Fixed choke and steel shot, choke size query

[Keith RW]

Apologies if this has already been covered elsewhere but I can't find up to date definitive answers

There's lots of contradictory info on various forums and that has been posted on the internet over last ten years and more as to what the maximum choke size is "safe"/"OK" for steel shot and fixed choke guns along with recommendations and guidelines from cartridge and gun manufactures stating nothing tighter than 1/2 choke should be used and which covers them from a liability point of view.

Presuming that steel shot cartridge manufacturing and the like has progressed over the years along with steel shot having been used by shooters for a considerable number of years also,  are there any members on here who have actually used steel shot consistently over the years through fixed chokes tighter than 1/2 and without any detrimental results in their 70's and 80's fixed choke shotguns.

Two out of three of my older guns are 1/4 and 1/2 so OK for standard steel but looking for clarification on tighter chokes such as 3/4 as I have a 80's Miroku I would like to make use of with steel.

[London Best]

Scully will be along shortly to clarify for you.

[Keith RW]

4 minutes ago, London Best said:

Scully will be along shortly to clarify for you.

Cheers LB, picked up on the odd post on here which gives me more confidence that 3/4 and std steel should be OK,  PW member reindeer from Netherlands posted back in 2020 that he has put thousands of Gamebore 32g No4 through his Miroku 6000 1/4 -3/4 without issue.

[Smudger687]

The CIP regulations only stipulate a maximum of half choke for so-called High Performance steel. 

For standard steel cartridges there are no restrictions on choke.

Physics and metallurgy pay no attention to regulations, however. The only way you'll really know if your gun will tolerate your chosen cartridge is to fire said cartridge down the gun and check for damage. 

Some rough rules of thumb are that larger shot sizes, heavier payloads, higher velocities and tighter chokes all increase the likelihood of causing choke damage.

Ultimately you will either have to decide between grabbing your balls and going for it, or playing it safe and using bismuth.

[6.5x55SE]

47 minutes ago, Keith RW said:

Apologies if this has already been covered elsewhere but I can't find up to date definitive answers

There's lots of contradictory info on various forums and that has been posted on the internet over last ten years and more as to what the maximum choke size is "safe"/"OK" for steel shot and fixed choke guns along with recommendations and guidelines from cartridge and gun manufactures stating nothing tighter than 1/2 choke should be used and which covers them from a liability point of view.

Presuming that steel shot cartridge manufacturing and the like has progressed over the years along with steel shot having been used by shooters for a considerable number of years also,  are there any members on here who have actually used steel shot consistently over the years through fixed chokes tighter than 1/2 and without any detrimental results in their 70's and 80's fixed choke shotguns.

Two out of three of my older guns are 1/4 and 1/2 so OK for standard steel but looking for clarification on tighter chokes such as 3/4 as I have a 80's Miroku I would like to make use of with steel.

I have for years used a Aya 3" Magnum no3 1/4 an 1/2 choke with 3" steel homeload B's 2's along with factory HP Steel as yet no problems a very good friend is a big fan of BBB Steel and puts it through full and extra full choke. My grandson has a Aya Matador 10 with 3/4 and 1/2 choke with factory steel 1's along with homeload B's and 2's again no problems. But having said this the choice is down to each individual. 👍

[neutron619]

As others have said, "it's up to you".

I was talking with the manager of my local shop about ordering a new gun last last week when another gun was dropped off for sale or return. Ten minutes later, one of the staff comes into the gun room to talk to the manager about it. The short of it was that although it was a nice example of an old but nonetheless 3" proofed O/U from a reputable maker, the barrels were obviously bulged in front of the chambers and it was out of proof. They weren't prepared to sell it in that condition. The other customer seemed to be well-known to them and the suspicion was that either he'd been using HP steel cartridges in it (for which it wasn't proofed), or possibly that some 3½" shells had found their way in there.

