Tuesday, June 25, 2013

Tab clearing...


Lewis said...

But but but poodle shooter!

Paul said...

Yep. Since the army just canned the replacement for the M4/M16 expect all the old trash on that platform to be recycled breathlessly.

What goes around comes around.

Kristophr said...

Nick does not represent libertarianism.

He represents the purist retards that see to it that big-L libertarians keep losing elections. They cannot unbend enough to even vote, since voting=initiation of force.

Ed Foster said...

As a somewhat younger engineer at Colt's several decades ago, I came in contact with the .gov mandated test procedure for M-16's and M-4's.

All weapons were assembles in batches of 100. 2 weapons from each batch had 6,000 rounds each fired through them. Of the total 12,000 rounds fired, we were allowed 5 stoppages for any reason. Rifle, ammo, mag, anything, 5 shots total out of 12,000 rounds fired.

Drop 6 rounds and the entire lot of 100 weapons was rejected. No exceptions ever. Please note that this was before the M-16 rifle received the M-4 feed ramps, which pushes feed geometry related problems entirely out of the picture. With those puppies, it's like pitching a watermelon down the Holland Tunnel.

To my knowledge, the only lot ever rejected was due to "operator error". There was this great old guy down on the test range who had been there since Sam Colt or damn near, and he could probably have been national shooting champion. Huge hands, missing a number of fingers.

Over a half century, he'd had several handguns go boom the wrong way, and lost some serious meat as a consequence.

It seems that as a result of the missing fingers, he had developed a unique way of loading mags from stripper clips. He put the clip loader against a wooden bench, then rammed the magazine down over it, beating hell out of the feed lips.

There are those who say the magazine itself is flimsy, and they might have a point. It was designed, by Army request, to be disposable. Use it and lose it, after stomping on it.

But it is also a brilliant piece of workmanship. There is a dimension, 1.357 plus or minus .003, from the bottom of the locking slot to the top of the rear feed lips, that guarantees a level of feed reliability unmatched by anything else in the firearms world.

A manually operated Mauser turn bolt won't have that better than 5 in 12,000 reliability level (we almost always went 0 to 2), and AK's routinely jam every few hundred rounds, if not sooner. In addition to shooting 6 or 12 inch groups (patterns?) at 100 yards.

Are there improvements that can be made in the magazine? Probably. The PMAG is the best thing out there, but their 1.357 dimension isn't as consistent as something coming out of O.K. or one of the other military producers. That plus or minus .003 is a real deal reliability factor, although nowhere near as important since everything got the M-4/A-4 feed ramps.

What I like best about the PMag is the cover. It not only keeps the crap out, the old Chieu Hoi wrappers did that, but it takes tension off the right feed lip while the magazine is left stored and loaded.

A few days or weeks at a time is all the aluminum mag can handle of that. The classic right lip failure results in a round popping up into the charging handle slot and being wedged/deformed into place by the handle, wrapped around the end of the gas tube.

Believe me, there is NO way to clear it except pulling the buttstock and buffer tube assembly and yanking out everything through the rear, then screwdrivering the bugger out. Reassemble in reverse order.

In a SHTF scenario, I would go through all my PMAGS and keep the 9 out of 10 that perform perfectly, then consider myself about as well off as I could be.

Ed Foster said...

As for pistons in AR's, the best of them (Stag's) is inferior to the Ljungman system.

I'm quite willing to show the test results I got up at Smith and Wesson on a major manufacturer's piston upper we tried a few years ago. The action was so violent it kept breaking lower receivers, and we had to use a number 3 buffer to keep it functioning at all.

Look up the engineering definition of the term elegant. This was not.

The sweet thing about the Ljungman/Stoner piston arraignment is the fact that there is so little bending moment applied to the receiver.

The gas gets piped through the bolt key to the back of the bolt, the bolt carrier is the cylinder, and the rear of the bolt, along with the gas rings, is the piston. Rather than moving the piston in the cylinder, it moves the cylinder off the piston. All while the tail of the bolt keeps everything in perfect alignment.

There is a slight amount of rotational friction along the side of the gas key, between it and the charging handle slot, but not enough to make any difference at all. That's it.

Also, the Ljungman system is more resistant to differences in powder burning rates than any conventional piston system. When it gets enough juice, it goes, and cuts off the flow as it moves off the end of the gas tube.

Almost all of the "evil gas being vented into the receiver" is actually blowing out the two exhaust ports in the side of the carrier/cylinder, the way it was designed to.

Compare that to an AK. The Kalashnikov receiver is quite flimsy, essentially a left wall, a huge crap catching ejection port, a very big magazine well, and a quite bitty right rail.

The piston assembly is well above the bolt, and when camming it open, puts an enormous amount of downward moment on the bolt, essentially trying to drive it into the magazine well.

