Overpumping the 880?

[bhh]

You're welcome for the help.

It looks like you are off to a good start. That's not bad at all for a stock gun. If that was a starling you would have hit it every time.

Thanks for posting the group. I'm going to have to get some of those to try.

Here's a couple pics you might find helpful:

Probe before and after:



Loading port mod to make it easier to load pellets. Seal off BB port with JB Weld too:

[Grampy ray]

Here is two other mods to consider. Porting the valve . elongate the slot in the arm that the roll pin rides to move the pistion closer to the  valve to tighten up the head space . It works well with the washer on pistion mod.
I did a lot of mods on mine porting valve ,shim the hammers spring, adding travel to hammer, flat top,  washer on pistion , elongate slot and Stony kill trigger.i don't have a chrony but it smokes for sure. I get valve lock at 18 to 19 pumps.
 BTW the groups you getting ant too bad with crappy trigger and a non dome pellet. a trigger mod will help with that.

[Bryan Heimann]

For a $40 plastic gun, with double the max raccommended charge, a soda straw barrel flopping around inside a sleeve, and cheap heavy pellets that are not the least bit aerodynamic- i'll take a group like that straight to the bank.  I'd call that good on small game to 27.5 yards.  Nice shooting.

[dlee]

Thanks guys for the encouragement on the shot group.

Definitely intend to do the trigger mod as soon as I get a chance. Also, probably the barrel tape mod and adding some weight to the stock and fore end - those seem to be the most helpful mods for making the gun easier to shoot consistently. That should leave me with a 20-pump 10-fpe plinker. Then with the piston flat-top mod and pre-compression of the rubber spring by adding a metal washer, I think it will be something like a 15-16 pump 10-fpe plinker, which I can totally live with. Or a 20-pump 12-fpe gun. For $40!

Again, thanks for all the expert advice!

[dlee]

This isn't a very active thread, I realize. I saw someone on YT who put Piledrivers through his 880 and wanted to give it a try just for grins. Here are the results in case anyone else was curious about it:
H&N Piledrivers (21gr):
10 pumps / 457 fps / 9.74 fpe
15/494/11.38
20/517/12.47
25/520/12.61
30.526/12.90
Also, results for the H&N Sniper Mags (15gr):
10/514/8.80
15/5.58/10.37
20/590/11.6
25/590/11.6

Also, thanks again for all the advice earlier - I've done the trigger mod (huge difference in my ability to tighten up groups longer than 30 yards), the barrel tape mod, and added epoxy with lead shot to the stock. I also stuck a Kruger 3-9x32mm scope on it, which also helped with the longer shots (by which I mean 30-40 yds).

Actually in the middle of turning one of the spare 880s into an arrow shooter - there is a neat video about it and I am tweaking that design to allow for a variable valve chamber volume because it looked like the one in the video was exhausting lots of extra CO2 on each shot. Also, I'm using HPA instead of CO2. Have a 26ci paintball tank with the reg output set to 1800 psi (it's a string of about 10-12 bellville washers, so I can always lower the output pressure).

[braskaboy]

Anyone just flat out break something overpumping?

[Back_Roads]

 Most often a sweat, ocaisional seals and such.

[avator]

Nope, because I don't do it.
As I've said before...
If the gun I have is not up to the task at hand I will go in the house and get one that is. 

[Ronno6]

Nope, because I don't do it.
As I've said before...
If the gun I have is not up to the task at hand I will go in the house and get one that is. 

Some folks don't have an arsenal at their disposal..... :'(

[avator]

Nope, because I don't do it.
As I've said before...
If the gun I have is not up to the task at hand I will go in the house and get one that is. 

Some folks don't have an arsenal at their disposal..... :'(

Keep over pumping those 880s and they won't have those either.   
And if you have the funds to upgrade it to withstand the abuse then maybe you have the funds to afford something that was meant to do the job.
But, it's like grandma used to always say... "It's yours, wash it as fast as you want".

[superchikn]

Anyone just flat out break something overpumping?

Never had an airgun as a kid but a few friends had 880s or more often 760s.  I always pumped them to 20 or more.  Air locked a few of them.  I am amazed I had any friends.

Of course now I know it is only air locked and how to fix it, but I don't overpump any of mine.  I'm not worried about breaking them but because I have break barrels and pcps I don't like pumpers so much and definitely do not want to spend anymore time pumping them than i have to. 
I also have plenty of guns that will put out the power I may need when I need it.

