MRPC NEWS

General Club Meeting for May 2018

Wednesday Night at 7pm

Open to all members

 

 

FULLBORE Rifle Practice

We will shoot this Wednesday on the Camp White Rifle Range at 5 PM.

600 yards,  22 rounds,   From either prone or bench positions

We are going to have a little work party after the practice and

then we will BBQ some hot dogs. Try to bring some extra food to add to the BBQ.

Calendar Items
USPSA Match   Saturday 8am   Sports Park Reserve Ranges
New Member Orientation     Sunday 2:15pm to 5pm
 

DIY Fixes: Troubleshooting Your AR

By Glen D. Zediker
If your AR-15 stops working, or works sporadically, it’s likely to be one of three root causes: it’s dirty, it’s beat, it’s got a leak. Details are coming.

Now, if it’s a new gun, function problems can be more tedious to solve. That’s because a freshly-constructed firearm has the potential for a slew of quality issues—build quality and parts quality. Not all are tested prior to shipment as they should be either. Problem with a new gun? Take it back where you got it.

You might have the best-running AR ever that is tuned to perfection, but what will you do if it starts malfunctioning?

Let’s focus on a previously ginning AR-15 that’s decided to go on operational vacation. I’ll be talking about cycling issues. If you pull the trigger and nothing expected happens, then, son, you got a broken part somewhere, and the fix for it is plainly to replace the part.

Since AR-15’s are semi-automatic in function, there are two essential operational errors. Failure to feed, failure to eject. Both of those together are a failure to cycle.

About the only shooter-supplied change creating function issues is ammunition. There are differences in available ammo, especially if we’re comparing commercial to Mil-spec. The handloader needs to do some double-checking on case sizing, and possibly some rethinking on propellant charge or choice.

Even though this may not be perfectly agreeable, given supplies and expenses, it’s best to run the same (known-to-work) ammo all the time, if, of course, the ammo is doing the job you’ve called on it to do. If ammo changed, the plainly easiest way to determine if it caused the problem is to try a few rounds of what it replaced.

I’ve talked around the horn a few times on this next, but cyclic failures are not always due to “light” loads. Not nearly. If you’ve either knowingly or innocently switched to a brand of ammo loaded to a higher pressure, what some call “overfunction” can fool us by its symptoms. Depending on the pressure levels of the before and after load, and depending on the rifle’s previous system suitability to function with the lighter load, introducing extra gas into the system can create excessive carrier velocity upon unlocking after firing, which can ultimately lead to excessively rapid return to battery. The carrier can outrun the magazine spring, in effect, and fail to chamber the next cartridge. Solutions for this require employing some means to slow carrier unlocking. I’ve addressed this before, but an adjustable gas flow system, a stouter buffer spring, or adding weight to the carrier can do the job.

AR-1115-4

Gas rings don’t last forever and a broken one, or well-worn set, can let too much
gas slip by. Replacement is easy and Glen thinks such should be part of anyone’s
maintenance plan.

AR-1115-1A

Here’s a new key (above). Staking can be done with a hammer and a prick punch, but likely
means it won’t result in a showroom-finish-quality job. As long as metal is displaced inward
from the key to secure the screw heads from rotating it will be functional.

If a spent case won’t eject, reduced gas flow or grit and grime top our suspect list. Could also be a broken extractor spring, or broken ejector spring. When either of these fails, they usually break, not just weaken.

Often a previously reliable rifle commences short-stroking. That’s when the carrier doesn’t get kicked far enough to the rear to pick up a cartridge from the magazine to chamber the round, or far enough to allow the bolt stop to engage and lock back the bolt. The cause for this is either not enough “flow” from the gas system (a leak) or too much operational friction (grit and grime).

If I suspect reduced gas flow, my first check is for a loose bolt carrier key. If it’s loose, then there will be your leak. Installed correctly, it should not loosen. Installed incorrectly, it probably will loosen. I have seen a slew of incorrectly installed keys.

