Predator Polymags. Can they get any better?

Over the years I've tried every variety in 22, and I'll call it the polymag trap. The best I could achieve was acceptable results with shorts at 40 yards with the shorts shooting low 900's with a Cricket I just tried it again with a Leishy shooting at just sub 800 fps with the 18 JSB's producing one hole at 20 yards, the groups were 3/4" at best with the poly mags. To date several Marauders, and Disco's performed even worse. 
 
Poly mags produce some of the best groups in my .25 Marauder...odd



1/2" @ 50 yards and very close to 1" @ 100.

I can get anywhere between 1/2 inch to 3/4 inch 5 shot groups at 50 yards. Then I get one or two fliers that open it up to 1 inch to 1 and a 1/2 inch groups at 50. This goes for both .22 and .25. I never bothered to try grouping past 50 yards after.

😐
 
.25 Predator Polymags, 52 yds 880 fps 5 shot groups: top three groups compared to Kings, bottom three groups, all shot from .25 FX Elite with original ST barrel.

Expand pic for better viewing.

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My BSA HORNET shoots these .25s just as well. 

The .177 Polymag Shorts shoot very close to the same sized groups as with 8.44 gr Exacts from my RAW TM 1000 at 20 fpe out to 50 yd and are deadly on small pests up to rabbit size.

Kind regards, Harry.