effect on choke of back boring barrels

[jwpzx9r]

Ok just a question about something that came to my mind.

How does back boring shotgun barrel effect chokes used in them? For example if I take my XTR and fit a choke that gives a full choke with a barrel bored at 18.4mm and fit it to my XTR which is bored at 18.7mm does this effectively increase the choking effect and make it extra full? Or on a fixed choke gun if it is bored form 18.4 to say 18.7 without adjusting the choking at the end of the barrel will this effectively tighten the choke? Or can you only really see what is happening at the pattern plate?

I have Müllers in my browning but the constriction of the choke is not actually given just the number and approximate equivalent that is what got me thinking.

Anybody dare to enter the twilight world of back boring and choking and give me their take??

 

[ips]

Or for some lighter debate what about a discussion on poi / poa

John your a trouble maker

 

[EdSolomons]

Just pop a couple of chokes in, shoot and don't worry!

 

[Skeet UK]

Ok just a question about something that came to my mind.

How does back boring shotgun barrel effect chokes used in them? For example if I take my XTR and fit a choke that gives a full choke with a barrel bored at 18.4mm and fit it to my XTR which is bored at 18.7mm does this effectively increase the choking effect and make it extra full? Or on a fixed choke gun if it is bored form 18.4 to say 18.7 without adjusting the choking at the end of the barrel will this effectively tighten the choke? Or can you only really see what is happening at the pattern plate?

I have Müllers in my browning but the constriction of the choke is not actually given just the number and approximate equivalent that is what got me thinking.

Anybody dare to enter the twilight world of back boring and choking and give me their take??

While Choke is relative to the bore, your example with XTR.  In order for the same choke tube to fit in either gun, then the dimensions need to be the same, for the choke to fit (at the end of the barrels). So you would have a wider bore at some point before the choke, then the dimensions would reduce to be the same (CYL) then go into the choke.

But it really don't matter much

Back boring, is just a more open bore than "standard gauge".  So less friction, less deformed pellets, greater velocity.

I doubt that a choke designed for an 18.4 bore, would fit the 18.7 would it?  You would have quite a step inside the barrel, if you get my drift

 

[jwpzx9r]

Ian the thing that got me thinking was that Full choke is nearly always given as 0.040" now putting aside interchangeable chokes if you had a fixed choke gun and had it back bored and left the chokes the same would you have in effect increased the choke on your gun... not tying to cause a  rammy honest guv!

Skeet again not wanting to cause a rumble but I don't think that is absolutely the case. I have read that back boring is meant to have all sorts of wonderful effects on recoil and choke effect/patterning. Or is it really just marketing hype?

 

[jwpzx9r]

Just pop a couple of chokes in, shoot and don't worry!

Don't use the Browning now all that adjustability was doing me nut in Ed. Just use the MX8 now fixed everything and when I shoot the right bit of sky the target just disappears, when I don't I blame myself not the chokes or the height of the comb

 

[ips]

I have no idea John. I don't concern myself with the mystery that is multi choke. Sometimes i cant even decide what socks to wear never mind what choke thing to bung in the end

 

[Will Hewland]

It is your absolute right to get into the whole choke science. However, having done it all when I first started out, I have now reduced my ballistic evaluation to firing my fixed 1/2 choke gun at some cardboard to ensure that the pattern is reasonably sensible. (Not too tight, not too expanded and not too uneven). A pretty quick tick in the box exercise to placate any worries, then just get out there and stick the barrels in the right place as often as possible. My only other requirements are that the recoil is medium and that the barrels aren't left looking like an unswept chimney.

 

[Hamster]

Ok just a question about something that came to my mind.

How does back boring shotgun barrel effect chokes used in them? For example if I take my XTR and fit a choke that gives a full choke with a barrel bored at 18.4mm and fit it to my XTR which is bored at 18.7mm does this effectively increase the choking effect and make it extra full? Or on a fixed choke gun if it is bored form 18.4 to say 18.7 without adjusting the choking at the end of the barrel will this effectively tighten the choke? Or can you only really see what is happening at the pattern plate?

I have Müllers in my browning but the constriction of the choke is not actually given just the number and approximate equivalent that is what got me thinking.

Anybody dare to enter the twilight world of back boring and choking and give me their take??

