Custom Rifles allow people to obtain the exact performance they have been looking for. People can have builds that perform bench rest accurate, or they can create an ultralight hunting build that they can take to the mountains. It is up to the user to choose. To give a baseline for comparison a Remington 700 off the shelf vs a 700 action built up by PRC.
Off the shelf
The off the shelf 700 will most likely come with your standard Remington stock. These stocks can expand and contract with different climates. This will cause your zero to change enough to miss that vital shot. In addition the Recoil lug sits into a cut out that is not properly fitted. In many cases we have seen factory rifles recoil off the receiver screw rather than the lug. While these screws can withstand this recoil it will put inconsistent torque on the receiver reducing the accuracy the rifle is capable of.
The stocks PRC puts their 700 action in are made out of rigid fiberglass and are filled with epoxy. These stiff materials result in minimal to no zero shift due to the climate's effect on the stock. In addition, PRC will add bedding compound to recoil lug,contact points, and the chamber area in order for consistent placement of the receiver.
Off the shelf
Standard Remington barrels are button rifled and are built within a certain tolerance; buttons that are used can be within varying degrees of sharpness. This will translate into barrels that have a tendency to like specific brands of ammo or a specific load type.
When picking a barrel we choose proof research barrels. These barrels are cut rifled. Meaning they are cut one groove at a time at 1/1000" per cut. Proofs barrels are held to a very high tolerance and their barrels are consistent throughout.
Off the shelf
Remington actions can have varying tolerances. The receiver face, lug abutments, lugs, and recoil are not all square. The lugs can sometimes have less than 60% contact on the abutments. The barrel threads on a 700 will be slightly off center meaning the barrel chamber will not be lined up with the receiver body. This will further reduce accuracy.
We will take these Remington 700 actions and square up all these surfaces. Our lugs will not leave our shop until over 95% contact is achieved. The barrel threads are re-cut to line up within 1 / 10,000 of center line of the bore.
Even with all the accuracy set backs, off the shelf remington rifles are known to be accurate shooters. However, when we take away all the set backs you can easily imagine the end result. The rifles PRC put out are guaranteed to be 3 shot 3/4 MOA with groups hovering under half MOA or better.