Donation

All Springer/NP/PCP Air Gun Discussion General > BB Guns and Such

Accurizing the no.177 Target special ( apparently increasing power too )

(1/1)

bantam5s:
I quite like them but accuracy could be better.

Originally I had hoped to find a cheap donor pistol or spare shot tube,  but I got tired of waiting/looking and I've got guns 2 so I bit the bullet on sacrificing one of my shot tubes.
I thought about it and couldn't come up with a way to retain the repeating gravity feed, so I took the simplest route and opted for a muzzle loading single shot like the 499.

This whole thing was actually pretty simple.

1-measure the overall length of your shot tube and the position of the BB detent wire


2-  drill both ends of the barrel out of the muzzle  and base pieces with a 17/64 drill bit.

3-  cut the BB feedway off of the base leaving just the threaded end.

4- cut and crown a properly sized length of 499b barrel

5- turn down both ends of your barrel to fit into the muzzle and threaded base.

6- file in a notch for your BB retention magnet.
The sidewall is 1.5mm thick, no amount of neodymium magnets I could fit had the strength retain a BB  , so I filed in about 1.mm and got good retention with a pair of 1/4 magnets

7 - press & glue everything together.








I temporarily super glued everything together so I could test it before proceeding, and here were my initial accuracy results.
( it does not like the match grade BB's used in the 499 )
A couple 6 shot groups before with the original barrel from about 7 feet away, standard daisy bb's.



And a 6 shot group from the same distance with the 499 barrel, same bb's


The trigger on these could be worse, but it's a bit heavy and quite thin, so it's hard to really tell just what this is gaining me.
The overall group size isn't that much less, but there was enough of a noticeable improvement for me to proceed.

For the final glue up I used JB weld, and to hopefully keep everything straight and square I have rod ( actually a Crosman 38T clearing rod ) pressed into a squarely drilled hole in a hardwood block.



Now the most surprising thing about all of this is that I gained at least 50% more velocity.
After noticing a difference I took it out back for some testing.
It is very noticeably more powerful, it has more pop and Carrie's much further.
I shot a can full of water with both of my guns and it was night and day.
This was originally the weaker of my 2 guns, and it will now cleanly penetrate one side of a pop can full of water while the stock pistol needs 2 shots in the same spot to just barely compromise the can.

Navigation

[0] Message Index