Easy/inexpensive way to boost fps/fpe on a Discovery

[TF89]

Now that I'm not on my phone.  I installed a Hillmanair depinger which took out the ping and reduces the air from 135 down to 131 ci.  I added the SSG for shot count and also to quiet down the hammer spring.  That thing was so loud with its big sproing noise.  My setup is very quiet, rat fart quiet anyway.  Sound of pellet exploding vermin is way louder than the gun now.

[KnifeMaker]

BNM kit for .22 disco, stock disco before conversion, 800 fps chp 14.3, 22 shots @4% using rear spring adjuster.  Now BNM kit, barrel and shroud shortened by 4 inches, ssg, 750fps, using
 same fill 1800 down 1050, get 28-30 shots at 4%.  Disco still stock internals.

What you blamed on the BNM Kit was apparently your fault, Not the BNM!

each inch you shortened the bbl. lost you 10 to 15 fps. That is 40 to 60 fps.  According to typical pcp math, the BNM lost you nothing. but you're shortening the bbl. did loose the fps !

Knife

[KnifeMaker]

Heavier hammer spring and power adjuster.  Beware though, I lost accuracy at farther distances.  I would port my valves but I too have a BNM breech and don't think i can do it.  with the power adjuster cranked full, trigger pull is harder.  Big loud CCCRRRAACCCKKK when it was fully cranked lol.



Of course you lost accuracy. If you are getting a crack, it over the speed of sound.  And merely backing the spring out could very well have you still in the trans sonic area. Either of which can and WILL make a pellet unstable at any thing over very-very short range. A huge reason that knowledgeable airgun shooters look down their noses at Gamo and other springer makers who build to ultra high velocity to hook less than knowledgeable shooter into buying pure, unadulterated junk!   

Knife

BNM Breech due to arrive Saturday. Double Woo-Hoo!!!

Be prepared to take a hit on your speed with the BNM. I love mine but was shocked by how much it affected the speed. If I remember right it dropped about 10%.

this happened to me too.

[KnifeMaker]

I have a bnm breach opened the ports to about .170 used mrod poppet and a lighter spring . Using a medium hammer spring and a power adjuster I'm also regulated to 1800 psi and can get the 18 gr pellets up over 1000 fps using my modded stock valve . Running 850 fps with the 18 gr pellets using stock disco spring and a Challenger hammer

And "THAT'S" the way we do it yeah! Good for you. Listening here folks?

I'm kinda bummed. Mine was supposed to be here Sat. However, usps jsut changed Sept 2nd to Sept 5th. Guess possibly a combo of fuel and traffic, not to mention logistics here in Texas due to the Hurricane. Grrrr!!!

Lots of Texans have a LOT more to worry about than my looking forward to a toy part. Things like food, water, place to live. Man. Bad!

Knife

[TF89]

  I just came back to this post.  I was on my phone so was not as clear as could have been.  I was actually surprised that I was able to get those numbers due to cutting barrel and expected loss from the BNM kit.  Happy days for me.  I see the quote is in the wrong place.  Don't know why I even try when I'm on the phone.

BNM kit for .22 disco, stock disco before conversion, 800 fps chp 14.3, 22 shots @4% using rear spring adjuster.  Now BNM kit, barrel and shroud shortened by 4 inches, ssg, 750fps, using
 same fill 1800 down 1050, get 28-30 shots at 4%.  Disco still stock internals.

What you blamed on the BNM Kit was apparently your fault, Not the BNM!

each inch you shortened the bbl. lost you 10 to 15 fps. That is 40 to 60 fps.  According to typical pcp math, the BNM lost you nothing. but you're shortening the bbl. did loose the fps !

Knife

[KnifeMaker]

Every thing on mine is working well.  The BNM is  SO much smoother than the factory breach!

Still waiting on factory replacement hammer pin. They were out of stock when I called. Made on from the shank of a 1/8" drill bit. LOL!!!

Huma reg still not giving a good flat string. I think the body is too large in dia. to allow the reg to vent to atmosphere.

We have a good bit of night vermin here. Sure is nice to not have to fumble with a pellet for a second shot in the dark! 

The more I use it, the more I enjoy the BNM Breech. 

Knife

Knife.