Weird/Quirky fps readings with the DF II 22 cal pumper

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Guys
This post is kind'a long, so please bear with me,

Can you figure out what is going on with the BOLD numbers, well over a 100+ fps jump,
all but one of the tests are in the 800 fps + bracket?.
I have checked, weighed and gone over everything with a fine tooth comb,
and can't fine the reason for these quirky fps jumps.

All most all of these numbers are in the 6-7-8-9 pump range/tests,
went back and checked the log book and all readings are in the correct order,
(no fat finger mistakes that I can find).

What is your SWAG on the reason for these weird fps jumps??

Summary of all the tests
Test  A     B    C    D     E    E-1   F     G     H    H-1    J    K    L1   L2    L3   L4    M+          HS3
1 p-265-288-262-255-259-269-269-262--252-236-223-242-272-252-232-295-232-------
2 p-288-321-380-383-383------393-377--305-367-357-380-351-377-354-433-357-------
3 p-322-354-462-465-465------452-390--383-449-452-456-436-426-429-439-449-------
4 p-465-361-524-528-521------479-436--416-495-508-511-482-465-459-457-452-------
5 p-515-597-574-570-567-574-538-488--449-511-515-531-511-495-482-495-535-------459
6 p-567-610-620-600-600------623-498--524-574-528-554-541-531-501-511-625-------495
7 p-600-616-643-626-623------646-639--567-597-538-561-577-567-565-544-666-------531
8 p-633-620-672-649-643------652-754--600-613-570-590-593-583-705-611-702-------554
9 p-652-651-688-659-662------708-810--633-757-577-623-639-597-761-757-779--------577
10 p-666-688-698-672-679-692-728-833-690-813-------603-666-662-613-823-800-823---816
11 p-678-----------688-683------744------711-856--------620-688-688-626-836-849-849---833
12 p-679-----------702-712------770------754-869--------643------754-643-866-853-869---853
13 p-681-----------712-718----------------801-------------898------------651-900-870*884*-889
14 p-680----------------721----------------------------------928------------661------915*884*-905
15 p-679----------------728-741-----------------------------980------------672------948*890*-923

(A Test)
Full 15 pump test x 3 pumps per the number,
pumps were a complete cycle, open then closed arm pump arm, per each pump stroke.
with the OEM Hammer spring is 18/19#'s at max compression, (coil bound), 3.150" long,
.390" dia  O/S dim, x  .300" I/S dim, with 15 coils.
Hammer weight is 876 grains x .745" dia, Hammer travel distance of 1.100",
with a valve stem protrusion of .180". 14gr Crosman ammo used in all the tests.
 
Stock valve = Bbl TP hole is .134" Dia, Action TP Hole is .134" Dia,
Air inlet hole = .100" Dia by .180" long, valve stem length protrusion of .180"
at the end of the valve. Brass TP has a hole Dia of .136" x .295" tall x .356" dia.
Valve spring =1.475" long by .295" O/S dia, 12 coils, spring weight of 3.5#'s,
 
(B Test)
1 complete turn on pump rod, using a 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S dia, 35 coils, .023" thick Flat wire, coil bound at less than 1.030", nothing else changed.

(C Test)
1 >10 pumps x 3 each per pump,
2 complete turns on pump rod head, nothing else changed, with a 11# Flat wire spring,
5" long, .415" O/S Dia, .252" I/S dia, 35 coils, .023" thick Flat wire, coil bound at less than 1.030",
14 gr Crosman ammo

(D Test)
1 >15 pumps x 3 tests per pump number,
2 complete turns on pump rod head, with a 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S Dia, 35 coils, .023" thick Flat wire, coil bound less than 1.030". All air passageways
opened up to .145" Dia (reamed), removed air filter at valve inlet.

(E Test)
Same test as all the previous tests, the only item changed was the hammer spring.
Using a OEM 6/7# Storm Rider Round wire spring, 3.360" long, .384" O/S Dia,
.300" I/S dia, 25 coils, .035" thick round wire, coil bound at 1.020", All air passageways
opened up to .145" Dia (reamed).

(E-1 Test)
Here is something I found out that is very interesting with this DF II, 22cal rifle
I lubed all pivot points, and the oil wiper seal and shot these Oiled 3 pump tests.

(F Test)
Same test as all the previous tests,
the only item changed was the hammer weight to 533 gr, Hammer spring weight of 9-10#'s.
Using a Flat wire spring, 2.500" long, .415" O/S Dia, .265" I/S Dia,.022" thick Flat wire,
25 coils, 2 complete turns on pump rod head, All air passageways opened up to .145" Dia,
(reamed), air filter removed at valve inlet.

