Luc V. wrote:
Interesting video, just pay attention to the take down lever... |
Good job AndyC!! Thanks
Had quite a few PM's asking why the Auto Mag X design was shelved. Here was my summation.
Indeed an interesting video with several things going on that I will point out. The block of wood was to keep the muzzle down in the camera frame and has no effect on rearward movement of the upper. It just arrests the muzzle climb.
This was early testing of the "X" design. The bolt did not have a flat spot before helix opening so no dwell time. This is how it was designed. This video was taken to prove what I was saying was true and the clocking barrel latch (take down lever) was an unexpected bonus.
When I mentioned the lack of any dwell time I was rather sarcastically told that the dwell was built into the bolt retractor attached to the bolt with a split pin and screwed onto the cocking piece. That is all well and good if you are manually cocking the pistol but not so when firing the pistol.
Watch the bolt in the video as it begins it's rotational movement as soon as it is fired.
When you fire the pistol the upper moves with the fired casing and pushes the the bolt rearward and the bolt immediately begins rotating due to it's interaction with the rotation pins. If you look at the video you will see the bolt is rotating the moment the pistol is fired. Quite a profound oversight in my opinion. Bolt rotation under pressure.
Below is a photo of the "X" bolt with no dwell before helix opening.
I painted it up with a blue marker so you can see there is no flat spot before helix opening.
The upper and barrel were made from pre-heat treated 4140 chrome moly steel ( because someone did not like stainless steel). A comment was made that the upper was not heat treated which is simply not true. I fired this pistol over 300 times (after adding the dwell time before helix opening) with only .001 lug setback with 1350 to 1450fps rounds being fired. Annealed 4140 would have never held up.
Anyone in the firearms manufacturing business knows working with pre heat treated steel is harder on your tooling but negates the chance of loosing parts dimensionally during post production heat treating and the added benefit of no dealing with scale or oxidation which can happen even in an inert atmosphere furnace.
At any rate the pistol would only attempt to load a second round if rounds fired were in the 1450fps + range and then only with specially ordered light recoil springs that did not have enough return pressure to push a round out of the magazine.
You will notice the bouncing cocking piece caused by the double helix and the torsioning of the recoil rods. The rods would loosen as it was designed not to use helicoils because someone did not like helicoils. After less than 15 firings thread fatigue in the cocking piece where the recoil rods were threaded in was evident. I could remove the cocking piece and tap the threaded openings on a paper towel and there would be metal powder. My suggestion was to go back with the helicoils or permanently attach the rods to the cocking piece and use locking bushings in the front of the recoil rods.
There were several more issues such as a 6:00 o'clock bolt lug and a slot in the bottom of the feed ramp in the upper. I believe this was attempted before by the same designer and Lovendale had to re-design it years ago.
Basically the 6:00 bolt lug would dig a notch in every piece of brass as the bolt moved over the next round round to be loaded and the slot in the feed ramp would put two carved lines in the brass. Basically your ejected brass looked like it had been beat with an ax.
Another issue was the bolt/firing pin retractor that was a threaded tube that screwed into the cocking piece holding the double cam helix behind the bolt. This is where the dwell time was supposed to be, in the slotted retractor.
Well it suffered thread fatigue and thread degradation and the slot in the retractor caused the most important part to be so thin that the metal began stretching after less than 100 rounds fired.
The "X" design was akin to a solid bolt gun and recoil forces were horrible on the wrist with even 1350fps rounds. As I have mentioned before the more weight launched rearward the more weight has to be arrested ( by your hands, wrist and arms). The recoil was horrid with this design.
There is still a schematic of the "X" design on www.automag.com if anyone is interested in seeing the retractor in the drawing.
At any rate there was supposed to be a fully functioning prototype and it was supposedly sold to a guy who writes Auto Mag books ( not Bruce ). I asked for the working prototype or a video of it working but was personally told by the owner he stuck it in a safe and had never fired it.
You guys would have probably had your Founders and Classic pistols about a year earlier if it hadn't been for the time and money wasted on the "X" design.
In closing the math did not support the weights and physics of operation and interaction of the moving parts as a working semi auto firearm within the boundaries of safe and reliable function.
I will cover the clocking barrel latch ( take down lever) in my next post and the cause was not what I expected but was easily cured.
Sorry I keep referring to the take down lever as the barrel latch. I am used to M60, M249 and M240's being referred to as a barrel latch. Old habits hard to break.
I apologize for another long winded post but hope I answered the question of why the "X" design was shelved. I would have liked to see where we could have gotten with "X" but was met with anger and resentment by the designer so I recommended going with the more original Classic design and making immediate needed improvements and gradually adding percieved improvements and measuring the benefits over time.
The Auto Mag is back and here to stay!
Knock um out Patrick and Larry!
Kind regards
Tim