Finally got a baseline for 1377

[AZAG]

Well I finally a pre-mod baseline for my 1377.  I suspect this is fairly typical performance for a stock 1377.

I didn't get any really light pellets, just stuck with medium to heavy.  I plan on trying some lite pellets (<7gr) but won't hold up the mods for it.

The pellets that I used were: Beeman Laser, CPHP, Polymag, RWS Superdome, JSB Exact, CPUM, Big Boy, and (because I just couldn't resist) Eun Jin.

Not surprising that the lightest pellets were the fastest but the fpe was pretty similar across the pellet weights for a given number of pumps.

Pellet   Beeman Laser   7.1   gr
Shot   fps   fpe   
2   292   1.34   
3   350   1.93   
4   377   2.24   
5   419   2.77   
6   430   2.91   
7   455   3.26   
8   473   3.53   
9   487   3.74   
10   499   3.93   

Pellet   CPHP   7.9   gr
Shot   fps   fpe   
2   272   1.30   
3   322   1.82   
4   356   2.22   
5   395   2.74   
6   419   3.08   
7   429   3.23   
8   449   3.54   
9   462   3.74   
10   474   3.94   

Pellet   Polymag   8   gr
Shot   fps   fpe   
2   293   1.52   
3   326   1.89   
4   359   2.29   
5   393   2.74   
6   413   3.03   
7   436   3.38   
8   453   3.64   
9   468   3.89   
10   479   4.08   

Pellet   RWS Superdome   8.3   gr
Shot   fps   fpe   
2   232   0.99   
3   295   1.60   
4   341   2.14   
5   376   2.61   
6   402   2.98   
7   417   3.20   
8   436   3.50   
9   458   3.87   
10   473   4.12   

Pellet   JSB Exact   8.4   gr
Shot   fps   fpe   
2   293   1.60   
3   319   1.90   
4   364   2.47   
5   387   2.79   
6   417   3.24   
7   447   3.73   
8   450   3.78   
9   459   3.93   
10   468   4.08   

Pellet   CPUM   10.5   gr
Shot   fps   fpe   
2   235   1.29   
3   287   1.92   
4   315   2.31   
5   346   2.79   
6   364   3.09   
7   386   3.47   
8   389   3.53   
9   414   4.00   
10   432   4.35   

Pellet   Big Boy   13   gr
Shot   fps   fpe   
2   216   1.35   
3   273   2.15   
4   292   2.46   
5   320   2.96   
6   340   3.34   
7   352   3.58   
8   368   3.91   
9   379   4.15   
10   391   4.41   

Pellet   Eun Jin   16   gr
Shot   fps   fpe   
2   Error      
3   233   1.93   
4   254   2.29   
5   275   2.69   
6   297   3.13   
7   310   3.41   
8   329   3.85   
9   336   4.01   
10   350   4.35   

At these low energies the real issue is which pellet is the most accurate, so I'll be checking this next.  I may write up reviews on each pellet as I go, if anyone is interested.   

[JEBert]

for a given number of pumps.

Can we assume that would be 10?
Cheers,

[AZAG]

Can we assume that would be 10?
Cheers,

It was actually reasonably similar from 2-10 pumps, between pellets.  I thought so anyway.

[JEBert]

OK, My bad. I see that now by the fps.  It was under the column Shot and I thought it was shot #2-10 and thought that #1 didn't register on the chrony for some reason.
Cheers,

[1377x]

hummm
numbers look kinda low
most 1377's shoot around 525fps or at least over 500
have you taken the gun apart yet!
do a tissue or powder test
take the tissue put it across the bolt and at the bottom of the breech where the transfer port is
pump a few times shoot no pellet necessary if the tissues moves you have a leak
works the same way with powder

[AZAG]

Bummer, i'm missing ~50fps. I did take it apart to do some trigger work and install a steel breech after this testing. I didn't see anything wrong with the transfer port o-ring but I didn't look real close either. I'll do the tissue test and report back.

[Smaug]

Just found this. Great post, thanks for the info. I saved the data in a Word file for future reference. I hope you don't mind.

It seems like 5 pumps out of the stock gun approximately equals a CO2 gun of about the same size.

[AZAG]

OK, My bad. I see that now by the fps.  It was under the column Shot and I thought it was shot #2-10 and thought that #1 didn't register on the chrony for some reason.
Cheers,

Not sure why I put "Shot" for the first column heading, its a little misleading. It should be "pumps."

[AZAG]

Smaug - No problem. I hope its useful information for your moding.

hummm
numbers look kinda low
most 1377's shoot around 525fps or at least over 500
have you taken the gun apart yet!
do a tissue or powder test
take the tissue put it across the bolt and at the bottom of the breech where the transfer port is
pump a few times shoot no pellet necessary if the tissues moves you have a leak
works the same way with powder

I tried the tissue test and there doesn't seem to be air leaking from the transfer port. Is there another test for missing fps? How can I tell if I am getting efficient pumping (if the piston is getting a good seal on the tube)?

[1377x]

im having the same problem with my 1389
at first i tought it was the breech/barrel set up switched to a steel breech and barrel(phase 3)
still the same fps very low
now im thinking its to much headspace between the piston and valve as for a test i dont have a clue
im going to try some flour on the end of the cup see if it transfers to the valve

[Make MY day]

Tried the tissue test and had the tissue blown off.  Not sure if it is the transfer port or the when the bolt kicks back some after firing.

[1377x]

Tried the tissue test and had the tissue blown off.  Not sure if it is the transfer port or the when the bolt kicks back some after firing.

what i do is turn the gun on its side lay the tissue aprox.where the transfer port is fire if it flies off there is a leak
then i lay the tissue to the top of the bolt if it blows off there is a leak.just fixed a bolt leak a couple days ago
after doing this test 

[Make MY day]

What did you do to fix the leaks??  On the steel sleeve, which way does the longer end go, Up into the barrel or Down?  Checked today again and still getting the tissue blown off both areas.  New barrel and bolt.

[1377x]

What did you do to fix the leaks??  On the steel sleeve, which way does the longer end go, Up into the barrel or Down?  Checked today again and still getting the tissue blown off both areas.  New barrel and bolt.

to fix the leaks i put new o-rings in
the sleeve goes big end up

[Make MY day]

Has anyone come up with an accurate Baseline for the 1377C up to 15-20 pumps???