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kazo

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Discussion starter · #1 · (Edited)
so that's how it started:

...So I got myself a Perazzi MX8 type 4 (eventually IDed as Mirage), as per a friend (excellent bunker shooter, shooting encyclopedia)
from the club, who made a beautiful stock for it.
I know next to nothing about Perazzi's guns, I really trust what he says, but what puzzles me is the fact that there is no model # stamped anywhere on the gun. Receiver on both sides is empty and smooth...
80363 & AZ indicate 1990 year, numbers match -receiver, barrels, trigger group, & forend; gun is tight and pleasantly lively when swinging, quite a change from my XT 'cannon' :)
Barrels 30", top is fixed full ~17.25, bottom changeable chokes, not much wear on the hammers.
My friend says that most likely it was special order where client didn't wish model stamping on the gun..


After several rounds lower barrel f.pin broke, replaced with new pins , removed the web on the hammer, cleaned the pin orifices; started getting light hits on top barrel, found that the new pin (striking part,) is shorter then then the old one is shorter by .5mm, put the old back in, less misfires but still some nevertheless.
-removed cocking bar (was moving freely ) and clean it, removed ejector trip rods (were sticky) & cleaned them and the channels, still light hits, removed them, still light hits, appeared less numerous.
-borrowed trigger group from a friend, four rounds - no problem.
-firing pins return springs arrived, decided to strip the receiver to give it a good cleaning, had a quite a problem to remove the top lever, lot of dirt and some burs removed with 600 stone, lubed lightly with lithium grease (that I used forever on my guns without adverse effects, but would like to hear you opinion on this type).
Noticed that the the hole where the f.pin return spring dwells has ribbed-like pattern, imprinted (I guess) by the gunk accumulated there, cleaning neglect, one may guess, for many years. That part of the of the hole not leally visible without top lever off. Proceeded with cleaning with a brush (pic), still looked rough. Took it under microscope (pics) as you can see it's not smooth.
Replaced the f.pins return springs and re-assembled, put a new top lever return spring for good measure (was a bit deformed).

And now if I don't have light hits no more, I would know if it was cleaning the far end of the hole or new f.p. return spring :unsure:

If the problem still persist I would be at loss...:(

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Discussion starter · #2 ·
...you could feel the roughness when running a needle across. The two thicker lines are, I believe, are the imprint left by the spring, but still the hole walls look and feel rough.., but maybe I'm splitting a hair here...
 
I know I sound like a broken record at this point, but firing pin protrusion must always be measured when new firing pins are put into a shotgun. Otherwise, you’re shooting from the hip in the dark; eventually you’ll hit something, but only by accident!

Brownells makes this tool:


…which is used in conjunction with a set of imperial calipers. I know you’re in Canada, but perhaps you can buy something similar there?
 
Well, If it was mine............I would change the trigger springs just for $hits and grins................I have found in the past 25 years of owning a few Perazzi's the trigger springs will weaken considerably without breaking.............Hence, light strikes.....................Just trying to help.
 
Discussion starter · #6 · (Edited)
I know I sound like a broken record at this point, but firing pin protrusion must always be measured when new firing pins are put into a shotgun. Otherwise, you’re shooting from the hip in the dark; eventually you’ll hit something, but only by accident!

Brownells makes this tool:


…which is used in conjunction with a set of imperial calipers. I know you’re in Canada, but perhaps you can buy something similar there?
Thanks Steve, as I mentioned before the pins are sticking out ~.072 (old) ~.068(new) , which I believe is >20% above minimums you mentioned in another thread. I'm measuring the protrusion with fairly accurate digital caliper, that I checked against a reference gauge of 30mm and measures 30.00mm, I'm introducing errors of ~.1 - .2mm :)

But, I have to point to myself that gun operated OK with the borrowed trigger group for 4 rounds, probably shot 50X upper bbl, 2nd shots and scraps, so it's not a big sample, but shooting the same with mine t.group I always had misfires. So we may assume that the problem is there. But besides hammer springs, that are new, checked hammer for cracks -none, and cocking foots happily moving free..., what else is left?

Anyway going to the club tomorrow for a practice before Sunday season-closing competitive shoot, and will report if the problem is still there.
 
Discussion starter · #7 ·
Well, If it was mine............I would change the trigger springs just for $hits and grins................I have found in the past 25 years of owning a few Perazzi's the trigger springs will weaken considerably without breaking.............Hence, light strikes.....................Just trying to help.
new leaf springs in
 
Thanks Steve, as I mentioned before the pins are sticking out ~.072 (old) ~.068(new) , which I believe is >20% above minimums you mentioned in another thread. I'm measuring the protrusion with fairly accurate digital caliper, that I checked against a reference gauge of 30mm and measures 30.00mm, I'm introducing errors of ~.1 - .2mm :)

But, I have to point to myself that gun operated OK with the borrowed trigger group for 4 rounds, probably shot 50X upper bbl, 2nd shots and scraps, so it's not a big sample, but shooting the same with mine t.group I always had misfires. So we may assume that the problem is there. But besides hammer springs, that are new, checked hammer for cracks -none, and cocking foots happily moving free..., what else is left?

