Daisy Powerline 880 Receiver Strengthening

If you never disassemble your Daisy 880, you’ll probably never need to do this modification. People like me who can’t make it a week without opening their rifle will quickly discover that the screws that hold the upper portion of the receiver halves together will strip out their holes leading to poor accuracy and problematic scope mounting.

Upper receiver halves to staying together
Upper receiver halves not staying together

More drastic measures may need to be taken later, but I’ve got a simple solution that so far has worked quite well. I carefully drilled out the existing holes with a 1/8″ drill bit, chasing the bottom hole a little deeper to give more thread engagement. The next thing I did was to thread them carefully using a 6-32 machine screw.

Location of holes that need to be drilled and threaded
Location of holes that need to be drilled and threaded marked by the long screws

Now that the holes are threaded, I cut a couple #6 screws and dressed the ends so they would fit my receiver perfectly. I reassembled my 880, tightening these top screws first, then working my way down. The heads protrude just slightly and could use some paint, but the important thing is that my scope can now hold zero because the halves no longer flex along the top.

The 880 receiver halves are locked in place now
The 880 receiver halves are locked in place now

Should this arrangement wear out, I’ll simply drill all the way through and hold the two halves together with a machine screw and nut. In the meantime, I’ve got my accuracy and spent next to nothing on the modification! A similar process can be used for the two small stock screws, as these tend to wear out as well.

Bear River Sportsman 900 Project

I picked up a refurbished Bear River Sportsman 900 back in July. Right out of the box, it had a intake check leak. I bought it primarily to develop a LDC for it, but went ahead and attempted to contact Bear River regarding the leak. They finally emailed me back a couple days ago. This got me to tear down the rifle and see if I couldn’t fix it myself since my communication has been slow with them.

Ready to slay some Special ops squirrels!
Ready to slay some Special ops squirrels!

Luckily, the leak was caused by a bit of fuzz sticking to the intake check seal. I reassembled the rifle and chronographed it. It averaged a measly 583 fps with 7.4 grain pellets at 10 pumps. Time to tear it down again and fix everything they did to keep kids from overpumping the rifle to valve lock.

The ugly face of headspace
The ugly face of headspace

The piston features 2 dimples, the valve inlet is a whopping 7/64″ hole 1/4″ deep, and the inlet check has a deep phillips screw pattern leading to terrible pump efficiency. The first thing I did was remove the check seal, chuck the check guide into my drill and grind down the face until it was smooth. I also removed some of the excess material, increasing valve volume and decreasing spring tension.

Making the inlet check better
Making the inlet check better

I then polished the face smooth. The next thing I addressed was that massive inlet hole in the valve. To do so, I drilled a 7/64″ hole into the inlet check and superglued a piece of hex wrench in it. This still allows air into the valve, but takes up almost all the dead space, leading to much higher pressures.

The finished inlet check optimized for maximum pressure
The finished inlet check optimized for maximum pressure

At this point in my project, I haven’t addressed the dimples in the piston head. Instead, I noticed that the metal head of the piston was able to move forward and backward. To eliminate this, I wrapped copper wire around the rubber bumper, forcing it deeper, locking the metal piston head in the foremost position.

Overview of the rifle's guts
Overview of the rifle’s guts

I did some tweaks to the trigger and striker that I’ll address in a future post. All the pump and valve o-rings were changed before reassembly. So where are we now that we’ve made these mods? The same 7.4 grain pellets now hit an average of 645 fps, a gain of 62 fps and 1.25 fpe. Basically, stock Daisy 880 territory. I’m going to continue modding this rifle, the rifle fits me perfectly, looks great, and shoots very accurately. There is still potential waiting to be unlocked. If you’d like to get a LDC like the one in the top picture, use the contact page to let me know, and I’ll help you get a hold of one.

Crosman 1322 DIY Free Flight Hammer

In my last post, I was working to turn my Crosman 1322 into an air conserving pumper. In spite of achieving some success with a short spring, there was still a bit of a fart sound to the report, indicating that there was still hammer bounce. I decided to build a free flight hammer to eliminate hammer bounce for good.

Free Flight Hammer Device
Free Flight Hammer Device

The one disadvantage is seen in the above photo – you get a good bit of protrusion when the gun is cocked. I’ll be trimming it down a bit to make it sleeker. So how is it put together? I threaded both ends of a piece of 3/16″ drill rod to 10-32. On the hammer end, I threaded a nut on and ground its perimeter until it would slide freely inside the hammer. I took my already shortened hammer spring and slid it over the rod. The end cap was then drilled to 7/32″ so the rod could pass through. To reduce noise and vibration, a o-ring was added, and everything locked into place with another nut. Here’s what it looks like when removed from the 1322:

Overview of the device
Overview of the device

Cocking is still very smooth and easy with this in place. This is a good thing, in the interest of pursuing more power, I plan to install replace my shortened spring with a stiffer version.

What about performance? Well, it has dropped down to averaging 465 fps on an initial 10 pump charge, with 7 pump refills. It is very consistent, so I am definitely on the right track. I’m working on raising the power level in a couple of ways. I’ve already mentioned a stiffer hammer spring. To complement the hammer spring, I’m going to install a much lighter valve spring to reduce valve cracking effort.

As mentioned in my last post, I was wanting a more consistent powerplant. I opted to purchase a flat top piston and valve. The piston is adjustable and includes an oiler.  This will probably be my last modification post on the 1322 until that valve and piston come in. Let me leave you with a short video clip that will let you see and hear the device in action: