Feasibility of the 4.5-6 mm Conversion
 

Hey just wondering if anyone has done the 4.5mm-6mm conversion before.
Just came across this 4.5 mm Browning MKII and I was thinking if it'd possible to convert it to a 6mm.
Browning Hi-power Mark III CO2 BB Pistol Table Top and Shooting Review - YouTube

All that we need to replace/fix are just the chamber and the loading slot on the magazine, the chamber could be obtained at some parts shops and the magazine turns out to be a little tougher to carry 6mm BB's.

What do you guys think?

Unless you somehow changed the power output, they would be shooting WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY too hot.

That would be a looott of machining for what you plan to do. Doesnt anyone make that gun in 6 mm?

Actually a lot! but just not at that price.

You mean the propulsion power?
I think most likely it would remain unchanged, outputting the a bit lower FPS due to the mass of the 6 mm bullet.
I recall Umarex has made lots of 6mm CO2 NBB's, anyone dig out the mag difference between the 4.5 and 6 mm version?

a 4.5mm steel bb weighs way more than a 6mm plastic...

Okay I understand where your coming from now. My major concern would be getting the dimensions of the chamber just right. There would most likely be quite a bit of machining done to get it to correct specs.

Everybody knows that. So I already said that it'd lose some FPS due to the mass discrepancy.

If propulsion remained the same yet the mass of the object (6mm plastic BB) greatly decreased, wouldn't the 6mm BB travel WAY faster?

Yep that makes sense Q=1/2*mass*velocity^2.
But experience showed me that the 4.5 one always gives a lot more FPS, I was thinking it might be due to the different degrees of penetration, or temporary impulse that the bullets offer when actually colliding with the chronograph's surface.
Anyways, kinder off-topic..

No. If the only thing that changed is going to a lighter projectile, you're going to be shooting hotter.
I'm not sure why you don't understand the physics. It's the same as changing to a heavier or lighter airsoft BB in; your FPS is going to drop or go up.

Apparently a .177 caliber BB weighs 5.1 grains, or 0.33g
Taking that into account, that BB gun that shoots 410 FPS would shoot 514fps on a 0.20g airsoft BB.

*Bang Head* Really? This reminds me of a girl in my physics class who didn't see the point in wearing a seatbelt, because "if the car stops you will stop too." Bad physics just.. pains me

WTF with the physics s***t, the only thing I know is pellets hurt way more than BB's.

I have the sudden urge to pull out my physics textbook for some reason now...

As for modifying the pellet gun to shoot BB's for the cost and reliability it would not be worth it. Get a purpose made BB gun instead I know that there are a couple of manufacturers that make the hi power (but that tend to be more for show), you might be able to convert a KWA CZ75 or try for another pistol unless you absolutely need this.

This plan stinks. Full stop.

That plan to get a springer High Power stinks too.

Plan A) Track down someone in Calgary who got one of the Tanaka Works Inglis pistols from Ken and is willing to part with it.
http://www.wgcshop.com/wgc2008/main/...no1=&orderno2=

Plan B) Keep waiting on the WE MKIII to be released.

Plan C) Find someone who does custom orders and get a Tanaka from overseas; either an Inglis example or a MKIII etc. whatever suits.