More T.O.F. Chrono test and free fps gains...

[K.O.]

 

Well first of all pumping up and warming then cooling my two problem children (PC77,2100b) did nothing to help them...

At least it did not harm them either.

Oh by the way the only times I have pumped them more than 10 pumps is in these chono test.


Today I decided to do some more testing.

this time was about how much an extended probe helps,

Had an clipped off end piece of low e string  (guitar),

bent it about where I thought it would seat the pellet just past the port,

got it just right first try  (.55");

I have liked the idea of the flow thru bolts,

less blockage and turbulence,

but now I think I will just stick with making a bunch of pellet seating tools,

shaped just right for better consistency than a guitar string.



these figures are in comparison to fps in last thread and are also average velocity over 15' with Crosman pointed.


It helped the PC77 the least but did help,

basically  it went from 508  to 535 once again number of pumps did not matter



The 1322

@ 10 pumps (466)
@ 12 pumps (489)
@ 15 pumps (520)  (mistake or anomaly yesterday?)

The 2100b (need a better seating tool also could not see port or how well pellets seated)

@  10 pumps (585 and 568)
@  12 pumps (638 and 652)
@  15 pumps (682 and 691)

need to measure distance to muzzle side of port and less bendy tool but inconsistency could also be from bendy plastic piston...

[K.O.]

figures from unseated test,


First the Good

I thought my  brand new stock 1322 was shooting an honest 460 fps Mv.

10 pumps  Av  454.5
12 pumps  Av  483.8
15 pumps  Av  535.7  (wow!)

now the bad

Lightly used  PC77

10 pumps  Av 508
12 & 15 pumps  507 & 505  (Wha da ? , Canadian valve?)

Lightly used 2100

10 pumps  Av  603
12 pumps  Av 621
15 pumps   no test

[K.O.]

What I learned

The PC77 took the most effort to seat the pellet past the port it is probably still catching on something,

I think that is why it had about a 30 fps jump,

The 1322 was almost effortless to seat

I just checked and I can get it to seat just past the port by pointing it downwards and giving a slight shake,

That may be why I was able to get the same result on 15 pumps without a seating tool last time.

Both the PC77 and 1322 when seated just by the bolt half cover the port.



I need to make a better tool for the 2100 and retest.


Chronographing can really help me learn about how my pistols and rifles are doing.

It takes thought but can be a valuable  diagnostic tuning tool.


I think my next test session will be after stuffing the pistons with 1/8th rod.

[arkmaker †]

My chrony is one of the best purchases you can make if you are going to do Amy mods. So glad I got mine 

[K.O.]

Mine is not very portable and has some disadvantages but is very worth setting up,

it also has the advantage of allowing me to spend my limited $ on a steel breech and barrels so I will deal with what I have for now.

I am not so focused on getting high fps but do have some goals in that direction.

But yep things like chairgun and a form of chrony really speed things up and are almost necessary.

[Rualert]

     If you have an I-Phone or Android phone there is a free "chrony" app that uses the same principle, you place the phone, or device centered between the muzzle, and target, it then "listens" for the shot, then the hit, and provides pretty close FPS readings. This might work for you. I saw the Soft Chrony program over on the Air Force board, but I have no idea if the original developer is still maintaining it or not.

Casey

[K.O.]

     If you have an I-Phone or Android phone there is a free "chrony" app that uses the same principle, you place the phone, or device centered between the muzzle, and target, it then "listens" for the shot, then the hit, and provides pretty close FPS readings. This might work for you. I saw the Soft Chrony program over on the Air Force board, but I have no idea if the original developer is still maintaining it or not.

Casey

Thanks for the suggestion...

One of my eccentricies is I do not like leashes so therefore have never owned a cell phone...

[Rualert]

     I can completely understand that one, however, since my work requires I am reachable 24/7 I'm stuck with one.

Casey