AR Parts/Accessories Help

Question: Thank you so much for your help. . I’m trying to gradually get the parts I need to assemble my 6.5 Grendel upper as the funds come available. I don’t know if I explained before, or if you remember my mentioning this, but I’m partially blind, and am lost as a round ball in high weeds sometimes when it comes to what’s best and what’s needed when BUILDING an AR. I know the ins and outs on furniture and most of the lower, but figuring out what the differences are in muzzle devices is way over my head. Do you have any advice on muzzle devices, or is it pretty much like furniture where it’s pretty much up to your preferences? Continue reading

One of the greatest aspects of the AR platform is the ability for anyone to build an entire firearm from scratch with very few specialty tools needed. In fact, many come into the shop at Fighting Sheep Dog and do just that!

There are a few parts that are easier to buy pre-assembled than to build. The bolt carrier group is one of them. But it need not be an intimidating process to assemble one!

Today, we’re breaking down the 5.56 Bolt Carrier Group – what’s in it, full auto vs semi, low mass options, the various coatings and processes, and more! Continue reading

For starters, you’ll know pretty quickly if the gas system isn’t working properly on your AR. The firearm may not cycle properly, or you may see premature wear.

In order to better understand the various types of gas lengths in your AR, we kinda need to explain what the gas system does in the first place.

Gas System Explained:
When you look at your AR barrel, you’ll see a tiny hole on one side. That’s the gas port. When a bullet is fired through the chamber of the barrel, the gas from the bullet being fired is forced through the gas port via the gas block and directed down the gas tube and into the upper receiver.

The gas is then used to power the bolt carrier and cycle the next round. This is known as “direct impingement”.

In most instances, the longer the barrel, the longer the gas system. Most 7″ barrels (and shorter) have a pistol-length gas system. Most 16″ barrels have a carbine-length gas system. Most 18″ barrels have a mid-length gas system. Most 20″ barrels and longer have a rifle-length gas system.

However, you will occasionally see terms like “SOCOM” on a barrel, typically used to describe a 16″ barrel with a mid-length gas system.

What Difference Does It Make?
The length of the gas system affects both the smoothness of the firearm’s cycling of each round, and it’s dwell time.

Dwell time is the term used for the amount of time a bullet is in the barrel after the gun has been fired.

Typically, the longer the barrel, the harder the gas system has to work in order to get enough air to cycle the next round.

It should also be noted that, the longer the gas system (for example, the SOCOM barrel mentioned above), the more air is being pushed through. The longer the gas system, the smoother the cycling. Smoother cycling can positively affect the overall performance of the firearm.

It should be noted that, as in life, too much gas is a bad thing. If your gas port has been expanded and too much gas is being pushed through the system, then recoil and premature wear will be a factor. Always let a qualified gunsmith work on your gas ports – it can ruin the barrel if you make a mistake here!

So What Gas System Should I Have?
As with most AR-related questions…it depends. It depends on your barrel length, what distance you’ll be shooting, and what you’ll be using the AR for. And anyone who tells you that they have a magical, mystical system for gas lengths without knowing all of the answers to the variations mentioned above are probably trying to sell you a barrel.

A lot of it has to do with the barrel itself (see the entire series we did on AR barrels), but remember that this is an entire system with each part feeding off the other part, so changing one piece changes everything.

The best thing to do with ANY AR is to change one piece at a time to make sure the gun does what you want. Especially if you’re troubleshooting a gas system issue and not just wanting to lengthen the gas system for smoother cycling.

Have a question for the gunsmith? Wanna know something about your AR? Submit your questions via our Questions/Comments page or email us at


The way we see it, there are three options.

The first is a DIY method requiring you to replace the trigger group springs with lighter ones like JP Enterprises makes. If you can remove and install the trigger assembly, this is an easy job.

There are also drop-in replacement triggers available from several manufacturers. Timney and Chip McCormick both make excellent units that are easy to install and are a huge improvement over the stock trigger.

The best and most reliable method is to have a gunsmith install install the trigger for you (We at Fighting Sheep Dog are stocking dealers for Timney and ALG/Geissele).

Avoid filing or stoning on the engagement surfaces of the hammer and sear. These parts are surface hardened and if too much material is removed, they will be ruined and can cause major malfunctions.

One of the often-overlooked, yet vital component of an AR is the trigger. In fact, second to looking through the front sites, pulling the trigger is often one of the first things you do when picking up an AR in a gun shop, at a show, or admiring the one your friend just got.

But alas, all triggers are NOT created equal.

Let’s look at some of the key components of a trigger, and what to look for the next time you fire a shot.

Key Components of an AR-15 Trigger:

ALF/Geissele Combat Nickel Boron Trigger for the AR-15

ALF/Geissele Combat Nickel Boron Trigger for the AR-15

  • Trigger
  • Trigger Pin
  • Trigger Spring
  • Disconnector
  • Disconnector Spring

So what makes one trigger different from another?

Most triggers are made from steel. They can be Duracoated to any color you choose. They pull (on average) between 6-12lbs. MOST standard triggers are guilty of “creep” – the amount of trigger movement before the hammer falls. They also may not have a smooth action…and smooth = fast.

That’s why we sell ALG/Geissele Nickel-Teflon Coated AR-15 Triggers.

So What’s So Great about an ALG/Geissele Nickel Boron Coated AR-15 Trigger?

  1. The ALG Defense ACT trigger pull is smoother and sharper than a stock trigger. This is accomplished by polishing the sear surfaces smooth and HardLubing the trigger components.
  2. Sear geometry has not been changed from the standard profile so the high reliability that the stock trigger is known for is unchanged.
  3. Trigger and hammer are made from true 8620 alloy steel military specification castings, correctly carburized, quenched and tempered for high surface hardness.
  4. Disconnector is 1070 High Carbon steel properly Austempered into the spring range of hardness.
  5. Springs are corrosion resistant and meet military specifications.
  6. A full force hammer spring is used for positive ignition of all type of ammunition.
  7. Trigger and hammer pins are improved over stock mild steel by using 4140 Chrome-Moly steel that has been quenched and tempered. Pins are centerless ground to a fine finish and a diameter 0.001” larger than stock to reduce play in the trigger assembly while retaining a slip fit into the weapon lower receiver. Both pins are Nickel-Teflon coated.
  8. Pull weight is above the U.S. Military minimum pull weight of 5.5lbs but does not reach near the upper limit of 9.5lbs. Generally, the pull weight is about 6.0lbs.