[uglydog]

My slug guns have hand me down scopes from rifles I upgraded. The recoil of a slug gun can be rather hard on a scope which is why I tend to favor at least lower mid-tier scopes. The two 12 ga guns 2 have 3-9x Burris Fullfield II scopes, one 20 ga has a 2-7x Thompson/Center "Recoil Proof", and the last 20 ga is topped with a 3-9x Busnell Banner.

The last gun is used the most, it is an H&R Handi-rifle Ultra Slug meaning it has a 12 ga barrel with a 20 ga bore. That makes it relatively heavy therefore pretty light recoiling which is probably one reason such an inexpensive scope has lasted so long. A hint is a fixed power scope is generally more recoil resistant than a variable as there are far fewer parts inside. I've tried cheap blister pack fixed power scopes on 12 ga slug guns and even a couple 375 H&H magnums for more rounds than I expected before failure. For a gun such as the H&R that may see 15-20 rounds for initial sight in, a couple rounds to verify sights every year, and maybe a couple rounds fired at game per year these cheap fixed power scopes can work well enough for many occasional hunters.

The Banner has lasted longer than I expected but these lower priced scopes can have some eccentricities. Many will shift point of aim/point of impact when the magnification is changed. The Banner changes 3"- at 100 yards between 3x and 9x. I sight in with 5x and leave it there as

 

[uglydog]

I agree. Choke tubes have a tendency to loosen up with shooting, not tighten. Maybe the poster is in the Southern Hemisphere? Things can be "backward" compared to here. 🤔

Far more likely crud is getting under the tube's skirt and debris is wedging the tube tighter. I would find that concerning to a degree as some day the gap could catch the projectile just right and be pulled out. That might damage the threads enough to require the barrel to be cut and retreaded. That has happened with bird shot a couple of times.

 

[uglydog]

Dang, bumped Send somehow.

As for scopes, my slug guns mostly wear lower middle tier rifle scopes. Scopes like Nikon Buckmaster, Burris Fullfield II, Leupold VX-I, Bushnell 3200/4200 and the like as I upgrade scopes on my rifles. Even today, these scopes or their equivalents will be well under that paid for your Mossberg. These are all variables, mostly 3-9x with a 2-7x added in here and there. Eye relief is decent, even on the highest magnification. The only significant difference between a "rifle" scope and a "shotgun" scope is the paralax on the rifle scope is typically set at 100 yards while the shotgun is set at 75 yards. On a target as large as a deer, the difference is not noticeable.

My cheap scopes currently are a 2-7x T/C "Recoil Proof" and a 3-9x Bushnell Banner. Both are on 20 ga guns, the first a pump the latter a single shot. The T/C is a step or two below the above scopes but it has lasted several years so far. The Banner is on an H&R Ultra Slug which is a 12 ga diameter barrel with a 20 ga bore. It is of decent weight with a decided muzzle heavy feel which cuts down on recoil quite a bit. The only real ideosyncracy is the Banner will change point of impact a fair bit as the magnification is changed. It also makes no sense as sighting it in on 9x might have poi move 2" toward 8 o'clock on 6x and move 3" towards 1 o'clock on 3x. So, I sight in with 5x and don't touch the magnification.

The cheap fixed power scopes can be fairly rugged as they are light and have few internal parts that can break or become damaged. I had a $20 blister pack fixed 4x Philipine made Simmons scope that I had to work hard to destroy. It did duty on a Savage 220 for several years then was tortured unto death by moving it to an Interarms Mark X in 375 H&H for a couple hundred rounds then a Savage 116 in the same caliber where it finally died just short of 100 rounds. Glass and coatings were OK and the turrets tracked slightly better but once it was sighted in it did not change.