Perazzi Back Boring

[TheColliniteKid]

Back boring or otherwise Newton's Laws of Motion don't suddenly stop applying. It's a struggle to reconcile how back boring reduces recoil - or rather if it does it directly implies that back boring is causing less energy to be imparted on the shot load.

Also given that the shot pattern from a shotgun is a probability distribution with numerous random processes affecting it whenever one sees any form of pattern testing where the sample size is low they have to be discounted as not significant. I could flip a coin ten times and get heads ten times, that doesn't mean that I'll always get heads. Same with shotgun patterns - sample sizes need to statistically significant. Run a few thousand tests of lengthened cones vs standard and then lets see if there's a difference, and if there is a difference is it statistically significant.

 

[Westward]

Back boring or otherwise Newton's Laws of Motion don't suddenly stop applying.

Quite. But what back boring is alleged to do, when shown graphically, is to increase the timebase of the recoil pulse and lower the peak amplitude thereby turning the thwack of the recoil into more of a push. Newton tells us that the area under the graph must remain the same of course because the free recoil energy cannot change, but it's supposed to feel better at the shoulder.

"Supposed" being the operative word here.

 

[CharlesP]

"But what back boring is alleged to do, when shown graphically, is to increase the timebase of the recoil pulse and lower the peak amplitude thereby turning the thwack of the recoil into more of a push"

How exactly?

 

[Wonko the Sane]

What Total BS!!

Mutilating the gun will accomplish absolutely nothing other than removing some $ from your account, devaluing the gun, and voiding any and all warranties. 

Everything about bigger bore is based on Hogwarts Physics.  Especially like the crap posted above.

But it is your gun and anyone is  certainly free to believe any BS that they might care to.

 

[CharlesP]

"Hogwarts Physics"

Love it

 

[Westward]

"But what back boring is alleged to do, when shown graphically, is to increase the timebase of the recoil pulse and lower the peak amplitude thereby turning the thwack of the recoil into more of a push"

How exactly?

I'm only passing on other people's theories here and I'm not supporting the idea but apparently it's exactly what happens with something like a gel or microcell pad...

 

[Wonko the Sane]

Not even remotely the same thing

 

[Geordieboy]

I may consider lengthening and polishing the forcing cones by Teague.  I trust their expertise.    But only if somebody has done this before and can verify the results.

If not.......my MX12 will remain in its current guise.  The shells I use are smooth and I don't get knocked about.   

 

[Wonko the Sane]

Nope - that doesn't do anything either.  Besides, Perazzi already have long forcing cones as do nearly all guns these days.  The times of short factory forcing cones is ancient history

There's nothing you need do to a Perazzi other than conscientious clean/lube .  Oh, and don't drop it

 

[Salopian]

A friend had a MK38 Miroku brand new some years ago with no visible chambers whatsoever , the chamber bore diameter just gradually blended into the barrel bore size , this was about five years ago it shot very well but no different to his other MK38 's  I wonder if this technology has been used by any other manufacturer ?

 

[MartynB]

25 odd years ago I had a cone and port job done on a Beretta 687 , work done via GMK was from a maching point of view excellent . It made not one jot of real life difference ( except the porting made big bangs and was a ***** to clean ) . I too rate Teague Precision , I’ve spent a fair few bob with them , and I’ve had a workshop   tour when i took my MK38 trap down their facilities are excellent  I didn’t waste any money with them on lengthening the Miroku short cones  . Having said that they probably do cones  because people ask for it  and why turn away money ? 

As an engineer , as yourself this  : if sticking a  reamer in the chamber end and a few minutes with a  flexi -hone makes all that difference,  why don’t all manufacturers add it in the production stage all of the time  when in would add basically coppers to the price of production . The answer would probably be that their research has found an optimal for a particular model’s barrel/ bore  size for coping with a wide variation of  cartridge loads and wads . 

 

[timps]

Ok I’ve already posted this on this forum sometime back but let me answer the Physics side of it to really put the cat among the pigeons.

Before anyone jumps down my throat I have gone on record on another forum and this forum stating that I don’t think the recoil difference will be noticeable at all by a shooter regarding the pressures used in shotguns but the physics behind it stacks up and tries to explain the thinking behind it.

Recoil is in 2 phases that feel like one to the shooter, the initial jolt propelling the projectile down the barrel (28g of lead) and then from the release of pressure once the wad leaves the barrel.  Now before anyone discounts this second pulse it is well documented and why muzzle brakes are used on guns when the pressure is very high. The projectile has left the gun so the only force they can be dissipating is pressure release of the expanding gas.

Therefore, regarding shotguns if you create more friction by a tighter bore, abrupt forcing cone or tighter choke the pressure build up has to increase, this is an increase in potential energy plain and simple.

This potential energy has to go somewhere as energy cannot be destroyed only transferred due to the conservation of energy.  Releasing this greater stored potential energy as the wad leaves the gun will push back on the shoulder with more force.

F=MA proves the point, the gas has a mass and once the gas under pressure is exposed to atmospheric pressure it will accelerate and an accelerating mass creates force.

The amount of force produced is covered by the formula F = qVe+(Pe-Pa)Ae    which takes into consideration the main bore of the tube, the bore of exhaust (choke), the pressure inside the tube (which is a constant throughout the tube) and atmospheric pressure.

 Play about with the bore diameters and pressures inside the tube and this changes the force produced.

As I have said many times I don’t think any shooter could feel the difference at all but it doesn’t stop the marketing men running with it.

Now before I get accused of going to Hogwarts again I do know the above physics is sound but in shotgun pressures the difference is minimal so not worth the price of admission.

However when Mr P says it reduces recoil he is probably right but I doubt anyone could ever feel the difference it is all just marketing with a hint of truth.

 

[Will Hewland]

Of course if the pressure from the combustion escapes past the wad, because with the the overboring there is a poor seal, that will reduce recoil. And shot speed of course..

 

[jwpzx9r]

Ok I’ve already posted this on this forum sometime back but let me answer the Physics side of it to really put the cat among the pigeons.

Before anyone jumps down my throat I have gone on record on another forum and this forum stating that I don’t think the recoil difference will be noticeable at all by a shooter regarding the pressures used in shotguns but the physics behind it stacks up and tries to explain the thinking behind it.

Recoil is in 2 phases that feel like one to the shooter, the initial jolt propelling the projectile down the barrel (28g of lead) and then from the release of pressure once the wad leaves the barrel.  Now before anyone discounts this second pulse it is well documented and why muzzle brakes are used on guns when the pressure is very high. The projectile has left the gun so the only force they can be dissipating is pressure release of the expanding gas.

Therefore, regarding shotguns if you create more friction by a tighter bore, abrupt forcing cone or tighter choke the pressure build up has to increase, this is an increase in potential energy plain and simple.

This potential energy has to go somewhere as energy cannot be destroyed only transferred due to the conservation of energy.  Releasing this greater stored potential energy as the wad leaves the gun will push back on the shoulder with more force.

F=MA proves the point, the gas has a mass and once the gas under pressure is exposed to atmospheric pressure it will accelerate and an accelerating mass creates force.

The amount of force produced is covered by the formula F = qVe+(Pe-Pa)Ae    which takes into consideration the main bore of the tube, the bore of exhaust (choke), the pressure inside the tube (which is a constant throughout the tube) and atmospheric pressure.

 Play about with the bore diameters and pressures inside the tube and this changes the force produced.

As I have said many times I don’t think any shooter could feel the difference at all but it doesn’t stop the marketing men running with it.

Now before I get accused of going to Hogwarts again I do know the above physics is sound but in shotgun pressures the difference is minimal so not worth the price of admission.

However when Mr P says it reduces recoil he is probably right but I doubt anyone could ever feel the difference it is all just marketing with a hint of truth.

