Derya MK 12 cycling issues

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aaron780

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Recently picked this shot gun up. Put 100 3" heavy shells through it and I didnt have a single issue with it cycling. Went out tonight and shot approx 75 2 3/4" challenger target load and I probably had 6 magazine jams. Would love any feedback as I'm largely inexperienced with this. Thanks guys!
 
Gotta break her in. I literally bought a case of 00buck and dumped the whole thing through my MK12 the first week I got her. No more issues (accept the hours of cleaning)
 
The MK12 needs to be completely tripped and Thoroughly cleaned of all shipping grease and oil. Relive with quality gun oil and bobs your uncle.
 
LeePeterson said:
Not all of them come with 2 pistons. The early models did not.
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Agreed. My Derya MK12 has a piston that is unmarked, I assume it is an early model. As you note: later models come with two pistons & they are marked Heavy, Light or something like that.

aaron780 said:
Recently picked this shot gun up. Put 100 3" heavy shells through it and I didnt have a single issue with it cycling. Went out tonight and shot approx 75 2 3/4" challenger target load and I probably had 6 magazine jams. Would love any feedback as I'm largely inexperienced with this. Thanks guys!
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I have found that my Derya does not like cheap shells with the aluminum rim... YMMV, especially if you have both pistons...
 
EL34/6L6 said:
What model MK12 do you have and did you buy it new recently or is it old stock?
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Ive got an AS-102S that I purchased from Bullseye in London. I don't beleive it came with two pistons unless. I don't know what I'm looking at. I did put a case of Kent 3 inch 00 through it with no issues. I will admit I don't know how to properly clean it. I looked for some videos but came up empty.
 
aaron780 said:
Ive got an AS-102S that I purchased from Bullseye in London. I don't beleive it came with two pistons unless. I don't know what I'm looking at. I did put a case of Kent 3 inch 00 through it with no issues. I will admit I don't know how to properly clean it. I looked for some videos but came up empty.
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Yes that's a first run 2017 model. I don't think it has the secondary piston included, if it did it would be located in the case near the top where the earplugs and chokes are.

There are videos on field stripping the gun, one in particular made by Derya themselves.
As for cleaning shotgun, clean it as you would any other shotgun or semi-auto shotgun. Clean the piston, clean any build up that you see anywhere, clean the bolt, clean the bore, clean the action. I recommend running the gun "wet" afterwards. Which just means use a lot of oil after the cleaning so that the moving parts are borderline dripping wet with oil.
 
EL34/6L6 said:
Yes that's a first run 2017 model. I don't think it has the secondary piston included, if it did it would be located in the case near the top where the earplugs and chokes are.

There are videos on field stripping the gun, one in particular made by Derya themselves.
As for cleaning shotgun, clean it as you would any other shotgun or semi-auto shotgun. Clean the piston, clean any build up that you see anywhere, clean the bolt, clean the bore, clean the action. I recommend running the gun "wet" afterwards. Which just means use a lot of oil after the cleaning so that the moving parts are borderline dripping wet with oil.
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I did watch the field strip video.... I did use some oil but I wouldnt say I used a ton. I will strip it tonight and try again at cleaning it/oiling
 
I had issues with one not cycling but after I completely stripped it down and cleaned it real good it was ok
I ran the bolt and slides extremely wet with oil
They do need to be broken in, even the newer ones with the two different gas pistons
 
Deathrawt said:
I had issues with one not cycling but after I completely stripped it down and cleaned it real good it was ok
I ran the bolt and slides extremely wet with oil
They do need to be broken in, even the newer ones with the two different gas pistons
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I just finished doing that exact thing. Should I look into ordering the light piston? Where does the standard piston that comes with the older version I have sit on the scale against the heavy / light pistons?
 
Dry. Run them DRY. That is the best way to break in the gun. The parts will wear in faster at the faying surfaces. Lube defeats this. Yes you will get more stoppages but it is the fastest way to the end goal.

Cheers
Moe
 
Maybe a stupid question, how can you tell if one is an early or later version ? Looking to pick one up in the next couple months, but no idea how to tell?
 
aaron780 said:
I just finished doing that exact thing. Should I look into ordering the light piston? Where does the standard piston that comes with the older version I have sit on the scale against the heavy / light pistons?
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The early version piston is close to the new light piston, just a tad more to the heavy side.
 
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