13xx, max power/fps

[cpu77]

Noah,

What mods do you have on your 13XX?   I trying to decide what my next build will be and your numbers are impressive:)

[ginoe]

1377 stock
458 fps @ 10 pumps
10.5 grain crosman dome from cardboard box
4.9 fpe

my stock 1377 pretty anemic, not the 600 fps that it says on the box it came in but she hits what i am at. i'll be watching this thread for power increase tips. with increased fps, will accuracy suffer? my guess is finding that 'sweet-spot' tune of max fps & max fpe & the correct pellet.

[breakfastchef]

Relatively easy power mods include a flat top piston and valve setup (@100 fps improvement at 10 pumps) and a longer barrel (@10+ fps per inch). Both of my FT setups from Mellon were plug-and-play; each developed 100+ fps improvement on two PC77 pistols. Longer barrels also improved fps by 10-15/inch on the same pistols.

[DBOdude]

Relatively easy power mods include a flat top piston and valve setup (@100 fps improvement at 10 pumps) and a longer barrel (@10+ fps per inch). Both of my FT setups from Mellon were plug-and-play; each developed 100+ fps improvement on two PC77 pistols. Longer barrels also improved fps by 10-15/inch on the same pistols.

so since a stock 1322 does about 425 with typical lead .22 pellets .... going from the 10 1/2 inch barrel to the 18 inch will get it in the 500 fps neighborhood and the 24 would take it to 550ish ? all with the stock piston/valve ?

[breakfastchef]

so since a stock 1322 does about 425 with typical lead .22 pellets .... going from the 10 1/2 inch barrel to the 18 inch will get it in the 500 fps neighborhood and the 24 would take it to 550ish ? all with the stock piston/valve ?

In my personal experience, I saw around a 7-8 fps increase per additional inch of barrel over the stock barrel on two 1377 pistol. YMMV. Also, the longer barrel increases accuracy, too.

[DBOdude]

ok , so using your more conservative personal results that puts the 18 inch barrel adding about 56 fps over the stock 425ish which puts it in the 480fps area . and the 24 inch barrel adds 98 fps over stock putting it right at 525 . those velocities are plenty for my purposes . but its nice to know i can still add another 100 fps or so with a piston/valve upgrade getting it to crack 600 fps if i need or want more down the road .

[breakfastchef]

ok , so using your more conservative personal results that puts the 18 inch barrel adding about 56 fps over the stock 425ish which puts it in the 480fps area . and the 24 inch barrel adds 98 fps over stock putting it right at 525 . those velocities are plenty for my purposes . but its nice to know i can still add another 100 fps or so with a piston/valve upgrade getting it to crack 600 fps if i need or want more down the road .

Numbers get thrown around a lot like 10 fps/inch. That is why I gave you actual velocity increases that I have personally experienced. Glad the information was useful to you.

[DBOdude]

real world results always trump estimates . thanks