The early (solid) AK's broke in half across the front of the magazine well. The stamped AKM's simply flex, hosing their shots up and down as a result. The AK gets it's "reliability" from a massive bolt assembly slamming back and forth through a constantly flexing receiver. It greatly magnifies felt recoil, not something conducive to great marksmanship.

It could be argued that the AK's illegitimate daddy, the American M-1 Garand, also had a serious camming moment. But look at the thickness of the left side of that receiver, and consider how much less mass is being cycled back and forth inside that massive hunk of steel.

With the AK, a difference in degree becomes a difference in kind.

If we're sticking with an M-16 compatible magazine, my thought is that, after more than a half century of constant type improvements, the well polished M-16 family is still by far the best way to go.

Under most circumstances I would prefer the rifle to the carbine, especially with non-milspec weapons.

In full auto, we got some nasty harmonics with the M-4 lower that required a much tighter mag well to beat. Colt had to eliminate something like .008 of magwell width on the M-4 to eliminate them, and the carbine's cyclic rate does increase noticeably over time, due to erosion of the gas port.

The carbine port taps into the bore at a much higher point in the pressure curve. The .062 diameter carbine gas port restricts a lot more volume of gas than the .093 of the rifle, but still has more pressure to deal with, meaning that the bolt accelerates faster at the beginning of the cycle, then decelerates faster at the other end.

If you don't have a bigger radius on the load side of the bolt's cam pin hole, you will crack bolts at about 1,200 to 1,500 rounds.

Not a problem on mil-spec weapons or bolts from CMT or Microbest, but to the best of my knowledge nobody else is putting that big .040 radius in by hand on the 11 o'clock to 2 o'clock position on the bolt cam pin hole.

Scott J said...

Only problem I ever had with the AR platform was when I decided to try using it to shoot Highpower.

I had a Colt 20" Match HBAR and was working out zeros on my friend's private 600 yard range (those were fun times). We discovered that when I got real tight with the sling I could flex the barrel enough to pull it off target at 600.

It turned out the barrel of the HBAR was only H for the part that stuck out past the handguards. The rest was as thin as the original A1 barrel.

Since my friend was a fan of the M1A I sold the Colt and bought a Polytech rather than change the barrel and/or do a free float handguard.

I never did compete with said Polytech. Life got in the way and I quit shooting Highpower a few months after buying it.

I never had further interest in the AR platform until 2010 when Palmetto State Armory put their lowers on sale for $60 each shipped. I figured what the heck and bought a couple to build at leisure. I decided to build as a carbine rather than rifle length.

I just completed one build earlier this year and have been slowly breaking in the barrel as recommended by its manufacturer. I had forgotten how light, handy and accurate the platform can be.

Sigivald said...

Ed Foster said: Also, the Ljungman system is more resistant to differences in powder burning rates than any conventional piston system

Is it?

I've got an AG-42B I've never fired (lazy, ammo's expensive, brass gets thrown everywhere, I'm told) - but the AG-42 fans all told me "it's temperamental and only really likes the original military load's pressure curve".

It'd be nice to find that it can handle Prvi Partizan 6.5x55 just fine...

Gewehr98 said...

A manually operated Mauser turn bolt won't have that better than 5 in 12,000 reliability level (we almost always went 0 to 2), and AK's routinely jam every few hundred rounds, if not sooner. In addition to shooting 6 or 12 inch groups (patterns?) at 100 yards.

Huh? Maybe a Khyber Pass AK, but none of my gaggle of AKs here goes more than 3" at 100 yards, and if they jammed every few hundred rounds, it would be because of crap ammo, not the gun. (Bulgarian SLR-95, Romanian SAR-1, Krebs Krinkov) Do I live a charmed life, or is that just hyperbole to make the Stoner guns look good in comparison? (Of which I also own a couple examples...)

Boat Guy said...

I'll contribute the SOLE mechanical failure of the system I've seen in nearly 40 years. Borrowed weapons from the _______ National Guard to conduct basic quals. Had ONE rifle with a hammer pin so loose it walked almost completely out of the lower before the rifle stopped. Pushed the pin back in and the rifle ran again. We did put it aside and told the supplying unit about it.
That's it.
If I had the money for all the 5.56I've expended either personally or that was expended under my direct supervision I could damn near afford the Obamas vacation...

Boat Guy said...

"Of course, when Charlie's running around loose on the US embassy grounds..."
If memory serves, those guys never left the Embassy grounds...except in bags.

Sklutch said...

Huh. Come to Tam's Porch for the snark, get a free gun history/smithing lesson...

It's nice to know smart people exist, I see *so many* dumb ones.

Validation: "Are galthco"

I don't work for Galth Corporation!

Will said...

