Charlie's has worked hard to bring you a historically correct and functional gas block for the M110 sniper rifle system.
Potomac Armory has spent over a year researching the original Mk11 and M110 rifle systems, and has created a gas block that is both functionally correct to work with the M110 barrels from Potomac Armory or Knights Armament.
This gas block has been engineered and tested to accept the M110 and Mk11. The gas block ships without an alignment pin. The alignment pin, or a small slotted pin is needed for use with a suppressor. This gas block is also backward compatible with the Mk11 and the Mk11 suppressor system, with a change in the pin location. The suppressor alignment pin should be installed at 7:00 for the M110 or at 6:00 for the Mk11.
This gas block is perfectly timed for a KAC barrel. Note: KAC SR-25 barrels have the gas port in a unique location, so most gas blocks will not work. This gas block will work with a KAC barrel, a Potomac barrel, or one designed to match KAC specs for SR-25 systems made from 2000 to 2012. Maybe later, not sure. At some point, KAC moved to the screw-on barrel nut for the gas block. This will not fit on those barrels. This is quite important. Charlie's knows that there are barrel makers who claim to make M110 barrels, but the process requires very tight tolerances, and very few do it right. The barrel itself is unique and the profile very specific, and when manufactured to correct tolerances, some barrels are tossed aside as not meeting spec by the best barrel makers.
Note: This gas block, should be installed only by a qualified gunsmith. The interior diameter of the gas block is machined to fit very snug against a 0.75" gas journal. In most cases, this will require the cooling of the barrel and the heating of the gas block and a strong mallet to push the gas block into place. The three pinholes that need to be drilled through the gas block and barrel to properly attach the gas block are milled out, but not started. A gas block and a barrel should become one unit. Once drilled and mounted, the gas block and barrel become a system, and should not be removed, and gas blocks with three pinholes drilled should not be mounted to a new barrel. The gas block requires (not included) two taper pins and one roll pin.
Note: This gas block is designed to fit a Knights Armament or Potomac M110 or Mk11 contoured barrel, and should not be used on another brand of barrel, as it might not align with the gas port. This is super important.
The Mk11 and M110 barrel use alignment pins at the bottom of this gas block for the suppressor. This was done so that one would not mistakenly install the wrong suppressor, while as similar as the Mk11 and M110 suppressor are, they are not interchangeable, largely because the M110 has a flash hider and the Mk11 does not. In the early days of the Mk11 program, roll pins were used as index pins for the Mk11 suppressor. Later, the M110 came with dedicated steel pins. If you intend to use a suppressor, you should obtain indexing pins, or use a roll pin, and install at that time of mounting of this gas block.
This is not the Knights Armament gas block, but similar in design and all the same in fit and functionality.
Note: The walls of the barrel tube are super thin at the point at which the suppressor gate engages. It is not uncommon for there to be small wear points when new from the phosphating process, or as used with the gates eroding every so thin of a layer of steel, probably measure at 1/1000th of an inch.
Note: some pics may show the pin properly installed, but not included. If you need a pin, contact our sales team, and we can direct you to a parts distributor who carries the pins. Often times the pins are out of stock, but simple roll pin will work, and in fact was the original pin for the Mk11.
Note: This part is available by invitation only, as we will sell to qualified armorers or customers using an armorer well schooled in the Mk11 and M110 barrel system. We have had bad experiences where gunsmiths have told customers that our gas block was out of tolerance, when it was the gunsmith that did not understand just how exact the installation alignment and tolerances are. This is not a typical gas block installation, and not a DIY project unless you are a machinist and have the correct barrel. Most commercially available barrels are out of spec.
Note: "Knights Armament" is a federally registered trademark and is of many trademarks owned by Knights Armament Co. Potomac Armory and Charlies Custom Clones are an independent manufactuers and dealers, respectively, which are not affiliated with or endorsed by Knights Armament. Reference to Knights Armament and KAC are for explanation and compatibility for the end customer.
Knights Armament (KAC)