Getting frustrated, need suggestions...

[daved]

Still struggling with getting my Hammerli Pneuma shooting consistently, and I'm running out of ideas.  Just in case I've missed something obvious, I could use a refresher/reminder of all the things that can cause inconsistent performance in a PCP.  I'm talking primarily accuracy here, and pellet preference.  I'll think I've got it dialed in with one pellet, but then the next day, it'll scatter that pellet and prefer a different one.  This is making me crazy, I'm about ready to start making "adjustments" with a sledge hammer :-).  What makes it worse is that when it's on, it's really on, it's already shown it's capable of ragged one holers at 30 yards when it feels like it.  Thanks, people!

Dave

[kirby999]

Clean the barrel good with GooGone , then pick the pellet that gave you the smallest group at 30 and start leading your barrel again . Could take as few as 10 or as many as 50 to get back to consistent. It's the only time I clean my airguns , is when the consistency goes out. Which pellets are you using. Some are dirtier than others and require that you clean more often . Also some barrels take as many as 1000-1500 pellets before they settle down. kirby

[longislandhunter]

Perhaps the rifle is not releasing a consistent volume of air when the rifle fires ???  That would explain quite a few things regarding accuracy and changing pellet preferences.....

Jeff

[melloroadman]

Have you seen these articles . There might be a leader in it for you .Marvin
http://www.pyramydair.com/blog/2009/06/hammerli-pneuma-part-3.html

[tat2dman]

Does it have a hammer spring guide?could it be binding,causing inconsistent hammer strike?Never had a Hammerli in my hands,but I`ve also never cleaned a BSA barrell,except outa the box ,I shoot a couple of clipped off q-tip heads 8)

[TCups]

Dave:

Sounds like you need to start shooting over a chrony.  Do you have one?  If velocities are fairly constant and the power curve is smooth, then look for dirty barrel, something loose in the action, etc.  And remember to check the action itself, not the screws, to see if it is tight, especially if you used LockTite on the screws.  A tight screw doesn't necessarily mean a tight action.

If the velocities are inconstant, and the flyers can be linked directly to variations in shot-to-shot velocity changes, then the internal mechanism is suspect -- hammer spring, spring guide, etc.  I know next to nothing about the internals of a PCP or CO2 power plant, but something may be "sticking" that needs a bit of lube or polish or what ever.  

[Leadhead]

I've read a few articles lately that stated that pellets used in a PCP need to be lubricated for accuracy. I'm thinking of trying this with my Marauder. I've been having some on & off days as far as accuracy.
Mac-1 sells a pellet lube called KryTech........might be worth a try........after a good barrel cleaning.

[daved]

Good suggestions all, some I've tried, some I haven't.  David, I don't know how many pellets have been through this thing, I got it used, but with very little use.  So far, I may have 500 or so through it, mostly CPH's.  I know, dirty pellets, so cleaning may well be in order.  It could be a barrel issue, I pushed a pellet through it at one point, and it felt a little rough.  If I had some JB Bore Cleaner, I'd probably give it a shot, since I don't, I may use some silver polish, see if I can polish up the bore a bit.

Jeff and Tommy, chrony results are surprisingly consistent, so I don't think the problem is in the valve, and I tore it all down and polished up all the internals when I first got it, so I don't think anything is hanging up.  I did have a valve leak at the beginning, I was able to pull the valve and lap the mating surfaces (with silver polish), that seems to have solved that problem.

Marvin, thanks for the link, I've read at least part of that, will go back and read the whole series.  From what I did read,the gun he describes isn't the same as the one I got :-)!  Guess your views are a little different when you're selling something.  I mostly agree with his conclusions, but with some serious caveats, the first one being that you be prepared to tear it down and clean it up before putting it to work.  This is a process somewhat complicated by the fact that there is NO info available for this rifle yet, but PCP's are pretty easy guns to work on.  Either that, or I'm a mechanical genius and don't even know it :-)!

Barry, funny you should mention a spring guide, it doesn't have one, but I was thinking of making one for it, since I think the spring can kink a little as it's being cocked.  Will keep you posted.

Raoul, I've never tried lubing pellets, I've yet to see anything that convinced me it's necessary.  That said, I may give it a try if all else fails, but if that's what it takes to make this gun shoot well, it's going away.  I've had enough other guns that shot great with unwashed, unsorted, unlubed pellets, I'd rather spend my time on shooting my guns.  Maybe if I were shooting competitively, but not now.

Again, thanks to you all, and I'll keep you posted.  Later.

Dave