Tag: tests

In the past, I have used high speed video to analyze various aspects of AR-15 operation. Today, I did some testing at the range with several action springs. This is intended to be an ongoing test, so all three action springs were brand new. They are: - Tactical Springs/Sprinco "Blue" recoil spring - Brownells M4 Recoil Spring - Chrome Silicon - Brownells AR-15/M4 Recoil Spring The test weapon was a 16" carbine gas AR-15 with a .063" gas port, H buffer, 5.56mm NATO chamber, M16/Auto bolt carrier, and AR-15 fire… Read More

Here's some high speed video comparing why free floated barrels move during firing. The results shouldn't be very surprising, but the cause is a lot more simple than some might think. The movement is not due to barrel fluting or piston/op-rod operation, but the simple act of a muzzle device placing uncontested force at the very end of the barrel. Because the barrel is free floated, it only has support where it meets the receiver. As a result, we see the barrel move a bit. When this same rifle has… Read More

Aberdeen Proving Grounds 1960 AR-15 Test Linked above is a PDF report from February, 1960, about some early AR-15 testing. I've had it for a while but don't believe that I've discussed or posted it in the past. There's a large amount of technical data, to include precise gas port diameter and location, distance the bolt travels before unlocking, precise travel of the front sight post per notch moved, and so on. It also includes multiple 10 shot group accuracy testing, 6000 round endurance testing, extreme heat and cold testing,… Read More

Much more to come.

We've been bombarded with a variety of coatings and platings over the past few years, most of which are called "proprietary" and given a cool name. In reality, there aren't a whole lot of finishes or metal treatments out there. Many are just variations on a theme, such as all the derivatives of nitrocarburization and nickel plating. Nickel boron is related to electroless nickel plating and electroless nickel with teflon (also known as Robar's NP3) with regard to the plating process. Nickel boron is reported to provide "permanent dry lubricity".… Read More

Standard disclaimer: I'm not a scientist and this was not a scientific test. Any conjecture on my part is purely an uneducated guess. As I've written before, POF-USA provided me with two of their upper receivers - one is of their standard P-415 design and the other is actually operated via a standard gas tube. It's called the RDIK. This gave me the opportunity to compare how each handled heat. That is, just how effective are all the design changes POF has made to the AR receiver, barrel nut, and… Read More

In a recent AR15.com thread, it was claimed that Federal 9mm ammunition identified as XM9HA was a contract overrun of 147gr HST hollow point projectiles loaded to the impressive velocity of 1180 feet per second. That's 9mm Major territory - and beyond. It was also reported that this ammunition had a high rate of failures to feed or failures to fire in a variety of handguns. I was recently sent a small quantity of this ammunition for testing via a chronograph. It was requested that I use a Glock 19… Read More

Over the past few weeks, I've been putting a fair amount of match ammunition through the BCM Mk12. Most of that has been Prvi 75gr Match, but I've also shot Hornady 75gr, Black Hills Blue Box 68 and 75gr, and my own handloads. Recently, a number of 10 shot groups were fired at 100 and 200 yards using two of the above: Prvi 75gr at 100 yards, and Black Hills 68gr at 200 yards. These groups were shot from the prone, using a Harris bipod for support, a Rock River… Read More

I've been told that the following information is OK to release. It's pretty self explanatory. I removed the names of certain individuals, but the information is otherwise unedited. Land Warfare Resources Corporation Engineering Memorandum Engineering Memorandum To: IAR Team From: Date Written: 8/8/07   IAR Drop Test “ Summary   Purpose: The internal drop testing of the LWRC Infantry Automatic Rifle was undertaken to determine how robust the Rifle and its component parts and accessories are and simulates a drop from a rotary winged aircraft at the maximum height a… Read More

Just a brief note... I don't have a large number of groups shot through it yet, but from the bench using handloads, I was able to fire a number of 1.5-2MOA groups with the BCM 14.5" Midlength. Those groups were 10 shots at 100 yards. The smallest was 1.46" (that was actually 12 shots because I apparently can't count) and the largest was 1.88". The load consisted of 73gr Berger HPBTs over Hodgdon Varget. I used a 10x Bushnell scope for those groups. For a more practical accuracy test, I… Read More