Mark Gale

An ejector tool gives you the ability to fixture the bolt for disassembly. It depresses the ejector so it removes tension from the ejector pin so it can be removed easily. Two 1/16 punches speed the job also. A shortened version is for breaking the pin free and the longer version is to complete removal. At some point, you WILL bend the a long one if you use it to break the ejector pin free.

There are a lot of broken charging handles in this thread. The issue I have is the reports are very SHORT on details. What was it made of, who made it and where did it break are very important questions. To simply state that a Brand X steel charging handle is stronger than any aluminum variant is disingenuous. I would dare say that a charging handle properly machined from a 7075-T6 forging is indestructable. A Colt charging handle would be a good example. I would have to guess that any bent or broken charging handles were made from 6061 aluminum which is a very poor choice for ANY piece that is part of the operating system on an AR-15. I am willing to go out on a limb and say that a 7075-T6 charging handle can't be bent or broken. At 74-78K psi tensile strength and 63-69K psi yield strength, you would have to be SERIOUSLY abusing your rifle to break or bend it. A charging handle made from 1144 stress proof (DSA) is undoubtedly a strong piece but I'm not quite sure it is better. DPMS does not state what type of steel their charging handle is made from. I have to believe it is a price point part as 7075-T6 is around twice the cost of any steel that a charging handle could be made from.

Repairing the index pin is not difficult but it is HIGHLY improbable that anyone will be able to properly torque the barrel extension AND time the index pin with the gas port. A set of machinists V-blocks is the best method for fixturing a barrel when installing muzzle devices. The DPMS upper receiver block pictured above and others like it are a terrible design. The clamshell style is the better device for holding an upper for rebarreling.

I have to politely disagree. Having removed and installed a couple of thousand ejector roll pins in my time, I can assure you that dressing a roll pin is unnecessary. Having an good ejector tool and a quality pin and starter punch set is all you need. That being said, I am not aware of a drill motor that has a chuck that will hold a 1/16 roll pin that is only 3/8 of an inch long. Most chucks will not grab something that small in diameter unless it is nearing an inch in length.

Roll pins are cost effective and they work. In this application, thermal expansion is another consideration. A roll pin has the ability to do its job while being subjected to heat without stressing the bolt any further as it has room to expand and contract. A solid pin would have to be an interference fit and may stress the bolt with an increase in temperature. I have to believe that it would also be much harder to remove/replace than the roll pin.

The Matech rear sight should be set on the 300 meter mark and zeroed using a 25 meter zero target for the M4 carbine.

FN has redesigned the FNP-9 platform with a new selector lever. It is very similar to the FNP-45. They are currently available in Europe. I tried to find a pic but had no luck.