We’ve wanted to design an optic mount for the M1 Garand rifle for years, and people have been asking us for one, but it always seemed like there was something else we had to do.  Well, here’s our M1 rifle optic mount prototype.  I think it’s going to be designated the M12 optic mount.  You saw it here first.

I don’t know how many people have told me that their “old eyes” can’t make use of the iron sights like they use to, or that it would sure be nice to have a simple way to mount a scout scope or dot sight on a Garand, etc., but it’s been a lot.

If you’re not familiar with the M1 rifle, it has to be loaded from the top, and when the clip of ammo you shove into the magazine runs empty, the clip is ejected forcefully out the top when the last shot is fired.  That means you can’t put an optic over the top of the receiver, ’cause it gets in the way of loading and ejection.  Some M1 rifles were used with scopes mounted off to the left side, but few people like that arrangement.  It works, but you need a special mount and I understand you have to drill the receiver on your classic rifle, plus your manual clip eject button (“clip latch”) is there on the left side.

This new mount replaces the handguard just in front of the receiver, clamping solid to the barrel with steel clamps and screws similar to the UltiMAK M8 for the M-14 rifle.  This is the prototype, and is left “in the white”.  The production units will be anodized and finished in black.  It sits low enough to co witness (use the iron sights without removing the optic, right through the optic, in case the dot fails) with most tubular dot sights which also means you need no comb riser to get a decent cheekweld.  On this example (a vintage Springfield war horse – Thanks Mr. Devoe) I can center the dot in the Aimpoint Micro, with the rear iron sight all the way down hard, and the rear aperture is completely out of the way, yet I can still aim with the irons if I want.  It’s as if the rifle, mount and Micro sight were all made for each other.  That’s the way we like it.

[shameless self promotion = “off”]

I’m not putting it on our web site just yet, because we have more tweaking to do, and a lot of other things before it goes into production.  This post is just what the title says.

The M1 rifle is fascinating for several reasons.  One reason is that the gas port in the barrel (where high pressure gas is bled off to operate the action) is right near the muzzle, under the front sight, so the operating rod goes full length form the charging handle to the front sight.  We were talking here the other day about how much machining went into one of these rifle, and how many were made in a short time.  Amazing.  Its design led to a whole family of long guns, including the M-14, M1A, Mini-14, Mini-30, and the M1 Carbine shares some things in common with it.  Back in the day the M1 was state of the art, but today it would be considered on the high end of heavy for a battle rifle, it holds a small number of rounds in the magazine, doesn’t lend itself to “tactical reloads” very well, but it sure is a lot of fun, and its .30-06 cartridge packs a punch.  And look how pretty it is.  Just..just look at it.

Maybe I’m the last to know, but I just found out that the nominal outer diameter of a gauge-numbered machine screw is defined as the gauge number multiplied by .013″, plus .060″.  The actual diameter is usually two or three thousandths or so under nominal.  I know ’cause we tried it.  And as you are all know doubt aware; once you reach a quarter inch, you’re going by fractional inch dimensions instead of gauge.  Wood screws go by their own, as yet mysterious to me, system, probably developed by some guy and his partner making screws by hand 250 years ago.

Who cares?  Well, we have run into problems with what we refer to as “stacking tolerances” in our production– a threading tap varies slightly (both initially and over time with wear) the anodizing depth varies slightly, and screw dimensions vary slightly even if you stick with one supplier.  If these variations all go in the wrong direction at once, you end up with customers calling you saying the screws are so tight in the mount that some of them are breaking, even though you’ve been doing everything exactly the same for years and it’s always worked nicely.  We started using +.001″ and +.002″ oversized form taps a few years ago, to make up for the thickness the anodizing adds to the threads, and then some, and the problem went away.  Now at least we can measure screws and know exactly how they vary from “nominal” as opposed to making simply comparative measurements.

This new (to me) tidbit of information is just icing on the cake for you engineers out there, in the unlikely event that you were as ignorant of such things as I was a few minutes ago.  What I still don’t understand is why we call a number eight screw a number eight screw instead of a .164″ screw.  Too many digits?  But then you’d not have to remember gauge x .013″ + .060″.

