A 1377, PC77 & A 1322 on the Chrony

[DRAGON64]

I have not been on this forum in a while, and for that matter, I have not even picked up an air rifle or pistol of any kind in nearly 7 - 8m months 

Nevertheless, I was looking at getting into a new project, and thought I would revive some old stalled projects... namely my Crosman pistols that I was begionning to mod.  I have an older 1377 that had a "Backpacker" air tube installed on it from the factory.  This tune erronously claiming that the pistol was a .22 call, when in fact it was .177... I fixed that, this pistol has been converted to .22 cal with steel breech etc.  I also have a PC77 from Walmart, and a 1377 I picked up from the refurb sales for $29.99:

1377 Refurb review: [youtube]https://www.youtube.com/watch?v=OypZ2sXlfFk&feature=channel_video_title#]1377 Re-furby[/url]

And the PC77 is just a rebrand for Walmart, called the Pump Master Classic...

So, I wanted to see what the differences are in FPS from a refurb 1377, and new PC77, and a 1377 converted to 1322.

Refurb 1377:

508
511
514
509
505
508
508
508
514
508
Average fps is 509

PC77:

500
502
503
505
503
497
497
498
491
494
Average fps is 499

1322 convert:

460
456
436
449
444
438
439
436
441
433
Average fps is 443.

What did I learn?  This small sample was fun t record!!  I learned that the two stock 1377 & PC77 pistols remained consistant at 500 fps, yet still far under the advertised 600 fps.  And the 1322 convert, only slightly lost some fps due to a larger bore and using the heavier 14.3 gr ammo.  A worth while conversion if you ask me.  I figure that the huge variance in fps of the 1322 could be attributed to that fact I have really put the pistol through her paces over the years, and it may be time to upgrade the internals to renew tired parts, and to use more efficient components.

I will add that all ammo used was Crosman premier for both .11 and .22 calibers, and the pistols were all pumped to a safe max of 10-pumps.

Since the refurb is kind of messed up (watch the video) I thought I might transfer the refreshed internals over to the 1322, and see if the pistol could benefit from the consistancy that the 1377 refurb showed in fps.  I can always swap back... and this is all just for fun.

[1377x]

i think the 10 pump max is a liability thing from the factory
we as consumers can go beyond that with a heavy hammer spring i can dump 20+ pumps in one shot safely
i have been going beyond 10 pumps for the last 6-7 years
there is a point when it is pointless to pump beyond x numers of pumps because the velocity doesnt go any higher or it starts to loose velocity.seems like every gun is different
i remember the backpacker gun
thanks for posting your results!

[DRAGON64]

i think the 10 pump max is a liability thing from the factory
we as consumers can go beyond that with a heavy hammer spring i can dump 20+ pumps in one shot safely
i have been going beyond 10 pumps for the last 6-7 years
there is a point when it is pointless to pump beyond x numers of pumps because the velocity doesnt go any higher or it starts to loose velocity.seems like every gun is different
i remember the backpacker gun
thanks for posting your results!

Thank you for an add on addition to the project.  I will chrono the same pistols at 15 and 20 pumps, to see the gains in fps.  What, if any, wear have you noticed on your hardware?  Have you had to make any repeated repairs due to pumping outside the factory liability of 10-pumps?

[1377x]

the only wear i experienced was from an improperly adjusted piston.that stretched the pump lever pivot pin hole,the pivot pin hole in the tube and the front grip screw .keep in mind this was from the improperly adjusted piston.the only thing that wore down was the oring on my adjustable piston before i start using 90duro orings which last a lot longer
as far as the other seals they are the same ones from 2 years ago
my phase 2 1377 had the same seals for 20+ years no problems.when i converted it to a phase3 upper i change the seals just because i was working on the gun
almost forgot
after i reset my piston no more wear and i pump to 15x-20x regularly

[JEBert]

Dragon,
If you have been reading much here, you probably know this but in case you don't, here goes.
When pumping more than 10 pumps, your specific gun might not dump all of the air out of the valve.  I have two 1377's.  One of them would dump 14 pumps from the factory.  I added a Mellon power adjuster (and stock adapter) and backed off of the adjustment screw until it would only dump 11 pumps.  It made for a slightly better trigger pull because of less tension between the hammer and sear.  My other 1377 would only dump 6 pumps from the factory.  I switch out the hammer springs between guns and it made no difference.  I  took the valves apart and checked the valve springs but couldn't find a difference between the two guns.  I know that there has to be a difference but I haven't found it yet.  I thought about switching out the valves between guns to see if the difference is in the valve but haven't tried it yet.
I added a Mellon power adjuster to the second gun and screwed the adjustment screw in until it will dump 10 pumps and have not noticed the trigger being any worse.
To check for dumping of air, I re-cock the gun after firing and pull the trigger again to see if any air or sound is produced from the barrel.  You can tell when there is absolutely no air in the valve on the second firing when it sounds exactly like the third firing (without additional pumps).
Of course, YMMV.
Cheers,
Jerry

[1377x]

jbert
have you checked for sear drag.sometimes the sear gets hung up on the hammer

[JEBert]

jbert
have you checked for sear drag.sometimes the sear gets hung up on the hammer

I haven't thought about sear drag.  Among other things, I have polished the sear, installed a trigger over-travel limit screw in the trigger housing and adjusted it 1/8th turn further out after the sear releases and locktited it.  How would I go about checking for the sear dragging on the hammer?
Thanks,
Jerry

[DRAGON64]

I have been away from airguns too long, so much of what I did know is obscured by cob webs.  Once I get going good, it will all come back to me... I made a new video today.  Once I get it all together, I will link to it on here.  For now, here are the pics of my set-up and ammo...

[DRAGON64]

Here is the video that I made earlier today:

[youtube]https://www.youtube.com/watch?v=5jEl0bv87aw&feature=channel_video_title#]Crosman Pump Classic Chronograph[/url]

[1377x]

great video!
i cant remember the sear drag test.
i think the reason your 1322 kept dropping in fps is you might need a new pump cup

[DRAGON64]

great video!
i cant remember the sear drag test.
i think the reason your 1322 kept dropping in fps is you might need a new pump cup

Since the refurb is shooting so nice and consistant, I thought I might borrow the pump parts and rebuild the 1322.  I might also mention, that the PC77 got real warm to the touch...  the other two pistols only slightly warmed up... needless to say, I did not do the 20-pump test.

[1377x]

the gun does get warm when pumping a lot
ill pump 15x wait a minute then pump 10x more
if you pump 25x fast then it will get hot
should have mentioned that earlier

[DRAGON64]

I managed to find an email in my address book for AC Custom so I sent an email inquiring about a new piston for the 1322 and the PC77.  I hope to get new pistons and valves for the two pistols and then run them across the chrony again.  Not sure what to do with the refurb.  It has the power and retains consistancy, but all the parts are crooked on the pistol, so it is inaccurate as heck without compensating for the misaligned parts.  For now it remains a donor gun.

Once I have the new piston and valves, I will go ahead and dress the PC77 with the new steel breech from Crosman, and the new barrel band from Bluefork.

[1377x]

maybe a new end cap will correct the cant.
this is the reason i stay away from refurbs,its the luck of the draw.you arent the only one who got 1 like that
there have been a few posts here about that.

[DRAGON64]

Ahh, but it remains the most consistant from a power standpoint.  When originally picked up the refurb, I had planned on modding the heck out of it.  Then along came the PC77, and I decided that I would use it as my .177 cal modding platform.  My plan right now is to use the refurb for testing pellets, and to be a parts donor if needed.