Folding Front Sight Bases have been out for years, and for the most part, they have been ignored as the Military stays with the cheaper "fixed" option. While the Army gets ready to examine the next generation of carbines, we figure its worth taking a look at some of the upgrades that are currently available to the M4 and M16s. This installment looks at what the front sight base does, what we are currently using, and what any changes would do.
Click the below images for lots of pictures, and new world of sights to see.
Lets start out with what a Front Sight Base (FSB) does. Once the bullet is fired down the barrel, it passes the FSB and then exits. In the time it takes for the bullet to pass the FSB and exit, the gas flowing behind the bullet is forced through a small hole, and goes up into the Front Sight Base, and through the gas tube which then forces the Bolt Carrier Group to the rear. The reason this is important is because a faulty FSB turns a weapon into a one shot wonder.
What is wrong with the current Front Sight Base? It depends on what you are doing. The current FSBs are drilled and pinned through the barrel. They function as a fixed front sight that is both functional and durable. If you shoot with an Eotech or Aimpoint on your carbine or rifle, you may find that the FSB being constantly in your view is a detriment. Most shooters like an open view through their optic, which is what brings us to the folding Front Sight Base.
Starting with the Front Folding Sight Base from Atlantic Research Marketing Systems, more commonly known as A.R.M.S., you can see that their offering strongly resembles the standard FSB found on the M4 and M16s we are all familiar with. With it raised, its form is familiar, but it folds down flat to provide an uninterrupted view through your optic. The A.R.M.S. 41b shown below is available with or without a bayonet lug. It also comes in two versions, one that is locked to the barrel via screws, and one that is drilled and pinned to the barrel. The A.R.M.S. 41b is raised by pulling it up, once in place it locks into position. The locking method is quite strong, and I've hit one multiple times with a mallet in an attempt to make it collapse (no luck breaking it). The 41b sight is adjusted the same way as your current M4 front sight, so there is no learning curve. This FSB can be left up or down, depending on the individual user preference.
Knights Armament Co. (KAC) is well known by anyone who reads the side of the rail on their issued weapon, but their parts invention go much deeper than just military rails. The Folding Front Sight Base from KAC is available in a pinned configuration only, which make sense as drilling and pinning a FSB to the barrel is a stout way to keep it locked into place. KAC uses a small lever to activate the sight into its open (up) position. KAC allows for the FSB to be locked in place, or to let it stay in place via spring pressure. Some shooters prefer that a folding sight be held in place by a spring, so that impact simply pushes it down preventing any damage. Other shooters want a folding sight locked into place so they can leave it up all the time. With the KAC unit, shooters have both options available to them. The KAC Folding Front Sight has a bayonet lug.
* Note * We did not have access to an uninstalled KAC unit for this article
Vltor Weapon Systems has a unique look to their Folding Front Sight Base as it is grooved like a 1913 spec rail on top. The Vltor offering is available in a pinned or cross bolt clamping model, and is also available with or without a Quick Disconnect (QD) socket. While the QD may not where you want to clip your sling in, its an option that is not found on the other models we are aware of. The Vltor models are all steel, as are all of the FSB that we are talking about, but Vltor states theirs is manufactured to weigh less than a standard forged FSB found on the M4. While pinning is generally acknowledged as the most secure method of installing a FSB, Vltor has shown that a properly installed Vltor FSB withstands over 100ft/lbs of rotational torque. At those levels, the indexing pin is snapping at the receiver, which makes for a defunct weapon regardless of how it happens. Vltor has a video on their webpage showing the torque settings being applied if you are interested. Vltor stands out from the others in that it uses an AK front sight post instead of the standard M4/ M16 front sight post. This may or may not be an issue as most people aren't playing with their front sight once its been zeroed. Use of this unit is as simple as folding the front sight lever up or pushing it down to get it out of the way.
Wilson Combat is the newest manufacturer of Folding Front Sights in this round up, but they don't act like new guys with their design. Like the others, the Wilson Combat unit is all steel. It attaches via set screws which secure into place by locking against dimples placed in the barrel. For shooters who want extra protection, you can stake the metal to lock those screws down tightly. To activate the Wison Combat sight, you press a button and a heavy spring launches it into place where it is retained, and locked into place. To lay the sight flat, you press the same button while pushing down on the sight, and it locks flat in the down position. The sight post is the same as a standard M4 or M16, so there is nothing to relearn when you have your guys zeroing weapons.
We end with a few different options to get to the same result. Perhaps the larger question becomes how much the standard fixed FSB bothers you as a shooter. I understand that some readers will look at this and think it is a waste, and that the current FSB is the ultimate way to do things. To those people, I'll ask this, do you honestly think we will see a fixed FSB stick up on any newly designed weapons down the road? Maybe the M4 and its many offshoots will continue to wear standard A frame for awhile, but we can already see that certain military units (who run with the latest toys) have already moved away from this. Can everyone else be far behind?
We'll be continuing with a series of items that are available which bring new life and form to the M4 and M16 family. Let me know what you think, and what sort of components you would like to see reviewed or discussed next. For everyone reading this who is deployed, stay safe, and let me know what you think when you get the chance.