Crosman hollow probe build

Hi Paul,
Have u noticed and skirt “reformation” with your beveled probe?
Makes me wonder if it might be worth making a dedicated “pellet skirt reformer press”?!?!
Something like a small press that holds the damaged pellet by the waist, and a beveled rod is carefully pressed into the skirt to re form it back to round. 🤔

Walk quietly, but carry a big stick.

That's interesting I got 652fps average over 10shots which is 15fpe
with hades 15.89gr out of box when first got 362.@8 pumps.
Page 14 of you got to be out there to see,has all 10 chrono numbers.

Seriously impressive results, well done

Quick update.

12 pumps = 19.16 fpe / 690 fps

Bent pellet skirt testing to come.

That... Is awesome. Fantastic results.

Glad you like it, It's been really enjoyable doing it.

I've been making drawings with measurements so I can make more bits later without having to take it apart and measure things again. It also helps me figure out the order of operations.

It's been a good day in the workshop. Today I took the 362 apart to work on the valve area,

Drilled out TP in the barrel to 4 mm

drilled out TP to 4 mm

shaped the outlet valve in the valve body

I started to slim the valve stem and broke it, so I ended up making a new one. I didn't thin out this stem, but round off the edges of the valve stem body for better flow around it, but only minimal difference.

I also made a delrin spring seat which would increase the hammer spring tension. This sits inside the hammer.

Photos to follow, and chrony results you will want to see at the end.

Spring ends on the hammer spring are horrific, so they got smoothed off.

New valve stem next to the broken factory one. Now I know I can successfully make them I might try slimming out the stem for better flow.

Delrin seat for hammer tension increase.

A couple of angles of the valve body. Trying to show the smoothed out angle for better air flow.

So what were the results?

Prior to this work I had already fitted a hollow probe: Using 18 grn JSB

8 pumps I was getting 13.80 fpe.

12 pumps 16.11 fpe

After the above works using 18 grn JSB

8 pumps - 15.71 fpe - 624 fps

10 pumps - 17.61 fpe - 661 fps

I'm pretty impressed with that. I packed it in for the night, but will see if all the air has been dumped and will try 12 pumps tomorrow. Then accuracy needs to be tested.

Billbobnz wrote:

Mate they are making me want to get a lathe.....

Hopefully getting one at work soon. So hopefully will finish a few projects around here.

That is exciting.