Well of course but can you put a tangible figure to any of that 

If any of what you have said actually produces a reduction in recoil that can be felt by the shooter then shooting a gun with a longer barrel and no choke is going to be the favourite for the recoil buffs as there is more than a 10% increase in bore volume moving from 30 inch to 33 as well as a 10 % increase in barrel area over a 1mm restriction on a standard 18.4mm bore so theoretically as you say more is less... and we have not even started to take into consideration the variation in the mass of metal involved which is definitely going to change the recoil.

The simple truth is that these reactions take place in such an inconsiderable time frame NOBODY can actually feel any of them other than initial one.. IMO

Further to the point why Perazzi got mired in this is anybody's guess. A small manufacturer like Perazzi should have just called out companies like Beretta and Browning, who have been advocates of back boring, for the sh*te it is but instead they have felt the need to follow suit. This could be for many reasons but I suspect that Perazzi felt that they needed to to become part of the tech culture to maintain or even increase their market share, instead of doing what the always have done and just made a great competition shotgun using the winning formula they have had for many years. But hey we live in a world where if something is not electronic we maybe have to add some concept to it to make it fit with a Hi Tech world?

 

[Geordieboy]

Ok I’ve already posted this on this forum sometime back but let me answer the Physics side of it to really put the cat among the pigeons.

Before anyone jumps down my throat I have gone on record on another forum and this forum stating that I don’t think the recoil difference will be noticeable at all by a shooter regarding the pressures used in shotguns but the physics behind it stacks up and tries to explain the thinking behind it.

Recoil is in 2 phases that feel like one to the shooter, the initial jolt propelling the projectile down the barrel (28g of lead) and then from the release of pressure once the wad leaves the barrel.  Now before anyone discounts this second pulse it is well documented and why muzzle brakes are used on guns when the pressure is very high. The projectile has left the gun so the only force they can be dissipating is pressure release of the expanding gas.

Therefore, regarding shotguns if you create more friction by a tighter bore, abrupt forcing cone or tighter choke the pressure build up has to increase, this is an increase in potential energy plain and simple.

This potential energy has to go somewhere as energy cannot be destroyed only transferred due to the conservation of energy.  Releasing this greater stored potential energy as the wad leaves the gun will push back on the shoulder with more force.

F=MA proves the point, the gas has a mass and once the gas under pressure is exposed to atmospheric pressure it will accelerate and an accelerating mass creates force.

The amount of force produced is covered by the formula F = qVe+(Pe-Pa)Ae    which takes into consideration the main bore of the tube, the bore of exhaust (choke), the pressure inside the tube (which is a constant throughout the tube) and atmospheric pressure.

 Play about with the bore diameters and pressures inside the tube and this changes the force produced.

As I have said many times I don’t think any shooter could feel the difference at all but it doesn’t stop the marketing men running with it.

Now before I get accused of going to Hogwarts again I do know the above physics is sound but in shotgun pressures the difference is minimal so not worth the price of admission.

However when Mr P says it reduces recoil he is probably right but I doubt anyone could ever feel the difference it is all just marketing with a hint of truth.

Well I love this stuff.  The engineer is coming out now.  The fact that the its all over in microseconds means we will more than likely not feel any difference.  The fact remains that the physics supports the evidence as stated above that it will reduce recoil by an amount....but not an amount that the shooter can feel.

My gun is 33" long....love it.....when I miss I just poke them after the shot and call a break...

I have decided what is happening now.  I am leaving the barrels well alone.  I don't feel recoil as it is.  A nice SC0 stocked High Tech will cost me £15,000 from the factory.  An SC0 stock made to fit me by West Midlands Gun Services will cost circa £2000.  So a new stock it is.  

I am sure that this lot has all been done to death before, so apologies for resurrecting it.  All the same it was an education and I appreciate that.

Cheers everybody!

 

[Will Hewland]

I’ve never compared back boring, but I can feel more recoil with tight chokes! Ed Solomons didn’t believe me. We had a bet going, but never met to do the test. Make of that what you will..

