Posts Tagged ‘precharged pneumatics’
by Tom Gaylord, a.k.a. B.B. Pelletier
The suggestion for this report came from blog readers ricka and Terd Ferguson, who both expressed concerns over the safety of precharged airguns. That’s safety…as in wondering if one can blow up!
It’s been a long time since I felt those same concerns, but I did at one time. Before I got my first PCP in 1995, I was quite concerned about keeping a scuba tank filled to 3,000 psi in my house. I’d seen the movie Jaws and was suitably impressed when the shark was blown up by a scuba tank at the end. So, these two readers are probably expressing the same concerns that hundreds of you share. I’d like to address those concerns in what I hope will be a straightforward series of reports that are easy to understand.
Do firearms blow up?
Veteran readers of this blog know the answer to that. Firearms do blow up, and I’ve shared at least one such personal story with you — my Nelson Lewis combination gun. I overloaded it and blew the percussion cap nipple out of the barrel! You can read that report here. In retrospect, it was my fault, so we can call that experience a stupident.
I’ve been involved in two other firearm blowups. One was caused by a rim failure in a .17 HM2 rimfire cartridge, and I’ve since come to find that this cartridge is known for that weakness. When it happened to me, shards of hot brass blew out the ejection port of the 10/22 clone I was testing for Shotgun News. One piece of brass cut my right arm and drew some blood; but aside from that and a lot of extra noise and smoke, no other damage was done. That event was out of my control, so it was an accident.
The other blowup was caused by a squibb round (one without gunpowder that drives the bullet into the barrel but not out again) in a Colt SAA revolver. I was firing very fast; and when the squibb happened, I was unable to stop before I thumbed off the next round. The revolver’s barrel was split lengthways when the second bullet hit the first one halfway down the barrel. That wasn’t an accident — it was a stupident.
Shooting a round into a bullet that was already lodged in the barrel burst this 7-1/2 inch Colt SAA barrel. The bullet was struck where the ejector housing screw was.
Do precharged airguns ever blow up?
Yes, they do. The causes are as random as they are with firearms, and the results range from sudden surprises all the way to death. The blog readers are entitled to a frank discussion of the kinds of accidents that can happen with precharged guns, and that’s what I’m about to give you.
When I bought my first precharged rifle—a Daystate Huntsman—and a brand new 80 cubic-foot aluminum scuba tank, I was properly awed. No, make that frightened. It was not unlike setting off my first charge of TNT in the Army! I respected the power potential of both that dive tank and the airgun I was filling.
Like any new thing, though, this awe and respect lasted only as long as it took me to become comfortable with the technology. If you do something enough times, the edge of respect starts to wear off—I don’t care what it is. It isn’t good when this occurs, but it’s human nature. Familiarity breeds contempt.
And then it happened. My gun blew up! Okay, it wasn’t actually the rifle; it was the hose that connected the rifle to the scuba tank. And to be honest, it didn’t really blow up. The soft wall of the rubber hose ruptured, violently releasing compressed air. The tear in the hose wall was about one inch long, and the warning signs were there before it happened. The hose had developed a noticeable bulge at the point the blowout occurred. That should have told me that the reinforced fabric liner under the outside rubber was failing, but like I said—familiarity breeds contempt. And I didn’t want to stop shooting my airgun. I took a risk and the explosion happened.
I was standing in my basement when the hose blew. The noise sounded like a concussion grenade, although I’m quite sure it was nowhere near as loud or forceful. The blast loosened a storm of dust from the floor joists above my head; and my wife, whose office was right above me, jumped out of her seat.
The net result was no injury to me, beyond a bruised ego, and no physical damage to anything other than the now-ruined hose. I was momentarily stunned, and it took about 15 seconds before I regained my bearings, because Edith had already gotten to the basement before I turned off the tank’s air flow.
I shared my experience with other airgunners who were more acquainted with precharged airguns and was told I had been lucky the hose hadn’t broken off completely, whipping me violently before I could turn off the scuba tank’s valve. That was when I discovered that nearly everyone who uses precharged airguns has either had an incident like this happen to them or knows someone who’d had one.
Can this be avoided?
Can this kind of incident be avoided? Absolutely! There are several things you can do to keep this from happening. First, if you use microbore air hoses, the likelihood of blowouts is reduced — not eliminated, just reduced. Microbore hoses carry the same internal air pressure as regular hoses, but the surface against which the air presses is so much smaller that it reduces the amount of stress on the hose material. However, most microbore hoses are stiff and will eventually soften at the point at which they are bent. That’s usually up near the tank, where they come out of the tank’s air valve. You still have to watch for that, because when they soften, they also weaken at the same spot. The hose I have linked to in this report has springs on both ends to prevent this bending to a large extent — but you still have to look for it.
Another safety measure is to use a hose that has a braided steel sheath on the outside. This sheath keeps the rubber that’s underneath from expanding and blowing out. The hose that blew out on me was an early rubber Daystate hose that had just a 3,000 psi rating. It was rated for nearly the same pressure it worked at (2,500 psi), which isn’t good. The hoses with braided steel sheaths are rated much higher.
