Author Topic: PSI in Multi Pump gun (Read 7105 times))

Ronno6 · « **on:** July 17, 2019, 03:56:34 PM »

What valve/chamber pressure builds up in a multi pump gun, such as a Crosman 2100 or Daisy 880?
I know it depends on the # of pumps, so lets say 10 pumps for example.

Wunderwerks · « **Reply #1 on:** July 17, 2019, 11:31:38 PM »

You would have to somehow attach a pressure gauge to the gun. A good math major could calculate the compression amount but that would vary with each gun. Different stroke length (it is adjustable to a small degree), quality of the compression cup seal and how tight the valve and compression chamber are to prevent bleed off. I'd hate to see a gun modified with a fitting to get that measurement. Maybe someone else has a better idea.

Ronno6 · « **Reply #2 on:** July 18, 2019, 12:16:35 AM »

I would have thought that it is a known quantity.............

jackssmirkingrevenge · « **Reply #3 on:** July 18, 2019, 05:18:22 AM »

Some data from rsterne's Millenium Pumper:

Tom Tucker · « **Reply #4 on:** July 18, 2019, 09:19:56 AM »

I would say around 800 PSI, give or take, for a healthy, unmodified pumper at sea level at the factory rated maximum number of pumps. If you know the valve volume, barrel volume, and FPE at a given pellet weight for a given gun, it can be estimated with a little more precision. Also, some people have actually tested them with pressure gauges. From what I have seen others post, the Benji 392, Crosman 13XX/2289, and Daisy 880 have all been tested to be around 800PSI at the factory max.

avator · « **Reply #5 on:** July 18, 2019, 01:49:44 PM »

RobM would be the one to ask..... he's all over that stuff.

Psipumper · « **Reply #6 on:** July 18, 2019, 03:06:08 PM »

Quote from: Tom Tucker on July 18, 2019, 09:19:56 AM

I would say around 800 PSI, give or take, for a healthy, unmodified pumper at sea level at the factory rated maximum number of pumps. If you know the valve volume, barrel volume, and FPE at a given pellet weight for a given gun, it can be estimated with a little more precision. Also, some people have actually tested them with pressure gauges. From what I have seen others post, the Benji 392, Crosman 13XX/2289, and Daisy 880 have all been tested to be around 800PSI at the factory max.

I agree , about 800 .

BrushPopper · « **Reply #7 on:** July 18, 2019, 10:07:51 PM »

In the first Ed. of “The Airgun Book”, they gauged a std Sheridan pumper @ 700 psi for 8 pumps.

10 made 835 psi.

Ronno6 · « **Reply #8 on:** July 19, 2019, 09:44:53 AM »

Good info! Thanks,y'all.

CraigH · « **Reply #9 on:** July 19, 2019, 09:52:18 AM »

Bob Sterne also did this pumping test:

https://www.gatewaytoairguns.org/GTA/index.php?topic=77463.0

Ronno6 · « **Reply #10 on:** July 19, 2019, 01:42:33 PM »

There we go.........Thanks!

Relentless Holiday · « **Reply #11 on:** August 16, 2019, 12:28:08 PM »

Quote from: CraigH on July 19, 2019, 09:52:18 AM

Bob Sterne also did this pumping test:

https://www.gatewaytoairguns.org/GTA/index.php?topic=77463.0

"There you go" for sure! Bob leaves me in the dust with a lot he does. The guy is a AG god. This I could at least follow.

Rob M · « **Reply #12 on:** August 21, 2019, 07:25:38 PM »

Had an 880 modded with gauge. Pumped to 2200 psi at one point. After ten punps the pressure was over 1000psi but id have to go back and read my own threads from years ago to be more specific.. I beleve a 1377 is also in the 1000 range after 10 pumps. Many of the guns are self limiting till you change the piston

Ronno6 · « **Reply #13 on:** August 22, 2019, 12:04:57 AM »

WOW !!

Horatio · « **Reply #14 on:** August 22, 2019, 02:07:47 AM »

Maybe some are more than 1000 then? Because adding a gauge adds volume.

rsterne · « **Reply #15 on:** August 24, 2019, 10:37:58 PM »

My tests of a 13XX valve and pump compensated (as closely as I could) for the volume of the gauge with a filler block inside.... With a stock pump cup, they are about 800 psi at 10 pumps.... much greater than that if you modify the pump cup and reduce the headspace.... A 2100/2200 would be a LOT more, because the pump swept volume is 50% larger and the valve volume is smaller....

Bob

Horatio · « **Reply #16 on:** August 25, 2019, 12:40:12 AM »

I loved my 2200 when I was a teenager.

To me the Crosman clamshell is ridiculous difficult to put back together compared to the daisy clamshell.

Ronno6 · « **Reply #17 on:** August 25, 2019, 09:40:25 AM »

Quote from: Horatio on August 25, 2019, 12:40:12 AM

I loved my 2200 when I was a teenager.

To me the Crosman clamshell is ridiculous difficult to put back together compared to the daisy clamshell.

You are correct in that, even if a bit off topic.
However, I have found that, if you have a simple jig to hold the Crosman internals in place resting in the right side receiver, the assembly of the left side is significantly easier.

Rob M · « **Reply #18 on:** August 25, 2019, 02:11:53 PM »

Quote from: rsterne on August 24, 2019, 10:37:58 PM

My tests of a 13XX valve and pump compensated (as closely as I could) for the volume of the gauge with a filler block inside.... With a stock pump cup, they are about 800 psi at 10 pumps.... much greater than that if you modify the pump cup and reduce the headspace.... A 2100/2200 would be a LOT more, because the pump swept volume is 50% larger and the valve volume is smaller....

Bob

Bob , when you pumped above 2200 psi did you find that the linkage pin had stretched the hole ?? was that the " weak link " in the system.?

rsterne · « **Reply #19 on:** August 27, 2019, 10:40:21 PM »

I didn't notice any issues during my brief testing.... I do not recommend such high pressures, of course....

Bob

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PSI in Multi Pump gun

Author Topic: PSI in Multi Pump gun (Read 7105 times))