(G Test)
Same test as the above test, only item changed was lengthen the pump rod head
to maximum distance, to not block the air inlet hole, and oiled the wiper seal oiler.
Using a Flat wire spring, 2.500" long, weight = 8-9#'s, .415" O/S Dia, .265" I/S Dia,
.022" thick Flat wire, 25 coils, Alum Hammer weight at 533grains.

(H Test)
Same test as the above test, only item changed was lengthen the pump rod head
to maximum distance, to not block the air inlet hole, and oiled the wiper seal oiler.
Using a Flat wire spring, 2.500" long, weight = 8-9#'s, .415" O/S Dia, .265" I/S Dia,
.022" thick Flat wire, 25 coils, Alum Hammer weight at 533grains.
All air passageways opened up to .1562" Dia (reamed).

(H-1 Test)
Oiled, no other changes, same as above test.

(J Test)
Used a valve with Peek air inlet seal and poppet, .180" air inlet hole,
this seal had a .170" nose that fit into the inlet hole, this nose was flush at the top of valve,
OEM spring. Valve stem lengthened to .375" from rear of valve, from the stock .180" length,
Same test format as above tests, Alum Hammer, 2.500" long, Flat Wire weight = 8-9#'s,

(K test)
Used a valve with Delron air inlet seal and poppet, .140" air inlet hole,
this air check seal had a .135" x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring, Valve stem lengthened to .375" from rear of valve,
from the stock .180" length, Alum Hammer 533gr's, 2.500" long, Flat Wire weight = 8-9#'s,
airways opened up to .156" Dia. No air left after any shot, in any of the above tests.

(L1 test)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145",

OEM valve spring and Valve stem length .180" from rear of valve,
Same test format as above tests, Alum Hammer 533grs, 2.500" long,
Flat Wire weight = 8-9#'s, airways opened up to .145" Dia. No air left after any shot.

(L2 test)
Used a valve with Peek air inlet seal and Peek poppet, .156" air inlet hole,
this air check seal had a .145" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring and Valve stem length .180" from rear of valve,
Same test format as above tests, Alum Hammer, 2.500" long, Flat Wire weight = 8-9#'s,,
airways opened up to .156" Dia. No air left after any shot.

(L3 test)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, Alum Hammer, 2.500" long, Flat Wire weight = 8-9#'s,,
airways opened up to .145" Dia. Air retained after shot =*.

(L4 test)
Used a valve with Peek air inlet seal and Peek poppet, .156" air inlet hole,
this air check seal had a .145" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, Alum Hammer 533grs, 2.500" long,
Flat Wire weight = 8-9#'s, airways opened up to .156" Dia. Air retained after shot =*.

(M Test)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, OEM lightened hammer 537grs,
11# Flat wire hammer spring, airways opened up to .145" Dia.

(HS#3 Test)
OEM Hammer 537 grs (lightened from 875 grs) with #11# hammer spring,
peek poppet/seals, .375" valve stem length, no other changes, 14 gr Crosman ammo.
No air retained after any shot. 3 test average on the #9 & 10 shots, No retained air.
I do not know what is going on here..........with the #9-10 pumps?

I do like the results, will test a couple more times, if it holds consistent,
I have found my Holy Grail...............

Your thoughts or suggestions............
Thanks Guys,
Don

[splitbeing]

X2 on request for thoughts from the pro tinkerers!

Been following Don's work on the dragonfly ii and these odd jumps in fps have stood out to me with intrigue (and at times concern) through following Don's impressive project.

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SB
The two items that is constant thru out these Quirky readings
is the use of the flat wire hammer spring and 800+ fps readings.

I thought maybe the spring tunnel hole Dia was to tight/small,
check and have the same Dia thru out all the hammer spring tunnels
in other makes/models of AG's I use them in and they all work fine.
 
The hammer material is both steel and Alum and they weigh within 10-15 grs of each other,
the spring guides are both Alum (OEM) and Peek and very smooth,
same length and Dia fits the spring inside dimensions as OEM dimensions etc.

I know the hammer spring expands when cocked, I also thought that maybe the screw
for the bolt cocking pin was hanging down inside the spring tunnel
and catching the flat wire spring, very smooth and no obstructions etc.

I cannot find a possible reason for these 100+ fps jumps, almost always in the 800fps
category or higher readings.
I am going crazy, (3/4 of the way there, now) attempting to find the reason.....

Tia,
Don

[splitbeing]

Often the difference between the first and second pump is a 100+ fps jump. This is normal.

Otherwise, the jumps are happening around the 700fps marker. Its as if the pressure required for a 700fps shot is also the pressure that changes something in the mechanism.

This is unrelated, but 671 fps is a magic number in my mind due to fpe calculations (speed at which pellet weight in grsins equals fpe). Coincidentally, its right around the mysterious speed of these odd jumps.