@ Ed Foster:

I left a couple alum mags loaded with 7.62x39 rounds for some weeks, and found the spot welds had failed, splitting the mags. Pretty sure they were Colt. Had them loaded past the point they would feed (tapered cartridge in a straight mag, think more than 5 would tip the bullet below the mag body edge).

(BTW, what ever happened with the Bobtail mainspring housing you offered for my Officers Model?)

Bubblehead Les. said...

So Sarah thinks she can ride the Libertarian Wagon for free to earn a paycheck, eh?

Maybe she'd have some more credibility if she'd finish a Political Job that she started, instead of running to the nearest TeeWee Camera.

RevolverRob said...

Sarah is running with the "Faith & Freedom Coalition" is a Libertarian system. I call bull-pucky.

I went over and took a look at that website, the about section has a quote from Alexis de Toqueville, "Freedom regards religion as the companion in all its battles and all its triumphs as the very cradle of its infancy and the source of all its claims.... because religion alone is the safeguard of morality, and morality is the best and surest pledge for the survival of freedom."

My first thought was, "What's in the ellipses?" So, I went to look and found that real quote is, "Liberty regards religion as its companion in all its battles and its triumphs, as the cradle of its infancy and the divine source of its claims. It considers religion as the safeguard of morality, and morality as the best security of law and the surest pledge of the duration of freedom."

Which is not the same quote, but is close, so okay, why not. But it's out of context, a single sentence that is proceeded by a paragraph, which reads: "Religion perceives that civil liberty affords a noble exercise to the faculties of man and that the political world is a field prepared by the Creator for the efforts of mind. Free and powerful in its own sphere, satisfied with the place reserved for it, religion never more surely establishes its empire than when it reigns in the hearts of men unsupported by aught beside its native strength."

Low and behold when you read that paragraph you see that the Faith and Freedom Coalition is full of it. de Toqueville clearly states that religion does not need politics and the world of politics. Yet Faith and Freedom Coalition clearly wants religion to be part of your political world and will twist the words of Alexis de Toqueville to do it. Just think, if they're willing to do that, what else are they willing to be dishonest about?

Yay, no thanks.


Tam said...


I was more referring to the snide asides in the body of the article.

I think my opinion of the God Squad and its effects on the GOP are pretty well on record.

RevolverRob said...


I definitely saw your point with regards to the article link. Making fun or Sarah Palin is so...gauche.

But after reading through the article, I did have to go check out Sarah's new political digs and my main complaint with her still remains. You can try to swing in the Libertarian, capital L, vote. Problem is, most Libertarians are pretty cynical and skeptical people. If the horse has always been Godly red and tries to come off as purple, I don't buy it and suspect something stinks.

Snide remarks and cheap shots which lack journalistic integrity aside, Sarah's new digs stink pretty hard.


WV: Nominut person; A person who is crazy about nominating someone or something for any office or award, when the nominee is not qualified to hold office or award. See: Democrat and Republican parties or Nobel Peace Prize committe for exemplification.

global village idiot said...

How come a rifle's a rifle, a carbine is a carbine, but the M4 is a "platform?"

In a weapons context, a "platform" is something you can put weapons on. A Cobra or Apache is a platform. The Iowa is a platform. The M1 Abrams is a platform.


Tam said...


"In a weapons context, a "platform" is something you can put weapons on."

Yes. :D

Ed Foster said...

Gewehr, I think you are lucky indeed. I have seen more AKS's shoot closer to one foot at a hundred than 3 inches. Someone is smiling on you.

Boat guy, the M-16 you shot had a replacement hammer put in by somebody who didn't press the J-Hook spring into the hole in the bottom of the hammer. It grabs the groove in the center of the pin. The grooves on the outboard ends of the pin are only to trap the legs of the hammer spring when the pin is being used for the trigger.

Will: Oh Shit. Get your e-mail to me at ewen55@att.net and I'll be all over it. Sorry.

Will said...

That FOB disaster in Afghanistan happened in '07, IIRC. I read the investigative report the .mil did on it. Lots of fail in decision making by all and sundry. Plus Murphy. Too few troopers for too much wire, and bad positioning of the camp, to include the topography of the camp itself.

Poor coms and coordination, and a belief that a wall of lead from a single troop, with no one to watch his back, repeated in several locations, will suffice to keep the bad guys outside the wire.

Continuous mag dumps, until the weapon fails from overheating, is not a winning proposition. Virtually every m4 was found in this condition.

I'm thinking they either need to limit the amount of ammo, or mags, or issue the AR15, instead.

The result of that "wall of lead" was to get them killed. That was my take-away from reading the report.
They weren't trying to stop a wave of attackers, but small handfuls and individuals.

The army locked out full-auto in Nam for most of their m-16s, due to this same mindless action. Past time to do it again. They are not belt-fed, water cooled MG's, and you can't pretend they are.