The stainless steel wire braiding on this air hose will prevent it from blowing out.
The most important safety measure is you! Examine your fill equipment every time you use it; and if you spot something like I did, you stop right away.
Another type of stupident
If you fail to fully connect the two halves of the Foster quick-disconnect coupling during a fill, the air pressure will disconnect it for you! It will be accompanied by a small explosion and often by the violent whipping of the air hose. Here’s another place where a microbore hose protects you because it doesn’t whip as much, plus it’s smaller, so it doesn’t hurt as much when you get hit. But the best thing is to never get hit at all. When you make the connection, listen for the click of the knurled ring on the larger female fitting as it snaps into position. That indicates that all the ball bearings inside the coupling are now safely inside the groove of the male fitting.
This female Foster fitting (left) has a spring-loaded collar that pulls back to allow the ball bearings to move outward. They go around the flat spot on the male fitting on the right, then the spring pushes them into the groove. They will hold the two fittings together under pressure, but only when the ball bearings are in the groove. It’s important to hear the two parts click together.
That is as far as I will go in this report. I know how important this information is for many of you, so I promise to come back to this quickly for part 2.
For now, however, I want to leave you with this thought. I’m being honest with you about the potential dangers that are present whenever precharged airguns are used. You have to keep an open mind about this because the things I’m presenting are not that common. They do happen and most of them can be prevented by the means and methods that we’ll discuss.
Operating a precharged airgun is no more dangerous than having a gas-fired hot water heater in your house or operating a lawn mower. There are things to be aware of; and if you follow the rules, no harm should come your way.
In 2009, I gave Pyramyd Air two articles about the basics of precharged pneumatics:
While I put a lot into both articles, there will be new things in this series of blog reports.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, we’ll look at the Disco Double out at 50 yards. I used the best pellets from the 25-yard test to speed up this test. No sense going over the same ground twice.
The first pellet I tried was the JSB Exact Jumbo RS. It did the best at 25 yards, plus it’s so light, at 13.43 grains, that it gives the rifle a little extra zing.
The rifle arrived at the range filled to 2,000 psi, so I went right to work. I clicked the scope up 5 clicks in elevation to account for the greater distance and began shooting. The day was surprisingly cold — about 28 degrees F. My trigger finger had very little feeling, yet I was able to feel when stage 2 engaged on the trigger every time. That’s important on this rifle because the trigger is very light on stage 2.
There was no wind on the range, which made this a perfect day for shooting a pellet rifle. The first 10 shots went into 1.558 inches between centers. That’s not as small as many 50-yard groups you’ve seen me shoot, but let’s keep testing.
Next up were .22-caliber Crosman Premiers. The first 3 shots went into 2.269-inches and I stopped shooting. These pellets weren’t going to work at 50 yards.
JSB Exact, 15.89 grains
Next up were the heavier 15.89-grain JSB Exact Jumbos that looked promising at 25 yards. They produced a 10-shot group that measured 1.778 inches between centers. It was a little larger than the JSB RS pellet group at 50 yards, just as it was a 25 yards. So far, no prize.
The last pellet I tried was the Beeman Kodiak, which just did fair at 25 yards. Here at 50 yards, they put 10 into 2.458 inches. That’s hardly accurate! I almost stopped shooting this group when I saw how the shots opened up; but I thought that after doing that with the Premiers, I ought to let one go the distance just to show you what it looked like.
Back to the JSB Exact RS
I wasn’t finished with the testing just yet. The rifle was topped off at 2,000 psi again, and I went back to the pellet that was giving me the best results — the JSB Exact RS. The next group of 10 was the tightest of the session, at 1.318 inches between centers. I’d adjusted the scope for the Kodiaks, so this one landed below the bull.
I then shot 2 more 10-shot groups with the RS pellet. The first measured 1.522 inches, and the second measured 1.543 inches. When I examined the target after bringing it back from downrange, I saw a pattern. The RS pellet wasn’t giving tight groups, but they were very consistent. Out of 4 groups, the total variance was 0.24 inches — from 1.3 to 1.5 and change. That’s pretty consistent.
What do we know?
We know this Disco Double can put 10 pellets into 0.365 inches at 25 yards. And with the same pellet, we know that it opens up to about 1.5 inches when the distance is doubled. We know it was warm when the 25-yard target was shot and cold when the 50-yard targets were shot.
And that’s about the only difference — other than I did remove the TKO silencer after shooting 25 yards. I think what I will do next is the following.
1. Clean the barrel.
2. Shoot 5 groups at 25 yards with the JSB Exact RS pellet.
3. Clean the barrel again.
4. Shoot another 5 targets at 50 yards.
One last feature I want to show you is the special optional barrel band Lloyd makes for the Disco Double. It has a Picatinny rail on the bottom, allowing you to attach a bipod at just the right spot with very little extra weight added to the gun.
