Muzzle Threads And Outer Diameter For Attachements

[paladinj 0]

Hello everyone!

 

I created my account to ask a question.

 

I have a shotgun with M22x.75 muzzle threads like the Saiga 12 and want to buy muzzle attachments for it, particularly a choke.

 

The outer diameter of the muzzle is approximately .83 inch though it could be .82-.84, I am working on getting better calipers. Will a choke like the one offered by SGM Tactical lock in to these threads? or is the difference too great?

 

Thank you for the help!

 

Paladinj,

[forsaken352 235]

Since I had the calibers out, I measured my barrel OD just before my Polychoke (didn't want to remove it, but I can if you need me to). It measured .880". However, if you're shotgun is already threaded for M22x.75, why would it not work?

[paladinj 0]

Because the Outer Diameter is different? I don't know I thought that that mattered and was excluded from the M22x.75 measurement.

 

Thanks for the help! No need to remove the poly choke (damn I wish I could get one in my country) but a quick question, is it a polychoke II that screws on top of the external muzzle threads?

 

Please advise tho, I need to know whether to cancel an order, I need to get to the bottom of this.

Thank you so much!

[forsaken352 235]

Because the Outer Diameter is different? I don't know I thought that that mattered and was excluded from the M22x.75 measurement.

 

Thanks for the help! No need to remove the poly choke (damn I wish I could get one in my country) but a quick question, is it a polychoke II that screws on top of the external muzzle threads?

 

Please advise tho, I need to know whether to cancel an order, I need to get to the bottom of this.

Thank you so much!

 

Yup. That's what I have is a Polychoke II. It has 2 pieces. One screws onto the external threads (in this case, M22x.75 for a Saiga 12), and it basically has these metal "fingers". The second piece threads onto the first piece and has several adjustments ranging from 2 reverse choke settings to extra full, and several in between. Basically, the tighter you thread the second piece to the first, the tighter it pulls the "fingers" together, and that's what adjusts the amount of choke. It uses a sort of ball detent (if I remember correctly) to help lock it in the desired setting.

 

 

It's like this, but I have the "breacher" model.

 

Also, I'm not saying the OD doesn't matter. I'm no expert on threads. That's for damn sure. However, I'd think that being threaded already, it would work. Also, when you say you measured the muzzle, was that measurement taken on the threads, or...?

Edited July 7, 2015 by forsaken352

[paladinj 0]

Hmm I wish there was a Poly Choke 2 like that for my model.

 

It's been threaded already and came with a flash hider that I can simply unscrew and replace. It's close, but not exact. the difference between .83 and .88 (although some Saigas go down to .86 I understand) is about 1mm, and the fact that the M22x.75 I would buy in the Saiga attachement is .5mm greater although compatible with the 21.5x.75 metric according to manufacturer specs it would still not be that close. It could work, or could not, I think it would take an expert to tell.

 

I measured at the actual muzzle itself, the very end before the threading begins. There are only about 10 loops of threads but that is plenty.

 

 

^This is exactly what it is. There is a rubber O-ring spacing a bit after the threads, but I don't think that makes a difference.

[forsaken352 235]

Well, I tried to get the Polychoke off to measure the diameter of the barrel past the threads, but I must've really cranked it on last time as it kept coming loose. Doesn't help the only tool for it is a small metal wrench which only locks into a small hole on the choke. It deforms the hole easily. Milling some flats for a proper wrench would've been smarter, I think.

 

Also, may I ask what kind of shotgun that is? Just curious now..

Edited July 7, 2015 by forsaken352

[paladinj 0]

Oh no need to take it off brother, it's meant to be a permanent attachment, how I envy you, you have the right to buy a Saiga 12. I'm stuck with a Benelli knock-off that is actually better tuned with a nicer trigger and gas system than the real thing, at least its semi-auto. But an AK shotgun would be so much better. Don't ruin your choke its fine

 

I just need to know at this point how much smaller than .88inch my OD can be and still have a M22x.75 attachment screw on.

 

It's a Hatsan MPA-TS. It's actually really nice, unfortunately thanks to useless draconian import laws you guys can't import them in such a tacticool configuration. What that does for "public safety" I don't know, just buy a Saiga 12 instead lol. If it was magazine fed and we could own +5 capacity mags it would be awesome. Ghost ring sights, rails on top and on the bottom, self adjusting gas system.

Edited July 7, 2015 by paladinj

[forsaken352 235]

I'll admit, they are loads of fun, but mine is actually out of commission at the moment. Where the piston threads into the carrier, there is a crack from the end of the carrier to the dimple. It's a design flaw and can happen to any factory carrier. I've been meaning to send it to a company which is listed on this forum, Cobra's Custom. He welds it, pins it, grinds it, smooths it up, etc., etc.. Just never get around to sending it out for repair...

