A little about o-rings

by Tom Gaylord
Writing as B.B. Pelletier

o-rings
An assortment of o-rings.

This report covers:

  • History
  • Flexibility is key
  • O-ring failure
  • O-rings as a face seal
  • O-ring-assortments
  • Hardness
  • Some o-ring facts
  • The seats or channels they sit in help o-rings work!
  • O-rings used other ways
  • Summary

An o-ring is a donut-shaped elastomer (pliable) seal that performs sealing functions for hydraulics and gasses. Airguns use o-rings a lot, and for different purposes. They help us enjoy our hobby with a minimum of fuss. But what do we know about them?

History

The first patent for an o-ring was by the Swedish inventor, J.O. Lundberg. It was granted in 1896. Not much is known about him, but Danish machinist, Neils Christensen who came to the U.S. in 1891, patented the o-ring in this country in 1937. No doubt his work originated from his development of a superior air brake that Westinghouse, a leader in air brake technology since George Westinghouse invented the first fail-safe railroad air brake in 1869, gained control of. In World War II the U.S. government declared the o-ring a critical mechanical seal technology and gave it to numerous manufacturers, paying Christensen a stipend of $75,000 for his rights. Long after the war was over and he had passed away his family received another $100,000 read more


Crosman Mark I and II reseal: Part 2

by Tom Gaylord
Writing as B.B. Pelletier


Crosmnan Mark schematic

Today’s report is another guest blog from reader Ian McKee who writes as 45 Bravo. He’s going to finish the report on resealing the Crosman Marks I and II CO2 pistols.

If you’d like to write a guest post for this blog, please email me.

History of airguns

Part 1 — resealing the end cap

Over to you, Ian.

Crosman Mark I and II reseal

Ian McKee 
Writing as 45 Bravo

This report covers:

  • Disassembly
  • Bolt removal
  • Hammer spring
  • Remove trigger guard
  • Remove the valve
  • Prep and assembly
  • The 4 o-rings in the pistol
  • Piercing cap o-rings
  • Assemble the pistol in the reverse order
  • Test the function

So, your Crosman MK1 is still leaking, even after you replaced the seal in the piercing cap as we covered in an earlier blog. 

There are only 4 o-rings in this pistol, only 3 have constant gas pressure on them when the gun is charged, and 2 of those are in or on the piercing cap assembly, and those we already covered.  read more


The basics of shooting: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

This report covers:

  • I can’t use open sights — my eyes are bad!
  • Bad eyes
  • The point
  • Fire Direction Center
  • So what?
  • Eye dominance
  • Sight with either eye
  • What can YOU do?
  • Exercise
  • What’s the point?
  • Pistols and scoped rifles — not such a problem
  • If you really can’t see, use a scope
  • Effect on accuracy?
  • Summary

Today we look at the subject of eyes and eyesight as it relates to the basics of shooting. This is a tough subject and I’m sure there is a lot more than I will address. I’m not an eye doctor, so everything I say today is based on my experience, or on the little research I’ve done.

I can’t use open sights — my eyes are bad!

Yes there are people who absolutely cannot use open sights. I estimate that of those who make this complaint perhaps 5-10 percent of them are correct. Today I want to talk about the others — the ones who just won’t try because they think it’s too difficult.

Bad eyes

In 2010 I was in the hospital for 3-1/2 months with acute pancreatitis. I coded once — a code blue with a crash cart and lots of doctors and other people. My blood pressure was 35 over 25 and they said they were loosing me. I said to somebody there (my eyes were closed and I couldn’t see anyone) that 35 over 25 was pretty low and he responded, “Hey! You shouldn’t be conscious!” Then I was out for three days and when I woke up I hallucinated for the next two weeks. Then they sent me to a different hospital.

