Crosman 760

[Mortblanc]

[Talon]

Did you chrono the gun before cutting 6"" from the barrel Mort?. Not that I've ever cut a pneumatic, I've only shortened and recrowned Spring air rifles . From what I understand though a precharged or pump up benefits from a longer barrel compared to a spring gun . The pump up or pcp having a larger amount of air pushing the pellet compared to the limited amount a spring rifle can compress in the cylinder . Like a steady push of air compared to the short sharp compression a spring rifle generates.I did once tune a career 707 in .22. The results were dramatic to say the least .
I quickly brought it back to 12ftlb's and sold it .
I'm curious if you saw any noticeable drop after the barrel cut.

[Mortblanc]

I have not clocked the BBs since I did the barrel cut but I will in the next few days. I need to get the chrono out and check the speed of the heavy JSB pellets out of the 2 PCP rifles.

I clocked them with 11 and 14 grain pellets when I first got them both but I have not checked the speed on the heavy 18.1 grain pellets and they are the most accurate I have found for either of those rifles.

With 14 grain pellets the Stormrider produces 27ft/lbs and the Gauntlet produces 21. The Gauntlet is a regulated system and it only varies 14fps across the entire 40 shot string.

The Stormrider is not regulated so it has a pressure curve and changes POI slightly as power goes up and down. You have to catch it on the flat part of the curve. I usually only pump it to 17 bar and stop shooting around 12 bar for best accuracy, which limits me to about 15 shots.

Even with a power curve the little Stormrider will put the JSB pellets into 1/2" @25 yards. The Gauntlet is a bit better.

I will probably not see much change in velocity from the barrel cut. This is the same power plant that is used in the 1377 pistol and this barrel is about the same length as that, I just have a rifle stock on it instead of the pistol grip. Coleman seems to use the same internals on almost all their multi-pump guns.

I will check speeds for both BBs and pellets when I run the test.

"Tuning" springers is easier than most folks would imagine. Polish the inside of the tube, apply some silicone grease to the spring, make some PVC washers and preload the spring as much as possible and still have it cock and you are about there. If you were just below 12 lb before you will be very close to 12 after.

My own problem, if you would believe such, is that my good rifles have too much power to allow me to compete in field target! We have a top limit of 20 ft/lb and both my rifles are above that.

That is why I bought the Umarex Gauntlet. I can work with the regulator and reduce the power enough to get below the limit and still retain the uniform velocity and accuracy.

[Mortblanc]

I have numbers!

The 5 grain steel Daisy BB shot is going 580 fps 5 feet from the muzzle for 3.74 ft/lb energy.

The Crosman .177 wad-cutter pellets of 7.9 grains are going 520 for 4.75 ft/lb energy.

Now we should compare to other well known guns.

The Daisy Red Ryder BB gun and all the lever cocking BB guns from Daisy use the same power plant and it gives 275 fps average speed for .84 ft/lbs energy. I know that I have killed hundreds of starlings and black birds with those shooters.

My favorite old style BB gun was the Daisy M25 which gave 350 fps and was probably the strongest Daisy power plant made. It gave 1.65 ft/lbs energy.

That is stepping down so probably step up one notch. The old favorite Weihrech HW30/Beeman R7 pushes a standard 8 grain .177 pellet at 620 fps from the add copy and some tests say it is actually 650. That is either 6.83 or 7.5 ft/lb depending on the number you use.

But the HW30/R7 costs $300US !!

All the other selections I can find here in the US are either weaker in performance or jump directly to the "magnum" power levels.

For $100US I can buy Crossman, Ruger, Umerax, Gamo 1000 fps gun. Those same guns would be available to you at 12 pound limits for less cost than the "better brands", some of which are owned by the less respected cousins.

With Gamo owning BSA and Umarex owning Walther, Diana and RWS ad building the Ruger air guns, and Beeman and Weihrech being partners one never knows what to expect.

Plus they all have Chinese production outfits