Paging Senor del la Airguns -- Crossman Shokwave
by John Meeker 
, Saturday, September 24, 2016, 19:44 (2984 days ago)
It is now printing a very low at 30 feet, with an 8" to 12" "high hold" the required drop for a hit, precludes any accurate sighting, and requires a contortionist to actually fire AND see both sights -- at the same time. yeah...really.
This, from a killer-driller of near and far 'needed dead' targets. . Even had found some rings, and a semi-solid scope, from out of the shoe-box. Bad Words - many.
So, after really verifying that above was not me for sure, and that the deviation was more than a screw turn or six, I start shimming the receiver. The reciver bolt holes thru the stock come out at an angle from two threaded sheet-metal studs, welded on the side of the receiver. The screws come in from the exterior of the stock, at a upward angle, just under the rear sight. This is where the slender 'scnable' design of the fore-end, is at it's thinnest.
The whole effect locks everything together into a secure 'pull', down into the molded bedding area. A big-headed Philip's bolt, just behind the trigger guard, secures the rear of the receiver. The design results in a very 'pointable' weapon. The local walnut-eater tribe has been diminished, thereby. And, the two-year old Chessie Gurl is now a squirrel fanatic. She goes out to the garden shed first thing in the morning, to see if those tails tacked to the under-eves for curing -- arew still there.
For the money, [129] the .22 pellet-pusher was OK. You do have to turn-in a bolt accessible thru a hole thru trigger guard. As a built in safety defense, there is a LOT of light take-up, before you sorta fall over the stout trigger pull. However, regarding the mfg due caution about making the 'adjusty' too light, I'm down to 'usable', without and perhaps can further.
My eventual thought was that the bbl was bent. However, I had never dropped or knocked it over. Soooo...I wondered that due to the stiffish-resisting gas-piston< I could have pushed it too hard, to fast, etc. and bent it? Grasped straws...and such.
Because of the angled-in front bolts, shimming [when tried] is limited, due to the need to engage the bolts and their seats at matching angles. Have not had much time lately to go further. If no relatively simple fix is 'known', then I better go looking again....it's busy time of year for me...and make sure I get an underlever of side-cocker For 'the bizness'. can use CB's, in the new-to-me vintage .22 Remington, Model 33, first issue. [i930's] Has a tidy contemporary commercial peep-sight mounted on the receiver, and a filler where the original rear sight sat on the bbl. Nice long bbl, too. Can't 'hoot it in town', so...I am discrete.
At any rate, tomorrow's workbench is just over behind my shoulder, but a "slap my forehead!" overlooked solution, wouldn't be a bother at all...to make some immediate working space, there.
Paging Senor del la Airguns -- Crossman Shokwave
by Paul 
, Saturday, September 24, 2016, 21:10 (2984 days ago) @ John Meeker
If I'm understanding your problem, you've got what is known as "barrel droop", very common in break barrel air rifles. Sometimes it can be improved on (if not cured) by working on the barrel latching system and ensuring that the latch is properly tensioned, adjusted, etc. But the general "go to" solution is the good ol' "drooper mount" that has built in correction for the problem. Here's links to a couple of likely candidates:
http://www.pyramydair.com/s/a/UTG_Drooper_Scope_Rail_11mm_to_Weaver_Adapter_Compensates...
One thing about this mount, it also allows you to use Weaver or Picatinny scope rings. I've been getting good use out of the UTG scope rings with four screws per scope strap and two screws per ring to hold 'em on the rifle. Never had an issue with scope shifting due to recoil using the UTG rings.
What I DON'T like about this RWS mount is the use of only two screws per ring to hold the scope in place. I'm guessing you're got a 1" scope, if you've got a 30 mm scope then they make the same mount with that size ring.
http://www.pyramydair.com/s/a/RWS_Lock_Down_1-Pc_Mount_w_1_Rings_11mm_Dovetail_Barrel_D...
Here's another option that just popped onto my radar, not familiar with it but it sounds interesting.
http://www.pyramydair.com/s/a/Hawke_Sport_Optics_1_Pc_Elevation_Adapter_3_8_to_Weaver_R...
If you're looking for a good underlever rifle, the one linked here is the same same as the Browning unit that passed through your hands. If you were to spring for the rifle and the full tune up by Mike Melik (I'm probably misspelling his name and too tired to look it up) you'd be paying a bit more than what a Browning sells for (the identical rifle, but with the Browning nameplate instead of Xisico) - but you'd be getting a rifle that's been through the hands of a gentleman tuner that's considered a master of the art as opposed to purchasing for full retail a Chinese roulette rifle (roulette = no telling what level of quality from the factory). It's not a "bargain basement" price, but a heck of a deal from what folks say on the forums. And it's cheaper even than the Gamo equivalents with the exception of the one linked below that. You could also just purchase the rifle itself or get just the "basic tune" that would ensure everything's in order in the new rifle and running smoothly. Details on the work involved in each level of tune are on his site.
http://flyingdragonairrifles.org/index.php?route=product/product&product_id=52
http://www.pyramydair.com/s/m/Gamo_ACCU_Air_Rifle_Premium_Combo/3799/7294
The Gamo is very similar in appearance to the Gamo CFX which was an excellent rifle (and will be again once I finish the rebuild) with the exception that it's got a better trigger than the CFX had from the factory. Hope something herein may be of service to you.
Perfect, Senor Paul....Not Sixguns, but appreciated...
by John Meeker , Sunday, September 25, 2016, 05:59 (2984 days ago) @ Paul
Thanks for the textbook solutions. The 'dropper' rings a bell. will rig an ad-hoc solution, and shop the meanwhile. Interestingly, the squirrels have stripped the neighborhood trees, due to the crop having been big walnuts, but not so many. Erynn looks for 'em faithfully, but sightings are rare the past few days -- as are any of the remaining walnuts. Weather is starting to turn, but no frost, as of yet. Leaves are still up, and week of good weather is on hand.
Perfect, Senor Paul....Not Sixguns, but appreciated...
I had this once and it was the seals going loss in vel dropped pellets below sights adj. Played heck figuring it out and finally the seal went all together. Rebuilt it and it shot fine again.
This is where a chronograph helps tell the tale...
by Paul , Monday, September 26, 2016, 16:49 (2983 days ago) @ uncowboy
a friend just told me that a rifle he rebuilt "shoots hard" - judging by how it sounds. He thought the same of his Browning Leverage, but the chronograph showed it generating only 550 or so FPS. Hardly a hard shooter. Running them over a chronograph occasionally takes a lot of guess work out of what is going on internally.
This is where a chronograph helps tell the tale...
by YJohn Meeker , Tuesday, September 27, 2016, 07:29 (2982 days ago) @ Paul
cheap-ie crono.....penetration tests in media. In this case, the velocity and pellet results are similar to it when I first tested it, upon buying.
My thought about the 'drop bbl' [I did look it up]: the cure of scope mount and built in sighting deflection is charted, so if scopes is an answer, perhaps that is an alternative. Since the drop is so much, the other idea is to jig up the bbl assembly and give the bbl an 'altitude adjustment' up-wards, testing incrementally, until it returns to basic zero.
Fall season has lots of distractions, here'bouts, and the local sqwills have been pared back, so the next report may not be tomorrow. However, I have a thirty feet of indoor range in the old general store basement. Also, can't wait to wring out the old Remington s.s. .22. It's so simple and easy to carry, that it will get a crack at game this fall.
Thanks, all. will report,
This is where a chronograph helps tell the tale...
by Paul , Tuesday, September 27, 2016, 08:43 (2982 days ago) @ YJohn Meeker
Barrel droop (sag, slump, dangle) is typical of some break barrel rifles (and the reason some of us favor fixed barrels with under or side levers) What I'm not clear on is, did this happen over time (is it progressive?) or is this an issue from the beginning? Also, my first response was made while half (or 3/4) asleep. I was thinking "scope", but now I get the impression your problem has been also with the "iron" sights. Are you having problems adjusting the iron sights, or is it a scope issue?
You also mentioned the possibility of the problem having been caused by the cocking action as you compress the spring (gas ram). I can't imagine they'd have combined that soft of a barrel with a gas spring, but who knows? I DO know that some folks practice barrel bending in order to bring a barrel more in line with the projectile's trajectory. A while back I read an article about some tests that showed that the barrel doesn't have to be perfectly straight in order to produce good accuracy. It's the last little bit that gives the projectile the path it will follow once it exits the tube.
Droop......with Iron sight. ....
by YJohn Meeker , Tuesday, September 27, 2016, 16:04 (2982 days ago) @ Paul
Review: gun shot to point of aim, very well -- 3 shot cluster, sqwill buster.
Then, started missing them, and didn't know how much, until I checked it on paper.
Mechanically, the assembly, lockup, and bedding still appear to be factory new, and all is tight,
The eight to ten inch drop started out of no where, so far as I can recall. No 'drops, bumps, etc.
Now due to series of old injuries and new 'doc stuff', it has been increasingly difficult for me to cock the bbl - from 'the hip and grip' ordinary pull-down to 'clack' latch. So, I started resting the butt on the ground, and using a downward push with both hands at the end of the bbl, in order to cock it. Despite the disappearing muscle, I still weigh 185 on a six-foot frame. Work labor a great deal when young, and have always had strong hands and arms; the crush grip contributed a lot to learning how to shoot a heavier caliber handgun.
My thought is that, despite what appears to be a perfectly straight bbl, some where down where the leverage is at it's most advantage, something has been bent or misaligned -- in the breech section, or just ahead of it in the tube. have not come up with a way to measure it, and again, not even sure that has any thing to do with it at all. Really need to establsih an actual diagnosis, before inventing a contolable bending jig!! ;~`) As life goes, no biggie....but the Chessies are miffed at those misses --