At the different hospital I had a young doctor who refused to give me a transfusion when my hemoglobin dipped below 7.0. I told my wife I couldn’t see anything, nor could I concentrate on anything. She found out about the low hemoglobin and the doctor holding back (a nurse told her) and demanded I be given a transfusion. I immediately had two units, followed by a unit per day for the next two days. I also got a different doctor. I was in a teaching hospital and saw 6 young doctors every day, but nobody did much of anything for me. I was fed through a tube in my arm. Reader Kevin knew how bad it was but most readers were kept in the dark.

When I was discharged from that hospital I went home with a feeding tube still in my arm. It remained there for another two months.

The point

My point in telling you all of this is, when I went home, I still could not see very well. My eyes had dehydrated and took six to eight months for them to return to normal. How could I continue writing this blog? My friend Mac helped me a lot in those days but I had to get back to shooting again quick.

I used powerful reading glasses to see the front sight. When I did I was able to shoot again. I might not have been at my peak, but I was certainly okay.

Fortunately I knew something that the people who won’t use open sights apparently don’t believe. You don’t have to see the target very well to hit it! All you need to see clearly is the front sight. Please bear with me on this because there is more to explain before I tie it together for you.

I am aware of this sighting situation more than most folks because I was a 4.2-inch (107mm) mortar platoon leader in the Army. My guns shot at targets 3,000-5,000 meters away — targets the guys at at the guns never saw. Our fire was directed by forward observers (FOs) who watched the target through binoculars that had a mil-reticle in them. They were excellent at determining their range to the target and measuring how far left and right of it (in mils) the mortar shells impacted. And, let me tell you — when a 4.2-inch mortar round explodes, there is no problem seeing it!

Fire Direction Center

My Fire Direction Center (FDC) knew where the FOs were. They also knew where the guns (mortar tubes) were, so when the corrections were called in to the FDC from the FOs, they calculated them from the FOs’ viewpoint, and then shifted their calculations around to the gun’s viewpoint. They then calculated what kind of elevation and windage changes each tube needed to make (each was unique) to hit the target.

Each gun (number one gun through number four gun) would make the traverse and elevation corrections, though only one tube was firing at the time. Once the corrections were made to their gun sights, the gunners looked through their sights and aligned them with their aiming posts that were about 40 feet in front of them. There were lights on the aiming posts for night operations, so they made their vertical crosshair split the light lenses in their centers. Then they leveled their guns until the bubble in the level on the gun’s sight was centered again.

When that tube (the one that was firing) got on target, and that happened within three shots at the max, we conducted a fire mission (we fired for effect) with 2 to 4 tubes — depending on the target. A fire mission is a certain number of shots fired from a certain number of guns. Downrange it is called a barrage. If you are in the place where the shells are landing it looks and feels like the world is blowing up.

One time during a fire mission we dropped a shell down the tank commander’s hatch (we shot at obsolete but real US tanks on the ranges at Grafenwoehr, Germany) and blew the turret off the tank! The division commander, a two-star general, was watching this with my forward observers and was highly pleased.

So what?

Hey, BB, I’m not a mortar tube! Why tell me how they adjust their sights? I shoot pellet guns.

I told you this because you adjust your sights in exactly the same way and for exactly the same reasons, whether you know it or not. The mortar tube’s aiming post is their front sight and it’s about 40 feet away from the gun. Their target may be 5 kilometers away and the gunners can’t even see it. Yet they can hit it consistently because they don’t worry about it. They concentrate on the aiming post. That aiming post is their front sight.

Your eyes are your forward observers and your brain is your fire direction center. It tells your hands how to adjust the front sight (by adjusting the rifle or pistol) to hit the target that SHOULD LOOK BLURRY to you. Nobody can focus on both the front sight and the target. The front sight is where you should focus.

I have taught dozens of people to shoot this way and it ALWAYS works. My best students are women and children who have no prior experience with shooting. That’s because they listen to everything I say, then they try to do it the way I tell them from the start. My worst students are 20 to 40-year-old men who come to me already “knowing” how to shoot. They have so much to unlearn!

Eye dominance

Okay, the front sight issue is out of the way. Now, which is your dominant eye? Keeping both eyes open, look at a spot about 10-15 feet from you. A spot on the wall is good for this. Looking at that spot, hold your hand at arm’s length and stick up your thumb to cover that spot.

