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Someone resurrected a 12 year old post about unitizing gas cylinders. It ended up with a question asking which modification has the most beneficial effect to improve accuracy. Some seem to think it’s the unitized gas system while others think it must be something else.

Unitizing has a particular function in the accuracy department. It helps stabilize the barrel by insuring it repositions itself after all the forces of recoil, barrel whip, stresses imparted by the bullet, and gas pressure move everything out of place. This helps insure consistency from shot to shot.

However, if the receiver moves around in the stock under all these forces, Unitizing won’t make up for poor bedding. It’s been proven that glass bedding is the single most advantageous modification one can do to improve accuracy. Bedding secures the back end in the stock, but a floating barrel band will still screw up accuracy. Unitizing works together with bedding to make sure everything stays in place and recovery is consistent.

Of course, none of this will help if you start with a bad barrel. Since we are discussing match grade accuracy a match grade barrel is necessary. A standard weight NM barrel helps, but medium and heavy barrels typically perform much better. They don’t flex as much which helps keep everything in place. Match grade barrels are also made to very close tolerances. Again, it’s all about consistency.

Flash suppressors do a lot of things that can screw up accuracy as the bullet passes through. They channel gasses that push the bullet out of the barrel. Once the bullet enters the suppressor, the gas, being under high pressure, flows around the bullet and it is exhausted out through the flutes and muzzle. Tolerances between the flutes and the passing bullet are quite close and this results in pressure against the bullet that is not always the most even. Note the wider web of the bottom flutes. This causes the bullet to be pushed upward as well as instilling a downward force which helps limit felt recoil. In order to impart a more even pressure with less disruption to the bullet, flash suppressors are reamed which does have a positive effect on accuracy.

There are three other modifications to an accurized M14. Sights are replaced with National Match versions giving finer adjustment and a sharper sight picture. The flat spring guide is replaced with one that is round and the trigger adjusted for minimal creep and weight of pull. These three things are not so much to make the rifle more accurate, but are done to help the operator control his or her shooting to get the best results from the rifle.

The NM sight allows ½ minute adjustments to achieve smaller point of impact changes on the target. At 600 yards this means one click of adjustment will move the bullets impact three inches instead of six. The thinner blade of the NM front sight and smaller aperture at the rear gives the operator a finer sight picture.

The match type spring guide makes the recoil spring run smoother. This has little to do with accuracy, but goes a long way to instill a degree of confidence, in the shooters mind, about how well his rifle functions. Smoother is better.

Last, but not least, is trigger adjustment. A good adjustment allows the operator to get his or her shot off with better control and less disruption to the rifle. The trigger is adjusted to break at 4.5 pounds of pull. This is the minimum allowed under both NRA and CMP rules for Service Rifle Competition. Triggers under 4.5 pounds are not considered safe and often result in double shots or a rifle that goes full auto. The adjustments also limit creep in the second stage. This allows a crisp break that seems much lighter than 4.5 pounds. The feeling of lightness comes from the operator concentrating on the second stage break after the first stage has been taken up. The first stage may take half the total weight of pull which is mostly ignored by the operator.

The point is that all of these things work in conjunction with each other to improve the rifles accuracy and the shooters ability to get shots off as consistently as possible. No one accuracy improvement has any great advantage over another. All of them help, but all rely on the others to get the best accuracy out of the rifle.
 
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