AllenLash
03-26-11, 15:29
I have been given a piston driven AR to T&E. I don't want to "name names" just yet so I'll just call it "Brand X". The LE rep for Brand X stopped by the range earlier this week and dropped off a piston driven AR and asked us to see what we thought. In the interest of full disclosure, while I don't have decades of experience with the AR platform, I do have a few years as a patrol rifleman, instructor and armorer. In that time, I have come to believe that the idea of a piston driven AR is a solution for a problem that largely isn't there--more proprietary parts to break, heavier and more complex to keep running in large numbers (we have over 600 rifles in service).
Yesterday, myself and our assistant armorer took the rifle out to the range and did a "stress" test-see how long it would shoot before it started puking. The plan was to fire as many rounds as possible, as quickly as safety and our loading ability allowed. We had nine magazines available and around 720 rounds (mostly Federal 55 grains and a few Winchester Ballistic Silver Tips, 55 grains).
First, we got a decent zero at 100 yards. The groups for both of us were larger than our norms with our own guns but I thought acceptable over all. Probably 3-4 inches for both of us. The trigger seemed heavier than my Colt or Rock River. We both had issues with short stroking the trigger on reset. Were going to look at that closer-check pull weight and do a side by side comparisons. Next we started the "stress" test in earnest.
We got through 6 and a half magazines, 28 rounds each, before we had our first failure, the weapon failed to extract an empty case. Before we started, I checked the bolt assembly and looked at the extractor-spring and black insert only. We cleared the stoppage and continued another 3.5 magazines and another failure to extract. Similar failures continued to occur at an increasing rate until we would have two failures on every magazines by the time we were done. I don't have the notes with me, but I believe all but one failure was an extraction issue. The other was a double feed, two rounds trying to enter the chamber at the same time. The Winchester ammo never failed to extract or feed, but it only accounted for around 5 percent of the total rounds fired.
We collected most of the cases that failed to extract (most required the "mortar" extraction method). We noted some signs of higher that normal pressure as all the cases had flattened primers.
Another issue we noted was the rear sight assembly came loose and all but fell off.
A few questions and thoughts: Was this a reasonable start for the testing process? Hindsight being what it is, I wish I had checked the chamber and headspace before starting, checked pull weight, and snugged that rear sight down. I think we shouldn't have to do those things because it should be "right" from the beginning. I know, that's not reality and I probably should have done those things before we started. I played Devil's advocate with my coworker and asked if a rifle should be able to fire 700 rounds as quickly as we can fire and reload magazines? Is that a valid test? How many rounds should it be able to fire? Less or more? In this case, I think it was, because I would hope that I didn't have a rifle that started out clean and well lubed to puke after only 180 rounds. When you put yourself in the shoes, well boots, of a Marine at Chosin Reservoir, facing ChiCom hordes this becomes very reasonable for a combat rifle. Ok, I'm not a Marine, I'm a cop and most LE shooting last only a few rounds. Typically. Then I think of Beslin. If (or more likely-when) that happens in the United States it will be cops who first engage an enemy who may be well equipped, well trained, and have mindset to create as much suffering and death as possible (that we in the West have trouble comprehending) before they become martyrs. Again, this test seems reasonable to me. What say you?
What are some additional tests? Put it in a freezer overnight and see what happens when you start shooting it in 70-80 degrees (replicating freezing cold gun going inside for a fight). Dunk it in mud? Sand/Dirt? Drop test? I don't necessarily want to break the gun. It's not ours after all. Although, the last rifle this rep gave us was sent back to the factory with the action inoperable. So, I guess he should have known better than to give us another rifle. ;)
My goal here is to develop a testing protocol for this (and other weapons) that will be defensible. So we can explain to our officers why they can't carry whatever they want and show the command staff and other weapon challenged folks why Brand A may be cheaper but not nearly as good as Brand B. And why quality matters in terms of cost of repairs and in lives.
Input, please.
Thanks in advance,
Allen
Yesterday, myself and our assistant armorer took the rifle out to the range and did a "stress" test-see how long it would shoot before it started puking. The plan was to fire as many rounds as possible, as quickly as safety and our loading ability allowed. We had nine magazines available and around 720 rounds (mostly Federal 55 grains and a few Winchester Ballistic Silver Tips, 55 grains).
First, we got a decent zero at 100 yards. The groups for both of us were larger than our norms with our own guns but I thought acceptable over all. Probably 3-4 inches for both of us. The trigger seemed heavier than my Colt or Rock River. We both had issues with short stroking the trigger on reset. Were going to look at that closer-check pull weight and do a side by side comparisons. Next we started the "stress" test in earnest.
We got through 6 and a half magazines, 28 rounds each, before we had our first failure, the weapon failed to extract an empty case. Before we started, I checked the bolt assembly and looked at the extractor-spring and black insert only. We cleared the stoppage and continued another 3.5 magazines and another failure to extract. Similar failures continued to occur at an increasing rate until we would have two failures on every magazines by the time we were done. I don't have the notes with me, but I believe all but one failure was an extraction issue. The other was a double feed, two rounds trying to enter the chamber at the same time. The Winchester ammo never failed to extract or feed, but it only accounted for around 5 percent of the total rounds fired.
We collected most of the cases that failed to extract (most required the "mortar" extraction method). We noted some signs of higher that normal pressure as all the cases had flattened primers.
Another issue we noted was the rear sight assembly came loose and all but fell off.
A few questions and thoughts: Was this a reasonable start for the testing process? Hindsight being what it is, I wish I had checked the chamber and headspace before starting, checked pull weight, and snugged that rear sight down. I think we shouldn't have to do those things because it should be "right" from the beginning. I know, that's not reality and I probably should have done those things before we started. I played Devil's advocate with my coworker and asked if a rifle should be able to fire 700 rounds as quickly as we can fire and reload magazines? Is that a valid test? How many rounds should it be able to fire? Less or more? In this case, I think it was, because I would hope that I didn't have a rifle that started out clean and well lubed to puke after only 180 rounds. When you put yourself in the shoes, well boots, of a Marine at Chosin Reservoir, facing ChiCom hordes this becomes very reasonable for a combat rifle. Ok, I'm not a Marine, I'm a cop and most LE shooting last only a few rounds. Typically. Then I think of Beslin. If (or more likely-when) that happens in the United States it will be cops who first engage an enemy who may be well equipped, well trained, and have mindset to create as much suffering and death as possible (that we in the West have trouble comprehending) before they become martyrs. Again, this test seems reasonable to me. What say you?
What are some additional tests? Put it in a freezer overnight and see what happens when you start shooting it in 70-80 degrees (replicating freezing cold gun going inside for a fight). Dunk it in mud? Sand/Dirt? Drop test? I don't necessarily want to break the gun. It's not ours after all. Although, the last rifle this rep gave us was sent back to the factory with the action inoperable. So, I guess he should have known better than to give us another rifle. ;)
My goal here is to develop a testing protocol for this (and other weapons) that will be defensible. So we can explain to our officers why they can't carry whatever they want and show the command staff and other weapon challenged folks why Brand A may be cheaper but not nearly as good as Brand B. And why quality matters in terms of cost of repairs and in lives.
Input, please.
Thanks in advance,
Allen