For those of you about to jump on me with the phrase "but that doesn't prove anything", no, it doesn't, but the point isn't about whether the chap actually ruined his gun with steel or not - it's this:

You (probably) aren't going to get blown up or hurt if you use steel cartridges in guns not designed for them. You might even get away with using over-sized cartridges without splitting your barrel. But if you come into the shop hoping to sell a £2000 gun to get yourself out of a financial hole or cover a heating bill or something like that, you aren't helping your chances if you go against the recommendations.

Guns are not fragile and the way the proof house go on about it sometimes makes it sound like they're made of glass. But in spite of the way some folk here go on about it, they're not made of adamantium or some other magical metal that can never bend, distort or break either. If you fire thousands of HP steel cartridges through poor quality or thin barrels / chokes - proofed or not - you are going to see some movement in the metal. You'd probably be able to detect, appropriate measuring equipment assumed, some moevement in modern, HP proofed guns too and perhaps not after so many cartridges.

Barrel steel will stretch, even if it's really, really hard to make it happen, in the same way that even super-strong carbide drill bits wear down, machine tools wear out, blades dull and so on. Nothing we use as a tool will last forever and guns are no exception. Bigger shot and higher muzzle velocity makes this wear more likely and the question is really not whether, but how long it will take to happen and how much do you care? If you treat your gun as disposable because you got it for £50 then you won't. But if not, you'll be disappointed if it happens whilst it's you and not the next guy who owns it...

I personally follow the HP steel recommendations because I can mostly get the patterns I want with still whilst staying inside them. The only exception is in a Browning semi where the choke labelled "Improved Modified" actually has a 0.020" constriction, which in my book, is an English ½ and therefore qualifies in a roundabout way. I will fire HP steel through that.

Measure your chokes with calipers - see if the constrictions actually are under the 0.5mm maximum - you might be surprised.

[wymberley]

Above and not to mention the associated comment in the Eley wad thread.

[6.5x55SE]

2 hours ago, neutron619 said:

As others have said, "it's up to you".

I was talking with the manager of my local shop about ordering a new gun last last week when another gun was dropped off for sale or return. Ten minutes later, one of the staff comes into the gun room to talk to the manager about it. The short of it was that although it was a nice example of an old but nonetheless 3" proofed O/U from a reputable maker, the barrels were obviously bulged in front of the chambers and it was out of proof. They weren't prepared to sell it in that condition. The other customer seemed to be well-known to them and the suspicion was that either he'd been using HP steel cartridges in it (for which it wasn't proofed), or possibly that some 3½" shells had found their way in there.

For those of you about to jump on me with the phrase "but that doesn't prove anything", no, it doesn't, but the point isn't about whether the chap actually ruined his gun with steel or not - it's this:

You (probably) aren't going to get blown up or hurt if you use steel cartridges in guns not designed for them. You might even get away with using over-sized cartridges without splitting your barrel. But if you come into the shop hoping to sell a £2000 gun to get yourself out of a financial hole or cover a heating bill or something like that, you aren't helping your chances if you go against the recommendations.

Guns are not fragile and the way the proof house go on about it sometimes makes it sound like they're made of glass. But in spite of the way some folk here go on about it, they're not made of adamantium or some other magical metal that can never bend, distort or break either. If you fire thousands of HP steel cartridges through poor quality or thin barrels / chokes - proofed or not - you are going to see some movement in the metal. You'd probably be able to detect, appropriate measuring equipment assumed, some moevement in modern, HP proofed guns too and perhaps not after so many cartridges.

Barrel steel will stretch, even if it's really, really hard to make it happen, in the same way that even super-strong carbide drill bits wear down, machine tools wear out, blades dull and so on. Nothing we use as a tool will last forever and guns are no exception. Bigger shot and higher muzzle velocity makes this wear more likely and the question is really not whether, but how long it will take to happen and how much do you care? If you treat your gun as disposable because you got it for £50 then you won't. But if not, you'll be disappointed if it happens whilst it's you and not the next guy who owns it...