Some of these oddities come down from the past in “organic” ways.  Firearm bullet and bore diameters are a good example.  Who the hell came up with .223, .308 or .452, as opposed to, say .200, .250, .300 .350, etc?  Some of these unlikely numbers, at least in part, come from the days of black powder, wrought iron barrels, soft lead bullets, and the manufacturing tolerances of yore.  The realistic tolerances back then were nowhere near what’s possible now, and it resulted in some pretty weird numbers that became standards out of expediency and in response to backward compatibility issues.  I use a .454 ball (that number’s still with us) in an 1850s .44 percussion revolver for example, because the oversized ball gets better purchase on the sides of the chamber and on the rifling.  We would now refer to a .454 bullet as caliber 45, though you were shooting it from what was called a .44 caliber pistol back in the 1860s, and the modern 45 cal bullets are .451″ and .452″.  Modern 44 caliber bullets are .429″.  Huh?  I definitely need to learn more about this stuff.  In another .44 percussion revolver I have I use a .457″ ball– you want a ball that’s bigger than the cylinder, and a cylinder that’s bigger than the barrel groove diameter, so everything gets a sure, tight fit with the soft lead ball.

We still use grains as a unit of measurement, which came from some king somewhere telling us that the official definition of a pound was “seven thousand plump grains of wheat” (what poor saps had to count them, then recount them, and who verified their work?).  Shotgunners use the dram, which converts to the tidy number of 27.34375 grains, or the “dram equivalent”, which is a charge of modern smokeless powder that generates about the same energy as that number of drams of black powder.

If we were to start all over and reinvent guns from the beginning today, we’d no doubt end up with simpler units and numbers, but the world doesn’t work that way.  Each incremental development is built upon the previous one, and you don’t immediately re-tool everyone in the business, make all the old versions unusable, and change all the established experience and data, just for that little increment of improvement.

Still, I keep saying someone needs to reinvent the computer OS (or the very concept of the computer OS– maybe the very use of the term “OS” is thinking too much inside the box) from the beginning.  There is of course no basis– no established school of thought or system of evaluation that would warrant such a claim.

I tried this before, but the camera/recorder I used then was equipped with AGC circuitry, and the extremely wide dynamic range of gunfire made for an unsatisfactory result.  This time I used a dedicated, stereo sound recorder with no compression.

Because the sound of live fire, even from the 400 yard distance in this example, has such a wide dynamic range, you need to crank up your speaker volume very high.  You’ll need a high quality sound system, or some good headphones with good frequency response, from low bass to the upper highs.  You should be able to clearly hear the sound of the rushing creek in the distance between shots, and the high-frequency bullet crack should almost hurt your ears.  Warning;  Make absolutely sure your computer or other device isn’t going to make any other sounds (chimes, alarms, etc.) or it will blow your head off.  Be sure to turn the volume down when you’re done.  When I play these files on the Altec speaker system with sub woofer, it sounds like it did when I was standing there making the recording.

We fired an AR-15 (.223) from 400 yards at plastic water jugs.  You can hear the sound of impact, but it’s not as loud as the bullet’s sonic “crack” or the low frequency muzzle blast that follows.  I was holding the recorder at a position behind a hill from the shooter, about 20 yards off to the side of the bullet path, and about 20 yards up-range from the targets.  This is the same recording in both WMA and MP3 formats;

01 223FireWMA.wma (1.4 MB)

223FireMp3.mp3 (584.91 KB)

Note that you’ve probably never heard this sound in movies or television, with the possible exception of Quigley Down Under, but in that case Quigley’s bullets were sub sonic well before impact at long range and we can forgive the “whoosh-boom” as being probably accurate enough.

An interesting development:

The TASER® XREP™ is a self-contained, wireless electronic control device (ECD), that deploys from a 12-gauge pump-action shotgun. It delivers a similar Neuro Muscular Incapacitation (NMI) bio-effect as our handheld TASER® X26™ ECD, but can be delivered to a maximum effective range of 100 feet (30.48 meters), combining blunt impact force. The battery supply is fully integrated into the chassis and provides the power to drive the XREP projectile engine.

Links to pictures here. Video here.

I wonder if I can get a couple of boxes of those from Wal-Mart. I could see having few rounds available if I ever got an invitation to go bird hunting with Dick Cheney and he got a little out of control again.

Via email from Kris.