.177 cal 12 FPE Discovery build - input appreciated

[AmBraCol]

Thanks for the feedback, Cliff!  I'd like to hear more about your tinkering, especially if you decide to dial it back to the 12 FPE range.  I'd not thought about the Marauder spring, need to get some into the next Crosman order, most of the rest of them make up my arsenal of spring swapping potential.  Don't know why the Marauder got overlooked.

[c_m_shooter]

The heavier hammer spring just moved the power curve to a higher fill pressure.  If you are tuning for a 3k fill it will be mandatory.  I liked the gun at 12 ft lbs, but if I shoot WFTF PCP here I am in a class of my own. The guys that shoot open at this club are among the best in the country and shooting 19 ft lbs.  I am not good in the wind and need all the help I can get at this point.

[AmBraCol]

The heavier hammer spring just moved the power curve to a higher fill pressure.  If you are tuning for a 3k fill it will be mandatory.  I liked the gun at 12 ft lbs, but if I shoot WFTF PCP here I am in a class of my own. The guys that shoot open at this club are among the best in the country and shooting 19 ft lbs.  I am not good in the wind and need all the help I can get at this point.

I kind of tend to go the other way.  Most of the folks here seem to want to play in our open class in FT, although there are some WFTF shooters.  It definitely takes some skill to run the lower power in the wind, no doubt.  I go one further in the "away from the madding crowd" direction - and that's WFTF springer.  Took first place in June in the nationals in that classification.  Not hard when you're the only one in the class!  My original goal for this current build is 12 FPE, but knowing the builder, he's probably going to want to run it up at the other end of the spectrum as well, especially playing with heavy pellets.  One thing at a time!

[Kerndtc]

Wftf disco is a fun little gun,

I've made a few of them using factory parts and a few of my own. I initially used the factory gauge block hollowed out to increase flow and add a few more ccs of air volume.

 I also use either a short stiff spring, or a homemade SSG. I would not recommend a debounce device, one more thing to catch up or drag, expand from temperature or ultimately fail. The SSG is a lot more reliable in my opinion.

Most people have addressed the issue with the dual barrel bands, I have the stock carved out right in front of the breech to put one band there. Helps support the front of the breech instead of too much stress on the tiny little breech screw.

A lightweight hammer would be very beneficial not just for efficiency, but also for a smooth shot cycle. If using a 22xx trigger or the factory trigger there will be sear drag on the hammer/ striker giving it less consistency.

The crosman spaghetti barrel should be well supported and you should consider sleeving it with a carbon fiber tube, it has been proven time and time again to help with harmonics and stiffness.

I have three discoveries and two maximus rifles. All tuned. I like them, and they make great little guns.

If I build one specifically for WFTF FT I'd do this.

1: Sleeve barrel with CF and use two barrel bands in front of the breech between the breech and the gauge.

2: Lightweight hammer (modified for no sear drag)

3: short stiff spring SSS or SSG

4: REGULATOR REGULATOR REGULATOR.
Remove the gauge block, throw a huma in there after you establish your perfect tune pressure without one.

5: Trigger, one of two. Is factory with two/ three screw mod and a new spring, or drop on a marauder trigger.

I started shooting FT with a discovery, and have tuned many of them. Most are at full power with 35 shots at 18fpe. But 12fpe is perfect for these guns.

[AmBraCol]

Thanks, Cameron!

[Kerndtc]

Thanks, Cameron!

You're welcome. Remember the factory hammer is hardened, very hard to work with. And it's only designed for 9/32 springs. If you bored it out to just over 5/16 your spring selection will increase drastically.

[Ribbonstone]

 Am fine with most of the advice so far....although for field target I really don't see how the plastic stock would be a help, and you'd have to be pretty creative with a fore end as holding onto a bare tube really isn't going to cut it.


As for regulation....not sure it's needed.

This is from some years back, using .177 JSB Stratons (yeah...the little pointy fellas).  Same ideas as my last post: simple strtiker spring adjuster, lighter flat sided striker, and a .1" transfer port (back then, I had to sleave a Disco port and drill the sleave out).