CFX Questions again

[RCnMo]

Well, I got my JM spring and Tesla seal.  I machined a delrin guide that fit the spring with just a bit of force to seat. I machined a new tophat and polished it to a mirror finish. Finished the spring ends to a shine and machined a  polished stainless washer to fit the spring guide so the spring could torque. Everything was de-burred and polished and lubed. This rifle is slick to cock and it seems to fire louder (no smoke)  Without going into more details, I seem to have a different rifle. Now it doesn't like crosman cpl's as much as it used to. It is sending them over the chrony at only 800-820fps (after about 400rds break in), the funny thing is.. Now it shoots RWS superpoints (8.4)grainers faster than the cpl's and with little to no variation (829.3 - 830. 1.5fps variation and that was over a 15 shot string. I was amazed at the lack of variation. I guess my question is why would it shoot heavier pellets faster than the cpl's. The only thing I can come up with is that the RWS skirts fit tighter than the cpl's. I was hoping for my old speed(860fps) and cpl accuracy. Anybody got any ideas?

[Gene_SC]

This is a very common accurance when you tune a springer. And as time passes and you have pushed a couple thousand pellets through her she may even changer her preference again. I own several Gamo air rifles including three CFX's and none like the same pellets after the tune. YOu will probably get alot of feedback on this post.

Have fun

Gene

[daved]

Gene called it, they do change preference after major overhauls.  One thing was a constant with mine, it HATED anything Crosman I tried to feed it :-).  When I first got my CFX, it loved Crow Mags, after break in, they were all over the place.  I'd try some other pellets, JSB Exacts 8.4 in the 4.52 size were best in mine, followed by RWS Superdomes.  The Domes were faster, the Exacts more accurate.  If you're a hunter, try some Predators.  They didn't load well in mine, so I never used them in my CFX, but they're popular and effective.  If they don't work for you, you'll have no problem finding someone here to take them off your hands.  The other thing you might consider is the Straight Shooters sampler pack.  Last thing, give it some more break in time.  400 rounds is like the old joke about 10 lawyers chained together at the bottom of the ocean, it's a good start :-).  With all you've done to it, you're basically starting over, so figure 1000 or more before it's fully broken in.  If you've been shooting a lot of Crosmans, clean the barrel, they're dirty pellets.  Hope that helps, and good luck.  Later.

Dave

[RCnMo]

I think cleaning the bore could have been some of the reason for the change.  This rifle has had about 4000 rounds through it and almost exclusively crosman premiers. (It loved them) I'll bet I ran 50 patches through the bore during the overhaul to get it clean again. Like you said, cp's are dirty.  The patches looked like  my powder burners after a full day out at the range. I think my bore must have opened about a thou and that probably adds to the slightly loose fit of the cpl's vs the RWS.  I may get a sampler just to see what it likes. I just hate giving up the luxury of going to the big chain store for cheapo cpl's and having to order pellets with outrageous shipping.