Jsb .177 redesigned aa s500

[vmaxpro]

Some intresting things today messing with the hammer. I lightened the hammer to 18 grams, shortened the stroke to .400”, cut the spring and made .015” spacers to tune the preload. It got intresting! With the reg at 140 bar, I shot through the chrono with 10.3gr barracudas. 928fps! With the sound of the gun I was expecting 500fps at best. A few more shims and Im at 1018fps. Tried some 13.4gr and 925fps. Doesnt sound impressive? Im using less than 1bar per shot. I did 30 shots and the needle barely moved. Air Arms left ALOT on the table with this gun. Im over 100 shots on the reg and fps only dropped 15 for the next 20 off the reg. The hammer weight/stroke/spring is way overkill on these guns. Keep in mind this is with a SMALLER poppet and throat diameter, along with no return spring ( which was stiff as hell). Still have more testing tommorrow!

 

[vmaxpro]

Heres the final hammer, 18.2 grams with factory shortened spring, stroke reduced to .400”:

 

[vmaxpro]

Done with tuning. Slugs seem to be more accurate in this barrel. I chose the best accuracy over power though. Final:

140 bar on reg

nsa 12.5gr @ 935 fps

75+ shots on reg, another 15 or so accurate off

Its making consistent hits on lemons ( had a bunch) at 100 yards which is good enough for birds/ground squirrels. I only shot paper at 60 yards and 20 shots were all under 5/8” so I stopped wasting slugs there. Im pretty happy with the results. I really wanted to see the 15gr do well around that speed but they just didnt. But ill take it!

 

[vmaxpro]

WOW, ok heres a 5 shot group at 100! Was not expecting that! Same 12.5 nsa slug

 

[8thman]

That’s some good groups! Nice work on your gun! I was going to get an aa500 but I just received a pulsar 177 and getting very similar results. The one thing that I didn’t expect was the Crosman premier 10.5 @1020fps are very accurate but for windy conditions and hunting the nsa 12.5 slugs are the way to go. I have not tried hi power or any jsb 16 or nsa 15 yet, but you’re results and shooting abilities are very impressive. Keep it up 

 

[vmaxpro]

Yep the premier brown box did fantastic too! I just tried the jsb 16.2gr and they are def hard hitting pellets. Speed is right in 890fps for about 28fpe and very accurate at 50 yards so far. I may end up choosing these over the slugs for hunting if they hold a group at 100.