Invector Plus Choke measurements puzzle

[Winyard]

Hi, hoping people can help. I have recently purchased a Browning XS Pro. It comes with Invector Plus Titanium extended chokes. I have never had a shotgun with changeable chokes before. I love the gun, but when i have put in what the internet repeatedly says is a 1/4 and 1/2 choke, a friend uses his choke measure tool which states they are in fact near open and 1/4. When measuring a modified choke, it shows as 1/4 choke. A full choke shows as 3/4. 

Can someone explain what’s going on? When he uses his tool to measure the rest of the gangs chokes they read as the choke says they do.

Thanks in advance

Edited April 17, 2022 by Winyard

[wymberley]

Two points to help make sense of this:

You need to define "choke measuring tool" and also need to measure/check the bore diameters. 

It's still likely that having done that, it'll remain a puzzle as making sense of chokes these days is high on impossible. Mixing terminology doesn't help.

Just noticed - welcome to PW. 

 

Edited April 17, 2022 by wymberley

[Winyard]

Thanks for the Welcome ). The tool looks like a staggered tube. Inserted into the choke it stops at one of the widths. It reads accurate for all my other gun chokes (fixed) and their changeable chokes. But my XS Pro is seems to show the chokes are 1/4 less than marked for every one in the box.

 

Having said that, i shot the best score ever today…. So not going to change them. Just wondered if anyone else had seen this or if the Invector Plus chokes widen at the end a little but a few MM in they are narrower.

 

Edited April 17, 2022 by Winyard

[bigroomboy]

30 minutes ago, wymberley said:

Two points to help make sense of this:

You need to define "choke measuring tool" and also need to measure/check the bore diameters. 

It's still likely that having done that, it'll remain a puzzle as making sense of chokes these days is high on impossible. Mixing terminology doesn't help.

Just noticed - welcome to PW. 

 

As stated above. The little plug type choke guages are near useless anyway. But it's likely your barrells are overbored so the correct constriction will still mean a bigger hole which thelay type of gauge can't account for. 0.4 mm us likely the inv plus oberbore which is 15 thou so would throw measurement way off.

[Wylye]

The degree of choke is relative to the diameter of the barrel. The only accurate way to measure it is to use an internal bore gauge, most proper gun shops have them. Plug-in chokes are all but useless.

[Centrepin]

Those brass drop in things measure every choke differant. 

All my invector plus and my sons invectors measure a couple or 3 sizes out like yours suggested. 

My KOFs is one size out and my SBS 2 sizes out.

Best bet is ask your RFD, mine has a more reliable type but even then it's best guess.

Just fit what you think you're going to be happy with and with the exception of cleaning and greasing the threads periodically forget them.

 

[Winyard]

Ok, every day’s a school day. So in essence the choke is in relation to the bore, rather than a fixed size. Explains a few things. Also makes the chokes i have a little more useful. Thank you all for the learning experience

[wymberley]

20 minutes ago, Winyard said:

Ok, every day’s a school day. So in essence the choke is in relation to the bore, rather than a fixed size. Explains a few things. Also makes the chokes i have a little more useful. Thank you all for the learning experience

If you're just starting off and on the grounds that you're going to be in this situation again - and again - a good investment is a telescopic bore gauge or two - one long reach for the bore and a normal one for the choke area (although here you could use a vernier but they cost more. However, although you can get the normal ones individually, you may have trouble getting just the one long reach and may have to buy a set. To read them you'll also need either a micrometer or a vernier - I prefer the former as they give better control. Whichever, there's plenty to be found cheaply. Although this won't match a competent RFD with his purpose built gauge for accuracy, with practice one can be sufficiently precise for all intents and purposes.

[Gordon R]

Irrespective of choke measurements, you bought a decent gun. Hello and welcome.

[vmaxphil]

The whole point of a multichoke gun is you can tune to your desired pattern at your desired distance with your cartridge of choice what size is written on it is immaterial, so go and pattern the gun at different distances and make a note of the chokes to use, or do as most do stick 1/4 and 1/2 in and concentrate on your shooting 👍

[Centrepin]

1 hour ago, vmaxphil said:

 or do as most do stick 1/4 and 1/2 in and concentrate on your shooting 👍

Nail and head comes to mind🙂

[Scully]

2 hours ago, vmaxphil said:

…….do as most do stick 1/4 and 1/2 in and concentrate on your shooting 👍

This. If it was fixed at 1/4 and 1/2 you’d just be doing this anyhow. 

