are a consumable product

More suited to heavy loads of big shot

 

The wads developed for steel shot are far above what is nessecary to protect the barrel

 

With this in mind crack on use whatever you are happy with and enjoy it 😊

 

All the best

Of

Just my thoughts 😊

[6.5x55SE]

Motty and OF 👍

Also I'd like to add Science and mathematical stuff claims Steel 4'shot won't kill Duck past 23.000001763 yrd and just bounce of Geese😂

And reading through all the Technical stuff my 🤕

[neutron619]

Also I'd like to add Science and mathematical stuff claims Steel 4'shot won't kill Duck past 23.000001763 yrd and just bounce of Geese

 

Ok - where?

[6.5x55SE]

Ok - where?

Have a good look and read in the reloading section on DHC forum 👍

[neutron619]

Have a good look and read in the reloading section on DHC forum

 

DHC? I'm assuming Duck Hunting Chat forum?

 

If so, I'm afraid I'm not a member of that forum and cannot therefore take responsibility for anything stupid or idiotic the denizens of that part of the internet may or may not have said.

 

However, the fact that - I assume - various members of an American hunting forum fail to correctly employ or deliberately mis-use scientific analysis in arguing their points as to the merits / failures of steel shot, does not in itself render all mathematical / scientific analysis a) wrong or b) worthless.

 

I'm just saying.

[wymberley]

Far too deep

My take on it ........ for what it's worth

Internal choke tube follow the manufacturer reccomendations

 

Fixed choke in a older gun

Any stretch caused by a big load in a tight could stretch the choke possibly causing a bulge the barrel

 

External aftermarket choke tubes are designed to stretch and return to the starting size they are a consumable product

More suited to heavy loads of big shot

 

The wads developed for steel shot are far above what is nessecary to protect the barrel

 

With this in mind crack on use whatever you are happy with and enjoy it

 

All the best

Of

Just my thoughts

There is no difference between the second and third paragraphs. The conditions which caused a fixed choke barrel to bulge, if repeated in a removable choke as detailed will have the same effect. This is simply because the elastic limit of the barrel or choke material has been exceeded.

[Old farrier]

There is no difference between the second and third paragraphs. The conditions which caused a fixed choke barrel to bulge, if repeated in a removable choke as detailed will have the same effect. This is simply because the elastic limit of the barrel or choke material has been exceeded.

The difference y on one it's inside your barrel and could wreck your gun

The other choke is outside your gun you may wreck the choke but a better chance of the gun still being ok

So there is a difference 😊

 

All the best

Of

[neutron619]

External aftermarket choke tubes are designed to stretch and return to the starting size they are a consumable product

More suited to heavy loads of big shot

 

Don't worry - I'm not going to get started on this one, but I have to ask:

 

If they stretch, what's the point?

 

I mean - 0.035"-0.060" constriction chokes for steel are what they are and people will use them or they won't - but if they're only (say) 0.020" constriction when the shot is going through them, what's the point? Why not just use a plain old half choke?

[wymberley]

The difference y on one it's inside your barrel and could wreck your gun

The other choke is outside your gun you may wreck the choke but a better chance of the gun still being ok

So there is a difference

 

All the best

Of

Naturally, that is perfectly correct. As you didn't mention it in the context of your post, so, neither did I.

 

What I can't take on board, is whereas the science is somewhat complicated, Neutron's posts make it relatively easy to understand such that we can all benefit from his knowledge and particularly as he repeats several times that assuming nothing silly is done by the shooter, then the effects are not critical and only adverse in the long term usage. I can relate to this by cross referring to the fatigue life of aircraft.