What is a buffer and how does it work?
The AR-15/M-16 rifle, as do all semi-Automatic rifles, needs a recoil spring to cycle the action. Due to the lightweight design of the AR, the spring also requires a buffer, or extra weight. The buffer is one of many pieces that helps your rifle to operate normally. When a bullet has fired the energy that it released pushes the bolt carrier backwards which then connects with the buffer within the buffer spring and tube. At the point of contact, the buffer pushes the spring backwards. Depending on the weight of the buffer and the strength of the spring the buffer will reconnect with the bolt carrier pushing a new bullet forward into the chamber to be fired.
Why are there so many options, and how does it matter?
We will start with the buffer spring. Most springs are fairly standard, but you will encounter different variations on the market. The springs for the rifle and the carbine are the same diameter, and made of the same steel alloy. The rifle springs have 41 to 43 coils, and the carbine springs have 37 to 39 coils. The brand-new length of the springs is approximately 12.75″ for the rifle and 10.5″ for the carbine springs. Make sure you start with a carbine spring if you have a Carbine buffer tube, and a rifle spring if you have a rifle buffer tube.
Above: top is carbine buffer, bottom is rifle buffer. Warning: they are not compatible...
As for choosing the proper buffer weight that can be a little tricky. First start with the mil spec Carbine buffer it should weigh 3 Oz. If your rifle fires properly and the bolt locks back after the last shot, Congratulations you have a properly functioning carbine! Many people aspire to dial in their carbine for better performance such as follow up shot target acquisition, or simply want their action to function smoother. You can achieve this by replacing your buffer with a heavier weight buffer. If you get a weight that is too heavy the rifle won’t be able to push the spring back and reload the weapon, so it is important to move up one by one in weight until you get the desired smooth action while still maintaining proper function. below are the standard variations for buffers:
- Mil Spec Carbine buffer 2.8 Oz.
- H Buffer 3.8 Oz.
- H2 Buffer 4.7 Oz.
- H3 Buffer 5.6 Oz.
Choosing the Right Buffer for your system
We have done extensive research and testing on over many configurations and calibers, we will share with you our findings now so that you can skip all the BS and go straight to the performance setup.
Carbine Gas Systems:
Let me begin by saying that we find the stock 2.80 Oz buffer to be way too harsh on almost any carbine setup, its loud, violent, and overall feels abusive. We equip all of our buffer and stock kits with the optimized buffer at 3.0 oz. This is a great all around buffer that keeps your rifle recoil in check. However For optimal performance and top end competition where milliseconds matter, we find that our H2 4.5 Oz. buffer will fit the bill. We standardized on the 4.5 Oz. weight instead of the 4.8Oz. because again that is where we found the best performance vs reliability ratio and have decided to offer this performance upgrade to our very loyal Customers!
Mid Length and Rifle Length Gas Systems:
We find that our Standard H Buffer equipped with all of our kits will be perfect for proper function and smooth action with less perceived recoil.
Proper buffer weights will result in a smoother functioning rifle and prolonged service life of parts. It keeps the rifle in battery slightly longer so the extractor has an easier time doing its job, and has more inertia bringing the bolt forward ensuring more reliable chambering of the next round. Adjusting buffer weights has the side consequence of improving the recoil impulse especially with the commonly over-gassed platforms commonly available on the shelves of most gun stores allowing for more efficient shooting.