Real-world velocities of a Sheridan CB9 in .20 caliber

[NickB79]

I'm tempted to pick one up, and I was wondering if anyone here has chronoed one with pellets in the 10-15 gr. weight range.  Thanks!

[Daysailer]

You are probably looking for the numbers on new guns...
But here are the recent numbers on my two older rocker Sheridan's.  (all  true Sheridans are .20 cal)
F-1 Crony, indoor.  Rarely get errors.

#Pmp  '71     '75   H&N Match Wadcutterers 10.5gr  weighed.
3        524     490  
5        631     591
7        708     658
8        731     680

#pmp  '71    '75   Benjamin Cylinders 14.3 gr
3        462    431
5        559    524
7        625    584
8        647    607

# pmp ---    '75   JSB Exact 13.4
3                 439
5                 535      (just got these and havent done complete crony'in)

I usually shoot 3 - 5 pumps for my target and plinking.  
Only pump over 5 for Crony #'s  

These FPS numbers are very consistant.   Since October I have repeated this test process to decide which gun to get drilled/tapped for Williams Peep. Each test gets 5 shot averages that never vary more thatn 4 fps from day to day, season to season.
My Crosman 766 is the same way.  Consistant, low ES and SD on all three of my pumper rifles.  ES usually under 5fps for 5 shots.  Wish my Springer ($300) was as consistant.  The two Sheridans set me back less than that.  And my 766 (about the same velocity as my '75 Dan, but in .177) under $40 when I bought it new in 1980.

When my '71 gets back from Tim at Mac1 with the breech drilled/tapped for a Williams peep,  I will try my hand at resealing the '75.
 

Read a Blog by a known Blogger that fast vs slow pumping didnt show any significant velocity differences.  
My humble check of this proved to be true with my guns.

I know how hard it is to get #'s sometimes.  Hope these help.
ds  
        

[lillysdad621]

i only pump it 6 times... average 595 fps with 14.3 cylindricals...

[ASAirifle]

Here are my pre and post MAC steroid numbers on a early 2000's .20 Sheridan:

14.3 Sheridan Cylindrical pellet
6 pumps  pre   post
              545  628
8 pumps  pre    post
              612    691
10 pumps post 729
14 pumps post 778

[airgunandy]

Had a few minutes with the right cloudy daylight to use the chrony today.

1965 Rocker Blue Streak shooting 14.3 grain Benjamin Cylindricals. Rifle was re-sealed about a year and a half ago. Sorry no time to test pump by pump today.

5 pumps - 559fps
8 pumps - 658fps

4 or 5 pumps is where I normally shoot it for plinking and paper.