M 4 .177

[TheBullsEye]

Can u up grade this gun to produce more power like a steroid mod mabe ?

[my80chevette]

I've not done any mods on one of the M4's but from everything I've heard they respond well to most 13XX type mods. Here is a post were they went over a lot of the mods but as I'm sure you know there are many more postings of 1377/22 and 760 Pumpmaster modifications out there ( www.gatewaytoairguns.org/GTA/index.php?topic=27657.msg435778#msg435778 ). Good luck and have fun!!

[rangerfredbob]

The M4-177 already has the Powermaster 66 tube, so the main mods to do to it are flat top piston and valve and those type of mods which are the same components as a 1377.

[TheBullsEye]

By how much does it increase power doing those mods?

[DavidS]

By how much does it increase power doing those mods?

The sky is the limit.

For under $15 US you can stuff the piston, shim the piston cup, install a weaker valve spring, and install a stronger hammer spring.   Once you do this you will be somewhere in the neighborhood of 12FPE if you do it correctly, though you will want to remove the bar that prevents manual uncocking as you will probably need to cock it to pump it.

[lillysdad621]

there is a limit... let's not get crazy... we still remember that there are 760 internals and really limited by their durability. But i dont see why we should not be able to get low 7s out of them... I have been toying with the idea of making one... and then calling for a service rifle friendly target competition... Place targets out to about 50 yards and see if we can consistenly hit them... my daughter came out with the idea of making target sheets with little green army man depictions, same size and all... then we can use the silhouette format, make them a bit bigger and place them at 15, 30 and finally 50 yards... headshots+2 kills. torso shots+ 1 kill and limb shots are just 1/4 kills... imagine a whole bunch of Mk177, m4 177, winchester m4, and that new winchester semiauto m4 look alike, with biggish optics from either prone,kneeling or standing position dukeing it out for service rifle replica ribbons... I think we are on to something... and lots of kids will love it too... customizing rifles should be interesting. even thought about getting a short distance compo going on with full auto BB rifles and maybe some airsoft... some of those guns  can shoot accurately out to 20 yards, so a time event of stitching targets at 6, 12 and 21 yards... i think i had way too much coffee...lol

[TheBullsEye]

Lol hey let the ideas roll sometime too much of a good thing (coffie) is a good thing   ive been thinking of pick up the m4 or the is it mk .177 ? I noticed the mk has more fps to begin with but it not as well of a design? Im sure i could do  mod ethier

[K.O.]

By how much does it increase power doing those mods?

I have ~15 fpe in 22 pumps from the 66/664 pump tube as a 18.75" .22

this guy did the same but went flat top and got 695  fps  with 14.3g at 15 pumps.

http://www.network54.com/Forum/275684/message/1396371412/1322ish+rifle

Pyramyd lists the barrel length as m4 .177 as 17.25"   https://www.pyramydair.com/product/crosman-m4-177-multi-pump-air-rifle-adj-stock?m=2631#Specifications

750 by 12-15 pumps with 7.9g seems very doable.