[pblawler]

I've over pumped all of mine to 20 since 1984 with no problems.  The brass tube guns will never have an issue with it.  The pinned abutment (newer guns) need the abutment pin replaced with a stronger pin.  I have moved to tool steel dowel pins.  Then they are good to go.  I have three 822s, and four 1977s that see 20 pumps all year long.  I run through around 1500 pellets a year through those guns and have only had one failure.  I had a 822 that cracked a valve body.  I am convinced it was a factory defect, as I have two others that have had no issues and built one for my father that gets pumped 20 times every shot with no issues.  I also run 1977 piston heads/springs on factory piston links on all of the 822s.  I have done the same 1977 piston upgrade on multiple 880s for friends with no issues, all of which are getting over pumped.  The 880 with the 1977 piston mod, shooting JSB Beast pellets, at 20 pumps can make 15 FPE.  That's illegal in England LOL.  So, 15 FPE from an 880 makes it capable of small game past the distance anyone can shoot accurately.  They can take the pressure, just on the new guns the abutment pin needs to be upgraded and periodically replaced. 

https://www.mcmaster.com/98381A172/

https://thedaisybase.com/2023/01/27/pblpowermod/

[braskaboy]

I've over pumped all of mine to 20 since 1984 with no problems.  The brass tube guns will never have an issue with it.  The pinned abutment (newer guns) need the abutment pin replaced with a stronger pin.  I have moved to tool steel dowel pins.  Then they are good to go.  I have three 822s, and four 1977s that see 20 pumps all year long.  I run through around 1500 pellets a year through those guns and have only had one failure.  I had a 822 that cracked a valve body.  I am convinced it was a factory defect, as I have two others that have had no issues and built one for my father that gets pumped 20 times every shot with no issues.  I also run 1977 piston heads/springs on factory piston links on all of the 822s.  I have done the same 1977 piston upgrade on multiple 880s for friends with no issues, all of which are getting over pumped.  The 880 with the 1977 piston mod, shooting JSB Beast pellets, at 20 pumps can make 15 FPE.  That's illegal in England LOL.  So, 15 FPE from an 880 makes it capable of small game past the distance anyone can shoot accurately.  They can take the pressure, just on the new guns the abutment pin needs to be upgraded and periodically replaced. 

https://www.mcmaster.com/98381A172/

https://thedaisybase.com/2023/01/27/pblpowermod/

Your mod is bad*ss.

I have a 922 I rebuilt.  What should I do with it to make more power?

[pblawler]

I've over pumped all of mine to 20 since 1984 with no problems.  The brass tube guns will never have an issue with it.  The pinned abutment (newer guns) need the abutment pin replaced with a stronger pin.  I have moved to tool steel dowel pins.  Then they are good to go.  I have three 822s, and four 1977s that see 20 pumps all year long.  I run through around 1500 pellets a year through those guns and have only had one failure.  I had a 822 that cracked a valve body.  I am convinced it was a factory defect, as I have two others that have had no issues and built one for my father that gets pumped 20 times every shot with no issues.  I also run 1977 piston heads/springs on factory piston links on all of the 822s.  I have done the same 1977 piston upgrade on multiple 880s for friends with no issues, all of which are getting over pumped.  The 880 with the 1977 piston mod, shooting JSB Beast pellets, at 20 pumps can make 15 FPE.  That's illegal in England LOL.  So, 15 FPE from an 880 makes it capable of small game past the distance anyone can shoot accurately.  They can take the pressure, just on the new guns the abutment pin needs to be upgraded and periodically replaced. 

https://www.mcmaster.com/98381A172/

https://thedaisybase.com/2023/01/27/pblpowermod/

Your mod is bad*ss.

I have a 922 I rebuilt.  What should I do with it to make more power?

That is a brass tube gun, I replace the elastomer with the piston spring from a 1977 on my guns with elastomers but there is not big power mod for those guns.  Other than the elastomer to spring swap I just pump them 20 times.  Those guns can take it no problem.  I would also recommend Ron's trigger mod on the 922.  You should expect around 12 FPE at 20 pumps and an 18 grn pellet.  If its building less might check the o-rings.  If it is an older model with clamp down barrel it will made less power also, they are not as efficient and I suspect leak some around the barrel seal no matter what.  With all that being said they are really cool guns and worth keeping even if they aren't the most powerful.