The document details a user's experiences with the FX Bobcat .25 air gun, highlighting significant issues such as air leaks, lever jamming, regulator inconsistencies, and scope sighting problems. The user faced repeated problems with multiple units, leading to considerations for refunds or replacements if not resolved adequately. Recommendations for addressing these issues include redesigns of the seal stack, regulator replacements, and adjustments to scope mounts.

1. Vaughn Cordle, CFA / March 7, 2014
FX Bobcat .25
Air Leak and Other Issues: New User Experience
March 15, 2014 update / First 1500 pellets

2. Summary of experience and problems with the new Bobcat 25
FX has designed an exciting new Bobcat that has proven to be very accurate and popular with
experienced air gun operators. This is why I bought the new FX product. However, as I quickly learned,
the Bobcat has air leak problems and other issues that must be addressed by the new gun owner
and/or distributor.
The new stock design required a lengthening of the male fill component for easy access and use. The
FX solution was a quick fix that involved stacking too many spacers/seals/washers in a manner that
results in air leaks if the fill component is moved or jarred. Normal use of the fill component
suggests that this poor design will require repeated adjustments of the seal stack over time to
manage air leaks. One fix could be a redesign of the stack and/or the fill component.
Those interested in buying the new Bobcat may want to wait until FX provides a proper design solution
to the need to lengthen the fill component. The first two Bobcats I received had leaks. The first was
replaced and I fixed the second one by aligning the misaligned 5 piece dowdy stack and tightening
the fill component. This was an easy fix.
Unfortunately, the second Bobcat had lever jamming, regulator, and sighting issues which impacted
the ease of use and accuracy. The second Bobcat was also returned to the dealer. While I like the
design, without the accuracy there is no reason to own the gun. So, if the dealer will not replace the
rifle with a new one, or correct the major issues, I will ask for a refund.
I’ll update this SlideShare presentation once the new or repaired Bobcat has been received and
tested.

3. Air Leak Issue
Air leaks may be the result of improperly installed dowdy seals/washers – 5 in total - that
are stacked to extend the male air fill component used in the new stock design. This
extend-the-fill-fix solved one problem but now requires its own fix to eliminate current
and future air leaks. The integrity of the stacked washers and welded copper pipe
should be a major concern for those thinking about buying the newly designed Bobcat.
Any bump or movement in the male fill component could break the seals and result in an
air leak.
Possible solution: Replace the 5 stacked seals with one unit.
The gun owner risks breaking off the
welded copper pipe when adjusting
misaligned seals to stop air leaks.

4. The distributor’s solution – replace seals - may fix the “stacked seal” leak problem, but it
creates exactly the same problem the stacked seals were originally designed to fix –
inadequate length of the male fill component when fitted into the new Bobcat stock. One
solution is to design a dowdy seal replacement that is as thick as 4 or 5 normal-sized seals.
This will reduce the risks of future air leaks caused by movement of the fill component.
The distributor’s solution is to replace five (5) stacked
seals/spacers with only two (2) dowdy seals. The leak-
prone stack includes three (3) dowdy seals and two (2)
additional spacers/washers.

5. Lever Jamming /Magazine Issue
The firing lever has jammed four times and this has resulted in the firing pin (#1) digging
into the pellet magazine (#2) and difficulty in removing the magazine after the last pellet
is shot. Jiggling the magazine in an attempt to remove has scraped off the edge of the
slot (#3) that slides into the gun. Small particles of metal – from pellet clipping and/or
from the magazine jiggling – likely impeded the hammer stroke which in turn caused
major drops in pellet velocity and accuracy problems. Occasionally the magazine would
not advance properly, and this in turn resulted in misfires or double pellet loading and
pellet clipping.
Possible solution: Replace magazine and/or adjust the delrin? guide set screw.
2
1
3

6. Regulator Issue
Large variations in velocity impact accuracy. Four chrony strings were
produced and compared to five other Bobcat owners results. Ted’s string
and 2 ft/s standard deviation represents an optimal consistency in
velocity. My test produced a high standard deviation of 8 ft/s when big
drops in pressure are excluded. Possible solution: Replace the regulator.
String #3: includes big
drops in velocity, likely
due to pellet clipping
and/or particles from
jiggling the magazine
when the lever jammed.
String #4 is very
inconsistent with a
standard deviation (8
ft/s) that is 4X higher
than Ted’s – when bad
shots are excluded.

7. Scope Sighting Issue
The second Bobcat I received requires the scope windage and elevation adjustments to
be at the extreme limits to match the crosshair with the POI.
Even at 30 yards the scope runs out of UP movement and is near or at the limits of the
UP and RIGHT settings at 80 yards. This may be a major problem if the barrel is out of
alignment. And, it is a very irritating problem when trying to sight the scope.
Possible solutions: Adjustable scope mounts or adjust the rifle railing where the scope
mounts attach. If it is a barrel alignment problem, replace the rifle.

8. Accuracy Issues I
Consistency in velocity impacts accuracy and a high standard deviation (SD) in velocity
(ft/s) will result in a wider variation in the target point of impact (POI) than a low SD,
especially over the longer ranges.
Example: For a 75 yard shot (scope zeroed at 50 yards and median of 888 ft/s) a low-
high spread of 20 ft/s will have a POI (height) variation of .29 of an inch, and at 100 feet
it will be .86 inch . A spread of only 4 ft/s has a POI variation of only .05 inches at 75
and .16 at 100 feet. This difference in accuracy is significant if the target is the head of
a small pest or if the rifle is used for bench rest competition. For this reason, the
Bobcat regulator must produce a consistent velocity if the rifle is to perform to its
accuracy potential.
Given the crony results of 6 different [regulated] Bobcat 25 owners, it appears that there
are large [velocity SD] variances in regulator performance in the first batch of new
Bobcats. A SD of 2 ft/s is optimal and SDs greater than say 5 ft/s should be addressed
and corrected by adjusting [or replacing] the regulator or hammer spring/preload?.

9. Accuracy Issues II
A median velocity of 920 (ft/s) provides tighter
groupings and less turns (clicks) for scope sighting
at 75 and 100 yards than the lower 888 ft/s.
And, a smaller low-high spread in velocity
improves variation in POI [height] accuracy.
The Zero Range is set to 50 yards

10. Accuracy Issues III
Regulated
Bobcat #1
(vaughn’s) has
a larger
variation in
velocity and POI
accuracy
than….
Bobcat #2
(Ted’s) that is
clearly more
accurate at 75
and 100 yards.