As part of my 2017 reviews, I'm going to discuss the Indian Creek Design Inc. (IDC) Adjustable Gas block (AGB). This low profile adjustable gas block is essential for a finely tuned AR15 rifle. Since I'm building a purpose built rifle for 3-Gun and range shooting with various light weight components, it is critical to make sure the rifle is tuned properly for reliability. Even if you are just plinking at the range, an adjustable gas block has several advantages over a standard gas block. Most AR15 rifles are over gassed for reliability, but this comes at a cost. If “recoil”, premature wear and carbon build up is a concern, than you will be thrilled to know the solution is a simple component wrapped around your barrel.
Before digging into the ICD AGB, I will provide some basic information on the function of a gas block. The purpose of a gas block in an AR15 direct impingement system is to redirect some the hot gasses from the bullet leaving the barrel through a small hole on top of the barrel through the gas tube, to the bolt carrier group, to help cycle the weapon. Most gas blocks are fixed static blocks, some are integrated as part of the front sight like the traditional A2, some have a picatinny rail on top, and others are low profile which fit under a free float handguard. Regardless of the style of these gas blocks, the majority are not adjustable. The good news is there is adjustable gas blocks available. The gas block, being an integral component for a reliable finely tuned AR15 is often over looked, not just by novice, but also advanced operators who do not realize the benefits.
Adjusting the gas in a rifle is nothing new, my first experience with an adjustable gas system was on a M1 Grand, which a good friend of mine who is a gun collector let me shoot over 10 years ago. I have to admit, it did not dawn on me it was a critical component for fine tuning the rifle at the time but I was intrigued. There very well could be older rifles with this type of capability to manipulate the gas system which I'm not aware of that an enthusiast could chime in on. Why adjustable gas blocks are not standard on AR15 rifles is likely due to manufacturers concerns the operator could adjust them incorrectly making the rifle less reliable, or simply because of cost. Regardless of the case, this is an upgrade every operator should at least be aware of as an option in my opinion.
Controlling the gas can be done in a few different ways on the AR15 platform. One less popular option is gas tubes which have needle valves for adjusting gas flow, it is not common and present their own set of problems. The gas hole size and location of the hole is another way to manipulate the system. The most popular way to control the gas is by using an adjustable gas block. There are many different models of adjustable gas blocks which come in different shapes and designs. Ultimately they all perform the same task by giving the operator the ability to fine tune the gas flow. What attracted me to the ICD AGB was the simple and elegant design. Knowing weight is an important factor for my light weight build, I appreciate the CNC work to help lighten the gas block as much as possible. Most importantly this "featureless" adjustable gas block does not contain set screws, detents, springs and additional metal tabs or bulge to host all these extra parts adding complexity and weight. The ICD concept is simple with a single adjustment screw coming out the front for easy adjustment. No need to remove the handguard or tighten set screws which strip easily.
The Indian Creek Design AGB is a low profile .750" adjustable gas block with three different types of finishes. It is manufactured all in house and made 100% in the USA using 416 stainless steel. The only component not manufactured in house is the fasteners which can be replaced through any major hardware store. I asked Gary, a Manager at ICD, about the source of material. He stated they purchase raw materials weekly for their own products and most customers. Some customers specify in their contract the raw material has to be sourced from US suppliers. This past year they have only once received imported steel, otherwise they normally source the raw material from EMJ and others within the continental US. The Cerakote finish is applied at a local vendor who handles these chemicals on a daily basis and is setup for this operation. The ICD AGG design is unique, I can say I have not seen any other adjustable gas block on the market which mimics this design and pattern. Gary stated this design helps cut down on weight while maintaining the integrity of the product and enhancing the aesthetics. He also brought up a valid point regarding competitors adjustable gas block designs when I asked if ICD recommends using any type of sealer to prevent the adjustment screw from backing out of adjustment. He stated out of the 6 ICD AGB he personally uses, only one of them has a drop of Red Loctite, while the other 5 do not and have never self-adjusted. He further explained:
"Carbon is a wonderful glue in and of itself. This is also why we dislike "detent" style gas blocks, as they can be rendered un-adjustable by carbon. With ours even if the screw is "carboned up" after a few "warming" shots it will be able to be adjusted with just a bit of torque applied to the screw."