I personally follow the HP steel recommendations because I can mostly get the patterns I want with still whilst staying inside them. The only exception is in a Browning semi where the choke labelled "Improved Modified" actually has a 0.020" constriction, which in my book, is an English ½ and therefore qualifies in a roundabout way. I will fire HP steel through that.

Measure your chokes with calipers - see if the constrictions actually are under the 0.5mm maximum - you might be surprised.

🙄🥱🥱

[Keith RW]

2 hours ago, neutron619 said:

Measure your chokes with calipers - see if the constrictions actually are under the 0.5mm maximum - you might be surprised.

Just spent the afternoon measuring the business end of 3 x 12g guns with digital calipers and comparing readings against bore dimensions stamped on their barrels for a rough estimate of constrictions and for comparison to the choke markings on the guns.

Browning and Baikal measure as expected

The Miroku, marked as being 3/4 choke in top barrel is only .023" down on the .729" barrel with a measurement of .706" putting it closer to  being a 1/2 choke (.020" restriction) than the indicated 3/4 choke (.030" restriction) on that barrel.

Bottom barrel (stamped as being 1/4 choke) shows .014" constriction from .729" bore and which falls between 1/4 (.010" restriction) and 1/2 (.020 restriction)

Wondering now if this is a "Miroku" thing with chokes being slightly differently sized to that indicated

Edited November 23, 2022 by Keith RW

[neutron619]

4 hours ago, 6.5x55SE said:

🙄🥱🥱

I'm enormously gratified that, whenever I take the time to give an opinion here, you're always on hand to ridicule.

It makes me wonder what's missing from your life that I'm a source of entertainment given that, as you seem to imply, I'm so dull a person.

I mean, I just disappeared for a year or so and then came back - how on earth did you manage without me? It must have been very hard for you - I'm sorry. If I'd have known I meant so much to you I'd have sent a card or something.

I'll promise to post more words, more often in response, although, I should warn you that, given our long and tight-knit history of me posting and you taking the pi$$, I may have to propose marriage, purely on the basis that you seem to pay more attention to me talking about shooting than, say, my wife.

Love you, sweetums.

[Ultrastu]

That's brilliant. 😁

[6.5x55SE]

42 minutes ago, neutron619 said:

I'm enormously gratified that, whenever I take the time to give an opinion here, you're always on hand to ridicule.

It makes me wonder what's missing from your life that I'm a source of entertainment given that, as you seem to imply, I'm so dull a person.

I mean, I just disappeared for a year or so and then came back - how on earth did you manage without me? It must have been very hard for you - I'm sorry. If I'd have known I meant so much to you I'd have sent a card or something.

I'll promise to post more words, more often in response, although, I should warn you that, given our long and tight-knit history of me posting and you taking the pi$$, I may have to propose marriage, purely on the basis that you seem to pay more attention to me talking about shooting than, say, my wife.

Love you, sweetums.

Predictable drivel as always. 👍 

[Keith RW]

Just reading a 2016 Gun Mart review on the MK38 Trap where author states :-

"that Miroku are one of the very few firms that individually regulate each gun in time honoured fashion at the plates"

and which might explain things with regards to why this Miroku's choke restrictions do not follow the set and specific .010" choke increments.

If they sort each barrel choke to pattern correctly at manufacture then bobs your uncle, job done

 

[wymberley]

38 minutes ago, Keith RW said:

Just reading a 2016 Gun Mart review on the MK38 Trap where author states :-

"that Miroku are one of the very few firms that individually regulate each gun in time honoured fashion at the plates"

and which might explain things with regards to why this Miroku's choke restrictions do not follow the set and specific .010" choke increments.

If they sort each barrel choke to pattern correctly at manufacture then bobs your uncle, job done

 

I doubt very much whether that is actually the case. Each 'model' I could believe. Different countries and even different makers have differing ideas on what measurement constitutes any individual degree of choke.