When I originally tested the .22-caliber Benjamin Discovery rifle in 2007, it was a pre-production prototype that was made out of a Crosman 2260. I shot several approximately half-inch groups at 50 yards with Crosman Premier pellets, but they were 5-shot groups. Now, I’m shooting 10-shots groups that I know are going to be larger. I didn’t use the JSB Exact RS pellet because it didn’t exist back then.
I believe this lightweight Disco Double has more accuracy than we’ve seen to this point. I think it must be capable of shooting at least one 1-inch group out of 5 at 50 yards. So, the test continues.
by Tom Gaylord, a.k.a. B.B. Pelletier
I’m testing 3 AirForce guns together — the Escape, the EscapeUL and the EscapeSS. All 3 are based on the same powerplant that is derived from the TalonP pistol. That’s why I am grouping them together like this. But each rifle has its own unique characteristics, too. And this is our look at the EscapeUL, which is the ultralight version of the rifle. It’s the lightest of the 3 air rifles and comes in either .22 or .25 caliber. I’m testing a .25.
As you will remember, the Escape is a collaboration between AirForce Airguns and Ton Jones, the star of television’s Auction Hunters. Ton had the requirement for a survival airgun and came up with the idea of putting a longer barrel on the TalonP pistol action, and AirForce did the engineering and development that turned it into a production rifle.
What does survival mean?
Survival is a word that’s charged with emotion, so the definition depends on the person who is using it. For many people, the term connotes a human wave attack with bullets and missiles flying everywhere — a last stand at the Alamo. But is that what survival really means? If you’re in the Alamo at that moment, I guess you would agree with that definition, but most of us will thankfully never be in that situation. But every year, millions of people are thrust into real survival situations.
Hurricane Sandy, a force 5 tornado, a blizzard that won’t stop or just having your truck break down 20 miles off Old Lincoln Highway outside Ely, Nevada, in the late summertime can all qualify as survival situations. Maybe all you have to do is hold out for 2 days before someone comes looking for you. You were exploring an old ghost town, and now they want to add you to the town rolls!
You don’t need a track-mounted machine gun or a Patriot missile launcher, but it sure would be nice to know you could defend yourself if a wild dog showed up! Or, if you had some way of popping one of those elusive prairie chickens that run along the ground and seem to stay just outside throwing distance. So, in your truck, along with the extra water, gasoline, MREs and sleeping bag (with cot, for this is the desert) you have a small canvas bag. Inside is a scoped EscapeUL, a hand pump and a tin of pellets. The rifle has been sighted-in, but you check it with one shot at an MRE wrapper stuck on a creosote bush 40 yards away — just to be sure. Then lay the rifle on top of the bag on the ground and put 10 pump strokes back in — 7 to get the air line up to pressure and 3 for the shot you just fired — and everything is good to go. The bag weighs 12 lbs., total, and has straps for shoulder carry. That’s what we mean by a survival airgun.
We took a good look at the Escape rifle for both power and accuracy and found that it can be plenty accurate when you use the right combination of pellets and pressures. Ton has pronounced it good to go, and his logo is on every Escape made.
The EscapeUL, however, is an AirForce idea. Ton knows about it and did test it, but it doesn’t bear his logo. It has slightly different features for a person with slightly different needs.
The EscapeUL is designed to remove all unnecessary weight from the rifle, while retaining as much of the power as possible. It has an 18-inch barrel instead of the Escape’s 24-inch barrel, so some velocity is lost. We’ll see how much in a moment.
The barrel isn’t just shorter, it is also thinner. Instead of a nominal 16mm diameter for the Escape barrel, the UL barrel is just 12mm. That diameter is only nominal. Some comes off when the barrel is ground before bluing. The barrel on my test rifle measures 0.477 inches across, which translates to 12.1158mm.
The net weight of the EscapeUL is 4.25 lbs., making it several pounds less than most precharged rifles and even less than some of the lightest ones.
Of course, we all want to know what a thinner barrel means as far as accuracy goes. That test will be next. But now, let’s take a look at power.
The EscapeUL shares the same 213cc Spin-Loc air reservoir as the Escape and TalonP pistol, so the number of shots per fill is going to be about the same. Physics being what they are, we already know what to expect. The powerplant is also the same. The same valve in the tank and same striker weight and spring tension will give similar performance. It’s the 18-inch barrel that makes the difference.
With the heaviest .25-caliber pellet, which is the Eun Jin pointed pellet that weighs 43.2 grains, the maximum velocity in the 18-inch barrel is about 910 f.p.s. The 24-inch Escape barrel gave a maximum of 1010 f.p.s. with the same pellet, so the UL barrel loses about 100 f.p.s. In term of muzzle energy, that’s 79.46 foot-pounds on the first shot, compared to the 97.88 foot-pounds for the Escape.
As with the Escape, the velocity drops with each succeeding shot. By shot 5, the velocity will be down to 855 f.p.s. That carries an energy of 70.14 foot-pounds.
