EunJuns and Jerry Slugs vs. 24 inch barrel
I did some quick testing to see the FPE diiference between 35.8 EunJuns up to 9 ring Jerry Slugs (another plug for Jerry Slugs). I actually built the 5,6,7 and 8 Ring by cutting down the 9-Ring.
I was using a .25 caliber Condor, 95 gram Tony Hammer with stock 24 inch barrel and had the tank at ~3000 psi (based on the gauge on the AirForce hand pump). I ended at ~2800 psi, or about 29 psi loss per shot. I also had the PowerWheel at 13/0.
26 gr at 1090 fps at 69 fpe (flyers)
35.8 gr at 998 at 79 fpe (one holer)
43.2 gr at 946 at 86 fpe (one holer))
Weight__Pellet__FPE
36.0__35.8 EJ__62
42.2__43.2 EJ__65
48.6__5-Ring__60
57.7__6-Ring__70
66.5__7-Ring__78
72.9__8-Ring__83
85.8__9-Ring__90
A stock hammer and a 43.2 gr Eunjun is right near the flattening of the velocity vs. time in barrel curve at 3.5 milliseconds.
But with simply adding a 95 gram Tony Hammer, the flattening of the velocity vs. time in barrel curve is closer to 4.5 milliseconds which is what a 9-Ring Jerry Slug 86 gr pellet needs.
I think the most significant thing that is shown is that the 24 inch barrel, has enough length to still carry the energy of the airblast higher, if heavier pellets were used, as the FPE keeps increasing.
There is one other notable difference (and maybe Jerry can explain this), is that the EunJun may have less surface drag on the barrel and the expandable tail section may seal better, as noted by the 43.2 doing better then a 5-Ring.
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Just turn that target around and shoot it with a 7 ring, ought to straighten it right out!
I recently shot some heavy pellets through my rifle for the first time. I wish someone had told me how hard hitting those Eun Juns are before I ruined my resetting swinger target Saturday. It may not be totally shot, maybe I can hammer the discs flat again on an anvil. I couldn’t believe it when I got close enough to see the damage, those heavy pellets hit like a demolition hammer. The top reset disc is now a cone. I now see why people claim AF rifles are one of the most powerful airguns made.
I changed my Condor around this weekend to shoot the 25 acp cast bullets with more velocity.
I altered a Airarcher spring by cutting it to 3.5 inches, opened up the inside of the first coil so it would fit over the PW, the wire size is .80 rather than the stock springs .62.
I set my stock Condor top hat out to .13 and I kept the Condor hammer and weight and the RLAirguns valve stem.
I hit a high of 1024 FPS with the 52 grain bullet, which is 121 FPE, which is a gain of over 20 FPE from where my fire control system was before.
I also opened up my lead to accept the unsized slugs without the aid of a miniture hydrolic jack. 😆
It provided the best accuracy I have had so far with these cast slugs.
Regards,
Roachcreek
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Yea they (6-rings) tend to shoot clean thru a subaru hatch no problem out of my 17″ barrel. I found 6 of them in the back of the car before they hauled it away.
I didn’t get a chance to try the 22.5″ chopped barrel on that car, but they bust firebricks in half quite easily.