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Old 07-13-2021, 10:53 AM
gcrank1's Avatar
gcrank1 is online now

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Apr 2018
South Central WI, USA
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100% (4)
I ran some chrono tests yesterday with the 1377.
Crosman WC's
Chrono at 5' out from muzzle
5 shots averaged
Started with 3 warm-up shots at 4 pumps, then the test.
3 pumps: 284
4 pumps: 326
5 pumps: 349
Fwiw, I tried 2 pumps but it stuck the 3rd shot pellet just into the 'throat' and of shots chrono'ed showed such wide deviation that I decided 3 is much better as a base. The extreme spread on 3 pumps for 5 shots was only 7fps too!
At 6 pumps the additional fps began to drop off enough that for me it is not worth the effort.
This is fine velo at 4 and 5 for WC target shooting and plinking.
As a comparison my Daisy 717 (1983, sgl pump pneumatic) does 390fps and the RWS (Diana) 5G, barrel cocking springer, does 430.
Could be that as I use it the velo may improve. It passes the 'tissue paper test' but a tear-down, cleaning and new seals wouldnt hurt either. If fact, just soaking the oem o-rings in ATF for a while might be fine too.
Tip for storage: pump once and leave the bolt open so the breech o-ring doesnt get compressed in the barrel leade taper.

Last edited by gcrank1; 08-07-2021 at 09:26 AM.
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