Ok, a couple years ago I rebuild my old Blue Streak because it no longer held air, I got it new in 1978.
It worked just fine, but I thought it was underpowered. After checking with a chronograph and online reports of others rifles, it was. That's not really a huge deal, but who doesn't want more power if its there to be had?
I tore the thing apart several times, trying this or that, hoping to get it up to snuff, sometimes gaining speed and then losing it.I got it stable yet still a bit low.
After reading every online thread or article I could find, it appeared the adjustable piston rod was probably a safe bet for more f.p.s.
I know Mac1 sells the whole thing but I thought I'd try a home brewed version before buying.

It's not the prettiest job, I don't have a lathe or a drill press, just basic stuff. I used a big bolt, cut off the head and threaded end off for stock. Drilling a straight hole down the middle of a bolt with a drill and a vice is not the way to go, but its pretty close. I then ground and filed a flat for the set screws, tgen drilled and tapped them.
I adjusted the rod to where the cup just clears the intake hole, before it was pretty far away, increasing headspace.
So, did it work?
Here's some mumbers with Benjamin 14.3 .20 cal
Before
4 pumps 442
5 pumps 484
6 pumps  516
7 pumps  550
8 pumps 575
9 pumps  584
10 pumps 611
11 pumps 633
12 pumps 642

After
3 pumps 440
4 pumps 508
5 pumps  544
6 pumps  586
7 pumps 622
8 pumps 650
9 pumps avg 665 but inconsistent numbers
I think at this level the valve is maxed out and cant take any more.

So from now on 8 pumps is the new max and for me good enough.
Here's a few pics

Good project. Good results.

I just chronod it with 8 pumps, it's averaging 654 fps with 8 pumps.

A few weeks ago I was given an older Blue Streak that works but is in pretty rough shape. The stock has chips missing and someone tried to engrave checkering on one spot. I didn't take any before pictures but I'm refinishing the stock right now. I'm not going to mess with the metal finish on this yet if ever (well maybe a few small parts).
Here's a pic of 2 trigger gaurds, top is 1978 and bottom is the older one (thumb safety model)

I know the saying "they don't make them like they used to" (and in this case they really don't), but I think the newer one looks a whole lot more classy.

I didn't like the old style trigger gaurd, so I reshaped it and blued it.

It's not perfect but looks pretty decent.

Here's some pics of pellets I still have from way back, probably from 1978 to 1983 ish. I used to get them at Big 5 which was inside of a store called WonderWorld in Las Vegas.

103 of these left


They changed the box, I remember not liking that, 75 Beemans in here from a box I don't have


Full box of these

my grandfather worked in the Racine factory in the 60s, I'd love to think he had a hand building that rifle of yours.  they really are classy little garden guns for sure.

never understood the reason for the brass barrel though