Having used a bulkier style adjustable gas block I can attest to what Gary is saying regarding the detents and set screws. If you have any experience with those, you will know set screws are easy to strip. A big advantage of the ICD AGB is you do not need to take the handguard off to tighten any set screws or make adjustments. Depending on the length of the handguard and gas system, a long hex tool is all you need to make adjustments without removing the handguard. Another key point with the ICD AGB is there is nothing proprietary in the threading, which Gary is a big champion of, so operators are not stuck in the field unable to find a replacement fastener. There is nothing more aggravating than getting on McMasterCarr or some other supplier to order a box of 100 specialty screws when all you need is a few, with the ICD, just head to the local hardware store. I commend ICD for being anti-proprietary for simple fasteners.
The goal of using an AGB is to minimize the amount of gas required to properly cycle the action by making finite adjustments until you have the desired results. Installing the ICD AGB is very similar to installing any other low profile gas block. I had a small problem installing this gas block on my custom barrel, the outer diameter of the barrel gas block section was larger by a few thousandths, I took some fine grit sand paper to the gas block inner diameter and opened it up for a very tight fit. This type of tolerance issues is not uncommon from my experience when interchanging components. Prior to installation, I noticed some fine burrs by the gas port, I removed the adjustment screw and ran a toothpick through the adjustment port to remove them and filed off a stubborn burr. I followed this by polishing everything with my dremel, although not completely necessary I’m just very particular. I suspect these left over machines burrs are an anomaly. I contacted Gary and let him know of my finding and he said it would be noted during machining for better inspection of future gas blocks. The majority of my time was spent tuning the gas block. This is how I tuned the ICD AGB. I backed out the adjustment screw counter clockwise so there is no resistance on the gas flow from the adjustment screw. I loaded my magazine with one round, fired and confirmed the bolt locked back. I tightened the adjustment screw clockwise 1/4 turn, reload another single round and repeated this process until the bolt did not lock back. When this occurs, you have restricted the gas too much, so back out 1/4 - 1/2 turn counter clockwise and repeat to make sure the bolt does lock back. If you are happy with the performance you are done and have a tuned gas system. Obviously depending on many factors like the ammo load, BCG, buffer, etc… it will vary on your rifle what the sweet spot is. This is how you tune your rifle gas system properly by running through difference loads you will possibly use. As I cautioned in my other reviews, if you are using the rifle for combat or duty, than you would want to air on the side of caution and give it slightly more gas for reliability purpose. There are many factors which affect reliability such as worn parts, how clean the rifle is and how well it is maintained. It is at the operators discretion to make a sound judgment on what is the sweet spot for the intended purpose.
Before digging into the ICD AGB, I will provide some basic information on the function of a gas block. The purpose of a gas block in an AR15 direct impingement system is to redirect some the hot gasses from the bullet leaving the barrel through a small hole on top of the barrel through the gas tube, to the bolt carrier group, to help cycle the weapon. Most gas blocks are fixed static blocks, some are integrated as part of the front sight like the traditional A2, some have a picatinny rail on top, and others are low profile which fit under a free float handguard. Regardless of the style of these gas blocks, the majority are not adjustable. The good news is there is adjustable gas blocks available. The gas block, being an integral component for a reliable finely tuned AR15 is often over looked, not just by novice, but also advanced operators who do not realize the benefits.
Adjusting the gas in a rifle is nothing new, my first experience with an adjustable gas system was on a M1 Grand, which a good friend of mine who is a gun collector let me shoot over 10 years ago. I have to admit, it did not dawn on me it was a critical component for fine tuning the rifle at the time but I was intrigued. There very well could be older rifles with this type of capability to manipulate the gas system which I'm not aware of that an enthusiast could chime in on. Why adjustable gas blocks are not standard on AR15 rifles is likely due to manufacturers concerns the operator could adjust them incorrectly making the rifle less reliable, or simply because of cost. Regardless of the case, this is an upgrade every operator should at least be aware of as an option in my opinion.
Controlling the gas can be done in a few different ways on the AR15 platform. One less popular option is gas tubes which have needle valves for adjusting gas flow, it is not common and present their own set of problems. The gas hole size and location of the hole is another way to manipulate the system. The most popular way to control the gas is by using an adjustable gas block. There are many different models of adjustable gas blocks which come in different shapes and designs. Ultimately they all perform the same task by giving the operator the ability to fine tune the gas flow. What attracted me to the ICD AGB was the simple and elegant design. Knowing weight is an important factor for my light weight build, I appreciate the CNC work to help lighten the gas block as much as possible. Most importantly this "featureless" adjustable gas block does not contain set screws, detents, springs and additional metal tabs or bulge to host all these extra parts adding complexity and weight. The ICD concept is simple with a single adjustment screw coming out the front for easy adjustment. No need to remove the handguard or tighten set screws which strip easily.
