AR-15 Bolt Carrier Assembly


Understanding how the bolt carrier works in your AR-15 is vital to knowing how the entire weapon operates. This means that a basic knowledge of the plating, weight, coating, firing pin hole size and choices of bolts will help you create a smoother, more reliable firearm.

The bolt and carrier of the AR-15 is the action of the weapon. The bolt carrier rides in the upper receiver and it houses the bolt as well as resets the hammer inside this device. The carrier also holds up against the gas pressure when the weapon is being operated. In fact, the pressure is what cycles the firing mechanism.

There are two basic configurations for the bolt carrier on the AR-15. The differences can be found at the rear of the configurations themselves. The AR-15 features a shorter section at full diameter found at the back of the weapon while the M-16 offers a longer section. The M-16 carrier also features a shrouded firing pin which means it has a big collar style.

The differences in the bolt carrier design between the M-16 and AR-15 also includes weight of which the M-16 is heavier, but only by an ounce or so. However, since owning an M-16 often requires having a tax stamp, you may want to stick with the AR-15 instead. There is a possibility that you might find an accessory market carrier that will match what you need for the M-16, but you will have to look.

The AR-15 Bolt Carrier Aftermarket Assembly Product

The original design for the bolt carrier comes from Dan Young and now is produced by Les Baer. The bolt carrier assembly has flutes to hold the lubrication and makes it easier to slide when needed. Plus, the additional weight works well with high pressure ammunition. The plating itself is easy to clean up with just normal wiping with a soft cloth required.

Many people prefer to have a heavier carrier if possible because it adds to the stability of the weapon itself. However, you can choose a bolt carrier from a popular company or one that specializes in this type of weapon. Either way, your choice will be based on quality, weight, and price. In truth, a premium part is generally only slightly better than a standard one, but you will have to be the judge about such matters.

You can use a plated or coated carrier which does offer a slight advantage, but not too much. This is because the accessory finish does make them easier to clean and maintain. However, for lubrication purposes they are really no better than a standard carrier, especially in terms of performance. If you want to spend a little less time cleaning up the AR-15, then by all means go with a plated or coated carrier. But it will not help your performance any by choosing that type.

Lightweight carriers are generally not liked by many people who use the AR-15. There are a number of reasons for this, but while they do soften up the recoil of the weapon, they also make it somewhat harder to handle and shoot effectively. Over the years, there have been several attempts to make a lightweight version really work, but the weight itself is actually an asset when firing the weapon so it appears that for the foreseeable future, lightweight carrier designs will not be generally desired.

Firing Pin-Hole Size

The size of the firing pin hole is critical to the performance of the weapon itself. If the hole is too big, then the primer which is pressure-induced will have issues in consistently firing the rounds. It will also lead to structural failures in the primer which means that they will not properly pierce on a consistent basis. This all has to do with the size itself as it will not handle maximum pressure loads.

This means that you will need to accurately measure the size of the hole to ensure that it is just big enough to do the job correctly and no bigger. Otherwise, you may compromise the effectiveness of the rifle itself.

Adjusting and Cleaning the Bolt Carrier

You’ll want to examine the bolt carrier before installation to ensure that all rough edges and ridges are properly smoothed for a better fit. Also, be sure that it is properly lubed as well to help smooth out the action. By addressing the bolt carrier itself and keeping it properly maintained with enough lubrication to ensure steady action, you’ll reduce any accidents that may occur.

This also means keeping the weapon clean as well. A build-up of dust, dirt or debris can clog up the function of the bolt carrier which reduces its efficiency. You should regularly schedule maintenance for your weapon and also clean it after events or other times when it has been used. You’ll want to get all the carbon build-up out of the recesses of the bolt carrier as well. In fact, engine cleaner makes for a great way to loosen up and clear out the carbon that can build up in this part of the weapon.

Things you Need to Know about your Bolt Carrier

You should have a carrier key when purchasing a bolt carrier, but if you do not, then acquiring one is a good idea. However, you can always use a specialized screwdriver to keep the screws in place. This is because carrier screws will loosen over time, so you will need to tighten them down after every use and check them before you first fire the weapon.

Check the firing pin retainers as well. Sometimes they are not up to code or not properly installed, so you will want to check them to see if they need replacement. You can be pre-emptive and use the old-style solid firing pin retainers which remove this problem.

Your bolt carrier assembly needs proper maintenance and cleaning in order to function properly. By following these procedures early on, you can minimize your maintenance and maximize your use of the AR-15 on the range.


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