Perazzi choke - sense check please

[Mel Jones]

Never had occassion to question it before, but today I actually measured the choke on my MX8.  

Bores are stamped as 18.4 (0.724).  The bore through the chokes appears to be 0.700 and 0.690, give or take a couple of thou.  

By my calculation, that gives me constrictions of 0.024 and 0.034, being 5/8 and 7/8 respectively.

Is that right?  I always thought the old cannon shot tight, but never dreamt it was that tight.  It was sold to me (new) as 3/8 and 5/8!

However, on the barrels are 3 rings and 5 rings, which I thought denoted choke.  Baffled now, but believe my micrometer rather than the stamps.

Might be a trip to see Mr Teague after all.

 

[Paul120]

You need to measure the bore and choke together not just refer to whats stamped on the barrel (18.4). i believe that the peoof meaurents are rounded up/dowen to the nearest 0 .1mm so using that method you could be nearly 1/2 a choke out. 

 

[Simbo]

Save ya money and just use 9's

 

[Mel Jones]

That's interesting.  0.1mm = 0.003thou, see what you mean, but its still drastically different from two whole sizes different to what I'd expected I had (for 15 years!).

Question is now, how am I going to measure the bore without special equipment?

Save ya money and just use 9's

Fibre wadded 9s at that.  Might stand back a bit further too, let the pattern open up naturally.

 

[Les53]

My mx2005 is allegedly 3/4 and full !!! Yeah right! Judging by the kills I would guess at more like full and extra full. But at the end of the day, the shells and the hardness of the clay can have an effect on what the kills look like.

 

[Cosmicblue]

My MX12 HPX/DSR is 1/4 and 1/2 fixed and up against a pattern plate is super tight - with barely any difference between either barrel - suffice to say targets are rarely chipped and mostly smoked.....

I've experimented with 9s too, currently using 28Grm/7.5 Fibre Flash carts for the close in stuff and the 24Grm/7.5 Jockers for everything else - the budget priced carts seem to give a slightly more open spread.  I realise its like buying a Ferrari and feeding it with cheapo unleaded  fuel but if it works then I'm happy... :smile:

I've toyed with a Teague/Briley upgrade but like the principle of fixed as its less to clean and not having to worry about the wretched things coming loose....

 

[Mel Jones]

Don't talk to me about HPXs - I'm trying to ignore the fact they exist, lest I find myself buying one. : )

 

[Doctor Lecter]

nothing wrong with 5/8 7/8    just use a skeet shell for stuff on the end of your barrel .   keep it simple  don't become a twiddler   , tight chokes are ok at orston esp .   :wink:  

 

[Geordieboy]

Twiddler!  Don't we all like a bit of a twiddle? Trouble is you end up with Black Finger if you're not careful! 

 

[Wonko the Sane]

That's interesting.  0.1mm = 0.003thou,

That would be .0039 so almost .004

actually a BIG difference

The 3 rings or stars are almost always a sorta light full and the 5's a sorta mod.  And they always shoot tighter than you'd think but that's just what ya get with a Perazzi.  don't even think about changing or complaining hahaha

 

[jwpzx9r]

That is interesting because my gun is choked half and full according to the stamps three rings and one. The bores are 18.4 according to the stamp  marks. One day at the club there was some debate about Perazzi chokes and there were several Perazzi chokes measured my gun measured 0.8 and 1.2mm constriction which is way tighter than the stamp as were all of the guns measured. What I will say is that when I am shooting well most of the targets are smoke. That could be because the chokes are tight or I am just really centring the target or a bit of both... but I am not complaining... if only I was as good as that gun though.

 

[squimp]

Surely it is the actual pattern that matters -  rather than a nominal choke constriction.

If the gun/choke shoots a pattern that does the job you want it to -  then the actual degree of choke is irrelevant.

I remember an article in 'Clay Shooting' a few years ago that tested after market chokes. All of them threw tighter patterns than they were 'supposed' to -  if the markings were to be believed.

Just for the record I once had a Krieghoff 20 gauge with factory chokes and the one marked Improved Mod shot much looser patterns than the one marked as Modified. 

 

[Rosso]

Quoted from the field mag blow. Choke size is a percentage of bore diameter. Pastarazzi's vary a lot on bore diameter so the choke size if fixed could measure differently on what appear to be identical guns with different bore diameters.