The key is secured by two screws with knurled heads. Most specs call for 30 to 40 inch-pounds of torque, but I say that’s not enough. They need to be tighter than that. Most of the better builders I know don’t even use a torque wrench for this op. They just turn them down tight—good and tight.
However, tight is not, by itself, enough. The last few new AR-15’s I’ve seen weren’t staked. There’s a trend toward using high-strength threadlocker (glue) in lieu of staking. Wrong. If the screws are not staked, the screws are not going to stay put. That’s that.

The area inside the bolt carrier where the tail end of the bolt fits will get caked with carbon. That fouling is tough to remove because it’s tough to reach. After this recess gets coated with carbon residue, the bolt gets “sticky.” There’s a specialty scraper-type tool I prefer, but GM Top Engine Cleaner (get it from Mr. Goodwrench, which is the parts counter at a Chevy dealer) and some brushing can dissolve the majority. This is a stout chemical.

AR-1115-5

Keep everything clean and lubed. Glen likes this stuff, but there are a number of
good lubes. What matters is your maintenance plan includes continual cleaning,
lubing, cleaning and so on. “Fresh” lube works better.

It’s known AR-15’s tend to develop function problems around the 2,500-round mark. Two likely reasons, aforementioned dirt if this area has been neglected that long, or the buffer spring. A conventional music wire spring lasts only 2,500 rounds. Replace it, and (better beyond belief) replace it with a chrome silicon or 17-7ph stainless spring. Then you’ll never have to think about it again.

The gas rings on the bolt won’t last forever. A break creates a leak, meaning gas is dissipated away from functional utility. Here’s an easy fix. Keep spares. A one-piece-design aftermarket ring normally holds up better.

Another area creating unwanted permeation of propellant gas can be the gas manifold (the apparatus the gas tube fits into on the barrel), especially when there’s an aftermarket gas block installed. Fit issues are common enough when there are incongruencies between block inside diameter and corresponding barrel area exterior dimension. It doesn’t take much gap to provide an outlet for gas under the sort of pressure we’re dealing with. You can usually see the blow-by firing the rifle from the hip, or look for dark streaks.

If you suspect this is a permeation point, make sure the block retaining screws are tight. Threadlocker on the screws helps keep them that way. I do not recommend applying any such glue to the manifold/barrel contact because there’s a risk of the glue getting into the gas port, which is a sure way to cap the flow.

Last, for this little ditty, but decidedly not the least, is keep the daggone rifle clean and lubricated. Clean the chamber! This area is often neglected in rifles with otherwise meticulously maintained bores. Thread a .357-caliber pistol brush on a short rod and scrub the chamber walls each barrel cleaning. Keep the bolt carrier assembly well lubricated (bolt body, cam pin, carrier body) and keep changing the oil: lube it, shoot it, clean it, lube it, shoot it.

AR-1115-3

A gas manifold should be seated flush and snug (top). Standard-duty threadlocker
on the set screw is a good idea, but don’t risk heavy-duty gluing the manifold
to the barrel. 

 

 

Back to Basics: Rifle Triggers

by Dave Campbell – May 10, 2018

Back to Basics: Rifle Triggers

Everyone knows what a trigger is … or do they? Merriam-Webster defines a trigger: “a piece (such as a lever) connected with a catch or detent as a means of releasing it; especially: the part of the action moved by the finger to fire a gun.” That’s pretty good, but I think we can do better: A trigger is a lever or a series of levers that restrain and release the stored energy in a spring allowing either a hammer to strike a firing pin or releasing the pin or striker mechanism in a firearm. Having a clear definition of a trigger is critical in the understanding of how it works.

