Bad consistency on my X-Valve this weekend, why?

[afultz075]

I meant to make a post on this the other day, but I forgot to. I was at the field with my RT Pro on Sunday, and I was getting horrendous consistency, if I remember correctly, one of the string of chronos I got was something like 297, 288, 282, 291. Even if that isn't right, it was pretty bad. So, what could possibly be causing this? I could occasionally get a set of shots that were pretty consistent, but they didn't last.

Could it be my tank? I was using a OLD steel 47/3k nitro duck (didn't get a chance to clean my Flatline), and it's definatly not a very good tank. Maybe dirt in the valve? They field I was at on Sunday was a private field and the only chrono they have is one of those little yellow ones, and I think the batteries were starting to go, so could it just be an inaccurate chrono?

[ß?µ£ §mµ®ƒ]

how did you chrono?
hold the trigger down let go and pull fast

[afultz075]

I just fired the gun normally, didn't know there is a special way to chrono the RT valve. Do those little yellow chronos let you chrono a string of shots? I don't think they do.

[Dayspring]

http://www.airgun.com/rtchrono.shtml

[t33kyboy]

Im not really sure how this works but, if you have to chrono the gun a certain way, wouldnt you have to shoot the gun the same way to get the same consistency?

okay so chronoing that certain way will simulate rapid fire, so if you dont shoot fast it'll be inconsistent?

[afultz075]

I just read that, thanks, good info to know. So is my problem as simple as not chrono'ing correctly?

I did notice if I let the marker sit in the sun for a few minutes and then chrono'ed the velocity would spike quite a bit.

[afultz075]

I opened up my valve and cleaned it out tonight, wasn't real dirty, but I got some gunk out of it. I noticed on the inside of the front half of the valve, near where the brass reg seat holder is there a two small, circular spots where tha anno is wore off, could that cause a problem?

[hitech]

A friend of mine had velocity problems that disappeared when he switched to a flatline tank. A tighter bore and "bad" paint will also be inconsistent.

[BlackVCG]

Those missing anno spots aren't a problem. They were probably there when the valve was brand new.

For consistency problems you need to first check your paint to barrel fit. Make sure it's tight enough it doesn't drop the the barrel, but you should be able to blow it out the barrel.

The next thing to make sure is that the chrono you are using is good quality. The little yellow radar chronos aren't all that accurate and if you don't hold it the same each time, it will read differently.

If you're still getting consistency issues, check the valve. Unscrew the two halves and lift up on the brass reg. seat retaining ring. Pull on the stem of the reg. valve pin and the o-ring, which is the reg. seat, will come out. Clean off that o-ring, the flat spot on the reg. valve pin that the o-ring touches and the backside of the brass retaining ring.

Put it all together, run some oil through it and dry fire it about 100 times and then put the barrel back on. Be sure you keep the barrel squegged to remove any oil/grime that accumulates in the barrel. Paint residue and oil will cause dramatic velocity changes.

[afultz075]

Yea, I did all that already. Just haven't had a chance to chrono it yet. I did have a problem the other week with brass shavings getting into the X Valve, but I cleaned all of them out awhile ago.

I was shooting Blaze at the field with a CP 1 piece.