Building Your Perfect 3-Gun Rifle: Part 2

(Reliability is paramount in Niki Clevenger’s 3-Gun rifle builds – photo credit Snippets of Life Photography)

Part 2: Functions, Classifications, and Build Strategies of the Ideal 3-Gun Rifle

In our previous article, we discussed the recent trends in the firearms industry to customize and improve upon standard rifle designs. We also introduced a few of Criterion’s sponsored 3-gun shooters. Each shooter was interviewed to discuss the various facets of their “ideal 3-gun rifle”. Before we delve into every component found in each shooter’s rifle, we wanted to find out what factors were most important when they selected components for their 3-gun rifle build projects:

Stewart 3 gun rifles

(Although these two rifles appear similar at first glance, each build is configured to fit two very different shooters)

What are the most important functions of a 3-gun rifle?

Niki Clevenger: Reliability is the most important (requirement). When I pick this rifle up, is it going to work like I need it to EVERY SINGLE TIME? This is hugely important with a rifle, not only in competition but in personal defense. When the buzzer goes off I pick up that rifle, put my sights on target and pull the trigger. Is it going to fire? That’s important.

Heath Clevenger: Reliability, accuracy, and maneuverability are the three most important functions of a 3-Gun rifle.

Sean Dexter: Three variables come into play: Reliability, accuracy, and consistency.

Madalyn & Thomas Stewart: Four factors come into consideration when it comes to rifle function:

1. Reliability: People spend countless dollars trying to add, delete, or modify parts of the rifle system in an attempt to cut tenths or hundredths off of the split times. Often times this is done at the cost of reliability. Just one malfunction in a match will have a much larger negative effect on stage time and final finish.

2. Accuracy: Your rifle needs to be consistent in maintaining a zero. Your rifle also needs to have an accuracy level that will provide you with the mental confidence that when you do your part as the shooter, you will know your targets will be hit.

A rifle that holds 2 MOA will probably not hold you back from most 3-gun stages. That said, I think you will be hard pressed to find a top competitor whose rifle cannot hold 1 MOA accuracy. About the toughest target you will face in competition is going to be a 2 MOA target at distance, with most being larger than that. Having an accurate rifle will help put the odds in the shooter’s favor when they have to make tough shots from awkward or unstable shooting positions.

3. Fit: The rifle needs to be set up to accommodate the shooter’s size and shooting style. The shooter needs to be able to bring the rifle up to a consistent shooting position while they are in less than ideal shooting positions or moving around obstacles.

4. Interaction with barriers or supports: The rifle needs to be set up with a handguard or rail accessories that match the shooter’s technique. Some shooters prefer round handguards. I prefer a rail with a flat section on the bottom and sides. With this flat section I feel I can build a more stable shooting position while using a barricade to rest or pin the rifle.

Other options include add-on grips or stops on the rail. These can be used to increase grip for those that choose to pull the rifle into their shoulder as they shoot. They can also be used to lean body weight forward into the rifle (preloading) when using a sturdy barricade.

Madalyns 3Gun Build

(Madalyn’s 3-Gun build incorporates a hand stop to help stablize the rifle when placed against barricades or obstacles)

Rifle Classifications

While it would appear that reliability is paramount from the perspective of each shooter, the design of each build will vary widely based on each different competition category (Open/Unlimited, Tac Ops/Practical, Limited/Factory, and Heavy Metal). We asked Thomas & Madalyn to describe the unique design requirements of each rifle classification.


In open division pretty much anything goes. The most common elements of an Open rifle are the ability to have two optics mounted on the rifle. This allows for a higher magnification scope to be used or left at a single magnification while using a 45° offset red dot sight for close targets. Bipods are the next most common item found on an Open rifle to aid in long range shooting. Other items rarely seen include laser sights, large compensators, or even sound suppressors.

Tac Ops/Practical:

Tac Ops is by far the most common classification and comprises about 75% of all match competitors. The primary defining characteristic of Tac Ops is that only one optic is allowed on the rifle. The most common optics are a 1-6x power scope with some 1-4 and 1-8x magnification optics mixed into the group.

These variable power scopes have the ability to offer magnification for shooting small or distant targets. The second key feature of these optics is the ability to offer true 1x magnification use with a bright illuminated center reticle section. This allows the shooter to engage targets with both eyes open, transitioning quickly from target to target while on the move. The rifles are also limited in the size of the compensator, which is generally 1” x 3”.

tom stewarts build

(Thomas Stewart’s Factory 3-Gun build (an American Defense MFG UIC Mod 2) netted him a best in class win at a recent Polo 3-Gun match)


Limited classification is primarily defined by the sighting systems allowed. Shooters may use iron sights or an optic, but they are limited to a 1x magnification. Other than that, the rifle restrictions are the same as Tac Ops. The change in sight restrictions provide a greater challenge with long range targets. Depending on the match and target set up, sometimes seeing or finding the target is a greater challenge than hitting them without additional magnification. A good example would be a grey steel set hidden in the shadows of a wood line.