 

As far as yours goes, I don't know if I'm able to help any further, but let me know if you do need something and I'll try my best.

Edited July 7, 2015 by forsaken352

[paladinj 0]

I guess the AK was never meant to carry such a large cartridge. Steel just isn't made and hardened to the proper specifications anymore. Isn't it cheaper to just buy a new carrier? Maybe gunsmithing doesn't cost as much over there.

 

Thank you so much!

 

I am still hoping for answer though as to whether the attachment will thread on correctly. And how small my OD can be.

[forsaken352 235]

I guess the AK was never meant to carry such a large cartridge. Steel just isn't made and hardened to the proper specifications anymore. Isn't it cheaper to just buy a new carrier? Maybe gunsmithing doesn't cost as much over there.

 

Thank you so much!

 

I am still hoping for answer though as to whether the attachment will thread on correctly. And how small my OD can be.

 

The only place I've found selling new carriers is R&R Targets, and from what I understand, their pistons aren't pinned, either. I'm not sure if they are susceptible to the same failure as the factory carrier, but it's $280 for a new carrier/piston, or $175 (if I remember correctly) to have the original fixed, stronger, and retain the serial number.

 

For your shotgun, do you have a specific choke in mind that you're looking to use? The reason I ask is because, with my Polychoke, it specifically says not to allow a gap between the bore and the choke. I needed to know that when I was trying to use a barrel nut behind the choke to help keep it locked in place. So, if you're looking for a choke, using external threads, that may be a concern. A break/flash hider you can get away with, though.

[paladinj 0]

That's a good point, another thing to consider so I don't get screwed, of course before firing I will check to see that there is no gap or difference in diameter. There is quite a bit of play tho because there is more thread on the saiga attachment than on the shotgun so it could go until the O-ring.

[forsaken352 235]

I don't believe the OD at the very end of the barrel really matters. It would seem what IS important is the OD of the threads being the same from the Saiga 12 to your shotgun, or very close, at least. So long as you have the same thread pattern, I'd think that any Saiga 12 muzzle device would work, with the possible exception of a choke due to the reasoning in my last post.

 

Just looking at this picture, you can see there is an obvious step down from the portion behind the threads to the muzzle. It HAS to make up at least .050" or so, putting you around .830".

 

[evlblkwpnz 3,418]

The O.D. at the unthreaded alignment section (alignment is all it is for other than allowing you the luxury of not worrying about damaging threads at the end of the barrel) is just slightly smaller than the minor diameter of the threads. My concern would be the I.D. of the Benelli barrel, which is likely .724" to .729" vs the Saiga 12 at .718" (ETA: to .722"). Chokes that are specifically for the Vepr 12 are likely a safer choice. V12 barrel has an I.D. of .728" to .729".

 

The unthreaded alignment portion on a Saihga 12 barrel should be about .814" or so.

Edited July 7, 2015 by evlblkwpnz

[paladinj 0]

The Saiga12 attachments that are compatible with V12 must be also accommodating of the V12, so I'm not too worried about ID, but you bring up a good point with the length. From the pictures of the MPA I posted and the muzzle of the Saiga do you think there will not be a gap? I would think not because the Saiga attachment has a lot of extra threads and there seems to be enough room for it to sit on the end of the MPA barrel. It looks like it would stop when the Inner Diameters meet instead of there being a gap left.

Edited July 7, 2015 by paladinj

[paladinj 0]

I measured and my ID is closer to the Saiga, at about .72. AFAIK it isn't a problem if it starts tight and gets more open slightly (won't blow up the gun or choke).

 

It seems as though that that concern is dealt with, any expert opinions on a potential gap? Would the choke sit close enough?

 

EDIT: It can't be any significant amount less than .72 or else it wouldn't be a 12 gauge, but it is very close to that so at least it is between the specs of S12 and V12, closer to the S12.

Edited July 7, 2015 by paladinj

[evlblkwpnz 3,418]

As long as the choke is larger I.D. I think fouling will be the only significant issue.

[paladinj 0]

OK I will keep it ordered.

 

Fouling unless it is extreme will not be a concern. I will take 30 shots at most with the choke on. Its just for hunting waterfowl. If I need to hit a target far away I'll just use a slug.

 

Thx!

 

If you have any more info about whether this will work please share!