Now, wink one eye closed or cover one eye with paper and watch to see whether the thumb seems to move away from the spot. It doesn’t matter which eye you cover. If the spot remains in the same place, uncover that eye and then cover the other eye to see whether your thumb seems to move.

For me the thumb covers the spot when I cover my left eye. But when I cover my right eye the thumb moves to the right. It moves about as far as my eyes are apart. That means my right eye is dominant. If it moves the other way — well, you figure it out.

What if the thumb doesn’t move regardless of which eye is covered? That means both eyes are dominant, and I guess that person can sight with either eye. I seldom encounter that situation, though I know it does exist.

Sight with either eye

While I am right-eye dominant, I can sight with my left eye. It doesn’t feel comfortable, but I can do it. However, there are people who find that incredibly difficult to do. My wife, Edith was one who couldn’t do it. So airgun maker Gary Barnes made a special offset scope mount that allowed her to shoot a Barnes Ranger precharged pneumatic.

barnes ranger
Gary Barnes made this special offset scope mount so Edith could sight with her left eye while shooting right-handed.Those two outriggers adjust independently and the scope rings swivel to align with the scope tube in any orientation.

Besides the trajectory correction she also had to make a correction for the sideways offset of the scope. So, shooting at different ranges was a challenge. But BRV was a bullseye game that was always shot at the same distance, so that’s where she competed.

edith shooting
Edith competed in BRV with a .177 Barnes Ranger PCP rifle.

What can YOU do?

You have options if you are what is colloquially known as odd-eyed dominant — a right-handed person with left-eye dominance and vice-versa. First, you might be able to learn to shoot with the other eye. I can do it, though I don’t like it. But when my left or non-dominant eye looks at sights I find it best to cover the dominant eye somehow. And I said cover — not close the eye by winking. I have an exercise to show you why winking your non-sighting eye doesn’t work.

Exercise

Poke a hole through a piece of stiff paper or card stock. Let’s make it around 1/4-inch or 6.35 millimeters in diameter. That’s roughly. Don’t sweat the measurements! I used the awl on my Swiss Army knife to poke the hole and it’s not very round.

hole in card
The hole doesn’t have to be precise. Even something as rough as this will work.

Now, keep both eyes open and cover your non-sighting eye. Bring the hole in the card up to your other eye about 3/4-inches away and the hole will appear to remain fully open. Then, close your other eye by winking and watch the hole shrink in size. The edges become blurry and you notice them closing in. The more you wink the smaller the hole becomes. That is what happens when you sight with one eye and close the other one by winking! Don’t do it because it makes the light through the peephole or through the rear sight notch decrease dramatically. Use an eye patch if you must, but keep both eyes open.

What’s the point?

The point is — don’t close your other eye when sighting. Train yourself to leave it open, because closing it by winking or squinting just reduces the amount of light that comes through your sighting eye.

Okay, that was option one — use the other eye. Option two is to shoot from the other side, i.e. a right-handed person shooting left-handed. I find it easier to do that with a rifle than a pistol. Some folks have no trouble doing it either way with both rifles and pistols. Those folks have already figured all of this out and they are waiting for the rest of us to catch up.

The last thing I recommend is getting a special gunstock or sights or a trick scope mount like I show above. They are just as difficult to live with as the problem they are designed to correct.

Pistols and scoped rifles — not such a problem read more


The basics of shooting: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

This report covers:

  • Accuracy from gross to fine
  • Rough airguns
  • Smooth airguns
  • Trigger
  • Cleaning the barrel
  • Sight picture training
  • The triangulation system
  • Making a triangulation sighting bar
  • Conduct of the exercise
  • A simpler, faster way to begin
  • Style of the sights doesn’t matter
  • The results you want
  • Summary
  • read more


    2019 Pyramyd Air Cup: Part 1

    by Tom Gaylord
    Writing as B.B. Pelletier

    Vendor's Row
    There were more vendors than ever this year! They were arranged on streets under pop-ups.

