Notes on Shotgun Modifications
for the
Remington M11/87, M1100 & M870

Over the years I learned a lot about shotguns, what works and what doesn’t.  I took that knowledge and applied it to both the competition and personal defense shotguns.  When I refer to a competition shotgun, I mean one that is suited for Bowling Pin and 3-gun matches, not Trap and Skeet.  

Out of all this there are really only two things that make a shotgun competitive: 1) Reliability and 2) Fast Handling.  To meet these goals I have always favored the Remington.  They offer easy disassembly and assembly for cleaning and maintenance; have a wide range of accessories available; have excellent parts availability; are very reliable; and offer low recoil in the M11/87 & M1100 due to gas operation.

Because weight has a direct relationship to recoil I prefer to use wood stocks instead of synthetics for competition.  As a rule synthetics tend to be lighter and increase felt recoil, which we want to reduce.  By cutting down the recoil and muzzle rise, recovery time is faster.  Synthetic stocks have their practical side for use in a working gun.

Barrel lengths usually run 26” for competition.  On the personal defense models barrel length runs from 18" to 20".  Contrary to old beliefs, barrel length controls the speed of a shooter's swing.  A short barrel moves from one point to another quicker than a long one.  Unlike the days of black powder where long barrels were required to achieve good powder burning and velocity, today’s powders require only 18" to 20" of barrel length.  A long barrel does not “shoot harder” or pattern any different than a short barrel. It is choke constriction that determines patterns.

With the wide acceptance of the screw-in choke tube today it has given the shooter a marked advantage by allowing one barrel to be set-up for almost any situation in a matter of minutes.  For choke tube selection we need to answer a few questions; will the shooter be using slugs, shot or a combination?  If shot, what size, how much (ounces), what powder charge and what distance(s) will it be shot at?  These variables will all affect the pattern that the shotgun shoots.  On selecting a choke tube for shot, the best procedure is to test at the distance(s) you plan on shooting using the same size target(s).  You may want to try several different choke constrictions and brands of shotshell to see what results are achieved.  We want a pattern that covers the target.  Not to large, not to small and without large holes, with even coverage.  And just because you use Brand X with one shot size does not mean you can use the same brand with a different shot size and get the same pattern.  Never change anything with the load(s) you have tested without making sure that you have also tested their substitute.  The worst place to start changing things you have not practiced with is at a match or in a pinch.

When shooting slugs, no matter what brand or type, they should never be shot through anything tighter than an Improved Cylinder screw-in choke tube.  Slugs shot through a tighter tube can either crack it or blow it out the barrel, not good.  Slugs can be quite accurate and trying several different brands, can be rewarding.  When shooting slugs, fully rifled barrels and rifled choke tubes are going to be consistently the most accurate and should shoot less than 3” at 100 yards compared to a good smooth bore barrel.  For shooting slugs in a smooth bore barrel you want the slug to be as close to the bore diameter as possible. You also want the bore diameter to be a consistent diameter the entire barrel length.  This is especially true with the Foster type slug.  The Foster is formed from lead and features a hollow base which can partially expand against the bore to provide a gas seal and provide support for the slug as it travels the barrels length.  If the slug is quite undersize in relation to the bore diameter inaccuracy will result.  This is due to the fact the slug cannot make solid contact with the barrel bore and tends to wobble down the bore.  The other factor that can be involved with poor accuracy not related to ammunition is that the barrel bore diameter is either not a consistent dimension, i.e. the diameter increases and decreases in size along the barrels length or the bore is oversize in relation to the standard gauge dimension which can be seen with barrels that feature overboring.  Even though the slug skirt might expand to compensate it would still not provide enough solid support for the slug.

On Buckshot I prefer 2¾” shells with  #00 in 12ga and #3 for the 20ga.  Realistically I think 25 yards is the practical limit for Buckshot in a Tactical or defense situation. The Improved Cylinder Choke works well if a use of slugs is anticipated otherwise a Modified Choke may provide better patterns.  In my opinion the shotgun with buckshot is for close range work. Go beyond 25 yards then a better choice is either slugs or a rifle.

The last item is sight selection.  The rule of thumb I go by is shot or slugs within 25 yards a bead or ghost ring sight is fast because it’s simple.  If Tritium is used I prefer just the Front Sight.  Go beyond 25 yards with slugs and I prefer rifle sights for accuracy.  I normally reserve scopes for slug shooting at 100 yards or beyond due to a limited field of view.  I feel they slow down the fast handling qualities of the shotgun.   A 4X Scope is more that enough at these distances.

One final point to remember is that shot and slugs may not shoot to the same point of impact.  So a little experimentation may be in order to determine how much sight change, if any is required.