Bionic .25 cal Webley Patriot/Beeman Kodiak

Thank you Gary !!

I'm hoping the 75kg is good to go. It came from Blackpool Air Rifles back when their Theoben rams for English Patriots were still in stock. It is for an airgun with only 114mm of piston travel, but there was room to spare on the stroke, so I'm hoping the end result (after my math and hacking) will yield 120mm of stroke, and deliver useful power that is still sedate enough for enjoyable use. If my math pans out correctly and my welds are true, the 120mm will be left over after the trigger reset without bottoming out on the compression stroke, and still have 2.6mm left over for preload.

...... i'd be careful with that transfer port , tho....7/64"....maybe 9/64" topps....that's the biggest ive seen ( chris pryjomski of c.a.p. airgun research taught me this with noble patriots).... when do we get to see the gun in its entirety ?

Click to expand...

Ugghh !

Now I'm really confused

Chris recently told me he went with .171, which is 11/64"

The machining and design is old hat to me, but the "voodoo" (aka experience) of determining the transfer port size is where I'm struggling. I changed the seal on an old HW35 (was being rebarreled) from leather to synthetic, and reduced the transfer port while I was at it, and it shoots really well... BUT... I was following recommendations of those who'd gone before. What really confuses me about the Patriot is hearing reports that opening the port can reduce piston bounce with heavy pellets, and cause harshness with lighter ones, while too small a port can increase piston bounce regardless of pellet. Seems like a good idea to pick a pellet weight, and sneak up on the manners that work best. My initial thoughts are to dedicate this Patriot/Kodiak to the 25gr JSB and leave the heavier pellets to my PCP.

As it sits it has a port that's about 4mm (.158")

This Kodiak has always required a palm bruising whack on the barrel to overcome the locking detent. Rather than put a weaker spring behind that latch pin, I've decided to make a thumb actuated sliding release aid, that rides on two miniature shoulder bolts mounted to the underside of the barrel block, neatly above the cocking lever in the existing gap. The 3D model below shows the 1/8" cube that will be inserted into a newly machined slot on the bottom of the barrel block. That "cube" will in turn fit in a matching groove on the bottom of the spring loaded internal latch pin. The arched protrusion is where the user's thumb can pull forward to completely release the barrel lock. That thumb perch will be resting on the left side of the cocking arm, with a profile that does not hang below the cocking arm, nor extend any further to the left than the underside of the barrel block, so no further mods will be required to accommodate its presence beyond the short slot, two threaded holes, and groove in the latch pin. It only requires 3/16" travel to fully release the latch, and the barrel will then droop just enough to clear the latching range, while the cocking arm moves approx 1/10th of an inch rearward to where it will start to engage the piston slot, where cocking can commence. Hope that made sense.

Gary I was in New Mexico from December 23rd until yesterday... nearly 3 months helping mom move into her new house after dad's passing. Have some catching up to do now that I'm back home, but this project is still on the bench and itching to resume progress.

More to follow as able

Ed