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Accuracy refers to a firearm’s ability to place shots in a tight cluster on target. However, “tight” is subjective. Bench-rest shooters demand sub-MOA (minute of angle) groups, such as five .22-caliber bullets in one hole at 100 or 200 yards. Varmint or big-game hunters may accept 1-1.5 MOA, equivalent to 1-1.5 inches at 100 yards. For this discussion, a hunting rifle should consistently achieve 1.5 MOA or better at 100 yards.
Experienced shooters dedicate hours to tuning hunting rifles for groups of 1.5 inches or less at 100 yards. Contrary to popular belief, rifles sent to gun writers are not specially selected for performance. Manufacturers and importers lack the resources to hand-pick test guns, so reviewers evaluate standard production models and report the results. When time permits, they may adjust a rifle to improve grouping.
Shooting skill significantly impacts performance. Seasoned shooters, who frequent the range, develop techniques that maximize a rifle’s potential. Less experienced hunters, shooting only occasionally, may struggle to achieve similar results. In tests, skilled shooters have halved a novice’s 2 MOA groups using the same rifle, ammo, and bench. Proper breathing, trigger control, and a stable rest are critical.
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Can a barrel lose accuracy after just 100 rounds? This is unlikely. Even high-powered magnum calibers, often equipped with stainless-steel barrels, retain accuracy for thousands of rounds. Most accuracy problems arise from three sources: barrel bedding, action bedding, or optic issues.
Optic Issues: The Primary Cause
Optic-related problems are the most frequent cause of poor accuracy. Even professionally mounted scopes can fail due to:
- Loose scope rings, permitting movement.
- A canted or misaligned scope.
- Residual grease on rings or mounts.
- Incorrect ring size or mismatched mounts.
- Loose or misaligned mount screws.
- Improperly drilled receiver holes (rare in factory rifles).
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For home gunsmithing, a padded wooden box or vise with felt-lined jaw protectors securely holds the rifle. A 20-inch-long box with notched, padded ends, weighted with shot bags, is effective. Small parts can be stored in the box to avoid loss.
If a scope appears canted, the bench and vise must be verified as level. The ring screws should be loosened, the scope rotated until the crosshairs align vertically, and the screws retightened. If bore-sighting reveals insufficient windage or elevation adjustment, a gunsmith may need to shim the mounts. Misaligned receiver holes, though rare, require professional correction.
Barrel and Action Bedding
Stock issues, particularly barrel and action bedding, often undermine accuracy. Wood stocks, even when well-inletted, can warp and press against the barrel, deflecting shots. In one case, a rifle that shot MOA groups in dry conditions produced 4-foot patterns after exposure to moisture, due to a warped fore-end. Inspection revealed an unprotected barrel channel that absorbed water. To mitigate this, the stock’s barrel channel should be inspected and sealed with marine spar varnish or shellac if unsealed.
Inletting compound, available from gunsmithing suppliers, identifies contact points between metal and wood. Excess wood should be scraped away to ensure proper fit. For free-floated barrels, the fore-end must not touch the barrel. For barrels requiring upward pressure, small shims (e.g., cardboard under the receiver) can be tested to optimize tension. Lateral pressure should be avoided, as lightweight barrels tend to shoot away from it.
Loose bedding screws can also degrade accuracy. These should be tightened carefully, ensuring the action and recoil lug bear evenly against the stock. Uneven contact may whip the barrel or crack the stock. On some rifles, such as surplus Mausers, small locking screws secure larger bedding screws and must be properly adjusted.
Barrel Maintenance
If bedding and optics are sound, the barrel itself may be the issue. Fouling can reduce accuracy, even in modern rifles with non-corrosive ammunition. The barrel should be cleaned thoroughly with a powder solvent and wire brush, followed by a bore-cleaning compound like J-B (used cautiously, as it is abrasive). Patches should be pushed through until they emerge clean. If the bore’s lands and grooves remain sharp, fouling was likely the problem.
Barrels eventually wear out. A heavily used magnum rifle, after 4,000 rounds, may struggle to shoot 1.5 MOA, down from sub-MOA performance, indicating a worn throat and the need for a new barrel. However, sudden accuracy loss after fewer rounds typically points to fouling or bedding issues, not wear.
Glass Bedding and Triggers
Glass bedding, which uses epoxy to create a precise fit between action and stock, can improve accuracy and protect against moisture. However, it does not compensate for poor stock work or transform an average rifle into a bench-rest performer. Full-length glass bedding may negate the benefits of upward barrel pressure, so partial bedding is often preferable for free-floated barrels.
A crisp trigger pull enhances accuracy. Many modern factory rifles feature adjustable triggers that can be fine-tuned. For non-adjustable triggers, a gunsmith can refine the mechanism or install an aftermarket trigger tailored to the shooter’s preferences.
Shooting In a Rifle
Some rifles improve with use. Minor burrs or roughness in the barrel may smooth out after 100-200 rounds, particularly in high-velocity calibers. This “shooting in” process also settles the action into the stock. Bench-rest shooters clean their barrels after every session, highlighting the importance of consistent maintenance.
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