Perazzi Back Boring

[Geordieboy]

Evening all. 

So then, what do we know about back boring? I have a perazzi HPX DSR. It has 18.4mm dia bores. Mauro perazzi has stated that the High Tech has 18.6mm to reduce felt recoil.

Has anybody increased their bore size? Who does it and what was the cost?

Thanks

 

[Hamster]

Evening all. 

So then, what do we know about back boring? I have a perazzi HPX DSR. It has 18.4mm dia bores. Mauro perazzi has stated that the High Tech has 18.6mm to reduce felt recoil.

Has anybody increased their bore size? Who does it and what was the cost?

Thanks

My 682e has 18.6 bores, does that mean Beretta woz HiTeching it 20 years before Perazzi ? 

In answer to your question, no, bore size makes no odds in terms or recoil. 

 

[chippy]

My 682e has 18.6 bores, does that mean Beretta woz HiTeching it 20 years before Perazzi ? 

In answer to your question, no, bore size makes no odds in terms or recoil. 

I fired a 28g 71/2 shot eley out of my dustbin and it was really smooth so there must be something in this over boring.

 

[Jonny English]

Overbored = dreadfull to clean

I have had 3 bored guns, an mk60 at 18.4, various Browning at 18.7 and now a dt11 that goes from 19 something down to 18.6

Mk60 was very easy to clean

Browning were stubborn but do able

Dt11 is an absolute pig to clean, pro pistons or fibres leave a hell of a mess

 

[Geordieboy]

I have to say......My barrels are always shiny and after shooting 3 different Fiocchi cartridges.....no detritus left in the barrels and easy to clean.

 

[Jonny English]

My mk60 took 3 soak and scrubs, the Browning usually took 5 or 6, the dt11 needs about 8 with plastic and maybe 12 with fibres, including scrubbing with a battery drill.

With regards to recoil, the mk60 kicked pretty hard, the Brownings were a lot better and the dt11 is smoother and softer still. Now if that is down to the back boring, or the weight and shape of the guns is debatable.

 

[Geordieboy]

I pop the brass brush with lead cleaner down both barrels for a few 'Shafts' OO'er .......then a Kitchen Roll on the swab holder and hey presto........Barrels all shiny!

Reason for asking about Back Boring is I picked up a High Tech......and I am really liking that heavier feel in the hands....

...so naturally you read all about it, and it is 40grams heavier in the action.....and the bores are 18.6mm to reduce the recoil......Thats what Mauro Perazzi said.  And reading loads about Back boring........thats what the gunsmiths say as well.........

So the engineer kicked in again..........

 

[squimp]

I've asked the very same question on here several times recently  - and have got no conclusive replies....

Does your DSR 'appear' to generate more recoil that you would expect? Or is there ano reason why you are considering opening the bores?

Just for the record; I looked at a used MX12 yesterday (at Coley's) and it had bores marked as 18.7. You can find every variation in 'standard'  Perazzis from 18.4 up to 18.7.

I have also looked at several recent Hi-Tech's lately and they vary too, some are 18.6 and some 18.5 . Mr P states that 18.6 is the best for recoil reduction in his video, which begs the question as to why some are still made at 18.5 ?

I was asking the question with regard to performance with fibre wad shells for game shooting, rather than recoil. 

 

[schmokinn]

Barrel bore in Perazzi is part of the customisable options when having one made for you.

I guess some people think they know better than Mauro?

 

[Geordieboy]

I know nowt!!!!

Not got a particularly heavy recoil.  Gun shoots okay.  I am playing like we all do.  How can I make it better, faster, stronger, quicker???

Wait a minute.....that was Miyamoto Mushashi's Quote............"everything resides within".

Can't help it.  I'm an engineer and want more!

 

[MartynB]

The most obvious change of back boring your existing gun out by .2 of a mil ( .008” approx ) will be to tighten all your chokes up by the same amount which is quite significant. Might not be such  a problem with a multichoke you’d just drop every choke by around a 1/4. If you have fixed  you’d need to factor in having those matched to the new bore , then either way a re-proof . I’m not sure mucking around with an expensive gun like a Perazzi is the way to go .It will end up with more bore / proof stamps on the barrels so it’s providence will be known to all if you  ever fall out with it

It’s all subjective anyway and certainly not measurable by the shooter IMHO . I have two guns I regularly use , a K80 with the Dural lightweight action 18.6 bore 3” chambers and longer cones , the second MK38  Teague trap 18.7 , 2 3/4 chambers , short cones . Both are  fitted to me which I feel has more bearing on recoil than the barrel bores.   For what it’s worth Neither of the guns are problematical to clean. 

