Sunday, July 29, 2012

A Simple Barrel Break-In Procedure

Our customers have requested a suggested procedure for the 'break in" of the barrel on a new DTI rifle.  While opinions on the necessity of this and the steps involved vary, performing the following tasks on a new weapon will not cause any harm and may increase initial and long term accuracy. 

DTI rifles, rifle kits, and complete upper assemblies are all test fired at the factory.  Like any new weapon, it is always a very good idea to perform a general cleaning of the upper, bolt assembly, and barrel before using it the first time. Before starting break in, 20-40 rounds of jacketed ammunition and a cleaning kit (including solvent and lubricant) should be obtained. Using a solvent containing ammonia that does not have any oil in it will aid in removing any oil from the barrel and properly prepare the steel for the "break in conditioning".  These cleaning products may have a strong odor, but break in cleaning should be done while at an outdoor range so this will aid the dissipation of the scent.  Popular solvents from manufacturers like Montana Xtreme, Butch's Bore Shine, or Sweet's 7.62 Solvent will prepare the barrel and remove carbon and copper from the barrel left by the fired rounds.

Step One: Cleaning the barrel with this same type of solvent should also be done after each shot for the first ten shots. Whether you use only a solvent soaked patch or a patch and a brush, a dry patch should be passed through before firing the next shot. In the interest of safety, always make sure there is no foreign material in the bore before firing the weapon.

It is suggested to allow the barrel to cool in between shots so that, in the future, it will be less likely for shots fired in succession to "move" dramatically as the barrel warms.

Step Two: Once the initial 10 shots have been fired and a cooling period/cleaning with solvent has been performed in between each shot, two shots may be taken with the same type of cleaning done previously for another 10 rounds.  Once this series is finished, a thorough cleaning (including a light lubrication of the inside of the barrel, if it will not be used for a period of time) should be completed.

Various or more extensive break in procedures similar to the one described in this post may be beneficial, but following these two steps will ensure that the "burnishing" process is complete.  Proper maintenance of your DTI AR-15 (cleaning after each shooting session, and intermittently when stored for long periods of time) will provide longevity of service and enjoyment of your weapon.  Always make gun safety a priority when shooting or even handling firearms. Thanks for reading our blog. If you have any questions about DTI rifles, the products we offer, or anything related to the AR-15 rifle, please contact us.

Sunday, July 15, 2012

AR-15 Gas Block Options

DTI sponsored 3 gun competitor Michael Chambers with PRI adjustable gas block

Depending on your application, the standard or F-marked front sight base found on a "stock" AR-15 may not be the best option.  It works, and does it well. However, if you want to install a low magnification scope-low on the upper receiver or desire to increase the sight radius on a carbine or mid length, a different gas block may be the better choice.  In this post, we will discuss gas block types (we will put them in 3 categories) offered at Del-Ton and which ones would best fit the way you use your rifle.

The first type we will discuss is the low profile gas block.  These are typically a small, steel cylinder that mounts with set screws or clamp screws at the bottom of the part. DTI carries a couple of models from brands like PRI, Daniel Defense, and YHM.  There is also an adjustable model from PRI that can help ensure the proper amount of gas is channeled for cycling with supressors or different ammunition types. One of the main benefits of this style of gas block is that it allows for the use of a longer free-float handguard on the particular gas system.  If you have a carbine gas system, a mid-length or rifle-length handguard can be installed that runs well past the gas block.  This allows additional room for mounting accessories and a longer sight radius if a flip up front sight is used on the handguard.

Railed gas blocks can be beneficial in that they provide  M-1913 picatinny rail space for the addition of sights or accessories directly to the gas block. Because heat can be transferred to the gas block, only accessories made of metal should be attached.  It is important to remember to select a front sight designed for a gas block so that it will properly align with rear sights (typically, the top rail on gas blocks is a bit lower than those on railed handguards).  DTI carries single rail (one rail on the top), two rail (one on top, and one on the bottom), and four rail gas blocks in this style.  Again, the main advantage here would be no fixed front sight to disturb the sight picture of optics with low magnification or a low mounting profile.

The final type of gas block we will discuss is those that come with a flip up sight on the part.  This can be a definite money saving opportunity.  DTI carries models from YHM, PRI, Vltor, and A.R.M.S. that allow you to use the iron sight when it is in the up position or folded down so that a clear, unobstructed view can be obtained.  They may cost a bit more than the models with rails, but with the sight included they end up being more cost effective. 

Installation of these is simply a matter of removing the muzzle device and the front sight base.  DTI front sight bases are installed with taper pins and these should be driven out from the bolt assist aside of the weapon. A larger punch should be used first to get the pins "moving" and then a smaller punch can be used to finish tapping them out.  A front sight base bench tool, like those sold at Brownells, is extremely handy for this task. Be sure to remove the gas tube roll pin and gas tube gently so that they can be reused if needed in the gas block (however, this is an excellent time to install new parts if you are concerned about their condition). It is typically easier to install these in the gas block before mounting the gas block on the barrel. It is also important to note that a low profile gas block may not cover the mark in the barrel where the front taper pin was installed.  Most of the railed and flip up front sight gas block models will cover both of the marks left by the taper pins for a more aesthetically pleasing appearance. Finally it is imperative to make sure the gas block is properly aligned over the gas port and in line with the upper receiver to ensure proper functioning. 

Thanks for reading our blog. If you have any questions about the gas blocks we carry or any other AR related questions, please feel free to contact us.