Commonly, one refers to the choke in a barrel as being true cylinder, improved, quarter, half, three-quarter or full. Gunmakers talk about “points” of choke. They measure shotgun choke relative to the bore diameter (which may vary considerably within any designated bore size rather than at the muzzle alone).
One point equates to a constriction of one thousandth of an inch. Below is what one would expect in a 12-bore gun.

• True Cylinder 0-1 points
• Improved cylinder 3-6
• Quarter (American Improved) 8-12
• Half (American Modified) 17-23
• Three-quarters (Improved Modified) 25-30
• Full 35-40
• Super full 40+

These descriptions should not be appraised in isolation of their observed effects, though. Properly considered, choke concerns the number of pellets any given barrel/constriction throws into a 30in circle at40yd. The quality of shot, the type of wad and other factors such as precise bore diameter and the form of choke – short or long, simple conic or conic cone plus parallel section (the favourite of British gunmakers) may all be significant.

Percentage of pellets inside
30in circle at 40yd

• True Cylinder     30-40
• Improved           50
• Quarter             55
• Half                  60
• Three-quarters   65
• Full                   70-75
• Super full           76+

Read more at http://www.thefield.co.uk/shooting/guide-shotgun-choke-22358#jbleDb7LvkFlTQYM.99

 

[Skeet UK]

That's interesting.  0.1mm = 0.003thou,

That would be .0039 so almost .004

actually a BIG difference

I can't believe you quoted him and did not correct him!

0.1mm is not 0.003 "thou" it isn't even 0.0039 / almost 4 "thou"

0.1mm is 0.0039 "INCHES" or 3.9 "thou"

0.0039 "thou" is 0.09906 "micro meters".

A "micro meter" is 1 thousandth of a mm.

#Pedant

 

[Wonko the Sane]

and you were the only one confused because I left off the " that in my naivete presumed anyone who has ever held a mic would know?  hahahaha

I can't say anything about current production barrels by Perazzi but the older models residing here are remarkably consistent in diameter.  Between gun there may be as much as 0.001", between barrels on one gun maybe half that, and the individual bores vary for their length so little that the needle on the dial where 0.0005" is easy to see hardly even moves.  The older Berettas that I've measured were the same.  I can't imagine any company doing significantly better than the Italian barrel makers.  Or even consistently as well for that matter.

and that's just simple fact not JMO

 

[westley]

When I had a 'P' gun, I did not know what it was choked, I just shot it. In fact I shot it so badly, it went !

 

[jwpzx9r]

When I had a 'P' gun, I did not know what it was choked, I just shot it. In fact I shot it so badly, it went !

I have a "p" gun.... I don't actually think about the choke too much at all really. I was shooting  UT today. I shot very, very badly 20 and 18. Its was nothing at all to do with the gun but more the tw*t behind it. You cannot make dust of 20 and then 18 targets on the first barrel and then blame the misses on the gun...  I think you may have had the same problem . It is difficult at times to stop, think, and then blame yourself for your results... fortunately I can. Others will for ever blame the inanimate object that cannot make comment about  how badly it is being utilised. Evidently you did realise just how badly you were treating that poor gun and let someone else have the pleasure.

 

[Wonko the Sane]

It's been my experience that a really proficient shot (not me by any stretch) can shoot reasonably well with a poor fitting gun.  I suspect that most people benefit from a properly fitted gun and to forego that aspect is to place performing well in jeopardy big time.  My evaluation process is to insure that both barrels shoot to the same place and then adjusto fit until that place is where I want it.  Good luck will be highly desirable  if you pass on that process.

 

[westley]

My biggest problem was in the trigger. The Perazzi trigger is just too good for a mere mortal of a Miroku user. You see after 40 years of crappy Miroku triggers, you sort of get used to taking up the 'free play' as you come onto the target, it is then a simple matter to pull ahead and take up the remainder of trigger pull as the lead looks good. The Perazzi trigger has already gone at the "as you come onto the target " bit. This results in a miss well behind. In fact I used to wake up in the middle of the night shouting "Youre' behind it". So much so,  I even went to the "Youre' behind it " school for shooting Instructors ! Still, on the plus side, I have not had to spend any money on having my crappy Miroku repaired and my range bag is lighter, now I have sold the spare 'P' bits. I just have to make do with 80% scores instead of 90% +  behind it's,  still "life's a female dog"