QB fans – experiences with recent barrels?

[Ribbonstone]

Going to dump on you...seems like a good place to get most of the QB thoughts out of my system without starting a new post on the same topic.

MAy not be a help to you, perhaps a help for others reading along.

HAve had a few bad ones  back in time....yours is one of the few new ones I've read about from a reliable poster having a problem for awhile (some other posts, but  not so sure there weren't other problems going on that failed to get looked at).


Going to lump all QB barrels. THe old "skinny"QB barrels (the 14mm version used on the orginal 78) and the "fat"QB 15mm versions used on the 2078/79,and 78D's.


In the last two years, 3 new QB barrels (going to count the ones on the Chief's as well as a QB co2 repeater),no complaints about them.  Do notice that the Chief used the "skinny"diameter.


One old .177 did have a problem.... got saved by cutting to carbine length...the tight spot was about 3.5" back from the muzzle. Had typical visual problems of the time(the bore wasn't dead-on center after it was cut),but still use that barrel as it shoots really well.

One .22  I just never figured out. LIke yours, nothing I did made any difference, and there wasn't anything I could point to for a reason.   Looked good,felt even when slugging (or lapping), recrowning didn't help.  Even whent so far as to cut off the breech end, machine it, make bushings,and try it in an AirForce Talon....still shot crappy.

(Idea above was that if it shot well in the AirFoce with it's new breech...I'd cut it again and make it work on the QB  as a carbine cut from the rear end.  It didn't, so I didn't, and it is still doing duty as a rusty garden-stake.)

HAd a good spare .22 QB (fat) barrel from a rebarreling project (5mm),so cut that one from the front to carbine and used it on the QB79 HPA conversion.

REBARRELING:

Rebarrling for me is a bit more labor intensive as I don't have a mill...did have a lathe for the shank diameter. With with time and effort,can make the loading platform with a grinder and files...or even a hack-saw and files.

OR you can make a detachable loading platform (black Delrin will work)and leave the barrel "flat breeched".  Remove the platform, de-top the QB without having to remove the barrel from the receiver.

THOUGHT that joining the barrel and reciever solidly might help.    Good idea in theorythat didn't work in practice; abandoned that.

Did find along the way that it helps to "spot in" the reciever to gas tube. Basicaly paint it with lay out blue (or lipstick...or soot if you got nothing else..something that easily transfers)to see if it sits down with a large contact area...or if it's teeter-tottering on a couple of high points.

(I'll do that on more expensive rifles as well...that does seem to help stability if not accuracy, but usally both.)


Two rebarrel QB's (one with an HW 5mm blank,other with an LW.25 blank) they shoot real well. One outtthe box QB barrel and one cut-down/worked over QB barrel  group just as well.

QB "swingers" club:

If you have more than one QB,can often swap barrels/bolts(or even the whole "upper"assembly). If a suspect barrel then shoots great,probably not the barrel at fault.  If the suspect barrel still shoots crappy on the known to be good rifle, probably is the barrel's fault.

Used "probably"...could be some other glitches going on.
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So thinking back...maybe 13 QB barrels (counting 2 Chiefs) that I seriously worked on.

 9 in the good-excellent level. Alot of that deals with both expectations and actualy uses.
2 that took some crowning,cutting,or polishing to get there.
2 that were just turds.

[crazyhorse1]

Thanks guys, I guess I just had the misfortune to get two bad ones in a row.  Certainly has shaken my confidence, and that may have as much to do with the good luck of previous years as it does the bad luck of this year.  I’ll report back when I get the latest one sorted out.

Did your barrels come with any front sight mounting for screws ?? I had an experience once when factory tapped barrel for front sight it caused dimples inside and pellet was impacted/thrown off...
(850 Air Magnum .177)....several owners affected.

[nervoustrigger]

Hi Robert, regarding your comments about other reported “bad barrels” over the years, I agree.  Certainly not just QBs but barrels in general, often times there isn’t enough information in a forum thread to confidently lay the problem at the feet of the barrel.  In some cases the owner probably knows and just couldn’t be troubled to chronicle all the troubleshooting drudgery.  Otherwise usually a barrel swap absent of any other changes is taken as proof positive, but even in that case there is a chance that disassembling and reassembling unwittingly fixed something subtle.  We’re usually just happy that it’s fixed so we’re not likely to put the “bad” barrel back in to see if it’s still bad.  However in my most recent example, the same action has now seen 5 different barrels, some of them through multiple disassembly/reassembly cycles and the issues consistently followed the two suspect barrels.
 
