3 pumps, a hard line or just a recommendation

[bantam5s]

 Most multi pumps state a minimum of 3 pumps in the manual. So I was wondering, can a gun can be harmed by using less than 3 pumps ? because I sometimes like to use 2 pumps for closer range army men plinking indoors and want to stop if it can damage my guns.

[bgmcgee]

I doubt it will do any harm. As long as it works for you then go for it.

[302U]

I would assume 3 pumps to ensure that the pellet leaves the barrel. Other than that I can't see any harm from 2 pumps

[BigTinBoat]

I would assume 3 pumps to ensure that the pellet leaves the barrel. Other than that I can't see any harm from 2 pumps

This/\/\

In all likelihood the manufacture did tests. If I were a betting man I would say that when "short stroked" and only pumped 2 times, the pellet (a heavier one possibly) had a chance of not exiting the barrel.  They probably got to 3 pumps before any combination of "short stroking" and pellet weight exited the barrel every time.

[north country gal]

As above, I would be concerned about a stuck pellet. Have seen what happens when a pellet lodges in the barrel and the shooter didn't notice it and shot another pellet and another. Very difficult to get your barrel cleared when that happens. Might be a good idea to watch for such a thing.

[bantam5s]

Well I've never had a pellet get stuck, and I'm very in tune with the sounds my guns make so I'm not really worried about that. I just don't want to damage my valve.

[phoebeisis]

My 1377 always manages to empty the barrel with 2 pumps
I think one pump did not clear
and in that case I think Crosman suggests to just pump it more recock and blast it out

Oh I did shoot 2 pellets at once -once
They shot OK- both dead on line(left right wise)   one about 3 inches above the other-

[Underdog]

My concern wasn't underpumping, but overpumping. Most of these multipump guns tell you no more than 10 pumps. I'm pretty sure the Daisy 880 and the Crosman 760 both say this in their manuals.

But Stonykill doesn't seem to think it will harm the 880. I wonder if that's really a concern?

[bbv13]

I ran accross a old post by Tim at Mac1 on another site where he spoke about this. I not sure but I think it was the American Vintage Airguns. Anyway he said that new soft sealed pump guns shouldn't be left with a full charge in them because the seals will deform and the gun will lose power over time. That's a quick over view of his statement. I leave my guns which are older with two or three pumps in them and have had no issues. I think he reccomends four pumps in the Steroid guns. I assume harder seals are part of the modification.

All of my pump guns including two Crosman 766's will fire with two pumps. I have never tried one.

Bryan

[Tater]

My concern wasn't underpumping, but overpumping. Most of these multipump guns tell you no more than 10 pumps. I'm pretty sure the Daisy 880 and the Crosman 760 both say this in their manuals.

But Stonykill doesn't seem to think it will harm the 880. I wonder if that's really a concern?

I think most Stonykills 880's are pretty beefed up.

[Underdog]

But I don't think he's using anything but stock seals.

[rangerfredbob]

the 10 pump limit in the manual isn't necessarily because it is going to break anything, there is a point of no return and for most stock guns that happens to be around 10 pumps. For example on a stock Crosman 760 or 1377  you can only get about 15 pumps worth of air in the valve, any more and you're just doing a bunch of work for no benefit. You can take that same 760 or 1377 and put a flat top valve and piston in it and probably keep getting more pressure up to about 50 pumps but it slows down considerably after 15-20 pumps. If you are going to do that though, it is best to do a few other mods to keep the valve where it is supposed to be. It's also similar to the reason that all the trigger springs are so stiff, the are stiff so people don't accidentally discharge the guns...

[bird blaster]

my 1377 still shoot with 1 pump but only about 10 yards. i never worry about under pumping just over pumping. i killed a hosp on 2 pumps once from 8 feet

[Underdog]

the 10 pump limit in the manual isn't necessarily because it is going to break anything, there is a point of no return and for most stock guns that happens to be around 10 pumps. For example on a stock Crosman 760 or 1377  you can only get about 15 pumps worth of air in the valve, any more and you're just doing a bunch of work for no benefit. You can take that same 760 or 1377 and put a flat top valve and piston in it and probably keep getting more pressure up to about 50 pumps but it slows down considerably after 15-20 pumps. If you are going to do that though, it is best to do a few other mods to keep the valve where it is supposed to be. It's also similar to the reason that all the trigger springs are so stiff, the are stiff so people don't accidentally discharge the guns...

That's been my concern too. My triggers have been quite light once modified...

[airgunaut]

The manual that came with my recent-year 880 recommends pumping two times for indoor shooting. My indoor distance is only 17' from target to muzzle and I always use 2 pumps with it for that. Works fine. It has never resulted in a jammed pellet, and the pellets I've used ranged from 7.25 grains to 10.something grains, though I mostly shoot 8.2-8.3 grain pellets with that gun.

[HOSPassassin]

Two pumps with an 8.4 grain pellet produces ~375 fps in my 901. It will kill a HOSP at 20 yards if you can get the trajectory right.

[splitbeing]

For a couple years I shot my dragonfly mk 1 more days than not.  And most of those days I was shooting 1 or 2 pumps.  No issues.

For 1 or 2 pumps, the ftt greens and sptizkugels are more accurate than other pellets. 

[Blowpipe Sam]

I have heard some folks express a concern that dry firing a pumper or a PCP is potentially bad for the poppet stem and/or the valve seat.  The concern is that without a cushion of air pressure in side the valve to absorb the hammer’s impact on the poppet stem the poppet can become brinneled.  I put three pumps in my knock-open guns to keep crud out and nothing in the self cockers.

Interestingly I prefer to leave my CO2 guns empty to preserve the seals.

[Berserkeley Mike]

I shoot BBs from my Daisy 856 often with one pump, ~280 fps.  (I put a bit of magnet on the probe to hold BBs).  I also have a sturdy cleaning rod just in case.

[bantam5s]

Wow this is an old one, I wonder how it rose from the grave ?