Issue with Hatsan Escort Autodefend - last shell stuck halfway out to shell carrier

[99octane]

Hi everybody, I'm writing as I have a problem with my Hatsan Autodefend 14" shotgun that I can't seem to figure out.
As it comes to its mechanism, the gun seems to be a replica of the Remington 1100, with some slight modifications, such as a self-regulating gas piston that allows it to function both with standard and magnum loads.

The gun is new.

It shoots ok (very accurate with slugs, actually) and very pleasant to shoot.

Only problem: when firing the second from last shot, the last shell often (not always) remains stuck halfway to 3/4 out on the shell carrier, the bolt almost to the rear, not locked open, just held there by the stuck shell, as it tries to rise the carrier.
A simple pull with the finger while holding the charging handle back and it will pop out on the shell carrier and, releasing the charging handle, the gun loads the shell just fine.
Very good for practicing clearing this kind of jams.
Not so fun or good for actual use.

TESTS I MADE
1)
it seems to do that just with light loads like 28 grams shot and target slugs.

2)
Problem almost disappears with loads > 32 grams

3)
Problem disappears with magnum loads.

4)
It won't do that manually cycling the action. The shell just gets ejected quite forcefully.

5)
If while manually cycling the action I push upwards against the shell carrier, it rubs against the shell and it becomes stuck as it does at the shooting range. Maybe a timing issue? (see below)


MY FIRST CONCLUSIONS
The magazine spring is for some reasons weak, and it doesn't manage to push the shell on the carrier fast enough before the bolt comes back and tries to lift it to the breech. Thus, jam.
So, either

Hypothesis A)
with heavier loads the recoil simply inertially "shakes" the last shell out of the magazine, circumventing the problem.

Or maybe

Hypothesis B)
with lighter loads the bolt doesn't go all way backwards and starts forward a tad sooner, engaging the carrier an istant sooner than it does with full power loads, so that it starts to rise with the shell still halfway out?
Other people with the same model didn't have this issue, so I tend to be suspicious about B).

FIRST ATTEMPT TO FIX THE ISSUE
I bought a new magazine spring for a few bucks, cleaned the magazine tube, cleaned the plastic follower, lightly deburred all corners in the action where the shell rim rubs.
Also lightly polished and deburred the shell carrier end to make sure it doesn't "bite" into a shell and the shell is free to slide out.
Tested the spring with scales and a dowel, new spring reads about 500 g more than the old one, at the same length of push, so I'm positive it's stronger.

I tested the gun at the range, and the issue was still there.

SECOND ATTEMPT TO FIX THE ISSUE
Since the problem arises with the last shot in the magazine, I just inserted at the muzzle end of the magazine a spacer the length of a shell, so that the spring is now compressed as if a shell is always present in the magazine (i.e.: the last shell behaves like the second-from-last).

This worked and the issue disappeared.

Obviously this turns a 5 shots shotgun in a 4 shots shotgun.
Less than ideal.

WHAT PUZZLES ME
Is that the springs were both OK: the first one new, the second one new and for a 5-7 shots magazine, so even tougher.
So, it's not the spring, it must be something else that interferes with the last shell being pushed from the tube to the shell carrier.

I noticed that the shell rim rubs against the shell stop on the right side of the receiver, looking inside the loading gate. But it seems designed to do so, to guide the shell while it gets loaded.
I'm at a loss.
Any ideas?

 

[entropy]

First; Did you disassemble the gun when you got it, and remove all the corrosive preventive preservative, then correctly relube it, or did you just take it out of the box and load it up and fire, like most people do?
If you did not clean it up first, it could be gummed up enough to cause the stoppage you've experienced. The below advice assumes that you have already cleaned it up:

1.)Clean up and polish the contact surfaces on the shell stop (s).
2.) Consider replacing the magazine spring with a longer (extended magazine size) one.
3.) If it's a copy of the 1100, on the 1100, they will do this if gunk gets down in the spring and follower for the carrier latch; solution is to disassemble the trigger group and clean out all gunk, then lightly relube and assemble. It can be cleaned without disassembly by spraying the trigger group out with the plastic-safe version of Gun Scrubber, but then it is harder to relube correctly.

I listed these in order of ease to do.

 

[99octane]

Thanks entropy.
Yes, I routinely field strip, clean and inspect any new gun I purchase, brand new or used.
Shell stops look shiny as they are, but I'll take a better look at them with a magnifying glass.
There could be machining burrs on the spring and follower of the carrier latch, so I'll have a closer look at that as well.
Thanks again.

 

[Cvans]

Clean, lubed and burr free it should work.
Is this a brand new gun. Some require one or two boxes of higher powered shells to be run through them before they will cycle properly.

 

[99octane]

Clean, lubed and burr free it should work.
Is this a brand new gun. Some require one or two boxes of higher powered shells to be run through them before they will cycle properly.

It cycles just fine... it's just the last shell that gives issues.
Anyway, put about 500 shots through it, of all kinds.

 

[Cvans]

Anyway, put about 500 shots through it, of all kinds.

I hope you can solve the problem. Sounds like your happy with it otherwise.

 

[99octane]

First; Did you disassemble the gun when you got it, and remove all the corrosive preventive preservative, then correctly relube it, or did you just take it out of the box and load it up and fire, like most people do?
If you did not clean it up first, it could be gummed up enough to cause the stoppage you've experienced. The below advice assumes that you have already cleaned it up:

1.)Clean up and polish the contact surfaces on the shell stop (s).
2.) Consider replacing the magazine spring with a longer (extended magazine size) one.
3.) If it's a copy of the 1100, on the 1100, they will do this if gunk gets down in the spring and follower for the carrier latch; solution is to disassemble the trigger group and clean out all gunk, then lightly relube and assemble. It can be cleaned without disassembly by spraying the trigger group out with the plastic-safe version of Gun Scrubber, but then it is harder to relube correctly.

I listed these in order of ease to do.

Hi, took down the trigger group but, at least by hand, the shell carrier latch and its plunger seem to work smoothly and without hitches. I didn't disassemble it as I didn't have time right now (I don't know this specific trigger group, but I know reassembling one of these little rascals can be a PITA if you don't know exactly how to proceed, and it's better to have some free time at hand before you try ).
Should there be any particular sign suggesting it's better to proceed with a full disassembly?

 

[entropy]

Gunk deposited in the area around it would be a good indication that a full disassembly of the trigger group would be in order. I don't really know if there are You Tube videos for the Hatsan specifically, but there are oodles of them for the 1100; Take pics of it fully assemmbled and during each stage of disassembly; I learned this one the hard way when I took an O/U shotgun down for re-bluing. It's just lucky I like puzzles, and studied the basics of gun design; it still took me about 10 hours of puzzling it back together. Now, I either find a You Tube video if one is available, or take pics. (or both.) The 1100 is one I don't need to do so for, I can do one in my sleep.

 

[99octane]

Yes, that's what I usually do, with new mechanical systems. I just need enough time to do it with due calm and a place where, should a spring take a leap towards freedom, it's not lost forever