Choke is an academic set of numbers at the breech/muzzle end but an actual one only when measured at a set distance from the muzzle by counting pellet strikes within a 30" circle to assess the percentage, in other words it is a performance and not gospel metal dimensions.

A full choke in measurement may well throw a 3/4 on paper and vice versa, either way what matters is whether you happen to get on with it.

 

[Hamster]

Skeet again not wanting to cause a rumble but I don't think that is absolutely the case. I have read that back boring is meant to have all sorts of wonderful effects on recoil and choke effect/patterning. Or is it really just marketing hype?

Back boring and over boring etc, are essentially marketing tools because their affects are not measurable before and after since you can only buy them one way or the other   and when people have modified existing barrels the results have been random and in blind tests the recoil thing has been disproved which is as it should be because removing metal will lower the weight of the gun and if anything recoil should rise.

 

[jwpzx9r]

Hammy since getting the MX8 I don't normally think about choke anymore because they are fixed and when on target the targets are hammered. My question was more a question of the enquiring mind since manufactures make many claims for the benefits acquired by back boring shotgun barrels.

 

[Wonko the Sane]

Back boring and over boring etc, are essentially marketing tools because their affects are not measurable before and after since you can only buy them one way or the other   and when people have modified existing barrels the results have been random and in blind tests the recoil thing has been disproved which is as it should be because removing metal will lower the weight of the gun and if anything recoil should rise.

Absolutely!

AND - John if you ever so much as touch those Perazzi barrels you'd best not mention it.  If you do, I swear that I'll personally see to it that you are properly beaten.  I know I've said this before but you insist on bringing up topics that make me think you need reminding.  You'll notice there are no smiley faces.

Charlie

well, OK, one    reved:

 

[Skeet UK]

Skeet again not wanting to cause a rumble but I don't think that is absolutely the case. I have read that back boring is meant to have all sorts of wonderful effects on recoil and choke effect/patterning. Or is it really just marketing hype?

No rumble needed

Back boring is uniform.

Berettas conical bore, as found on the DT11 and to a lesser extent, the 692 COULD reduce felt recoil, because the bore is that much larger at the breach end.

Same applies to longer forcing cones.  A smoother transition can only ever be good for the pellets...but as Hamster says...by what perceptible amount?

 

[Bryn12]

 

[Les53]

OK I'm a sceptic when it comes to back boring/over boring,or whatever else the marketing blokes call it. I have owned guns that are back/over bored and to be blunt, I noticed sod all advantage at all. I heard the hype about better patterns, less recoil etc, but I didn't notice anything miraculous!!! I did once have a multi choke trap gun, the patterns from each choke tube seemed to throw tighter patterns than I thought was normal for the level of choke in use at the time. I got Nigel Teague to look into it, as it turned out all the tubes were tighter than they should have been, given the barrel diameter. Nigel re worked the tubes and everything was fine!

 

[garry2749]

OK I'm a sceptic when it comes to back boring/over boring,or whatever else the marketing blokes call it. I have owned guns that are back/over bored and to be blunt, I noticed sod all advantage at all. I heard the hype about better patterns, less recoil etc, but I didn't notice anything miraculous!!! I did once have a multi choke trap gun, the patterns from each choke tube seemed to throw tighter patterns than I thought was normal for the level of choke in use at the time. I got Nigel Teague to look into it, as it turned out all the tubes were tighter than they should have been, given the barrel diameter. Nigel re worked the tubes and everything was fine!

Did you get the DT11 looked at ????????????????? :hunter:

 

[Les53]

Did you get the DT11 looked at ????????????????? :hunter:

Nope!!!!! But the stock looks bloody brilliant!!!  :biggrin:

 

[ips]

I may be wrong but i don't think over boring is a new thing i think its been re named back boring by a marketing guru and sold to un suspecting punters as the latest must have,

psst - Mr Wonko will no doubt be along soon he loves all this new fangled stuff. A 32" multichoke adj stock back bored ventilated muzzle teflon coated and wild engraving is just up his street

 

[jwpzx9r]

Ian I don't know what you might call it back boring or re-boring but could it be an old way of changing the constriction of an old fixed choke gun before we went screw in? Say for example you had a gun that had a 1/4 fixed choke and you wanted a 3/4 could you not just ream (Back bore) the barrel 20 thou not touching the choke area of the barrel to get the 30 thou constriction? Or is it not that simple ?