 

[Hamster]

I'm more than game anytime Mr. P or anyone else wishes to demonstrate their ability to detect recoil variations between barrels of 18.5/6/7 in a blind test with guns of identical weight. 

 

[westley]

Well, I have become 'overbored' now  !

"MAN OVERBORED"    chuck him a bouy  !

 

[Westward]

Just for the record; I looked at a used MX12 yesterday (at Coley's) and it had bores marked as 18.7. You can find every variation in 'standard'  Perazzis from 18.4 up to 18.7.

I have also looked at several recent Hi-Tech's lately and they vary too, some are 18.6 and some 18.5 . Mr P states that 18.6 is the best for recoil reduction in his video, which begs the question as to why some are still made at 18.5 ?

I doubt if the variations were deliberate. My take is they were probably all intended to be 18.6. If they work like Beretta or CG the bore size is stamped after manufacture.

Will is the engineering guru on here but I would have thought a tolerance of plus/minus 0.1mm when making barrels would be pretty normal. CG barrels are bored to a nominal 18.7 but mine are stamped 18.6 and I've seen another stamped 18.8. Their chokes however are highly accurate, presumably because they are ground, and sized to suit bores of 18.7.

 

[chippy]

Will is the engineering guru on here but I would have thought a tolerance of plus/minus 0.1mm when making barrels would be pretty normal. 

I think its plus/minus 1mm in his gearboxes

 

[Will Hewland]

I think its plus/minus 1mm in his gearboxes

If only..

0.1mm (or 4 thou “ as I grew up with it) isn’t hard at all to regulate within a long bore like a gun barrel. 

 

[Geordieboy]

After lots of reading....and youtubing.....

....lengthening and polishing forcing cones whilst keeping the bore diameter the same....seems like a good idea.

https://www.outdoorlife.com/articles/guns/2016/09/shotgun-test-how-altered-forcing-cone-can-improve-pellet-patterns

Several other gunsmith advocate this as well. Teague provide that service too.

 

[CharlesP]

One always has to bear in mind a possible profit motive when service providers advocate a particular service!

Vast amounts of effort and experiment have gone into the search for the holy grail of the ideal dimensions of a shotgun barrel, right from the early days when "The Field" held complicated and lengthy trials into the products of a number of gunmakers. It was Mr Greener who won those, the rib of the shotgun in my avatar is so inscribed. The trials ended in 1879. A lot of things have changed since then. Virtually every aspect of cartridge design has changed - wads, shot, propellant, primer and the case itself. Gun manufacture has changed a lot too.

But one thing hasn't changed. That's the desire of people who sell things to convince you that their product, and their service, is the one that deserves your money. Sometimes whatever they're promoting is genuinely better than the competition, but all too frequently the claims made are akin to those of the snake-oil salesmen.

It's worth bearing in mind that before corrosion-resistant barrels and improved primers, many thousands of guns were fine bored more than once in their life, and indeed frequently re-proofed when the enlargement was sufficient to render them out of proof. It's surprising that nobody noticed the improvement in performance when the work had been done, you would think someone would have spotted it!

Given the range of temperatures through which a gun barrel may pass on a winter morning - from "brass monkey" to "glad I have a wooden fore end to hold" it's also surprising that nobody has noticed an improvement in recoil, pattern etc as the gun gets hotter. I'm pretty confident that the coefficient of expansion of steel is quite enough to make a measurable difference in bore diameter. I remember being shown years ago how a gun straight from a customer's cold car boot can be "just in proof" when it got in the shop, but "just out of proof" after holding the barrels in a warm hand or resting it on a radiator for a few minutes. This was using a "go" and "no-go" gauge, of course. but later experiment with a Chubb gauge demonstrates the principle.

I won't be sending any of the guns in my cabinet for unnecessary bore enlargement, nor will I mess with the chambers or cones.

 

[Westward]

The good people at Teague know what they're doing and will take care of you but I have my doubts as to whether you'll notice any difference. Given the amount of expertise that goes into a Perazzi it seems to me that if there was any benefit from lengthened/polished cones they'd be doing it in the factory. Almost every modern gun has overbored barrels/longer cones and they all claim benefits such as improved patterns or less recoil or whatever, but I've yet to hear of anyone who can verify any of the claims.

If you simply wish to reduce felt recoil there are less costly and far more effective ways than boring out the forcing cones.