    This report covers:

    • Big
    • Downrange
    • Down to the public ranges
    • Repeating crossbow pistol
    • American Airgunner
    • Air-air-air!
    • Gee whiz!
    • Summary

    Big

    I knew it was going to be good when I first saw it driving up. I saw rows of colorful tents arranged like a country fair. They turned out to be several streets with vendors on each side, and as the morning advanced they were filled with representatives from their companies. We had been told that the Pyramyd Air Cup site was bigger this year and I have to report that it certainly was!

    In fact, on day two I was shown the other side of the facility and discovered that what I was on was the small side. The real facility is several times larger than what I had seen on the first day. And that other side includes a clubhouse/event center that has an indoor swimming pool! The banquet Saturday evening was held in that facility.

    Camping sites were in the woods on this side of the road and equipped with everything a RV or tent camper could desire. You guys who camped there please correct me if I’m wrong, but I saw hundreds of well-equipped hookups.

    The Cup started on a Friday with competitors shooting in both the inaugural benchrest competition and the Gunslynger that has run for many years. There were a large number of competitors on the line when I arrived at 8:30.

    Benchrest briefing
    I’m looking at half of the benchrest competitors. The other half is behind me. This is the pre-match safety briefing.

    Downrange

    The benchrest targets were 100 yards downrange and the wind was blowing 10+ m.p.h. with frequent gusting. Everyone was having their pellets blown to the left — sometimes by several inches.

    downrange
    The range flags were blowing right to left at 100 yards!

    Leapers

    I stopped by the Leapers booth and saw a new 4-16 scope with improved light transmission. It has an etched-glass reticle and the adjustment knobs are calibrated in the same increments as the reticle lines. This makes adjusting the scope easier, as no mental conversion is required. They are sending one to me to test for you, and I can’t wait. Did I mention that it is very compact — only a little longer than a Bug Buster.

    I also saw a new high-tech bipod that I will soon be reviewing for you. This one is really slick and after my experiment with the Daisy Buck a few weeks back, I’m excited to try it

    Down to the public ranges

    This venue is huge! I bet the public shooting ranges are a quarter-mile from the competition and Vendors’ Row. Pyramyd Air had several range carts to ferry people, so I hopped on one and went down to the public ranges. These are where you can try many different airguns that Pyramyrd Air and some of the other vendors provide. The also had a sales office down there and everything they sell was marked down by 20 percent with free shipping! But I also saw some things that hadn’t yet been seen by the public.

    Repeating crossbow pistol

    The first new thing was a 6-shot repeating crossbow pistol from Europe. It is way cool and so new that it doesn’t have a name yet, but it sells in Europe under the name Steambow. I was surprised by how accurate it is and also by the power — 16+ foot-pounds!

    Steambow
    This crossbow pistol is every bit as much fun as it appears in this picture. BB wants to to test one! Heck — he wants to own one!

    The real news with the Steambow, however, is not the pistol. There is also a full-sized crossbow that is cocked buy CO2 pressure! I saw it cocked and shot several times, and I even shot it myself a couple times. It is supposed to be highly accurate. I don’t know how long we will have to wait to see this reach the market but I can tell you that Pyramyd Air is working on it as fast as possible.

    big Steambow
    The full-sized bow is cocked via CO2 pressure. This is a bow that will compete with top-quality crossbows like the Sub-1 and the Ravin.

    There is more than one version of the full-sized bow coming to market, so there will be more to say as the details are refined.

    American Airgunner

    The American Airgunner television show was at the Cup and host Rossi Morreale was competing in several events. When he wasn’t doing that he was interviewing people all around the event. You’ll get to see parts of the Cup online and in next year’s show.

    Air-air-air!

