Hatsan MPA cycling issue?

I totally disagree with the "keep it dry" suggestion.
I had the same hatsan. Same issue at first.
Polished the mag tube. And slick with oil.
Ran perfectly after that.
Put approx 500 rounds of all cheapo shells without cleaning once. Just a spray of gun oil on the mag tube to keep it slick.
When I assemble the hatsan I roll the o ring onto the mag tube until about an inch before where the gas piston sits.
Then slide the barrel on.
This allows the o ring to seat itself firmly into the gas block.
 
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From the pic of your gas piston and o ring.
If assembled this way the o ring is on the wrong side of the gas port. Assemble like I suggested and give it a go.
 
Weird. I just bought the same shotgun 2 weeks ago. I have fired 75 federal target loads, 2 slugs, and 2 #4 turkey shot. Only had one failure to eject out of those and it as a target shell. I didnt have to polish anything. I just keep the mag tube and o-ring slightly lubed and it runs fine.
 
Adamlxlx said:
Weird. I just bought the same shotgun 2 weeks ago. I have fired 75 federal target loads, 2 slugs, and 2 #4 turkey shot. Only had one failure to eject out of those and it as a target shell. I didnt have to polish anything. I just keep the mag tube and o-ring slightly lubed and it runs fine.
Click to expand...

Quality varies and not all guns are the same.
It takes about 20 minutes to polish the tube and minimal tools.
Even though you only had one failure a polish will improve things....
 
Thanks very much for the input everyone. Just a small update, so for a second time I pulled it all apart and polished every thing I could find, magazine tube, action, and gas system. I also have picked up an oring from a Hatsan dealer as I think potentially the one that I have on it may not be the original. It seems to small, so now I have an original.

As soon as I get a moment to step out to the forest I'm going to shoot some more target loads, slugs and 3" target loads to see if I still have the same problem. All in all I'm
Very impressed with the MPA, and I'll be super happy if I can fix this issue. I was also made aware that it had a 5 year warentee, so if no solution has been found I'll take that road.

Thanks again everyone.
 
So here is a question for you guys... The new O ring I got from the local Hatsan dealer seems to be really big. Could any one check if there o ring... This will be hard to discribe, but if you look in the collar that comes off the bottom of the barrel, inside it you can see that there are two holes for gas from the barrel. Right behind that is a raised ridge, then a flat spot then the raised end of the collar.

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When I put the new o ring in it slides in just until it hits the first ridge where the two gas ports are.
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But the old smaller o ring for right up against the very front raised lip.
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Would any buddy be able to tell me what size there O ring is and where it settles in on the gas system? I can't find any pictures of this online.

When I put it on the mag tube after assembling the gas piston and I put the barrel on, there is no longer the 1/4 slop movement of the piston.

I guess I could just try shooting with both o rings? Any thoughts?
 
Here is a couple pics of mine the o-ring is on the forward part of the piston, I don't think it was meant to be on the mag tube since it is way too big.

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Must be hit and miss. I picked up mine a few months ago from fishing world in Hamilton. Put a few rounds of buck through it, then tried a few target loads (can't remember what kind, green shells) and failed to eject almost every one. Picked up a few boxes of S&B 2 5/8" slugs and ran them through with no problems. Tried the same bird shot green shells, and cycled everyone perfectly. Picked up a case of clever target loads and took it skeet shooting (the old boys weren't impressed) but went through 5 boxes with no problems. My O ring is tight on the mag tube. I have the tube a light sanding during the first cleaning. A bit of oil on the o ring is all I use. It's been a great gun.
 
Thank you for all the advice everyone. After some unsuccessful attempts at the local Hatsan dealer to get the right O ring. (And charged me $12 for the wrong one) I ended up at an auto parts store and we found the right one out of there O ring kits. This gun still doesn't really enjoy target loads but it cycles every thing more powerful with zero issues.

I have tried both the Winchester #4 from Canadian tire and challenger 7.5 from sail and both tend to short stroke the action.
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We then tried this 2 3/4 target load, that a friend had and it cycled flawlessly. But I have no idea if I could even get more of this. I'm not even sure where you would look.

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It will also cycle 3" target loads with no problem at all, but I haven't found any at a good price to shoot for skeet. Does any one know of any target loads that are slightly more powerful then the Winchester or challenger shot but still is available at a good price?
 
Have you tried the new Imperial 7.5 stuff from Crappy Tire? Same box as the old 1980's era Imperial stuff, but I think it's made by Challenger for someone else to their spec. It's loaded in Imperial colour dark blue hulls.
 
Buzzballer, out of curiosity, did you lube the mag tube? I found mine seems to work best almost dry there. In fact, I use a dry moly lube on the mag tube, but I grease the o-ring. I have successfully used the shells you tried (both brands) without issue. The only other thing I can think of is make sure your gas ports aren't blocked somehow.
 
Hmmm...

I only ever really use the Score #7.5 target loads anymore... Too many issues (with a number of different guns) with the Fiochi and Winchester target shells. Never really thought much about it in terms of my Hatsan, because that's the only target shells it's ever seen. Good quality, brass base hulls, decent amount of punch for a target shell (I find the Winchester target loads to be just a bit on the light side).

AmmoSupply.ca usually has some in stock, and WholeSale Sports has taken to stocking them as well. Maybe pick up a box or two to try?
 
Give the chamber a Polish. Perhaps it's a little tight and the El cheapo target brass/aluminum is binding on extraction?
 
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