Well, it happened again this year like it did last year. Night temps here in Montana have been -40F, -32F and -30F for the last three nights. I received several new tins of JSB Exact King Heavy MkII pellets from AoA as well as a new DonnyFL Tanto suppressor and had to go out in the cold and do some testing. Pellets are accurate, suppressor works great, and waiting for warmer weather to do the final zero of the new pellets. But, the cold weather shrunk back my seals and the rifle developed an air leak like it did last year. So I simply fixed the leak without disassembling the rifle and replacing the input valve seal, which is holding so far. Read on if you want to know how I did it.
FWIW, my rifle shoots 25.4 grain JSB Exact King pellets at 3/8" 5-shot groups at 50 yards. 31 grain H&N Baracuda pellets at 1/2" groups at 50 yards. My zero is set at 60 yards on my Hawke Nite-Eye scope with SR-6 illuminated reticle. I have killed an untold amount of prairie dogs with this rifle out to 100 yards and beyond. Kills are rarely less than 50 yards. Depending on pellet, my gun is set at 40-45 FPE and speeds of over 900 FPS with light pellets, which I almost never use anyway. H&N Baracuda runs at about 800 FPS. My best accessory is my Leica Rangemaster 2400-R rangefinder, which really has ranged out to 2405 yards in field use, and it simply blows away that old $300 Bushnell rangefinder. The Leica cost me almost as much as my air rifle, but the Bushnell was totally inadequate for use with my CZ 550 7x57mm Mauser which I shoot at 500 yards and beyond. Most of my rifles are powder burners and I prefer CZ as they are all very sub-minute of angle with handloads and premium bullets at a sub-$1000 price, but shoot like a Sako or custom build. I typically handload thousands of rounds per year and do quite a bit of target practice. The BSA Lonestar is by far the best air rifle I have ever owned. I will admit that I am far more into firearms than air rifles, but a prairie dog habit gets expensive really quick even with .223 Rem handloads in my CZ 527 Kevlar Varmint, and quite frankly, there is about zero effort required anymore with that rifle and the air rifle gives a lot more challenge and the low noise does not cause nearly as much fear in the PD's. What amazed me the most was just how deadly the .25 cal pellets are on PD's. Or any other small varmints for that matter.
But back to the leaky Lonestar. If you do some research on Buna o-rings, you will find that they are not rated for the far sub-zero cold we often get here in Montana. I have found that when an o-ring develops a leak, it tends to keep leaking. What I am telling you will not work on old delapidated o-rings that are cracked, pitted, cut or otherwise destroyed. My air rifle is stored in a hardcase on a cool concrete basement floor when not in use. The trick to getting the o-rings to seal again is to treat the o-rings with a couple of shots of Napier Power Airgun Oil and then warming the air chamber for a while. With low pressure in the chamber, otherwise the oil will be spit out if the input valve is leaky, and in a dusty place like Montana the input valve will see some dirt ingress, I stand the rifle vertically and fill the valve (an extension tube on the spray head helps tremendously) and then pump up the rifle until the air valve pops open and the oil goes in, then I repeat the process again to insure enough oil got in to coat the valve o-ring, and the next thing I do is bring the rifle up to 232 Bar using my FX hand pump. DO NOT suddenly fill an oiled air rifle from a high pressure tank at a fast fill rate. At about a 2000 pound per second pressure rise, the heat and pressure rise will cause detonation. Also, only use a synthetic oil. The Napier oil is specifically made for airguns, and I am NOT recommending YOUR oil, OK? From a high pressure tank, the pressure rise must be VERY SLOW, and a restrictor valve should be inline anyway, but fools are born every day, so the warning remains in effect. Would be better if we all used dry nitrogen as far as o-ring health goes, but air is basically free, even if somewhat dusty where I live. MY FX pump has the optional inline filter installed. Now that I have oil in the pressurized chamber, I hang my rifle up with the muzzle pointing down and leave it overnight so that the valve gets a good oil soak. The next day I pump the rifle up to full pressure again, and then I apply heat to the air chamber near the input valve with a hair dryer for about 5 minutes until it is very warm, but not too hot to grab hold of. Very high heat is not necessary, just constant warmth like on a hot day in the sun at a prairie dog town. I repeat this about every 15 minutes for 5 minutes at a time for about an hour. I then take a radiant space heater and place it at about a foot in front of the heat element to keep the valve toasty warm, but not really hot enough that you cannot grab hold of it, and leave it like that for a few hours. If cold weather caused a leak to start from o-ring shrinkage, this can fix the problem. Like I said, the weather we have here in Montana is sometimes colder than what Buna rubber o-rings are designed to handle. I have never had leakage problems in hot weather. If you develop a leak in hot weather, do not expect this fix to work for you. Time for new o-rings in that case.
