GTA
PCP - HPA - C02 Gate => QB-7X Gate -W/Co2 & HPA => : Wallis June 15, 2006, 04:16:22 PM
-
OK here's the jist.....
I have a QB79 in .177 caliber Right now it's hitting around 690 in 70 degree weather. I have done the mods listed on charlie's website. I even opened up the bolt probe to allow more 02 to flow, opened the barrel port to the largest size. what else can be done to get my little friend over 700. BTW the pellets I use is the gamo hunters which 8.3 grains, I have had the best of luck with these, and they group the best in my gun.
any ideas on this Charlie, mike, anyone ?????
-
You may have a restriction at the bolt probe, time to center drill, bob and install an extended one. Look for the little flags in peoples yards from lawn spraying companys and wire locaters. Ask if you can have one when they are done with them, the wire is just a hair over 1/16th inch in diameter and will work good for a probe, a good 2 part epoxy glue holds them in place just fine. I've gained 50 fps on some rifles by doing this. Also check your valve stem seal, if it looks ragged sent it to Alan at AB Airguns in Kansas, he will replace it with a new material that will help the fps, just make sure you don't get any dirt in the gas tube as these seals will not seal with dirt in them. I have gotten an increase of about 40 fps on some rifles with these seals and use them in all of mine that I sell.
-
thank you mike. I will look into that.
-
Mike,
I found my problem. the stem(part number 408) O-ring had swelled up so bad it burst inside the valve. I replaced the stem with another one I had here, for such and emergency.
-
Send that blown to to Alan, you won't regret it.
-
got a address or website for alan.
-
ABairguns.com, I think. give it a google if not
-
Thank you again Mike