New. 1377 question

[Gapmaster]

I picked up a new 1377. Picked up at Big 5 for 59 bucks. Can any of you 1377 owners that has done a rebuild or modification tell me what kind of fps you were getting using a after market piston and valve? Has anyone had any luck getting 8 to 900 fps with a piston and valve change, or is that impossible with this gun? I'm curious what I can eventually end up with staying with a pump set up. I'm not interested in converting to pcp or anything like that. Thanks for your input. Don. P.S. forgot to ask if you did make the change, what piston and valve did you use?

[breakfastchef]

On two of my 1377 builds, I saw an increase of @100 fps at 10 pumps on each after installing a flat top piston and flat top adjustable piston from Mellonair. Longer barrels add @8-10 fps additional velocity per inch beyond the stock barrel. Are you going to make a 1377 pumper go to 900 fps? Probably not without a commitment to lots and lots of pumping, valve mods, very long barrel, and, probably, hammer and hammer spring changes. A more realistic goal would be 700 fps at 10-13 pumps with a 7-9 grain pellet. All this depends on what your goals are.

[crossliner]

Actually my 1377 is still stock inside as well as the barrel although I have two 24" spares..Using a local brand of wadcutter pellets ( incredible accuracy btw it is a ragged 1-holer at 20 yards..Well not exactly ragged as the 5-pellet hole looks like an "l") I have yet to miss a shot when targetting roof rats..I use 3 pumps only and yet they die just fine. Range is from 10-15 meters and I use a red dot. This goes to say that I am not in the quest of increasing its velocity two- folds.. Best regards.

[1377x]

i think crosshairs got 790fps 20 pumps to do it. a barrel less than 24" produced that velocity also.it would go over 790 if the barrel was longer
[youtube]https://www.youtube.com/watch?v=hj7YK-Jvb2w#ws]Custom 1377 Chrony Test 790 fps[/url]