In .22 caliber, the energies are all lower because the pellets are lighter. With a 28.4-grain Eun Jin dome the maximum velocity is 980 f.p.s. on the first shot. That’s 60.58 foot-pounds of muzzle energy. By shot 5, the pellet leaves the muzzle at 900 f.p.s. and generates 51.09 foot-pounds.
You can discuss their performance in several different ways; but to my way of thinking, the Escape rifles are best in .25 caliber. I’m glad that’s the way I will be testing this one.
The trigger, adjustable stock, automatic safety and scope mounts are identical to those found on the Escape. It’s plenty for a scope, scope level, tactical flashlight and laser. There’s even enough for a coffee grinder, if you can find one that will fit!
I’ve already been asked if the Escape rifles will run on CO2. They should, but it will need to be tested to say for sure. Since they were not designed to operate on CO2, I’ll have to find a way of filling the reservoir. No CO2 coupling I know of will mate with an air coupling, so it may take me some time to work it out.
I’ve also been asked on the back channel how quiet these airguns can be. Quite frankly, I don’t know. Given all the technology in the world, they can probably be made quieter than a Marauder; but once I answer that, the next question will be if all that technology can be reduced in size to fit in a pocket! We criticize the U.S. Air Force for asking that everything be made from unobtainium (strongest metal known whose forms weigh nothing and add lift to airframes), yet we do the same thing when it comes to powerful airguns. “Great,” we say, “but can they also be quiet and get lots of shots, too?”
There’s survival and then there’s daydreaming. We’re talking survival here.
by Tom Gaylord, a.k.a. B.B. Pelletier
Last time we looked at the accuracy of the AirForce Escape at 50 yards. I shot the rifle on low pressure and a low power setting on that day to see what it could do. You may remember that at 50 yards, I got a best 5-shot group with JSB Exact King pellets that measured 0.594 inches between centers. That’s great for a .25-caliber PCP, but I know it left some of you wondering what the rifle can do at its maximum power. Today, we’ll look at that.
The heaviest .25-caliber pellet I have is the Eun Jin pointed pellet, which weighs 43.2 grains. So, it’s a little heavier than the standard bullet of a .22 Long Rifle cartridge. We know from testing that this pellet leaves the muzzle at up to 1010 f.p.s., generating 97.88 foot-pounds of energy.
I also had some Eun Jin domed pellets to test. At 35.8 grains, they’re lighter than the pointed pellet but might be accurate enough to make a difference. As long as I’m testing, I thought why not test them, too?
The wind had just started to pick up at the range. I had finished testing the Benjamin Marauder with synthetic stock and shifted to the Escape because I felt the power of the gun and weight of the pellet wouldn’t be affected by this wind nearly as much as a smaller pellet moving at lower speed.
The first thing I tried was the heavy Eun Jin pellet on max power and with a max power setting on the gun. The first 2 pellets went through the same holes at 50 yards, and I thought I was on to something. Then, shots 3 and 4 moved 2 inches to the right but also landed in a single hole. Shot 5 then landed an inch to the left of the first 2 shots, giving me a 5-shot group that measures 2.478 inches across the widest centers. While that is adequate accuracy for larger animals at 50 yards, it wasn’t as good as I’d hoped it would be.
Five Eun Jin pointed pellets on maximum power with a 3,000 psi fill at 50 yards. The group measures 2.478 inches between centers, but look how they landed. The first two are left of the pellet, the next 2 are to the right of the dime (in the same hole) and pellet 5 is all the way over to the left.
I remembered that there are 10 good shots on a fill of the Escape’s small 213cc reservoir, so I shot the next 5 pellets at a different target. The scope wasn’t adjusted. The reservoir pressure at the start of this string was about 2,600 psi. This time ,all 5 went into 1.622 inches. That’s a significant improvement. According to the velocity test data, these shots ranged between about 71 and 82 foot-pounds.
I was satisfied with the results of this heaviest pellet, but I’ve never gotten the best accuracy with pointed pellets. I felt I might be at the limit of this pellet’s performance. Time was passing and the wind was building, so I moved on.
The lighter domed pellet remained to be tested. On max power with a 3,000 psi fill, I got several open 5-shot groups that all hovered around 2 inches. While that’s okay, it isn’t what I wanted. Then, I shot a couple groups with the power set to max and the starting air pressure set at 2,600 psi. The only reason I did it that way was because of the results of the heavier pointed pellet I’d just tested. And that’s where the magic happened!
The first 5-shot group on this setting (power set on max, starting fill pressure at 2,600 psi and shooting the 35.8-grain domed Eun Jin) measures 1.177 inches. Four of those shots are in 0.555 inches! That’s fantastic! I don’t have the velocity data for this pellet on that setting, but I’ll venture a guess it’s producing around 60-70 foot-pounds.
Like you, I wondered if this single group was just a fluke, so I filled the reservoir to 2,600 psi, again, and shot a second group. This time, I put 5 into 1.089 inches. Three of those pellets are in 0.214 inches. If you overlay those 3 pellets on top of the other group, they all go to the same place!