[Fellside]

Hi Winyard,

This is a common cock up. As mentioned above Invector Plus barrels are ‘backbored’ i.e larger diameter than usual. Your choke gauge measures relative to a nominal (approx’ 729 thou) 12 bore. However with your ‘Invector Plus’ barrels being about  738 thou - you are whole choke nomination out. 

I would forget the choke gauge.  It won’t take long to find the Invector Plus choke measurements on line. The 1/4 is 8 thou. Can’t remember the 1/2. If you’re getting decent scores though, you may have found your favourite combo anyway……?!
Nice gun BTW. 
 

 

[Lloyd90]

One of those cheap £5 choke gauges works lovely and matches up with my Beretta Mobil chokes no proble, but on my Maxus with Inv+ chokes is miles off. 

Wouldn't worry about it. 

[wymberley]

If you have such a gauge which has a hole for a split ring, then they make a fine beach casting weight and being the only thing that they excel at. 

[Fellside]

3 minutes ago, Lloyd90 said:

One of those cheap £5 choke gauges works lovely and matches up with my Beretta Mobil chokes no proble, but on my Maxus with Inv+ chokes is miles off. 

Wouldn't worry about it. 

The old mobilchoke are close to the presumed nominal per choke gauge. 

To be honest there are so many different bore measurements and choke variations - the choke gauges are often more trouble than they’re worth. Only a micrometer is of any real worth if curiosity gets the better.

There’s nothing quite so effective however as putting the pattern in the right place. 

3 minutes ago, wymberley said:

If you have such a gauge which has a hole for a split ring, then they make a fine beach casting weight and being the only thing that they excel at. 

Ha ha ha…..excellent..🤣

[JohnfromUK]

15 minutes ago, Fellside said:

To be honest there are so many different bore measurements and choke variations - the choke gauges are often more trouble than they’re worth. Only a micrometer is of any real worth if curiosity gets the better.

Correct, but a proper bore micrometer (such as a Chubb Multi Gauge - see this thread) is expensive - and only gives an approximation to the actual 'achieved pattern'

 The achieved pattern (i.e. the percentage of pellets inside a 30 inch circle drawn around the centre of a pattern taken at 40 yards) is what is really meant by choke.  It will depend not just on any measurable feature of the barrel, but also the cartridge, wadding type etc.  Different cartridges can give a very significant difference in pattern density.

[Fellside]

You raise a valid point Johnny - I think most of us pattern geeks are on board with this. The OP was however trying to measure his choke tubes relative to bore.

To be honest, for most popular mass produced O&Us the info is available on the net anyway. 

I still think the best use for a brass choke gauge has been developed by wymberley above. Have a look. 

[wymberley]

For a one off purchase, the tools described above will cost way less than a slab of cheap clay cartridges. The one big advantage is that they can tell you what the internet can't and the seller may not want to especially when buying used guns. I'm sure I don't need to explain.

Anyone desperate for a gauge, 2 or 3 can probably be found directly offshore from the Geo Needle on the cliff top at Orcombe Point.

[Winyard]

Thanks all. Your measured and knowledgeable replies give me hope that not all forums are bad! I shot my best score ever with the gun at the weekend. So i think i will be sticking with the chokes as they are for sure. I can always experiment with others at a later date. Just having a gun that fits and feels responsive is a real delight as well and so far the XS Pro has been a very good purchase. I have always wanted a Beretta but they just don’t fit me, the Browning just feels a little bit chunkier and fits me better.

[Fellside]

Well done that man 👍

It sounds like you’ve found a hitter. 

[wymberley]

On 18/04/2022 at 13:09, wymberley said:

If you have such a gauge which has a hole for a split ring, then they make a fine beach casting weight and being the only thing that they excel at. 

All new bathroom just (almost) finished.

Tad different: Another use possibly.

Prototype                                                                                    

Edited April 23, 2022 by wymberley

[wymberley]

On 22/04/2022 at 18:58, wymberley said:

All new bathroom just (almost) finished.

Tad different: Another use possibly.

Prototype                                                                                    

Mk1

Edited April 24, 2022 by wymberley