[evlblkwpnz 3,418]

I don't know much about the various Benelli shotguns, so I don't have much to add. I am very interested in whether or not this works, so please let us know.

[paladinj 0]

OK Everyone!

It screws on perfectly and holds tight.

 

Only potential issue is that there is about 1/16th of an inch of a gap between where the barrel ends and the forcing cone starts, not that that area is much wider. It is close enough that the barrel reaches the taper of when the forcing cone is about to start on the choke but doesn't quite meet it by the aforementioned gap.

 

I removed a tiny rubber ring around the end of the threaded area on the Hatsan to get it this close, is a rubber ring that necessary? I'm not too worried about it, seems like a great move in order to get the barrel and forcing cone even closer. It's screwed on very tight and almost all threads on the choke are engaged with the Hatsan, the Hatsan just has a bit less threading.

 

If I clean it diligently and don't fire more than 30 shots before a cleaning is it even remotely possible that the choke could get ripped off with the threads or I could get a kaboom?

 

This seems very unlikely to me and I feel safe experimenting with some precaution, what are your opinions? I want to know if to keep shooting to a minimum only for a bit of testing and then waterfowl to better feed my family or if I can take more liberty with more practice and recreational shooting?

 

30 shots should be 20 birds and that would fill myself and companions daily bag limits. (passing the shotgun, each shoots his own)

 

I would also find it extremely helpful if someone could get a lit picture of the muzzle of their S12 with the choke attached so I could see how close the barrel and forcing cone meet and if there's a gap.

Thank you so much for the help and confidence! Maybe one day I will be free to own a S12 and truly become part of this community lol! 

[forsaken352 235]

Can't say one way or the other if a 1/16th" is enough to cause any problems. I wouldn't think so, so long as, like Evlblkwpnz said above, the ID of your choke is larger than the ID of your bore. If there's a lip for a wad or a slug to catch on, I wonder if it would A. beat the hell out of your threads due to the stress caused by the velocity of each projectile catching said lip, B. cause a buildup of wad material/lead and cause issues there over time, or C. all of the above?

 

Anyways, here's a couple of pictures of my bore/choke. Please excuse how dirty it is. Haven't gotten around to cleaning it, yet.

 

Bottom of choke

 

 

 

Top of choke. If you look closely in the top right where the bore meets the choke, you can see that something is a little "off" as the black ring disappears in that section.

 

I ran my pinky finger down the bore and felt around where the two meet, and I can tell you there is VERY little gap if any on mine.

[paladinj 0]

Mine pretty much looks exactly the same, tho the choke itself is a different style. Thanks for the info and pics! I think the fouling is the only issue and I will clean very often.

 

Around that gap do you feel a bit of a sloping in the choke because it looks like there would be, as tho the ID of the barrel is less and then the choke begins tapering to where the forcing cone really "starts" at the fixed angle.

 

Fortunately I do not have the misalignment where at one point the choke is tighter than the barrel at the side where you mentioned, it is very well centered. Russian QC eh?

 

If that inconsistent spot which could cause snagging or huge friction doesn't disturb the wad then I doubt a small gap would. Pressure makes things tighter not more open, good thing on the SGM Tactical there's a taper before the forcing cone starts. After all if lead is fluid under such pressures (hence why chokes work) plastic should not cause any trouble without too much buildup.

 

I might get the chance to post some pictures later, any more advice?

 

Paladinj,

[forsaken352 235]

Mine pretty much looks exactly the same, tho the choke itself is a different style. Thanks for the info and pics! I think the fouling is the only issue and I will clean very often.

 

Around that gap do you feel a bit of a sloping in the choke because it looks like there would be, as tho the ID of the barrel is less and then the choke begins tapering to where the forcing cone really "starts" at the fixed angle.

 

Nope, can't say I do.

 

Fortunately I do not have the misalignment where at one point the choke is tighter than the barrel at the side where you mentioned, it is very well centered. Russian QC eh?

 

In fact, I've never noticed it before I took the pictures. Never once messed with functionality, even with all the 100s of cartridges run through it.

 

If that inconsistent spot which could cause snagging or huge friction doesn't disturb the wad then I doubt a small gap would. Pressure makes things tighter not more open, good thing on the SGM Tactical there's a taper before the forcing cone starts. After all if lead is fluid under such pressures (hence why chokes work) plastic should not cause any trouble without too much buildup.

 

I'm 99.9999% certain it would work fine, it's just that I really don't want to give out bad advice and it come back to bite me, or even worse, you in the ass.

 

I might get the chance to post some pictures later, any more advice?

 

I've got nothing left to add other than I hope it works for you. Good luck!

 

Paladinj,