Here’s the miracle I was talking about. Same starting air pressure, and 5 pellets went into 1.089 inches. Three of them are in 0.214 inches and in the same place as the 4 pellets from the last group. This is significant!
What I’m saying is that somewhere around this power setting and fill pressure, there’s a super sweet spot the Escape loves with this domed pellet. By spending more time refining the fill pressure and by adjusting the sights for this combination, the Escape will become a tackdriver. It doesn’t get a lot of shots like this, but remember — this is a survival rifle. You want one shot — one kill. I think this gives that to you!
I could continue to refine my pressure settings with this pellet, but I don’t think I have to. I’ve now shown you 2 different ways the AirForce Escape can make very small groups at 50 yards. If you’re looking for a powerful air rifle to do some serious hunting, you should consider this one. I think Ton Jones and John McCaslin both have reason to be proud of their creation.
I was prepared to exchange barrels at this point and try the .22-caliber Escape, but I think I’ll let that slide for now. If I’m any judge, most buyers are going to get the .25-caliber Escape. Once they see these results, I expect they’ll do similar tests. Therefore, I plan to switch over to the EscapeUL next. That’s the ultralight rifle that has an 18-inch barrel. I’ll give you a combined introduction and velocity/power report, followed by a range test like this.
by Tom Gaylord, a.k.a. B.B. Pelletier
Benjamin Marauder .177 caliber: Part 1
Secrets of loading the Benjamin Marauder magazine
Fixing a Marauder magazine
Benjamin Marauder .25 caliber: Part 1
Benjamin Marauder .25 caliber: Part 2
Benjamin Marauder .22 repeater with synthetic stock: Part 1
Benjamin Marauder .22 repeater with synthetic stock: Part 2
Benjamin Marauder .22 repeater with synthetic stock: Part 3
Benjamin Marauder .177 caliber 50-yard test: Special part
Benjamin Marauder .22 repeater with synthetic stock: Part 4
Today, we’ll look at the Marauder’s accuracy at 50 yards. I had to wait a long time for a calm day at the range for this.
Clearing the air
Before I begin the report, though, I want to address something. The new Marauder — both the one with the synthetic stock and the one with the wood stock — are the same rifle in different stocks. The actions are identical. Crosman waited to bring out the wood-stocked model, but both rifles have the new set-back trigger and also the new valve and hammer depinger. Which brings me to my second comment.
Owners who have used the new Marauder seem to like it a lot. They praise it in their comments on the product page. But those who don’t own one are making comments such as, “Tom Gaylord said the new .22-caliber Marauder only gets 860 f.p.s. Where is the 1,000 feet per second that Crosman claims? And where are those extra shots?”
Let me make this very clear — Tom Gaylord DID NOT say that the new Marauder only gets 860 f.p.s. What Tom Gaylord did was test the new Marauder exactly as it came from the box. He discovered that his test rifle seems to like a 2,900 psi fill, instead of the 2,500 psi fill suggested in the owner’s manual.
Tom Gaylord shot his test rifle at 25 yards and showed you the accuracy the rifle got when filled to that pressure. Today, he is going to show you how well it does at 50 yards, and it will also be filled to 2,900 psi.
This is a pet peeve of mine. When people read all the performance specs of an airgun, they lump them together as though the gun does all of them simultaneously. The new Marauder may very well get 12 percent more shots per fill because of the new valve. And it may very well shoot a .22-caliber pellet at 1,000 f.p.s. And it may also be very accurate. And very quiet. But don’t expect it to do all of that at the same time — just as you don’t expect a new Corvette to go 0-60 in 4 seconds and also get 21 miles per gallon. You get one or the other — not both at the same time.
I haven’t even adjusted the gun to see how fast it will shoot. And I haven’t played with the fill pressure, either. All I’ve done to this point is take the rifle out of the box, put a scope on it and test it for accuracy. During that testing, I’ve accomplished several things:
1. I know the best fill pressure of the test rifle as it stands right now — 2,900 psi
2. I know the most accurate pellets — 14.3-grain Crosman Premiers and Beeman Kodiaks.
3. I know that for top accuracy, I can count on getting 2 full magazine’s worth of shots on a fill — 20 shots.
Now, don’t go running around claiming that I just said the new Marauder only gets 20 accurate shots. What I said was for top accuracy I can count on getting 2 full magazine’s worth of shots. There are a lot more than 20 accurate shots in this rifle!
If you’ve been following this report, you know that I’ve eliminated several pellets during earlier testing. They didn’t hold up to the 2 I chose for this test. That’s not to say there aren’t other pellets that might outshoot these 2 — just that, of the pellets I’ve tested, these are the best.
Testing at 50 yards
The day was completely calm — perfect for this kind of test outdoors. I shot the rifle off a sandbag rest. The first group was with Crosman Premiers, the pellet that proved to be the most accurate at 25 yards.
