First off make sure about the number of gas ports, the 19" should have 3 and the longer 20 something" should have 2.
Remove the gas plug and feel around in there with something small like an allen wrench or paper clip.
There's a place that does warranty work, I'll look for the info.
Here's the place to contact Cadiz Gun Works
When Red Jacket Will came out to Arizona last year I asked him what would be the best home defense weapon for me, specificly. I'm 67, open heart survivor and my neighbor's houses are 50 ft or so on both sides of me. I had a pump 12ga but with the thinners I take my shoulder would turn black and blue every time I shot it. Also my companion wouldn't use it as she's 5 foot nothing. He came up with a KalashniKoch. Looks like a HK but functions like an AK. .410, 8" barrel, gas puck is old style non adjustable. I played with a lot of different ammo before I got it to work perfect for home defense. It shoots estate 7.5 birdshot real well in the factory mag and the surefire. It likes Sellier and Bellot 00 Buck in the factory mag and the 10 rd surefire. S&B 3" is too long for the 15rd mag and jams. I tried the Federal Premium, personal defense #4 buck and it will only load in the factory 4rd mag. Too long for the surefire mags. It's a lousy personal defense load also. It's nothing but copper BBs packed in what looks like salt. This MP5 look alike won't cycle any steel cased 410 ammo at all. My conclusion is that the russian powder is not fast enough to properly build up pressure in such a short barrel.
The ammo that worked best for this weapon is the Winchester Super X Hi Brass 000 Buck. One look at the quality of the manufacture tells you why it cost 1.20 a round. The quality is there. It loads and cycles perfectly in the factory 4 rd. the surefire 10 rd and the surefire 15 rd. mag. Never a hickup. with a 15 rd mag you got 75, .37 lead balls out the barrel in less than 7 sec. at 1200 fps and 700 foot lbs. energy. My partner comes to the range now just to shoot it and prefers it to any pistol for HD. I get a 5" spread at 12 yds with the full choke on 000 buck. Iknow lot's of people poo-poo the 410 but for me it's the perfect gun with the perfect usage.
That looks like a winner! .410 buckshot is more than enough for a home defense situation. I remember a discussion a while back where we discussed a Saiga .410 as one of the perfect all-around home defense solutions. Woman-friendly recoil and the aforementioned buckshot solutions and you can't go wrong.