Getting the Most out of  The 12 Gauge 3-1/2 Shotgun and Ammunition

By the 1950s, the versitility of the 12 gauge established its dominance as an every-day shotgun.  

The 3 1/2" 12 gauge  is an elongated version of a 12-gauge shotshell, the objective to make the 12 gauge a better long-range, large bird gun.   

The 3-1/2 shell  offers additional space in which to use more components, bulkier powder and/or more payload.  How  you use that space will determine your success with the 3-1/2" 12 gauge shotshell.

Questions most often put to our technicians about the 3-1/2" 12 are whether this is a shell equal in performance to the 10 gauge and whether the  additional space should be reserved only for extra shot payloads.  The answers depend on how you plan to use it.

With the additional length you have a 12 gauge hull that is the same overall length as the standard 10-gauge magnum hull.   The diameter remains the same at a nominal .729" (12 gauge) compared to .775" (10 gauge).  The additional length (but not diameter) offers several performance choices for the 12 gauge 3-1/2" handloader: additional payload choices, additional velocity or happy medium of "more." 

So, based on the success of earlier evolutions, should the 12-gauge again try to be a 10 gauge?  You have to take marketing with a grain of salt sometimes.  Regardless of some pretty bombastic promotional claims, hull length, by itself, does not create extraordinary shift in performance or capabilities.

Turkey hunters may opt right off the bat for more payload; denser patterns at a cost of feet per second.  Pass shooters may want to use the space for some of the markets newer space-hogging powders (with excellent burning characteristics) to  propell loads faster, with more energy.   Let's look at both options a bit more in detail.

Guns Designed for Specific Loads:
If you are choosing to avoid a 10 gauge because of what you have been told about fierce recoil, don't believe it; someone is either pulling your leg or inadvertently passing along mis-information.  I have shot one since I was 13 and by no means do I resemble King Kong.  Punishing recoil is a result of a poor matching of firearm and ammunition.  

This applies, as well, to the 12 gauge 3-1/2".   The modern 3-1/2" shotgun is a completely different species than earlier 12-gauge shotguns.  The guns are designed to accomodate non-toxic loads as well as iincreased chamber pressures.   The frames are modern alloys, very solid and stout as well.  Most are semi-automatic, which will absorb recoil.

Physics of Recoil:
You can make loads that are punishing to shoot.  A box of 12 gauge 3" loads with 41 pellets of #4 lead buck weighs in at a solid 2 ounces.  The recoil produced by this load, in  a lighter 12 gauge, just plain hurts.  A shooter may succeed in firing an entire box of these repulsive loads in a morning's shoot, maybe developing a flinch, a headache and, since low velocity loads such as these are not designed for moving targets; go home empty handed.   Have you reached a performance objective?   No.  Is a 2-ounce load therefore useless?  No.  Just keep in mind that it's a relationship between firearm and loads.  If you are shooting heavy loads, you will want a heavy-framed gun.  Don't assume your favorite sporting clays double should also be used for heavy turkey loads.

Ballistic Comparisons by Gauge
Because of design differences between the 12 gauge and the 10 gauge (bore diameter, surface area, choking area, etc.)  a 10 gauge has better potential to kill a goose. Here's why:

Bore diameter is the difference between the gauges and why specific gauges are more compatible with different payloads.

Understanding Bore Diameter
In any given amount of shot, the bore size will determine the maximum speed the shot can be driven. The smaller the bore size, the less speed a given amount of shot can be driven, at a given chamber pressure ceiling. Furthermore, in passing through a smaller diameter tube, a greater percentage of the pellets remain in contact with the bore throughout the transition.

Conversely, in a larger bore, more shot may be placed in a load and driven with higher speed. Larger pellets may also be used without incurring pattern density or consistency reductions. The reason for this phenomenon is that a greater number of pellets and/or pellets of a larger size can work their way through the constricted area of a choke at the same time.

Once an adequate amount of shot is in a load to take the intended game, it is in the handloader’s best interest to drive up the speed, increasing the lethal quality of the load throughout its effective range.