Curious, if you use the same setup but change pellet weights, does the odd jump in fps remain at the same pump number or the same fps reading?

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SB
I haven't tried the changing to different pellet weights,
but will dig out a can of lighter & heavier weights, and see the results from a test.

I was using the Crosman's pellets as I can get them locally (50 to 75 mile drive),
and don't have to order them and they are cheaper for doing a test like this,
as I won't waste good pellets do this stuff.

Tia,
Don

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Ok
Here are a couple of other pellet weights,
Sig Alloy = 12grs and H&N FFT = 16 grs.
Using the same as above tests, only change was pellet weights.

( Sig Alloy 12gr pellets)
1= 246 fps -
2= 403 fps -
3= 505 fps -
4= 538 fps -
5= 557 fps -
6= 593 fps -
7= 606 fps -
8= 613 fps -
9= 629 fps -
10= 633 fps -
11= 662 fps -
12= 675 fps -
13= 685 fps -
14= 702 fps -
15= 780 fps -

(Sig Alloy 12gr pellets)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, OEM lightened hammer 537grs,
11# Flat wire hammer spring, airways opened up to .145" Dia.

(H&N 16gr Pellets)
1= 196 fps -
2= 360 fps -
3= 452 fps -
4= 501 fps -
5= 511 fps -
6= 518 fps -
7= 533 fps -
8= 563 fps -
9= 574 fps -
10= 580 fps -
11= 590 fps -
12= 598 fps -
13= 600 fps -
14= 620 fps -
15= 644 fps -

(H&N 16gr Test)
OEM Hammer 537 grs (lightened from 875 grs) with #11# hammer spring,
peek poppet/seals, .375" valve stem length, no other changes, No retained air.

Summary of all the Quirky 100+ fps jump tests,
         B        D     E   G   H-1    J     K    L2    L3   L4    M+ HS3 12gr 16gr
1 p--288--255-269-262-236-223-242-252-232-295-232----246-196
2 p--321--383-393-377-367-357-380-377-354-433-357----403-360
3 p--354--465-452-390-449-452-456-426-429-439-449---------505-452
4 p--361--528-479-436-495-508-511-465-459-457-452---------538-501
5 p--597--570-538-488-511-515-531-495-482-495-535--459-557-511
6 p--610--600-623-498-574-528-554-531-501-511-625--495-593-518
7 p--616--626-646-639-597-538-561-567-565-544-666--531-606-533
8 p--620--649-652-754-613-570-590-583-705-611-702--554-613-563
9 p--651--659-708-810-757-577-623-597-761-757-779--577-629-574
10 p-688--672-728-833-813------603-666-662-613-800--816-633-580
11 p-------688-744------856------620-688-688-626-849--833-662-590
12 p-------702-770------869------643------754-643-853--853-675-598
13 p-------712----------------------889----------651--870--889-685-600
14 p---------------------------------928----------661--915--905-702-620
15 p---------------------------------980----------672--948--923-780-644

(A Test)
Full 15 pump test x 3 pumps per the number,
pumps were a complete cycle, open then closed arm pump arm, per each pump stroke.
with the OEM Hammer spring is 18/19#'s at max compression, (coil bound), 3.150" long,
.390" dia  O/S dim, x  .300" I/S dim, with 15 coils.
Hammer weight is 876 grains x .745" dia, Hammer travel distance of 1.100",
with a valve stem protrusion of .180". 14gr Crosman ammo used in all the tests.
 
Stock valve = Bbl TP hole is .134" Dia, Action TP Hole is .134" Dia,
Air inlet hole = .100" Dia by .180" long, valve stem length protrusion of .180"
at the end of the valve. Brass TP has a hole Dia of .136" x .295" tall x .356" dia.
Valve spring =1.475" long by .295" O/S dia, 12 coils, spring weight of 3.5#'s,
 
(B Test)
1 complete turn on pump rod, using a 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S dia, 35 coils, .023" thick Flat wire, coil bound at less than 1.030",
nothing else changed.

(D Test)
1 >15 pumps x 3 tests per pump number,
2 complete turns on pump rod head, with a 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S Dia, 35 coils, .023" thick Flat wire, coil bound less than 1.030",14 gr Crosman.
All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.

(E Test)
Same test as all the previous tests, the only item changed was the hammer spring.
Using a OEM 6/7# Storm Rider Round wire spring, 3.360" long, .384" O/S Dia,
.300" I/S dia, 25 coils, .035" thick round wire, coil bound at 1.020", 14 gr Crosman ammo.
All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.


