You can get online owner's manuals from Winchester's web site, or here:
http://www.stevespages.com/page7b.htm
Keeping the gun FULLY loaded depends on you.
Most people keep their gun in "cruiser ready" condition. That is, the magazine fully loaded, the chamber empty, hammer down.
All that's needed is to pump the fore end to chamber a round.
This is the preferred method, since it's safer and doesn't leave the action springs under tension.
Most modern guns like you Winny will not have hammer spring problems even if left cocked, but should be checked periodically.
Leaving the magazine loaded has two cautions:
First many, or most magazine springs will loose at least some tension over time if fully loaded.
The "fix" is to download the magazine by one round.
If you have a 7 round magazine, put only 6 rounds in it.
The reduction in tension goes a long way to prevent spring problems.
Another "fix" is to simply buy high-grade magazine springs and replace the spring once or twice a year.
Unloading the gun to "rest" the spring does NO good, since cycling a spring actually causes it to deteriorate faster.
The second big problem with leaving a shotgun magazine loaded is actually a BIGGER problem than any possible spring issues.
This is "shot shell compression".
Plastic shot shells tend to collapse under tension in a magazine.
What happens is, under spring pressure the plastic cases tend to collapse and develop bulges between the steel shell head and the shot column.
These bulges can cause failures to feed and extract.
This is quite common with plastic shells, and first appeared in police guns that were left loaded long term, when the plastic shells were introduced.
How fast and how bad the shells bulge varies, depending on the shells.
You should closely monitor your gun to see how fast the brand of shell you use develops bulges.
There are several "fixes" here.
The first is to simply shoot up the rounds every month or so.
Second, buy only high-grade American made shot shells, since foreign made and cheaper shells seem to be made of plastics that are less stiff and bulge faster.
"Resting" bulged shells does NOT do any good.
Once bulged, the shells stay bulged, and as soon as they are replaced in the magazine, they start bulging more.
When you find bulged shells, the best thing is to just use them for range practice.
Cleaning a pump gun is fairly simple.
The first and most important task is to THOROUGHLY clean both the bore AND the chamber.
Another "problem" with plastic cases is, they burn all lube from the chamber, and the chamber can rust if not properly cleaned and coated with a rust proofing lube.
Use a NEW bore brush or chamber cleaning brush and a good bore solvent to scrub the bore and chamber.
After scrubbing, wipe out with several solvent-soaked patches, dry, then closely inspect.
Check the bore and chamber for any "streaks" that indicate lead or plastic fouling. If you see any thing suspect, scrub more with brush and solvent until the entire bore and chamber is clean.
If you have a screw-in choke, use the wrench to remove it, and soak in solvent or choke cleaner solution until all carbon and lead and plastic fouling is gone.
Coat the bore, chamber, and choke with a good rust-proofing lube, and wipe out he excess.
To clean the action, disassemble per the instructions.
Brush out all plastic, metal debris, and burned powder particles.
Coat everything with a THIN coat of lubricant and reassemble.
Once a year, or more often depending on how much you shoot or the conditions the gun is used in:
Disassemble the magazine assembly and clean the inside of the magazine tube, the spring and follower.
Re-lube and reassemble.
Remove the trigger group and spray it DRIPPING wet with a good spray lube like Rem-Oil to blow out all fouling and foreign matter.
Shake off and allow to drain.
Wipe off the excess lube with cloths and an old tooth brush and reassemble.