Tuned for the hull and the shotgun the 3-1/2"12 gauge can be an advantage to the hunter and reloader. The 12 gauge 3.5" hull can improve your shooting provided the space is used for components that increase lethality of the load - all of the separate elements accounted for: speed, consistency,   sufficient pattern.   As you prioritize, speed is a dominant factor of lethality.   Most frequently, fewer, more lethal pellets make the killing load.

The 20-gauge 2 3/4" is a very nice upland bore and often the shotgun is designed for quick and comfortable work. However, the 20 gauge 3" hull does not make the 20 gauge a goose gun.  You can make the ammunition, but it has to be compatible with the gun.

An overloaded shotgun is at a point where the best potential of the shotgun has been surpassed and the results now get worse (diminishing returns).   Furthermore, due to physical constraints of shell length versus bore diameter, pattern development potential inside the barrel erodes.  They no longer are consistent.  Generally, part of the consequences is also reduced load lethality.

The 20 gauge can be stretched toward the 12 gauge performance envelope by use of the 3" hull, but the performance level does equal that potential of the 12 gauge, especially as other factors, such as pellet size, relative to bore diameter, are considered.

As it attempt to poach on the magnum territory owned by the 10-gauge, the 3 1/2" 12 gauge can be loaded to diminishing returns.   The 12 gauge 3-1/2" will come up short, just as the 20 is to the  12.   The trick with the 12 gauge 3.5" is to find its domain, and utilize all of its advantages.

What are we getting at here?
Is the 3 1/2" 12 gauge a loser? The answer is an emphatic no! We are simply saying is that reception of the 3-1/2" 12 gauge potential has been off a couple of degrees. It has been stamped  into our collective shooting hats that it is a direct replacement for the 10 gauge.  Just as the 3" 20 gauge is not a direct replacement for the 12 gauge, neither is the 3 1/2" 12 meant to do a 10 gauge's job.

We know which payloads work best in a 12-gauge 3-1/2".   These are a bit different than 10-gauge loads - don't look for absolute parity, look for absolute performance and specific applications.  Use these loads. Make them fast by taking full advantage of the Pagoda Principle. Utilize the extra length to create tight seals for absolute consistency.

Defining Applications for 12 gauge 3-1/2" 

For the turkey hunter
: It is a great choice.  Excellent patterns, shotguns with great versatility and easily manipulated loads with a lot of room for variations, including multi-gas seal designs that improve all aspects of load performance and consistency.

For the 12 gauge steel shot loader: Extraordinary velocities can be coaxed out of 3 1/2" loads.  We have noted in our recipes some very consistent loads, even at the top edge of useable velocities. We even have some loads just under 2000  feet per second published for the 12 gauge 3-1/2"  (See Status of Steel). 

For the slug shooter: The versatility is being applied to new G/BP 12 gauge Dangerous Game slug loads.  We use multiple seals to create conditions for utterly stable velocities - which will translate to pinpoint accuracy.  We are, as usual, pushing the upper edge of velocity and finding some very accurate and lethal big game loads -- even at extended ranges!

Get More Guns!

The 3.5" 12 gauge will never be a replacement for the 10 gauge. The 12-gauge bore diameter remains the same whether or not the hull is 2 3/4", 3" or 3.5". The final recommendation from us is that one shotgun cannot fulfill all needs.  Additional shotguns are your only solution.  Inform your spouse, immediately.

The excellent hunter needs to own and learn to best utilize all available shotgun gauges and types. To state that one shotgun can handle every type of shooting is a rationalization for not being better at a multi-dimensionl sport.  For instance, the golfer does not use just one club.

The 20 gauge is a crackerjack in the upland brush. Other folks love the lightness of the 28 gauge to carry all day. The 16 gauge provides many of us with fine late season shooting when cover is sparse and the birds are tougher and warier.  Light ducks need a solid 12 gauge and perhaps the steel shot situation calls for a different 12 gauge (a 3 1/2" maybe?).  Pass shooting geese - there is only the 10-gauge.  Try it once and you'll just know.

Many of us would use 8 gauges if the ill-informed people manufacturing our waterfowl hunting laws had not bungled. In countries such as Scotland, an 8 gauge is not only legal, it is considered proper. Clean kills are the rule.

We hope this helps our hunter friends improve their time in the field........BP