Disclaimer:
The information provided in this blog post is for educational and informational purposes only. Redleg Company Inc. does not assume any responsibility for the use or misuse of the techniques and procedures described herein. Firearms modification, including bolt lapping, can be complex and may affect the safety and function of the firearm. It is strongly recommended that any gunsmithing or modifications be performed by a qualified and experienced professional. Redleg Company Inc. disclaims any liability for injuries, damages, or accidents that may result from the improper application of the information provided. Always follow proper safety protocols and consult a professional gunsmith before attempting any modifications to your firearm.
At Redleg, we pride ourselves on our precise gunsmithing techniques, especially our bolt lapping process, which is essential for enhancing the accuracy of bolt-action rifles. Bolt lapping ensures that the bolt lugs engage smoothly and evenly with the corresponding surfaces in the rifle's action. Proper engagement is key for consistent bolt lock-up, which directly impacts the rifle's accuracy and the durability of its action.
Guide of Redleg's Bolt Lapping Process
Preparation:
Start by cleaning the rifle's action thoroughly. It is not necessary to remove the barrel, but make sure to clean the receiver bolt abutments and bolt lugs carefully. We use a special tool to make this step easier.
Inspect the bolt for any burrs or uneven surfaces on the bolt lugs and the corresponding lug recesses in the action.
Checking Lug Contact:
Keep the trigger in the receiver to accurately check and lap the lugs. The trigger's pressure pushes the bolt up into the rear bridge of the receiver, mimicking the conditions when the rifle is fired.
Use a permanent marker to color the back of the bolt lugs and let it dry completely. Before closing the bolt, push the bolt handle forward to clear the camming surfaces. This step is crucial to avoid a false reading.
Slightly lift and lower the bolt handle 5-20 times to allow the marker to transfer, showing the contact areas on the lugs.
Before removing the bolt, push the bolt handle forward and lift it to ensure the bolt lugs clear the lug abutments, preventing a false reading. Repeat this step each time you insert or remove the bolt.
Inspect the lug contact. Most factory firearms will usually only have one bolt lug contacting.
File Fitting the Lugs:
If all lugs are making proper contact, you can skip this step. If only one lug is contacting, use a needle file to carefully remove material from the high spots on that lug. Remove only the metal that has the marker removed! This will speed up the lapping process and ensure the bolt lug stays more perpendicular with the bore's centerline.
Continue filing and check until all lugs show contact. Clean the inside of the receiver with acetone after every other check to avoid false readings from residual marker ink.
Check frequently to avoid excessive metal removal, which can lead to a loose bolt fit or improper headspace.
Applying Lapping Compound:
Apply a fine abrasive lapping compound, such as silicon carbide or aluminum oxide in grease, to the bolt lugs and lug recesses. A grit size between 300 to 600 is ideal to avoid removing too much material while achieving a smooth finish.
Lapping Process:
Insert the bolt into the receiver, pushing the bolt handle forward to clear the camming surfaces. Manually cycle the bolt handle up and down slightly 20-40 times. This distributes the lapping compound evenly and allows the abrasive particles to gradually smooth down any high spots on the lug surfaces.
Monitor the process closely to ensure the material is being removed evenly. Check frequently to avoid over-lapping, which can lead to a loose bolt fit or improper headspace.
Checking the Contact Pattern:
After a few cycles, remove the bolt, clean it, and inspect the contact pattern using a spotting compound or marker.
The goal is to achieve at least 50% contact on both lugs, but ideally 80% or more, for consistent bolt lock-up. Both lugs should show equal contact.
Reassembling and Testing:
Once the desired lug engagement is achieved, thoroughly clean the bolt and action to remove any remaining lapping compound.
Reassemble the rifle and test the bolt for smoothness and proper lock-up. Also, check the headspace and ensure no unintended alterations have occurred in the chamber.
Fine-Tuning and Final Adjustments:
If necessary, repeat the lapping process with a finer grit compound or polish specific areas to ensure optimal performance.
Pay attention when cleaning do not leave lapping compound in your rifle
Benefits of Redleg's Bolt Lapping Process
Improved Accuracy: Ensures consistent bolt lock-up, reducing variations in receiver and enhancing shot-to-shot consistency.
Increased Bolt Smoothness: A well-lapped bolt operates more smoothly, making the action easier to cycle and improving the shooter's experience.
Extended Rifle Life: Even lug wear reduces stress on components, potentially extending the life of the rifle's action and bolt.
At Redleg, our bolt lapping method is a blend of precision and care, aimed at maximizing rifle performance while preserving the integrity of the action. Our approach is highly respected in the gunsmithing community for delivering exceptional accuracy and reliability in custom-built and accurized rifles.
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