Since I didn’t know when the wind might kick up, I went fast in this test. There were 2 other air rifles to test on this day, and one of them was the Double Disco that shoots the same velocity as the Marauder. I wanted to complete this test so I would have time for that one afterward. I also had an AirForce Escape to test; but given how powerful that rifle is and also given the heavy weight of the .25-caliber pellets I’d be shooting, I thought that one could endure a little breeze.
At 50 yards, 10 Premiers went into a group that measures 1.112 inches between centers. It’s a reasonably round group that has 7 of the 10 shots in 0.558 inches. There’s nothing wrong with that!
Next, I shot a group of 10 Beeman Kodiaks. This was on the same fill as the Premiers. Again, I was going fast to finish before the wind kicked up, so I didn’t stop to adjust the scope. Ten Beeman Kodiak pellets went into 1.516 inches at 50 yards, with 9 of them making just 0.888 inches. As with the Premiers, this group was also reasonably round.
Here comes the wind
When I finished the Kodiak group, the breeze was just starting to blow. I refilled the Marauder and tried one other test pellet that I’m evaluating for Pyramyd Air, but it didn’t do very well. So, I ended the test for the Marauder.
The new Marauder is very accurate. This test shows that clearly. As far as the absolute top velocity it can get or anything else, I still have to test that.
In my opinion, the new Marauder shoots as well as the old Marauder did. I do like the new synthetic stock for its slim profile and lighter weight; but as far as accuracy and quietness goes, I don’t see any difference between the new rifle and the old Marauder.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, we’ll look at the accuracy of the Disco Double. Before that, however, I mounted a scope, a TKO airgun silencer that they call a muzzlebrake or a lead dust collector, and something I’ve never seen in print before but something I’ve used on many precharged air rifles over the years — a bolt keeper!
What’s a bolt keeper?
First, let me tell you that when I mounted the TKO silencer, it fit the barrel perfectly. There were no barrel alignment issues that I was warned about, and I checked closely. This unit is very well made and looks beautiful on the gun. The unit I’m testing is 8-1/4 inches long; and, yes, Lloyd, I checked that it indeed is a .22 caliber before mounting it. However, when the silencer is on, the top end cap does not fit.
When I shot the gun with it on the first time, I have to say I was underwhelmed. It was quite loud. A second shot confirmed this. Then, I held the rifle to my shoulder and fired a third shot. That’s when it hit me — a blast of air in the face not unlike the glaucoma test eye doctors do. The bolt was opening and discharging compressed air with each shot!
This happens a lot with precharged guns and it doesn’t matter how cheap or expensive they are. The bolt handle lifts up and air comes back through the action. On the lightweight Disco Double, it only begins to happen when the rifle is at the bottom of the power curve, which is where it was when I tested it this time.
A simple fix is to fasten a rubber band around the bolt handle to hold it closed during the shot — a bolt keeper. Once on the gun, I just leave it there. Even though it’s not needed until the end of the power curve on this rifle, I don’t want to worry about it. You can cock and load the rifle with the band in place.
With the handle held closed in this fashion, the rifle suddenly became very quiet — as in Benjamin Marauder quiet! I now understand why shooters have been so excited about this unit. It really works!
NOTE: Due to several reader questions about this silencer, I am removing it from the rifle and returning it to Lloyd. Silencers are a very touchy subject, since owning one that will function on a firearm requires a license for each specific silencer. I don’t want to mislead any reader, so in the interest of clarity I am simply not going to use or possess this item any longer. I wrote an article on silencers that can be accessed here. If you have any questions on the subject, I recommend you read that article.
The rifle now weighs 6 lbs., 11 oz. with everything installed. That’s very light for a serious air rifle.
I mounted a UTG True Hunter 3-9X40 scope on the rifle. Since UTG packs rings with this scope, I used them, but they’re Weaver-style mounts. So, I had to use a UTG Weaver to 11mm dovetail adapter to make them fit the dovetails on the rifle’s receiver.
I’ll be shooting from a rest at 25 yards today. The range is indoors, so wind is not an issue.
Sight-in was accomplished with .22-caliber Crosman Premiers; so after I was on the paper, I shot the first group of 10 shots at 25 yards. The hole they made is a little taller than it is wide, but it measures 0.569 inches between centers. While that’s okay for 25 yards, it isn’t great. I’d like to see something a couple tenths smaller.
Next up were Beeman Kodiak pellets. They’re identical to the .22-caliber H&N Baracuda pellets that Lloyd tested the rifle with, and they were what I had available. They put 10 into 0.655 inches between centers. Like the Premiers, that’s not bad…but not as good as I’d hoped.
Beeman Kodiaks opened up more, to 0.655 inches between centers. Only use them if you need a heavy pellet.
JSB Exact RS
I followed the Kodiaks with some JSB Exact Jumbo RS pellets. They’re even lighter than the Crosman Premiers, and sometimes they can be very accurate in precharged rifles. This was one of those times. Ten pellets went into 0.365 inches, which is exactly what I’d hoped for the Disco Double. This is the pellet for this rifle!