Today, firearms are generally discharged in one of two ways: either via a hammer or via a spring-loaded striker. A hammer is a chunk of metal with three basic components: a pivot point, a sear and a striking face. When the hammer is cocked it is held in place by a sear that engages a terminal point on the trigger. The hammer—and often the trigger—are held in place by spring tension. To fire the firearm, the trigger is usually pulled by the index finger of the shooting hand; it overcomes the spring tension holding it in place, disengages the sear, thus freeing the hammer to pivot under its own spring tension and strike a firing pin that strikes the primer and fires the gun. In other rifles—bolt actions being the primary example—the firing spin or striker is held under spring tension by the trigger engaging a sear located on the pin. Pressing the trigger frees the pin or striker to move forward with enough velocity and momentum to strike the primer with enough energy to fire the gun.

https://assets.americanrifleman.org/media/3147557/trigger_brownells-double-set-trigger.png 
A double set trigger allows the shooter to fire the rifle with minimal disturbance to its aim. In this double set trigger from Brownells, the rear trigger sets the front, and all it takes much less pull weight on the front to set it off. Image courtesy Brownells

One of the first triggers did not release any spring tension. On a matchlock firearm, the trigger was a simple lever that moved a serpentine-shaped hammer that held a glowing match toward the flash hole. Flintlocks were one of the first to utilize a spring-loaded hammer, as well as a set trigger—more about that later. Once rifling was introduced, marksmanship became a skill that was held in high regard, and early on marksmen figured out that a good trigger—one that could be released with little disturbance to aiming—was a critical factor in their success to place a shot where they wanted it to go.

Until the Savage Model 95, virtually all lever-action rifles utilized an external hammer. Bolt-action rifles, as mentioned, use spring-loaded firing pins. Most semi-automatic rifles use an enclosed hammer within the receiver. Slide-action rifles may use either an internal or external hammer, though some, like the Remington 141 use a spring-loaded firing pin.

Rifles use either a single-stage or two-stage trigger. On a single-stage trigger, the action is pretty direct. Pressure on the trigger eventually overtakes the spring and friction resistance, disengaging the sear from the trigger and firing the rifle. Most sporting rifles have a single-stage trigger. Military and some target rifles have a two-stage trigger. With a two-stage trigger there is some take up—perhaps as much as 1/2" and often referred to as “slack”—of the trigger where no movement of the trigger on the sear exists. Once that take up is achieved, the engagement is like a single-stage trigger. The trigger overcomes the spring tension and friction and disengages the trigger from the sear. Some call two-stage triggers a “poor man’s set trigger” because the take up serves as a safety to help prevent an inadvertent discharge.

https://assets.americanrifleman.org/media/3147560/trigger_winchester-70-trigger.png?width=311&height=206  https://assets.americanrifleman.org/media/3147561/trigger_winchester-94-trigger.png

The original trigger on Winchester’s Model 70 rifle (left) was one of the easiest for an experienced gunsmith to adjust. As timeless as the Winchester Model 94 is (right), the rifles often had gritty triggers. However, with some careful work, a competent gunsmith can turn a gritty and heavy factory ’94 trigger into an acceptable one. Images courtesy Winchester 

As we have seen, knowledgeable marksmen often prefer triggers that do not disturb the aiming of the rifle. To make a long-range or precision shot requires that the rifle be absolutely free of movement or anything that would disrupt the aiming of the rifle. Riflemen often use the following terms when describing a trigger.

Blade: This is the portion of the trigger exposed from the rifle that the trigger finger (usually the index finger of the shooting hand) engages. Blades have traditionally been curved to mimic the contour of the trigger finger, but lately some have gone to a flat-face trigger blade. The thinking there is that a flat trigger reduces the feel of the amount of pressure needed to fire the rifle. In reality, it is a personal preference often overshadowed by its looks. Some feel that a flat trigger blade looks cool.

Break: The point where the trigger disengages with the sear.

Creep: The amount of movement needed before the trigger breaks is called creep. Creep is undesirable because it allows movement of the rifle while trying to fire the shot.