The Indian Creek Design AGB is a low profile .750" adjustable gas block with three different types of finishes. It is manufactured all in house and made 100% in the USA using 416 stainless steel. The only component not manufactured in house is the fasteners which can be replaced through any major hardware store. I asked Gary, a Manager at ICD, about the source of material. He stated they purchase raw materials weekly for their own products and most customers. Some customers specify in their contract the raw material has to be sourced from US suppliers. This past year they have only once received imported steel, otherwise they normally source the raw material from EMJ and others within the continental US. The Cerakote finish is applied at a local vendor who handles these chemicals on a daily basis and is setup for this operation. The ICD AGG design is unique, I can say I have not seen any other adjustable gas block on the market which mimics this design and pattern. Gary stated this design helps cut down on weight while maintaining the integrity of the product and enhancing the aesthetics. He also brought up a valid point regarding competitors adjustable gas block designs when I asked if ICD recommends using any type of sealer to prevent the adjustment screw from backing out of adjustment. He stated out of the 6 ICD AGB he personally uses, only one of them has a drop of Red Loctite, while the other 5 do not and have never self-adjusted. He further explained:
"Carbon is a wonderful glue in and of itself. This is also why we dislike "detent" style gas blocks, as they can be rendered un-adjustable by carbon. With ours even if the screw is "carboned up" after a few "warming" shots it will be able to be adjusted with just a bit of torque applied to the screw."
Having used a bulkier style adjustable gas block I can attest to what Gary is saying regarding the detents and set screws. If you have any experience with those, you will know set screws are easy to strip. A big advantage of the ICD AGB is you do not need to take the handguard off to tighten any set screws or make adjustments. Depending on the length of the handguard and gas system, a long hex tool is all you need to make adjustments without removing the handguard. Another key point with the ICD AGB is there is nothing proprietary in the threading, which Gary is a big champion of, so operators are not stuck in the field unable to find a replacement fastener. There is nothing more aggravating than getting on McMasterCarr or some other supplier to order a box of 100 specialty screws when all you need is a few, with the ICD, just head to the local hardware store. I commend ICD for being anti-proprietary for simple fasteners.
The goal of using an AGB is to minimize the amount of gas required to properly cycle the action by making finite adjustments until you have the desired results. Installing the ICD AGB is very similar to installing any other low profile gas block. I had a small problem installing this gas block on my custom barrel, the outer diameter of the barrel gas block section was larger by a few thousandths, I took some fine grit sand paper to the gas block inner diameter and opened it up for a very tight fit. This type of tolerance issues is not uncommon from my experience when interchanging components. Prior to installation, I noticed some fine burrs by the gas port, I removed the adjustment screw and ran a toothpick through the adjustment port to remove them and filed off a stubborn burr. I followed this by polishing everything with my dremel, although not completely necessary I’m just very particular. I suspect these left over machines burrs are an anomaly. I contacted Gary and let him know of my finding and he said it would be noted during machining for better inspection of future gas blocks. The majority of my time was spent tuning the gas block. This is how I tuned the ICD AGB. I backed out the adjustment screw counter clockwise so there is no resistance on the gas flow from the adjustment screw. I loaded my magazine with one round, fired and confirmed the bolt locked back. I tightened the adjustment screw clockwise 1/4 turn, reload another single round and repeated this process until the bolt did not lock back. When this occurs, you have restricted the gas too much, so back out 1/4 - 1/2 turn counter clockwise and repeat to make sure the bolt does lock back. If you are happy with the performance you are done and have a tuned gas system. Obviously depending on many factors like the ammo load, BCG, buffer, etc… it will vary on your rifle what the sweet spot is. This is how you tune your rifle gas system properly by running through difference loads you will possibly use. As I cautioned in my other reviews, if you are using the rifle for combat or duty, than you would want to air on the side of caution and give it slightly more gas for reliability purpose. There are many factors which affect reliability such as worn parts, how clean the rifle is and how well it is maintained. It is at the operators discretion to make a sound judgment on what is the sweet spot for the intended purpose.