Anyway going to the club tomorrow for a practice before Sunday season-closing competitive shoot, and will report if the problem is still there.
What method did you use to measure the FP protrusion? Meaning, did you manually hold the hammer all the way forward before measuring protrusion?
 
The fact that one trigger group is acting up while one is giving good results is an indication of things to check.

Try new (straight) ejector trip rods and make sure the short end of the trip rod is not being hit by the front of the hammer, only in the side cutout.

don
 
Discussion starter · #10 ·
thanks gents, went for a practice yesterday, removed ejector trip rod from up bbl, shot with new pin and old one, using different ammo...
Going now for our season closing shoot, will try to summarize my findings, conclusions and ask questions.
 
Discussion starter · #11 · (Edited)
her we go:
@Stveven and et al, measured protrusion again of the old pin, just on the top BBL that gives problems, for a new one you have to deduct .020, that's by how much the pin is shorter as a whole, and the length is reduced in the working part of the pin, (new one I gave it back to the guy who sold it to me to compare with other that he has), so fully pushed in flush with the receiver (correction back of the pins is sticking out a bit above the receiver back-face) =~.098, when pushed in by hammer =~.060.
As I understand the dynamic of f.pin movement, the inertia force would move it all the way out to full .098" if there is no primer to hit, how deep it goes with the shell in, depending on the hardness of primes, but looks like without inertia calculated in, it should penetrate .060" which I understand is enough. With the new pin the numbers would be .078 & .040 and that may be not enough (?), depending what criteria apply.
See the shells pic, two hits, verry light and good, got some in-between, that with Sellier&Bellot would end with a misfire (invariably worked when transfer to lower bbl) but would go off with CLEVER T1.
From what experienced I assumed that the hammer somehow is not hitting with full force, I believed I looked into most of the causes for it and felt perplexed buy lack of positive outcome...
Although when I got the gun, I serviced t.group, sprayed it liberally with electric contact cleaner (hat comparing to breaker spray leaves no deposit), blew it with compressed air , I know it may not be a good idea, as the small particles, crud that is not really removed can get deeper in the bushings etc and make things worse, but anyway I took a shortcut.
Yesterday night, convinced that the problem somehow is in the t.group I looked at it again, removed the hammer springs and checked the hammers movement, and although they moved freely I heard some squeaking, so I soaked it again, blew again and applied just couple of drops between them and the plate separating them, and...today NO light hits, not during the shoot and not during two practice round after making a point to shoot the 2nd shot all the time.
The ejector rod in the top BBL was removed, but it looks like my laziness in servicing t.group bit me in the arse 🥴.
One more thing to admit, because I didn't take it apart and lubricate it properly, I applied what I use in my hunting guns, i.e. Rem DriLube, and I think it may not be the right stuff for this job, that I'm going to do soon, armed with Don's educational videos on the subject.
Image
 
Discussion starter · #12 ·
The fact that one trigger group is acting up while one is giving good results is an indication of things to check.

Try new (straight) ejector trip rods and make sure the short end of the trip rod is not being hit by the front of the hammer, only in the side cutout.

don
thanks for your input Don,
don't have the new rods, and it's not easy to get them parts in Canada :( , but the ones that are in look strait and the ends are landing on the hammers cutouts you mentioned.
When I took them out (ejector trip rods) firs time to clean them they were sticky and after cleaning less, but still staying in place with some resistance, which I figured out is the intended nature, otherwise, if loose, and the gun is moved vertically before opening, they will fall back as far as the cutouts in the hammers are and the ejector(s) won't be tripped right?
Looks like it's accomplished by some eccentricity of the holes/channels they are guided through right?
Image
 
@kazo don’t overthink firing pin protrusion. Also, don’t worry about measuring firing pin overall length. All you are measuring is how far the hammer directly causes the firing pin to protrude. That’s it. You’re looking for .045” on the short end, and .060” on the long end.

Your supposition on the trip rods is correct. They should move with some resistance, which is achieved either by friction in the slot at the rear or by putting a gentle arc in the rod which introduces moderate friction inside the tunnel (the tunnel itself is straight and round).
 
Discussion starter · #14 · (Edited)
@kazo don’t overthink firing pin protrusion. Also, don’t worry about measuring firing pin overall length. All you are measuring is how far the hammer directly causes the firing pin to protrude. That’s it. You’re looking for .045” on the short end, and .060” on the long end.

Your supposition on the trip rods is correct. They should move with some resistance, which is achieved either by friction in the slot at the rear or by putting a gentle arc in the rod which introduces moderate friction inside the tunnel (the tunnel itself is straight and round).
thanks for the clarification Steven, so the new pin is not sticking out enough..., will clean the t.group properly and observe.
I prefer grease over oil, do you have an opinion on Lithium grease for gun maintenance applications (especially in t.group) ?, that's what I use over many years.
 
thanks for the clarification Steven, so the new pin is not sticking out enough..., will clean the t.group properly and observe.
I prefer grease over oil, do you have an opinion on Lithium grease for gun maintenance applications (especially in t.group) ?, that's what I use over many years.
Keep firing pins and channels clean and dry.

Hammers and sears are better served by molybdenum grease, although cold climates like Canada may require synthetic oil like SLIP 2000 in winter.
 
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