What had me scratching my head was the long happy streak of good to excellent QB barrels, that I just couldn’t reconcile the odds of getting two bad ones in a row.  Especially since they were different calibers so it’s not like they were from the same manufacturing run.

[nervoustrigger]

Crazyhorse, thanks for the reminder about the front sight screw.  I didn’t detect a restriction there when pushing pellets through.  Also I’ve spotted that type of defect before by the way light bends when looking through the bore and I didn’t see that either.  I’m going to take another look though because it’s quite possible that was the case with the .177 that I coaxed into working with the lead lap.  There was a restriction just before the muzzle  so that might have been the location.

[Ribbonstone]

Good catch....I forgot about the screw holes.

Going to have to check...but I remember QB78's and 79's as having screw attached front and rearsights. YEah...of the ones that didn't get a rebarrel,only the AR2078 didn't have screwholes.

Did have some holes drilled too deep...and some that weren't quite throught, but the screws were too long....could check it at first...go nuts on the mounting screw and find a problem later.

[Mr. Panther]

Hi Jason, I just got a new QB79. When I test it out I will let ya know how the stock barrel performs. Ive been lucky so far as none of mine have been bad yet.

[Ribbonstone]

The one thing I couldn't do with QB's.....could never really leave them as issued.

This from a guy who sees airgun simpllisity as a virtue...and yet I compulsivley un-simple them.

Why I ended up with so many passing though....INTENDED to leave it alone (at worst,mildy tuned)...failed....bought another one with the same intention....failed....etc.

Still have that urge....know it's not going to happen.

Best I could manage was to keep 5 (jury is out on the 6th one).

[nervoustrigger]

Cole, best wishes for tiny bug holes with the new rifle. 

Robert, yes I can relate.  QBs practically demand to be modified.  So much potential on tap waiting to be enjoyed that it seems a shame to leave it be. 

[nervoustrigger]

I checked the .22 barrel for possible damage at the front sight screw but I had forgotten it’s from an AR2078 so it actually doesn’t have one. 

However while looking more closely at the bore, I noticed a light scratch about 5” from the muzzle.  Looks like a perfectly circular scratch cutting across the lands and grooves.  Then I flipped it around and it turns out there is at least one more closer to the breech end.   I’ve never seen a defect like it before so I have no idea how they got there.  I could not feel them with the poured lead lap so I don’t know if they are related to the poor performance but it’s the only thing that stands out. 

[Ribbonstone]

Another "dump"...seems better here than starting a new topic.
Do think there is still a place for making QB's into something they didn't start out being.MAy not be cost effective,but you lean a whole lot about co2,HPA,PCP airguns. That carries over to whatever other airguns come your way.
THe 5 "keepers" (over the last 12 years): 9 to 60 foot pounds
DSCN1990 by Robert Dean, on Flickr

They all still look "QBish" to me.....one even looks kind of "stock".

Maybe the inportant part is that "12 years"...they are easy to repair, don't seem to wear out anything but the easily replaced seals.

#6...I just don't knowwhat it would do "better"than be a repeater.
 Beeman 1085 .177. Jusy is out on this one. Scope sight line and the low cheek of the stock.  IF I add a cheek riser (even if it's just glued on),would be happer.
DSCN2193 by Robert Dean, on Flickr

Stock fits better with iron sights....but not as useful as it would be scoped. But it's still pretty much un-messed with (different sights and LDC...other wise as it came out the box.)
DSCN2307 by Robert Dean, on Flickr
Give into the urge to change things? Have the parts to try,stock is even inletted for the tank block...everything just needs to be assembled (although wood stock would be even lower than the pastic).
DSCN2671 by Robert Dean, on Flickr

Considering my past history....sure bet what's going to happen...NOT a sure bet that it will earn a place with the other 5.

[Mr. Panther]

I took my new QB79 out and finally shot it. It required some messing with the front sight height, but after that it was dead on the money. I forgot to clean it and it still shot great. Almost afraid to clean it now that I have it all dialed in LOL.  Took all my Oriental "girls " out today All 7 of my QB's and my three Gauntlets topped off the tanks and put fresh cartridges in the two CO2 's and had a blast . Except for the Gauntlets they are all set at 1100 psi except the heavly modified one that is set at 1175. I must have won the barrel lotto on those guns because they all shoot rather well. So out of the two newer barrels ,( both .22 15 mm) they both seem to be good shooters.

[Ribbonstone]

Good going....they can be very useful/accurate just they way they are.

Good barrel is a good barrel no matter who made it.