JSB MK II Heavy Velocity

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Hey PlanB, you bring out a great point that I failed to speak to earlier...and that is pellet length! I discovered this several years ago with my .25 cal. Sumatra 2500...at one point I decided to try the EunJin 43gr pellets, and just couldn't get them to shoot well at all...and noticed a lot of resistance as the probe pushed them into the barrel. So after loading a pellet I pushed it backwards out of the chamber with a cleaning rod and noticed that the tip of the pellet had rifling marks on it for about two millimeters. I then loaded an Exact King and pushed it back out also and noticed it had no marks on it at all.

At that point I called my brother who has been a reloader for about 35 years and told him what I discovered. Well it turns out that guys like him who reload their powder burners seat their bullets to a specific depth so that they just barely touch the rifling, but do not show any engraving marks...and was told that it is very bad to seat a projectile into the rifling, and that it is just as bad to seat it too far away from the rifling and cause it to jump a gap into the rifling, because it may enter the rifling slightly off center and will continue down the barrel askew and will leave the barrel with a wobble and be inaccurate. This is not a problem for us guys with smooth twist barrels that have no rifling, but for you guys with rifled barrels it can make a big difference. 

I am not sure how much effect pellet length has on smooth twist barrels but it is something to think about...but I will tell you that just for fun I shot some pellets at the range today that I had forgotten about, that I found on a shelf in my gun closet the other day...
H&N Field Target Trophy 19.5gr - avg. 993 ft./s - shot horrible at 25 yards :(
EunJin Domed 35.8gr - avg. 800 ft./s - shot into one hole great at 25 yards, but terrible at 50 yards. :(
H&N Grizzly 31gr - avg. 850 ft./s - shot horrible at 25 yards. :(
H&N Crow Magnum 26.23gr - avg. 906 ft./s - shot into one hole great at 25 yards, but terrible at 50 yards. :(
JSB HEAVY 33.95gr - avg. 824 ft./s - shot into one hole great at 25 yards, into one hole great at 50 yards, and into 1/2" super great at 75 yards! :) 

I am sharing the above data from the range today to illustrate my point that we have to shoot lots of different pellets to eventually find out what our gun likes the best. And also that just because our gun may shoot one kind of pellet lights out accurate, it may not shoot others worth a darn. Whether a particular brand of pellets shoot well or not may depend on many factors, so for those of you who want to save yourself a lot of time and money start your testing with the JSB line of pellets first...and you will probably be so thrilled with their performance that you won't have to look any further. :)

Best regards, Chuck


 
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Amen Brother Monkeyshine! You have my gratitude for backing up my conclusion because you and I and many others have been through the "arms race" thinking that faster was better. I shudder to admit how much money I spent on my .25 cal. Sumatra, and on custom barrels I bought for it from Dan Lilja, and for barrels with all kinds of twist rates that I paid Martin Rutterford to machine to fit on that Sumatra, and for swaged slugs, and for cast lead slugs from my friend Bob Vogel...

My point is that others out there can save themselves a whole lot of grief if they will heed our advice and respect our experience...or ignore it at their peril. After getting my Wildcat .25 last February and seeing what it will do with the 33.95gr Heavy pellets I turned around 180 degrees and abandoned the "arms race". It took a long time but I realized that "if you want a more powerful gun, Buy One... don't try to turn yours into one!" With that in mind I promptly sold both of my .25 Sumatra 2500's, and four other air rifles. For now and the foreseeable future I am a one rifle man...hey that even sounds cool...Chuck The Rifleman! :) Thanks again Monkeyshine...I will never go back to the lighter Kings either.

Best regards, Chuck
 
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Teekn you could PM longbrownbox, he loves his Wildcat as does chuck. He may also give some of his crony info to help with your pellet picks. I feel that your 776FPS probably would start wobbling at longer range maybe 80y. As stated you just never know unless you can film the pellet through trajectory or just check for accuracy at your shooting distance. Goodluck and enjoy your gun. 
 
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My Impact .25 cliber give me an average of 875 fps at his best setting for accurancy .
5657bf233dbbd00185908f20fd021bfe.jpg

Here is 10 pellets at 60 yards.
ac97371520483e21753bba5f33fcf267.jpg

And my ballistic coefficient is excellent.
7e7cf203b55c31e2d4afe726a7c8adc1.jpg

 
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