What's the easiest way to build a 12 fpe, Crosman 1377 carbine?

[NickB79]

If I start with a Crosman Morning Play pack, which comes with a steel breech and carbine stock, and then add an 18" barrel, what other available mods offer the easiest way to an 10-12 fpe bird buster?  I'd like to stick with .177-cal for the flatter trajectory and cheap pellets.

Thanks!

[BenjiHunter]

Flat top valve and piston.

[NickB79]

And that's all?  Just plug and play?

I think I can do that :-)

[rrdstarr]

And that's all?  Just plug and play?

I think I can do that :-)

And a RVA(Rear Velocity adjuster) which I sell several models of!

[BenjiHunter]

And that's all?  Just plug and play?

I think I can do that :-)

Yeah, that's it.

[DavidS]

A better piston will not get you 12FPE by itself.

Easier than the Flat Top Piston, and likely to get you closer to your goal is:

• Stuff the piston, buy inserting steel rods in the pockets of the piston length wise (they should be slightly to long and pressure fit).
• Install a bit lighter of a Valve Spring.
• Install a stronger hammer spring.
• Do the poly tube transfer port (look around the forums there is a lot of info on this).
• Install a longer barrel You already listed this, though it is important.

There are other mods to get even more power, thought keeping it simple that should get you pretty close to your goal.

If not yet done, I would recommend recrowning the barrel, pollishing the trigger/sear and sear/hammer contact surfaces, and installing a lighter trigger spring.  There are a few other things that can make the trigger even better though that is a good start.

[breakfastchef]

10-12 fpe is a pretty high benchmark. Forget the 18" barrel and go with the 24". You are going to need it.

Going to need to do valve modifications, too.

http://www.airgununiverse.net/13xxvalve.html

[BenjiHunter]

Mine has a FT valve and piston, steel breech and a 16" barrel.
I don't have a chrony but it blasts thru a 1" phone book with 15 pumps.
I think that's probably 12FPE or more.

[BillK]

I have a 1377 with an 18* barrel, Mountain Air flat top piston & valve, 5/32" transfer port, extended bolt.  Stock hammer & valve spring.
15 pumps w/8.18g pellet @757 fps = 10.4 FPE    Same at 20 pumps is 11.1FPE

[BenjiHunter]

I'm sorry.
I missed the fact that you wanted a .177.
Mine is a .22.

[K.O.]

Not exactly simple but not to difficult either.

mount it all on a 66 pump tube...

[DavidS]

Not exactly simple but not to difficult either.

mount it all on a 66 pump tube...

+1

Though the only good .177 Crosman I have left is a 66, so I be biased.