Nex, I tried the RWS Superdome pellet that’s always recommended. I don’t often have good luck with them, but a lot of shooters do. I stopped after just 4 shots, though, and you can tell from the lateral spread that measures 0.634 inches between centers that they weren’t going to perform.
JSB Exact Jumbo
The last pellet I tested was the JSB Exact Jumbo. These are usually among the top pellets in .22-caliber precharged air rifles, so I felt they deserved a chance. The first 2 shots were on a fresh 2,000 psi fill, and I’m not sure the rifle wasn’t overfilled by a slight amount because they both landed away from the main group. Shot 9, however, was shot while the rifle was grouping well, and I have no idea why it’s above the main group. The 10-shot group measures 0.647 inches between centers, making this the second-best pellet I tested in the rifle.
These 10 JSB Exact Jumbos measure 0.647 inches between centers. The first 2 shots are the holes at the right and bottom right of the main group. Then, the rest of the pellets went into the big group, except for shot 9 that went high. There is no explanation for that one. This is a pellet I would keep trying.
Filling from a hand pump
The biggest feature of the Benjamin Discovery, aside from the low price, is the fact that the maximum fill pressure is just 2,000 psi. It’s full right where other PCPs have run out of air. And that makes the Discovery extremely easy to fill with a hand pump.
Using the Discovery factory pump, I began the fill at just under 1,000 psi and pumped until the onboard pressure gauge read 2,000. It took exactly 100 pump strokes to fill the gun; and, until the final 20, they were as easy as inflating a bicycle tire. Only when the pressure passed 1,800 psi did I notice an increase in pump handle resistance.
One tip when filling with a hand pump is to go slow. Allow time at the top and bottom of each pump stroke for the air to flow through the various stages inside. If you don’t, you just waste energy and heat up the pump unnecessarily.
Observations so far
So far, I’m thrilled by the performance of the Lightweight Disco Double. The number of shots I get on a fill is large enough for serious shooting before it’s time for a refill and the rifle’s performance leaves nothing to be desired. A glance at the onboard gauge needle, and I know the status of the fill.
When I tested the original Benjamin Discovery rifles in both calibers, the guns I used were pre-production prototypes. I shot groups under 0.6 inches with both calibers; but at that time, I was shooting only 5-shot groups. The JSB Exact RS pellet did not exist at the time of that test. So, it’ll be interesting to see what this rifle can do at 50 yards with 10 shots. Remember — this is the first Benjamin Discovery production rifle I’ve ever shot!
by Tom Gaylord, a.k.a. B.B. Pelletier
Okay, all joking aside — today, we’ll look at the performance of the Lightweight Double Disco that Lloyd Sikes built. Lloyd tested this exact rifle when it was still in its factory original condition, so we can compare that to the performance of the rifle after the conversion. I was pleased to see that my chronograph results and Lloyd’s are very close.
Before the conversion, the stock Benjamin Discovery accepted a fill to 2,000 psi. From that fill, the rifle got 21 shots of .22-caliber Crosman Premiers at an average 845 f.p.s., which works out to an average 22.7 foot-pounds. Lloyd did get more shots in his string, but he discounted all those that were not within 4 percent of the average velocity. That’s a subjective choice, but it’s what drives the numbers Lloyd is giving us for the factory rifle. The maximum velocity spread in this string of 21 shots was 40 f.p.s., with a low of 820 f.p.s. and a high of 860 f.p.s.
After the Lightweight Double Disco conversion, Lloyd shot the same Crosman Premier pellets on a similar 2,000 psi fill and got a string of 33 shots at an average 849 f.p.s., for a muzzle energy of 22.9 foot-pounds at the average velocity. Again, this number includes all shots that fell within 4 percent of the average velocity. The maximum variation in this string of 33 shots was 34 f.p.s., with a low of 831 f.p.s. and a high of 865 f.p.s.
The shot count made possible by the Lightweight Double Disco conversion went from 21 to 33 shots. The average velocity did increase by 4 f.p.s., but I wouldn’t concentrate on that because these numbers will change a little each time you record them. Essentially, the gun shot this pellet the same before and after the conversion — it simply got more shots after.
What did I get with Premiers?
I filled the rifle to about 2,100 psi because I wasn’t sure that my best pressure gauge agreed exactly with Lloyd’s gauge. I wanted to start in a slightly valve-locked posture and move up into the power curve as I went, and that’s exactly what happened. Here’s my shot string.
1-20 21-40 41-end
802 856 836**
822 856 832
817 852 828
826 852 825
831* 857 824
831- 855 820
833 857 816***
837 853 STOP (47 shots)
- Slowest shot in acceptable string
+Fastest shot in string
* First gauge photo
** Second gauge photo
*** Third gauge photo
If I accept the shots in this string starting at No. 5 and continuing through No. 41, I get 37 shots. They’ll have a maximum spread of 29 f.p.s., with a low of 831 f.p.s. and a high of 860 f.p.s. If I’m more critical and start with shot No. 8, which went 837 f.p.s., and still stop at shot 41, the total is 34 good shots, with a maximum spread of 24 f.p.s. The low in this string is 836 f.p.s. and the high is 860 f.p.s.