Heavy Metal:

Heavy division rifles are defined as .308/7.62×51 NATO or larger. Some matches also divide the Heavy division by optics (1x or magnified). The rule set beyond that varies widely from match to match as to what limitations are applied to handguns and shotguns. The rules may also vary with the rifle for how many hits are required to neutralize a target. Most will allow one hit from a .308, but some will still require two (just like the .223 rifles).

Build Strategies:

Each shooter held a different school of thought regarding their unique build requirements. The style of each rifle was dictated by a number of variables, including the match type, shooter size, and even the personality of each shooter.

Sean: I try to gear my rifle toward what I know the stages will likely be at the match I’m going to shoot. For example, matches where the maximum (target) distance is 350 yards, I will use a rifle with a 16” or 18” barrel. Distances out to 600 yards will get a 18-20” rifle (barrel). Quick, short matches with target distances of 200 yards or less will get a 16” lightweight barrel.

I also prefer the longest functional gas system available for the chosen rifle barrel length. I’ve recently begun to incorporate lightweight bolt carriers, adjustable gas blocks, and lightweight buffers. Shooting a gun with these features, properly adjusting your ammunition, is a surreal experience. It’s a huge difference.

Niki: I prefer an 16” barrel on my 3-gun builds, but as a female shooter I have a few unique design requirements. I prefer a light weight rifle for my string bean lady arms, allowing me to effectively hold up and manipulate the firearm. I also need an adjustable gas block, because as a female I can never make up my mind. Adjustable is always better (laughs)!

Heath: Some people like a rifle length gas system and say that it is the only way to go. They say it shoots softer. I have built an 18 inch rifle length gas system rifle before and still used an adjustable gas block to cut down on the gas.

The extra barrel length will add bullet speed for less hold over. I did not notice any real difference in my hold overs from 300 to 400 yards on standard style steel targets when compared to a 16.5 inch barrel. I am sure there are a few inches difference in point of aim and point of impact, but not enough to affect the hold over point in the scope.

I like the shorter barrels for maneuverability, and 16 inches is all I can get without a tax stamp or welding the brake on the barrel. I want a barrel that I can install and change parts on myself legally. I prefer the mid length gas system in a 16.5 inch barrel. The benefit of longer gas systems is less heat and carbon in the BCG. Rifle length systems are less dirty than mid length and carbine length systems. So I use as long as I can get on the barrel I like to use.

I use adjustable gas blocks to meter the gas in the operating system. In theory, it takes a certain amount of gas to push the BCG to the rear and operate the system. No matter the length of the gas system. So, rifle or mid length does not matter in regards to recoil. The recoil that goes straight back does not matter so much, it is the recoil that moves the rifle off the target when it is fired that matters. A light weight bolt carrier group should transfer less energy into the rifle as it works back and forth, therefore not moving the rifle off target as it operates.

Thomas & Madalyn: There are two basic types of 3-gun matches that need to be accommodated, although some integrate features of both.

The classic 3-gun match is considered a natural terrain match. These are generally defined by the length of a stage. Measured in time, round count, distance covered by the shooter, and distance to targets. For these types of matches the most common rifles incorporate an 18” barrel with a rifle gas system. With the longer distance and generally more accuracy-centric rifle targets, a slightly heavier, more stable rifle benefitting from the slight velocity boost of a longer barrel provides a few additional advantages.

Bay style matches and stages are all about speed. Rifles built to excel in bays are designed to be short and light. The small size helps in many aspects of a bay style stage, starting with the gun transition where the rifle is picked up off the table. These rifles are quicker to scoop up off the staging table and getting into your shooting position. Bay stages are known for lots of targets in a small area. The light, compact rifle aids in fast driving of the rifle from target to target. Bay stages can also incorporate a number of obstacles (barrels, walls, ports, etc.) that the shooter will have to maneuver and shoot around. The compact rifle also helps when trying to shoot while moving around these obstacles. These rifles are generally built off of a barrel with a 16” mid-length gas system, as they are the easiest to purchase and build (due to all the red tape surrounding NFA regulations). Many people try to take this a step further and run 13.5” or 14.5” barrels with pinned and welded compensators to accommodate NFA regulations. These are also the rifles where shooters attempt to use the lightest handguard/rail and compensators they can source to cut weight off the muzzle end of the rifle to aid in rapid target transitions.

In the remaining two segments we will carry out a piece by piece analysis of each shooter’s “ideal 3-gun rifle” broken down between the upper and lower receiver groups.

Part 1: Introduction to the Perfect 3-Gun Build
Part 2: Functions, Classifications, and Build Strategies of the Ideal 3-Gun Rifle.
Part 3: Upper Receiver Component Selection.
Part 4: Lower Receiver Component Selection.

Criterion Barrels always welcomes feedback and input from shooters using our products. If you would like to share details regarding your ideal 3-gun rifle build (that includes your preferred Criterion barrel model), feel free to send us a list of build specs and a photo of the rifle, submitting your response to [email protected]

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