Crisp: A crisp trigger has no perceptible movement before it disengages the sear. Some liken it to the breaking of a glass rod.

Gritty: As opposed to a crisp trigger, a gritty one feels as if there is inconsistent pressure needed to get to the break. Some characterize it as like sandpaper. A gritty trigger usually is caused by a couple of things, movement detected before the break and rough machining of the engagement surfaces. Gritty triggers are usually also heavy triggers, meaning that they require a lot more pressure to disengage.

Lock time: The time it takes to fire the rifle measured from the point that the sear is disengaged. A shorter lock time means there is less time for the firearm to move off target once the trigger is pulled.

Over-travel: Some triggers often have some over-travel to them, meaning that there is detectable movement of the trigger after it disengages. This movement can affect the practical accuracy of a rifle because the over-travel can induce some movement of the rifle before the bullet leaves the barrel.

Reach: Usually a term used with rifles with pistol grips, reach is the distance from the rear of the pistol grip to the center of the trigger. Folks with shorter fingers can find that getting the correct placement of the trigger finger on the trigger to be difficult. On the other hand, a person with a very large hand and long fingers can have the same problem with just the opposite condition. Either way, if the reach is incorrect it can affect the shooter’s ability to get the most from his or her rifle.

Reset: Reset applies mostly to semi-automatic rifles. It is the distance needed for the trigger to reset on the sear after the rifle has cycled. Some shooters hold down the trigger, thus not allowing it to reset properly. A shorter reset is desired by some competitive shooters so allow them to address subsequent targets more quickly.

Sear: A piece that restrains the hammer or striker from moving and striking the firing pin is called the sear. The sear can be a part of the hammer or striker, or it may be a separate piece of metal. Once the trigger disengages the sear it frees the hammer or striker to discharge the firearm.

Set Trigger: For those who really want precision, a set trigger is the way to go. Set triggers come in two types, single and double. A single-set trigger has one blade. To engage the set, the shooter presses the rear of the blade, moving it forward until he feels it click. It takes usually on the order of about 2 oz. of pressure to fire the rifle. A double set trigger has two trigger blades. Usually it is the rear blade that sets the front blade. Most set triggers can be fired in a conventional manner if necessary.

Shoe: A trigger shoe is an aftermarket device that attaches to the trigger blade making it wider and giving the shooter the impression of a lighter trigger.

Stacking: Stacking describes the phenomenon of a progressively increasing amount of pull weight needed to fire the rifle.

Stop: A trigger stop is a device—often a set screw in the trigger blade—that can be adjusted to prevent over-travel in a trigger. These are more popular with pistols than rifles.

For most of today’s popular rifles there are aftermarket triggers available that can make a world of difference for the discerning shooter. Timney has been making aftermarket triggers since 1946 for just about any bolt-action rifle, as well as some AR-style rifles. It triggers are adjustable for weight, but you can specify just about any reasonable weight when you order one and it will arrive factory pre-set. McCormick, J.P. and Jewel make some superb aftermarket triggers as well.

https://assets.americanrifleman.org/media/3147558/trigger_timney-for-ar.png?width=248&height=330https://assets.americanrifleman.org/media/3147559/trigger_timney-for-remington-700.png?width=233&height=344
Timney has been making quality aftermarket triggers for a variety of rifles since 1946. The one for an AR-type rifle (left) takes just a few minutes to install and increases the practical accuracy several fold. Aftermarket triggers for bolt-action rifles started as a cottage industry between World Wars I and II when many shooters brought home Mausers, Enfields and Springfields for sporterizing. The Timney trigger for a Remington 700  (right) can be ordered with a pre-set pull weight of 1  1/2 lbs. Images courtesy Timney Triggers

