Thursday, November 26, 2020

Smoothbore Upgrade! A Daisy 499 Barrel into a Crosman 1600 pistol

BB gun accuracy conversations usually begin and end with the Daisy Avanti 499 BB gun combined with the Daisy Precision Ground Shot.  That combination is considered the gold medal standard for smoothbore accuracy in this class of gun.  A few weeks ago, writer Tom Gaylord and several of the regular commenters on the Pyramyd Airgun Blog were lamenting that there was no smoothbore BB PISTOL equivalent to the Daisy 499 BB gun.  Of course, this immediately turned into speculation and "what somebody really ought to do" statements from those of us in the peanut gallery.   After we confirmed that Daisy did indeed sell the 499 barrel separately, a few of us readers volunteered to actually retrofit various BB pistols with said 499 barrels and report what happened. Because, you know, for knowledge and the greater good...

Anyway, here's how my project played out:

Daisy calls this a "shot tube" assembly.   Its what the rest of us call a smoothbore barrel.  The barrel assembly and three containers of Precision Ground Shot ended up running about $35 shipped direct from Daisy.  They actually included a 5 meter test target with the barrel.

Removed the nut and pulled the barrel out of the black plastic collet.



This is where my project takes a hard left turn and some caveats.   I don't have much in the way of BB guns.  What I do have is a terrible test mule for an accuracy based project.  I've got a Crosman 1600 semi-auto.  It's a 16 shot, linear feed design.  Feeds from a 90 degree rotating shuttle with a double action trigger.  The 1600 is also equipped with a bare bones non-adjustable fixed rear sight. So, there's that.

Crosman made this pistol in two versions, the 454 and this 1600.  The 454 had an adjustable rear sight and much nicer grips.  We documented a rebuild on this model several years ago here.

I referred to that old blog and took a few more pics to help during reassembly later.

Take out any CO2 cartridge.

This set screw holds the barrel in the valve.


 More pics to remember what goes where.

Here's the Crosman BB barrel.  It's .250" in diameter.

 A small c-clip locates and sets it's depth against the front of the valve body




Chucked the Daisy 499 barrel in the Taig lathe and turned the end down to a matching .250" diameter.




Ground a quick tool and cut a 0.030" groove for the c-clip.




Test fit.






Cut a longer leade into the breech end.

Turned the barrel down between centers to .250".  Initially, I only turned down about half the barrel length.  This proved to be a mistake and I had to go back and turn the entire barrel to .250" diameter.



Cut the barrel to length for the pistol and re-crowned.

Made the new barrel about 1/2" longer than the Crosman, so I had to bore out the front sight plug.



The longer barrel is a snug slip fit through the sight assembly now.

After polishing the new crown--before I went back and recut the entire length to .250" diameter. 

Test fit.

Moly grease on the trigger pins and trigger bar.

One more quick detour/upgrade:  I don't have a 454 model, so the 1600's fixed sight had to go.



Scrounged up an old Daisy sight in my parts bin.



Thinned it down by 0.055" to fit into the sight pocket on the 1600.



Made some mounting hardware.

Not a perfect fit at the front of the pocket, but it works and will finally let me move the point of impact to correspond to point of aim.



The original sight can be reinstalled in a minute if that ever matters.

So here we are.  I even remembered to shoot some pre-conversion groups for comparison.

Old barrel:

Crosman 1600 stock barrel and Crosman BB's.  5-shots at 21 feet.  Yep, she's a shotgun.  This is one reason I'm not keen on BB guns.



Another group with the stock barrel and Crosman BB's

New Daisy 499 barrel:



Daisy 499 barrel and Daisy Precision Ground Shot.  5-shot group.



Daisy 499 barrel and Daisy Precision Ground Shot.  10-shot group.


The groups are running over 40% smaller with the new Daisy barrel and Daisy shot.  Substantially better.  Though I know this isn't the pistol Mr. Gaylord is really asking for in that Pyramyd Airgun post, it certainly shows the potential of the Daisy 499 barrel combined with the ground BB shot.  I'd imagine if a 499 barrel was retrofit to a single stroke pneumatic with a decent trigger (maybe a Beeman P17?) it would do even better.  What this Crosman pistol does do well--unlike most pellet shooters out there--is hold 16 shots in rapid-fire succession.  It's a backyard pop can shredder. 

Happy Thanksgiving everyone. Be safe.