Is it possible to use Benjamin Discovery .22 tube with .177 barrel?

[Dee_Noy]

Hi all,

This maybe silly question but is it possible to use Benjamin Discovery tube in .22 cal with .177 call barrel?
I want to build .177 Discovery but unable to find .177 tube. One in PyramidAir is in .22 cal and wonder if I could use it in my project.

Thank you.

 

[IRBent]

Looking at the parts diagram linked below, it appears there's only one part number for the tube. I'd say that Pyramyd Air could confirm this if you called to order.
See part #2

https://support.crosman.com/hc/en-us/article_attachments/202423474/BP1K77xx_and_BP9M22xx_EVP.pdf

 

[SteveV]

Yes you can, the tubes are identical with the exception of the caliber decal -

 

[Dee_Noy]

Looking at the parts diagram linked below, it appears there's only one part number for the tube. I'd say that Pyramyd Air could confirm this if you called to order.
See part #2

https://support.crosman.com/hc/en-us/article_attachments/202423474/BP1K77xx_and_BP9M22xx_EVP.pdf

Thanks @IRBent
I'm going to drop message to PyramidAir.

 

[Dee_Noy]

Yes you can, the tubes are identical with the exception of the caliber decal -

Thanks @SteveV

 

[Bob-in-WV]

You will need a .177 bolt and seal too.

 

[IRBent]

You will need a .177 bolt and seal too.

Tube vs barrel? Maybe I misunderstood his question earlier today.

 

[Dee_Noy]

You will need a .177 bolt and seal too.

Thanks Bob.
I believe I can get .177 bolt & seal easily. PyramidAir stating that the tube will only fit .22 call only so I was wondering whether I can use it on my .177 barrel or not.

 

[Dee_Noy]

Tube vs barrel? Maybe I misunderstood his question earlier today.

Sorry to make you confuse.
I'm not sure about this tube since PyramidAir stating that their tube will only fit .22 cal.

 

[Dr. Kralenstein]

I've built many a discovery rifle and the tube is the same for both calibers. Breech works too, just need the bolt probe and barrel.

 

[Dee_Noy]

I've built many a discovery rifle and the tube is the same for both calibers. Breech works too, just need the bolt probe and barrel.

Thank you @Dr. Kralenstein
Did you ever use regulator on your Discovery? I read on some post that Discovery shot will drop after about 15 shot and I think adding regulator will increase shoot count.

 

[Dr. Kralenstein]

I never did, but I can tell you, if you want more shots it's all in the tune. I used to run a smaller transfer port and run higher pressure with the magnum airpower valve screws and spring. 60 shots at 20 fpe is possible. I had one on my 22 discos up to 55 fpe.

 

[Dee_Noy]

I never did, but I can tell you, if you want more shots it's all in the tune. I used to run a smaller transfer port and run higher pressure with the magnum airpower valve screws and spring. 60 shots at 20 fpe is possible. I had one on my 22 discos up to 55 fpe.

Is it safe to run higher than 2000 psi?
60 shot at 20 fpe is impressive let alone 55 fpe.
Which part did you tune beside transfer port?

 

[Dr. Kralenstein]

Is it safe to run higher than 2000 psi?
60 shot at 20 fpe is impressive let alone 55 fpe.
Which part did you tune beside transfer port?

I used a set screw that was threaded into the valve exhaust port, drilled that out to a smaller hole, around 7/32". Put in a power adjuster and .045" hammer spring that was 2" long, the upgraded valve screws, and had the pressure at 3200 psi. Stock barrel and ports. I was getting the 60 shots off that at 800ish fps with 14.3s

The 55 fpe tune was only 8 shots, but that was ported to .165" on the barrel and valve, and a custom transfer port to match. Same spring and power adjuster, and was running a 3500 psi fill pressure. Also had the magnum air power valve with super light poppet spring. The rifle actually had about a magnum 22 rimfire kick to it. So loud though, even with a tko.

I usually ran my 22s around 30 fpe for 30 shots, and only had one in 177 that was tuned down to shoot around 14 fpe for 80 shots or so.

Basically, high pressure and small transfer ports will yield a good shot count and power too, since you're using higher pressure vs volume of air to push the pellet.

 

[Dee_Noy]

Thank you very much @Dr. Kralenstein