This trigger stuff attracted the attention of then CEO of Savage, Ron Coburn. He and his engineering team quietly set about designing a trigger that could easily be adjusted by the end user to a pull weight between 1.5 and 6 lbs., yet remain safe in virtually any condition. As a bonus, the trigger has an incredibly quick lock time of 1.6 milliseconds. The Accu-Trigger made its debut in 2002, and to say it set the rifle world ablaze would be an understatement. While it may look a bit unconventional with its safety blade protruding from the center of the trigger blade proper, that safety blade allowed those of us who really need and want a light trigger, with little to no creep to have one, and it was available from the factory. Today there are a number of copies and spin-offs of the Accu-Trigger, but it remains one of the best factory triggers extant.

https://assets.americanrifleman.org/media/3147562/trigger_accu-trigger-1.png?width=483&height=288

Savage’s Accu-Trigger, introduced in 2002, revolutionized the concept of a good, safe factory trigger.

The trigger is the point of interface from the shooter and the discharging of his firearm. It is a mechanical device, and as such, it needs thought and consideration, as well as an occasional cleaning. Regardless of design, Rule 3—Keep your finger off the trigger until your gun is on target, and you are ready to shoot—is the best means of preventing a negligent discharge. A lot of engineering has gone into the modern trigger to make it accurate, reliable and safe.

 

Lt. Colonel Oliver North Poised to Become NRA President

by American Rifleman Staff – Monday, May 7, 2018

Lt. Colonel Oliver North Poised to Become NRA President

Lt. Colonel Oliver North, USMC (Ret.) will become President of the National Rifle Association of America within a few weeks, a process the NRA Board of Directors initiated this morning.

“This is the most exciting news for our members since Charlton Heston became President of our Association,” said NRA Executive Vice President and CEO Wayne LaPierre. “Oliver North is a legendary warrior for American freedom, a gifted communicator and skilled leader.  In these times, I can think of no one better suited to serve as our President.”

North said he was eager to take on this new role as soon as his business affairs were put in order. North is retiring from Fox News, effective immediately. “I am honored to have been selected by the NRA Board to soon serve as this great organization’s President,” North said. “I appreciate the board initiating a process that affords me a few weeks to set my affairs in order, and I am eager to hit the ground running as the new NRA President.”

The NRA Board acted quickly to begin the process for North to become President, after former NRA President Pete Brownell announced this morning that, in order to devote his full time and energy to his family business, he had decided not to seek election to a second term. In his letter to the Board, Brownell wholeheartedly endorsed North for President.

“Discussing this with Wayne LaPierre,” Brownell said in the letter, “he suggested we reach out to a warrior amongst our board members, Lt. Colonel Oliver North, to succeed me. Wayne and I feel that in these extraordinary times, a leader with his history as a communicator and resolute defender of the Second Amendment is precisely what the NRA needs. After consulting with NRA-ILA Executive Director Chris Cox, First Vice President Childress and Second Vice President Meadows, I can report there is extraordinary support for Lt. Colonel North.”

“Pete has served the NRA with great courage and distinction,” LaPierre said. “I am grateful that he joined me in enthusiastically recommending Oliver North to the Board of Directors.”

After the announcement, NRA First Vice President Richard Childress informed the board that he had multiple commitments in the next several weeks and was unable to be immediately available to serve as interim President. The Board then selected Second Vice President Carolyn Meadows to serve as its interim President. Meadows will step aside in a few weeks, when Lt. Colonel North is prepared to take on his new role as NRA President.

LaPierre congratulated the NRA Board for its action. “The board acted quickly and with great vision,” LaPierre said. “Oliver North is, hands down, the absolute best choice to lead our NRA Board, to fully engage with our members, and to unflinchingly stand and fight for the great freedoms he has defended his entire life.”

“Oliver North is a true hero and warrior for freedom,” LaPierre said, “and NRA members are proud to stand with him.”

 

 

 

This information is provided to our members solely as a service. 

The opinions expressed are not the official position of MRPC, its Board, Officers or Directors. 

Each member is encouraged to conduct their own study of these matters.

 

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