There is an excellent article at the link below to explain the choke process for shotguns.
Modified.
Yes
* Full *- Improved Modified ** Modified **- Improved Cylinder **$ Skeet *** Cylinder Bore
only if your choke is improved cylinder or modified, full chokes are a no,no. the barrel will bulge or burst!
Either. In general, slugs can be fired through any standard shotgun barrel. An exception is for Extra Full Chokes, which are not standard. Best accuracy with slugs in probably modified choke.
Yes chokes are designed to tighten shot patterns.
There is no "Standard" choke. A5's could be purchased with one of many different chokes, however, the more common chokes on a 28" barrel were Full and Modified
You can use a sabot in any shotgun, as long as the barrel is not choked. If you have screw in chokes, you will want to use ONLY the Cylinder or CYL choke. Otherwise, you will need to look on the barrel to see what it is choked in. If you do not have screw chokes, unless it says CYLINDER or SLUG, it is probably choked. (It may say Improved, IM, Modified, Full, etc)
Break open the action and it should be engraved on the metal that is normally unseen when the action is close, that or it should be on the barrel. If the chokes are removable then it should be engraved on those as well.
M=MODIFIED IC=IMPROVED CYLINDER S=SKEET F=FULL Also, as stamped on receiver: * Full *- Improved Modified ** Modified **- Improved Cylinder **$ Skeet *** Cylinder Bore
The question can have two meanings...if you are asking if the shotgun has a modified choke, usually it will say on the barrel if the choke is fixed (full, "imp cyl" for improved cylinder, "mod" for modified). If your barrel has interchangeable chokes, you just need to unscrew the choke tube and read what it says. If you are asking if it was modified from the factory configuration, modifications that aren't blatantly obvious (sawed off barrel or stock, magazine tube extension, shell holders, combat sights, aftermarket stocks, etc.), may be hard to tell, like a trigger job. For gross changes, have a factory picture and compare. Subtle modifications may be hard to tell.
To determine the choke of a Springfield Model 67 shotgun, you can measure the constriction of the barrel at the muzzle. This is done using a choke gauge or calipers to measure the inside diameter of the barrel at the muzzle and comparing it to the diameter further back. Standard chokes include cylinder, improved cylinder, modified, improved modified, and full, each corresponding to specific constriction measurements. Additionally, you can test the patterning by firing the shotgun at a target and assessing the spread of shot to gauge the choke's effectiveness.