(G Test)
Same test as the above test, only item changed was lengthen the pump rod head
to maximum distance, to not block the air inlet hole, and oiled the wiper seal oiler.
Using a Flat wire spring, 2.500" long, weight = 8-9#'s, .415" O/S Dia, .265" I/S Dia,
.022" thick Flat wire, 25 coils, Alum Hammer weight at 533grains.

(H-1 Test)
Oiled, no other changes, same as above test.

(J Test)
Used a valve with Peek air inlet seal and poppet, .180" air inlet hole,
this seal had a .170" nose that fit into the inlet hole,
this nose was flush at the top of valve, OEM spring.
Valve stem lengthened to .375" from rear of valve, from the stock .180" length,
Same test format as above tests, Alum Hammer, Flat wire hammer spring,
airways opened up to .156" Dia. 14gr Crosman ammo.
No air left after any shots.

(K test)
Used a valve with Delron air inlet seal and poppet, .140" air inlet hole,
this air check seal had a .135" x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring, Valve stem lengthened to .375" from rear of valve,
from the stock .180" length, Alum Hammer 533gr's, 2.500" long, Flat Wire weight = 8-9#'s,
airways opened up to .156" Dia. No air left after any shot.


(L2 test)
Used a valve with Peek air inlet seal and Peek poppet, .156" air inlet hole,
this air check seal had a .145" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring and Valve stem length .180" from rear of valve,
Same test format as above tests, Alum Hammer, Flat wire hammer spring,
airways opened up to .156" Dia. 14gr Crosman ammo.
No air left after any shot.

(L3 test)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, Alum Hammer, Flat wire hammer spring,
airways opened up to .145" Dia. 14gr Crosman ammo.


(L4 test)
Used a valve with Peek air inlet seal and Peek poppet, .156" air inlet hole,
this air check seal had a .145" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.156"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, Alum Hammer 533grs, 2.500" long,
Flat Wire weight = 8-9#'s, airways opened up to .156" Dia.

(HS#3 Test)
OEM Hammer 537 grs (lightened from 875 grs) with #11# hammer spring,
peek poppet/seals, .375" valve stem length, no other changes, 14 gr Crosman ammo.
No air retained after any shot. 


(Sig Alloy 12gr pellets test)
Used a valve with Peek air inlet seal and Peek poppet, .145" air inlet hole,
this air check seal had a .135" Dia x .370" long nose that fit into the inlet hole,
this nose was flush at the face of the valve. TP hole =.145"

OEM valve spring and Valve stem length .375" from rear of valve,
Same test format as above tests, OEM lightened hammer 537grs,
11# Flat wire hammer spring, airways opened up to .145" Dia.

(H&N 16gr pellet Test)
OEM Hammer 537 grs (lightened from 875 grs) with #11# hammer spring,
peek poppet/seals, .375" valve stem length, no other changes, No retained air.

I do not know what is going on here..........This pumper is Haunted!

Your thoughts or suggestions............
Thanks Guys,
Don

[Back_Roads]

  Is that what they mean when they say ghost gun
Might need a pressure gauge on the valve to get some other numbers. I should go shoot mine, but too beat from work to pump, let alone shoot a PCP off a bottle LOL.

[splitbeing]

Thank you, Don. The abnormally big jump with the sig pellets is right around 700 fps again. No abnormally big jumps with the h&ns, which never got up to 700.

If it were me, I'd shoot the heavier pellets and feel safer about the smooth graph of pumps vs fps increase.

Don, are you gonna keep trying to crack the 700fps big jump mystery nut?

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SB
IMHO, I think I'll let sleeping dogs lie, in ref to the mystery fps jumps,
if after over 200 views and no valid information has come forth,
I am beating a dead horse.......attempting to find the information,
as no one here knows.

As long as I can get the best accuracy out of whatever pellet at over 700 fps,
I consider myself good.  I now have to find at what pump levels the best accuracy is.

But first I have to build a scope base that goes from the rear site base to the front half of the action, level with the top plane of the action, and then add about 3-1/2", same thickness base to the rear half.

This is a major problem with this type of action, very short and no room for a good scope
mounting length to fit normal average scopes.  I can't see Iron sights any more,
I have to have a scope to see/shoot.............

Thanks,
Don

[splitbeing]

It's a shame no one is chiming in again with expert advice, Don. Sorry I can't be more help myself! I have enjoyed the crazy ride with this gun you are working on with such passion!

Yeah, scoping the dragonfly is a challenge. My standards are probably lower, but I found a 2-7x hawke vantage with dovetail rings to do the job. I used to use simmons scopes but after a couple years of shooting my dragonfly so frequently (easily every week and often more, significantly more) I upgraded a bit. The action issues I am living with as long range accuracy isn't there, at least for my dragonfly.