As always, YMMV.
Phil
FWIW, my rifle shoots 25.4 grain JSB Exact King pellets at 3/8" 5-shot groups at 50 yards. 31 grain H&N Baracuda pellets at 1/2" groups at 50 yards. My zero is set at 60 yards on my Hawke Nite-Eye scope with SR-6 illuminated reticle. I have killed an untold amount of prairie dogs with this rifle out to 100 yards and beyond. Kills are rarely less than 50 yards. Depending on pellet, my gun is set at 40-45 FPE and speeds of over 900 FPS with light pellets, which I almost never use anyway. H&N Baracuda runs at about 800 FPS. My best accessory is my Leica Rangemaster 2400-R rangefinder, which really has ranged out to 2405 yards in field use, and it simply blows away that old $300 Bushnell rangefinder. The Leica cost me almost as much as my air rifle, but the Bushnell was totally inadequate for use with my CZ 550 7x57mm Mauser which I shoot at 500 yards and beyond. Most of my rifles are powder burners and I prefer CZ as they are all very sub-minute of angle with handloads and premium bullets at a sub-$1000 price, but shoot like a Sako or custom build. I typically handload thousands of rounds per year and do quite a bit of target practice. The BSA Lonestar is by far the best air rifle I have ever owned. I will admit that I am far more into firearms than air rifles, but a prairie dog habit gets expensive really quick even with .223 Rem handloads in my CZ 527 Kevlar Varmint, and quite frankly, there is about zero effort required anymore with that rifle and the air rifle gives a lot more challenge and the low noise does not cause nearly as much fear in the PD's. What amazed me the most was just how deadly the .25 cal pellets are on PD's. Or any other small varmints for that matter.
But back to the leaky Lonestar. If you do some research on Buna o-rings, you will find that they are not rated for the far sub-zero cold we often get here in Montana. I have found that when an o-ring develops a leak, it tends to keep leaking. What I am telling you will not work on old delapidated o-rings that are cracked, pitted, cut or otherwise destroyed. My air rifle is stored in a hardcase on a cool concrete basement floor when not in use. The trick to getting the o-rings to seal again is to treat the o-rings with a couple of shots of Napier Power Airgun Oil and then warming the air chamber for a while. With low pressure in the chamber, otherwise the oil will be spit out if the input valve is leaky, and in a dusty place like Montana the input valve will see some dirt ingress, I stand the rifle vertically and fill the valve (an extension tube on the spray head helps tremendously) and then pump up the rifle until the air valve pops open and the oil goes in, then I repeat the process again to insure enough oil got in to coat the valve o-ring, and the next thing I do is bring the rifle up to 232 Bar using my FX hand pump. DO NOT suddenly fill an oiled air rifle from a high pressure tank at a fast fill rate. At about a 2000 pound per second pressure rise, the heat and pressure rise will cause detonation. Also, only use a synthetic oil. The Napier oil is specifically made for airguns, and I am NOT recommending YOUR oil, OK? From a high pressure tank, the pressure rise must be VERY SLOW, and a restrictor valve should be inline anyway, but fools are born every day, so the warning remains in effect. Would be better if we all used dry nitrogen as far as o-ring health goes, but air is basically free, even if somewhat dusty where I live. MY FX pump has the optional inline filter installed. Now that I have oil in the pressurized chamber, I hang my rifle up with the muzzle pointing down and leave it overnight so that the valve gets a good oil soak. The next day I pump the rifle up to full pressure again, and then I apply heat to the air chamber near the input valve with a hair dryer for about 5 minutes until it is very warm, but not too hot to grab hold of. Very high heat is not necessary, just constant warmth like on a hot day in the sun at a prairie dog town. I repeat this about every 15 minutes for 5 minutes at a time for about an hour. I then take a radiant space heater and place it at about a foot in front of the heat element to keep the valve toasty warm, but not really hot enough that you cannot grab hold of it, and leave it like that for a few hours. If cold weather caused a leak to start from o-ring shrinkage, this can fix the problem. Like I said, the weather we have here in Montana is sometimes colder than what Buna rubber o-rings are designed to handle. I have never had leakage problems in hot weather. If you develop a leak in hot weather, do not expect this fix to work for you. Time for new o-rings in that case.
As always, YMMV.
Phil