    The guns at the Cup run on air and Pyramyd had several of their compressors going all the time, filling large tanks. Even so, they were hard-pressed to keep up with the demands of so many shooters.

    compressor
    These Air Venturi compressors were going most of the day, filling dozens of large carbon fiber tanks. read more


    The difference between strikers and hammers

    by Tom Gaylord
    Writing as B.B. Pelletier

    A history of airguns

    This report covers:

    • What are firearms?
    • What is an explosion?
    • What starts the burning?
    • Ignition
    • Smokeless powder
    • The hammer-fired system
    • Evolution
    • Hidden hammer
    • Striker
    • On the airguns
    • Valve stem
    • Summary

    Today I want to explore a gray area in airguns. It’s gray because airguns operate differently than firearms, so we will begin our discussion with firearms for better understanding.

    What are firearms?

    Firearms are devices that launch projectiles by means of a chemical explosion. To start the explosion there needs to be some kind of initiator. In the beginning, when the gunpowder that we call black powder was in use, all it took was a spark or a hot coal to start the explosion.

    What is an explosion?

    An explosion is a violent expansion of gasses. Pop a balloon and it explodes. Anything that burns can explode under the right circumstances — even dust. The flour that bread is made from can explode so violently that it can kill people and even level huge buildings.

    An explosion requires the right conditions. A handful of black powder placed on a tree stump and set afire will burn in a flash but will not usually explode. Confine the same powder to a vessel that restricts the expansion of gas, though, and the explosion will be quick and powerful.

    What starts the burning?

    If we are talking about black powder, heat starts it burning. Even a small spark can ignite it and, once the burning begins, it spreads to the neighboring particles of powder at a speed of 8,000 to 11,000 f.p.s. HOWEVER — if the black powder IS NOT packed tight and there is air space in-between the powder granules (but the powder is inside a container) the speed of ignition increases, often producing so much pressure that it blows the container apart!

    Smokeless powder, on the other hand, burns very slowly when it’s loose and in the open, but extremely fast when confined. It actually burns much faster than black powder when it is tightly confined.

    Now let’s look at a video demonstration of the relative burn rates for smokeless powder and black powder when both are burned in the open.

    Ignition

    Black powder can be ignited by just a spark. That’s what makes the flintlock possible. The piece that held the flint was called the cock in the beginning, because people thought it looking like a rooster with something in its mouth, as it “pecked” at the frizzen. As time passed, the term hammer crept into the vernacular and both cock and hammer were used until the end of the flintlock era, around 1830-45.

    Jamell Fowler flintlock fired 1
    The cock, or hammer, has fallen against the hardened steel frizzen, both pushing it back out of the way and striking sparks from it with the flint. Some of the sparks fall down into the pan where the priming powder is and they set it off. Part of the fire from that small explosion moves through the vent hole into the main powder charge at the rear of the barrel.

    Here is a video that shows a flintlock in operation, in case you have forgotten.

    In the early 19th century (CA 1807) mankind learned how to create sufficient heat to ignite black powder by means of a secondary explosion that was set off by concussive pressure. The percussion system was born.

    To create the percussion that ignited the explosive material required the hammer that had held the flint to be turned into a hammer that could smash. Instead of a touch hole, a nipple with a hole in it provided the anvil that the percussion cap sat on.

    Nelson Lewis combination gun nipple
    The nipple is the anvil that the hammer smashes the percussion cap against. The hole directs the fire from the cap’s explosion down onto the powder charge in the barrel.

    Smokeless powder

    Percussion caps were not hot enough to set off smokeless powder reliably, plus the nipple they used allowed gas to escape. Smokeless powder burns too slowly to explode when there is any possibility for the gas pressure to escape, so a new system of ignition had to be invented — the primer. The primer worked in conjunction with an enclosed copper cartridge case (later brass) to contain the gas pressure, allowing it to increase to explosive levels.

    The hammer-fired system

    I have told you all of this to make the point that the first smokeless powder cartridges were ignited by a hammer that looked very similar to the percussion hammer. But this new hammer either contained a firing pin to smash the primer directly, or it may have hit a separate firing pin that then hit the primer.

