Crosman 1377 Piston And Valve Mods

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Some updates. The homemade massacre. and my E-bay order's!
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Joshua Purple: nice detailed walk through of the pumping mechinisms of the 1322/1377...I have actually been looking for somthing like this for awhile now...I have my new alchemy airwerks power RP pumper valve coming today and wasen't sure what I needed to do to take the valve off/apart....still looks like its gona be a pain lol

Mekratrig: Nice, clear, explanation and reason for doing the mod. Thumbs up.

quicksilver40: Thanks for the vid on the flat top parts I've been looking to add.

toneknob: another plus for using a multi pump pneumatic is that you can get full power all year round, unlike CO2..

seller559: Thanks for sharing that. You made it very understandable.

makeil kalashnicov: I really know  how to spot an accent, your accent sounds like you're from maybe northeastern Oklahoma?

steve l: I live in the UK and the instructions state if I exceed 10 pumps  the  excess pressure is vented off, how is the pressure vented and could this be over-ridden to increase the pumps to say 15 without damage

Bob Barker: Great video I have to say though I felt like it was richard kuklinski talking.

Qyuubi786: Hey Mike do you know what type of thread the piston uses, It looks like 1/4" BSP but when I try to use a 1/4" fitting they don't fit.

NotSoDumb: What isn't mentioned is that with a modified valve, one that has had the capacity increased and a lighter spring and using a high pressure piston, you can now pump the airgun many more times than the recommended 10 times.
I've done a lot of the mods, including a longer probe pin and pumping my gun up to 25 times, which seems to be the sweet spot now. You'll find that you need to put more air in the valve to get the pressure up.
Replacing the hammer spring and a longer bolt probe, which places the pellet further into the barrel, keeping the pellet skirt from being centered in the transfer port hole and a few other things like a better breach, you can make these pistols really sing.
Some people say that the longer bolt probe actually slowed the pellet down. That might be true for some but for me, just using 12 pumps, I chrony tested a 7.9 gr. Crosman Premiere and saw a difference of an additional 20 feet per second.
At 25 pumps, I'm seeing a bit over 700 fps this old 1377 American Classic with which is unbelievable with the stock barrel.

w1bmw: Great explanation! I just picked one up today and really appreciate the lesson. I've got my stock, barrel, steel breech, etc on the way, but had no idea where to start on the innards. Thanks!

Terry Watkins: I have a older model probably late seventies, only problem I have is the pin has a washer clipped on it so I can't just tap it out. Does anyone know how I should remove that, it's pretty heavy metal and it's hard to grip with pliers

Aldo Rini: Hey Mike, thanks for the video. Where do you recommend to purchase the modified valve and piston? Want to mod my new 1322.

TheVabene73: perfect video thanks but i want to ask you if the stock 1377 can kill a dove at 50+ meters with bodyshoot

Sierra Madreme: 4 years later,and your video is still helping people.Thanks for the how it works video..very easy to understand and well presented.

Thank you again.

Decklan Cox: When I pull back my bolt it won't stay back and it takes several shot to decompress. I think it is something to do with the hammer and hammer spring. Thank you

miketheknife2: Thanks has the FT sets.

Aldo Rini: Hey Mike, great video..really enjoyed it. I have 1322 and wanted to add this modification. Where can you order this valve?

Marc Hills: A lucid, well-presented explanation of the 1377/1322 piston/valve operation, and exactly how the modifying them can increase performance. Nicely done and thank you.

J Martin: What are your best results with modified {all out/anything goes } 1377 ??  
Crosman 1377 piston and valve mods 5 out of 5

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Crosman 1377 piston and valve mods