 

[Hamster]

I’ve never compared back boring, but I can feel more recoil with tight chokes! Ed Solomons didn’t believe me. We had a bet going, but never met to do the test. Make of that what you will..

I used to think I could till I realised it has to have more to do with the fact we tend to deliberate our movements when we KNOW we have tight (3/4 or Full) chokes in. The phenomenon of recoil being much more noticeable whilst firing at a pattern plate goes some way in describing this, IF there is any Measurable (not perceptible) difference in recoil then it has to be due to velocity variations, I remember the thread/argument and would still back against it in a blind test. 

 

[timps]

Well of course but can you put a tangible figure to any of that 

If any of what you have said actually produces a reduction in recoil that can be felt by the shooter then shooting a gun with a longer barrel and no choke is going to be the favourite for the recoil buffs as there is more than a 10% increase in bore volume moving from 30 inch to 33 as well as a 10 % increase in barrel area over a 1mm restriction on a standard 18.4mm bore so theoretically as you say more is less... and we have not even started to take into consideration the variation in the mass of metal involved which is definitely going to change the recoil.

The simple truth is that these reactions take place in such an inconsiderable time frame NOBODY can actually feel any of them other than initial one.. IMO

Further to the point why Perazzi got mired in this is anybody's guess. A small manufacturer like Perazzi should have just called out companies like Beretta and Browning, who have been advocates of back boring, for the sh*te it is but instead they have felt the need to follow suit. This could be for many reasons but I suspect that Perazzi felt that they needed to to become part of the tech culture to maintain or even increase their market share, instead of doing what the always have done and just made a great competition shotgun using the winning formula they have had for many years. But hey we live in a world where if something is not electronic we maybe have to add some concept to it to make it fit with a Hi Tech world?

Yes I could put a figure on it, and loads of people have including a lot of research by the US and British army if you google secondary recoil and how to combat it. However, I have no intention of carrying out the complexed calculations to work it out, maybe Mr P will if a customer asks.

The initial recoil is over in a fraction of a second and you can feel that.

In simple terms the secondary recoil can (by some actual tests carried out but not limited to shotguns) be up to 50% of the primary recoil so it is not insignificant and on very high powered rifles it can be higher and does need to be dealt with by the use of muzzle brakes, the US and British Army have some very interesting papers on it so maybe engraved muzzle brakes are the next big thing.

However, as I keep on saying and mentioned twice in my post above I don’t think the pressures involved with shotguns it comes anywhere near 50% and that any shooter could ever feel it so that is something we both agree on for shotguns, however it is just my opinion and I stand to be corrected on that last bit.

Why Mr P has done it is quite simple for someone to spend money and change guns you need something new and better to tempt them to change.

Regarding tight chokes if you run simple numbers through the above equation I quoted the difference between the bore diameter and the exhaust diameter (choke) makes a big difference to the force so the physics backs up tight chokes more than back boring.

I genuinely can’t comment on whether you or anyone else can feel it or not, I can only comment  just the physics side of it.

 

[Will Hewland]

I can feel it.. let’s do the test.. I noticed it years ago while not expecting it at all.

 

[Wonko the Sane]

Well of course but can you put a tangible figure to any of that 

The simple truth is that these reactions take place in such an inconsiderable time frame NOBODY can actually feel any of them other than initial one.. IMO

I believe that Mr. Winston has demonstrated that the ejecta is well clear of the barrel before there is any appreciable movement discernible in the gun itself.  In the event that may not have a clear association with the topic it simply means that chamber pressure affecting recoil is only BS.  And the associated physics are incredibly simple.

But of course anyone is perfectly free to make the scenario as complicated as they wish 

And as to tighter choke?  The physics of that situation would seem to be that a tighter choke would in effect be pulling the gun away from the shooter and thereby reducing recoil (as would short/steep forcing cones).  But once again, IIRC Mr. Winston demonstrated that choke has no effect on recoil at all.

have a nice day

fat *******s