Do you see how this works? It’s entirely subjective. I’m deciding what to accept and what to reject. Once I start accepting shots, though, I keep on shooting until the last shot in my acceptable string has been fired. I can’t ignore any shots in that string because I won’t be able to chronograph my shots when I’m shooting in the real world, away from the chronograph.
You must pick the starting and ending points that you feel are best for what kind of shooting you want to do. That’s why a chronograph is so essential to the owner of a PCP. If I were to shoot this same string again with the exact same starting pressure, which is very difficult to control, I might get numbers that are similar but slightly different from these.
Next we will look at the performance with .22-caliber H&N Baracuda pellets. Lloyd tested the rifle with them, but I didn’t have any .22-caliber Baracudas on hand, so I substituted the Beeman Kodiak, which is the same pellet under a different name.
With the Discovery in factory trim on a 2,000 psi fill, Lloyd got a string of 22 shots that averaged 717 f.p.s. They produced an average muzzle energy of 24.2 foot-pounds (compared to the 22.7 foot-pounds produced with Premier pellets in the factory trim). Heavier pellets will almost always produce more energy in a precharged rifle. The maximum velocity spread with the Baracuda pellet in the factory Discovery was 29 f.p.s. The low was 697 f.p.s. and the high was 726 f.p.s.
The Lightweight Disco Double conversion running on the same 2,000 psi fill with Baracudas gave a string of 38 shots that averaged 713 f.p.s. The low was 699 f.p.s. and the high was 729 f.p.s., so the spread was 30 f.p.s. The average muzzle energy was 23.9 foot-pounds.
Baracudas got more shots per fill than Premiers
With Baracudas, Lloyd got 22 shots per fill in factory trim and 38 shots with the Lightweight Disco Double conversion. In both cases, the rifle gave more shots per fill with the Baracudas than with the Premiers. My thinking is that the heavier, slower pellet holds the valve open a bit longer and is able to go to lower pressure before it falls off the power curve.
What did I get with Beeman Kodiaks on a 2,000 psi fill (refer to the first photo of the pressure gauge to see where I actually stopped the fill)?
1-20 21-40 41-end
702 712 701
699- 720 693
707 716 695
714 718 696
709 714 683
719 726 STOP (45 shots)
- Slowest shot in string
+Fastest shot in string
While this string has fewer shots than the first one with the Premiers, there are actually more usable shots here because I learned where the needle on the gauge had to be in the first test. No air was wasted at the start of this string. I would accept everything from shot No. 1 through shot No. 41, giving me a total of 41 usable shots, with a spread of 29 f.p.s. The low was 699 f.p.s. and the high was 728 f.p.s.
I got more usable shots from Beeman Kodiaks than from Premiers, just like Lloyd did with H&N Baracudas. Our data seems to agree very closely. Lloyd’s low velocity was 699 f.p.s. and so was mine. Lloyd’s high was 729 f.p.s. and mine was 728 f.p.s. How is that for consistency? As I said, the H&N Baracuda and Beeman Kodiak are the same pellet.
Analysis thus far
The Lightweight Disco Double increases the useable shot string significantly, even though the rifle is no larger nor heavier than a factory Discovery. You can tell from a glance at the onboard pressure gauge if the rifle is still on the power curve, so there’s no need to count the shots.
All of what you have seen to this point was done with the stock Discovery striker spring (0.035″wire, 0.289″ OD, 1.99″ long , 16.5 coils) in place. But Lloyd also provided and tested a heavier striker spring (0.041″ wire, 0.300″ OD, 1.78″ long, 19 coils) that gives both the factory Discovery and the Lightweight Disco Double conversion more power.
To see what the heavier striker spring can do with Baracuda pellets in the Lightweight Disco Double, Lloyd recorded that the average velocity climbed from 713 f.p.s. to 764 f.p.s. That is an energy increase from 23.9 foot-pounds to 27.5 foot-pounds. The total number of shots dropped back from 38 to 25 shots. This shows how the Disco Double allows the power to be increased, and the total shot count to remain the same as the less powerful factory gun.
I haven’t reported on the trigger, yet. You may recall that I had Lloyd install an optional trigger from a Benjamin Marauder. Lloyd told me in a message that it’s set for a light first stage, and then an extremely light second-stage pull. I found at first that it was so light that I pulled straight through both stages without recognizing stage 2. But when I adapted to it, it’s really not as sensitive as a 10-meter target pistol trigger. Stage 1 takes 14.4 oz. of effort; and stage 2, while recognizable, does not increase the number on the electronic scale. It’s on the order of 10 grams or less.
So far, I’m delighted with the Lightweight Disco Double. If it turns out to be accurate, it could become my go-to PCP!