    Webley hammer
    Early hammers, like the one on this 1916 Webley Mark VI revolver, show how focused the designers were on crushing the primer! Nothing prevents this hammer from directly crushing a primer. read more


    The AirForce Ring Loc Kit: Part 1

    by Tom Gaylord
    Writing as B.B. Pelletier

    Ring-Loc Kit
    AirForce Condor Ring-Loc Kit.

    This report covers:

    • Condor
    • Flexibility
    • Goof jobs
    • More power
    • For the latest Spin Loc valve
    • What it does
    • The kit
    • AirForce testing
    • Widest range of power today/li>
    • So what?
    • Summary

    Today we start looking at what I believe is a really big deal. This is what I teased you about on Tuesday. The Ring Loc Kit from AirForce takes the world’s most powerful and flexible air rifle and expands both its power and flexibility by an order of magnitude! That’s a strong statement that I will now begin to justify.

    Condor

    The kit we are looking at is for the AirForce Condor and also for the CondorSS. The Condor has a 24-inch barrel. The CondorSS barrel is 18 inches, so everything you read about the Condor will be just a bit less in the SS. As you know, in PCPs barrel length makes a difference.

    I was working at AirForce when the Condor first came out and I hand-tested the first 100 production rifles to make certain they would shoot a .22 caliber Crosman Premier pellet at 1,250 f.p.s., because that was the AirForce ad campaign. They never launch anything without first making certain that it will deliver as advertised. We recorded each serial number and the velocity it produced with a Premier, just so we could be certain that each and every rifle we sold delivered what was promised. After testing those rifles we knew with confidence that the valve design was right on the money and production was making them the way we thought. We could go back to testing a sample of production and not every gun.

    Flexibility

    I have said it many times before — when you buy an AirForce sporting rifle you aren’t buying just one air rifle; you are buying an entire system. No other airgun on the market allows you to change barrels for three different lengths in 4 different calibers (that’s 12 combinations), has a primary power adjuster that operates without the use of tools, and has a secondary means of power refinement in the valve cap. The secondary means of power adjustment involves adjusting the height of the valve cap to control the length of the valve stroke. In turn, that determines how long the valve remains open for the air to flow. And it doesn’t stop there. You can put a standard air tank on a Condor to reduce the power, and even install a Spin-Loc Micro-Meter air tank to take it right down to nearly nothing (12 foot-pounds in .177 caliber). I tested that for you in 2008. So, a Condor can be almost whatever you want it to be.

    Goof jobs

    However — as soon as the rifle came out in 2004 the couch engineers had to “fix” the things that AirForce got wrong. One of the popular early modification was to install a heavier striker weight, thinking that a harder blow would hold the valve open even longer. What it did was pound the Delrin valve seat into the valve stem, ruining the valve. And, on Mr. Condor’s personal rifle, it also bent the aluminum frame of the gun, so that when we rebuilt his gun for him (one of the original 100 to go out) we weren’t able to repair the frame. We got his rifle working within specifications again and he stopped posting his fixes on the forums, but I often wondered where that poor beat-up Condor is today!

    Mr. Condor's valve
    I saved Mr. Condor’s destroyed valve, or what was left of it (the valve cap and stem were broken off), to show people what happens when you fool with things you don’t understand. My Condor that’s just as old still works perfectly.

    Now you understand my background. I was there and saw this from the inside. The Condor was a world-beating air rifle that produced up to 65 foot-pounds of muzzle energy when it first came out in .22 caliber. Today it is offered in .25 caliber and goes out the door capable of 80 foot-pounds, mostly due to the heavier pellets that have come into the market.

    More power

    As Tim the Tool Man Taylor tells us — what we need is more power! For those not living in the U.S., that’s a reference to a comedy television show, Home Improvement that ran from 1991 to 1999. It’s based on comedian Tim Allen’s humor. And AirForce has listened! The Ring Loc Kit that I’m reviewing for you starting today (and continuing for I don’t know how long) does just that. It takes the 80 foot-pound .25 caliber Condor up to 105 foot-pounds! That’s

    Escape read more