barrel swapping the B51 with a regulator

[TheBman]

I've been curious what the results would be with my B51 I regulated in .177 if I swapped barrels to the .22 and dialed up some spring tension on the hammer to up the fps not touching anything else.  I never changed anything on the regulator or the stroke length, or port sizes. I only adjusted the spring tension and here is what I got. I was hoping to have a barrel swapper so to speak, one for field target and one for larger pests. The 18.1's at this setting shot nicely at under 1/2 at 40 yards. The most accurate pellet was the 15.9 JSB at the same settings and it will literally stack them pellet on pellet at 40. I did not shoot a string on them today but did fire 3 over the chrony and they were right at 857 fps. I need to order some more to be able to run strings with them. 40+ good shots with 18.1's and 26 ft lbs  is a heck of a squirrel rifle!

JSB 18.1  3000 start  1650 end

813  811  813  816  812  815  811  813  811  810

813  814  811  810  809  810  813  816  814  813

812  811  814  813  815  813  814  813  815  816

815  815  816  814  816  813  814  813  815  813

812  812  815  812  812  809  810  807  806  806

Not the most efficient, but will cover dual duty well.

Brent

[Motorhead]

50 GOOD shots at what looks @ what 26-27 ft lbs ?  Not a thing wrong with that !

[TheBman]

Thanks Scott! That's kinda what i thought :-) Cheap old Crosmans went about 865 and you won't miss with them either.

[SpiralGroove]

Nice work Bman ,
I used the same strategy on my .22 cal B51 that I did on my .177 cal B50, except I used a 25 plenum and opened all ports to 11/64" -> only got 62 shots at 850 fps using 15.99 JSB's.  You got roughly the same results with smaller plenum/ports

Kirk

[TheBman]

Have another one to do this week for my cousin, he's wanting 850-900 with 18.1's.