EverHopeful wrote:
How thick are the walls between the chambers at the thinnest point? Just a bit worried they might let go and turn into shrapnel.
I was also thinking this... Drilling took out 1mm which is not that much, but doesn't leave a lot of material id say
approx 1/2 of the original wall thickness. Maybe before I start cutting barrels, I will fire it without the barrel in
place and see how it responds to the stress. I'll just wrap the outside with a thick cloth to catch any debris,
should anything break loose..
rav wrote:
For your info, the Umarex Walther CP Sport is nearly identical to the Walther CP99 which I have. Both of them have exactly the same mechanics and muzzle velocities. With 7gr .177 lead pellets mine shoots max. 356 and min. 322 fps for an 8-shot string at 19C. Assuming the same .22 cal barrel length as the original one (3.3"), with 14gr .22 lead pellets you can expect approximately 230-250fps at the same temperature and a bit higher at, say, 25-30C. If you install a stock 2240 barrel (7.5") you could roughly get to 300-310 fps?
IMHO even if you succeed with that conversion, it is not worth your time.
Thanks for the info.. I would imagine the super short barrel also contributes to such a low FPS. I dont have a chrony
yet but am making one. If all the other parts hold up in conversion, I would then be looking at a tighter hammer spring
and altering the valve with a goal of at least 400fps. I read somewhere about a similar setup getting a good improvement
with a longer barrel alone. If I cant get 400 ~ 420 FPS id be more than happy