RWS 48 breech and piston seal life span?

[photrod2000]

I am at around 4 - 5000 pellets on the .22 and .177.  I noticed the velocity on the .22 dropped (can actually see the pellet hit home), along with penetration into the pine board backing.  So, I shelved it for the time being.

The .177 displayed the same this past weekend, I could actually see the pellet thru the scope arch toward the target.  It is also no longer penetrating a soup can at 20 meters. Some of the pellets I picked up from the dirt by the can were in really good shape with no or little deformities.

I am thinking the breech seal and maybe pistol seal are due for replacement?  Does this sound about right?

[rufus80]

Maybe,  but one question the the gun feel easier to cock? Diana's are known to not have spring longevity. The spring may have broke. To check the breach seal lay a tissue over it when firing and see if it moves from air bypassing the seal.

[Toxylon]

For the 350 Mag Diana promises a mainspring life of 3500 shots, which seems ridiculously low to me. Your guns' springs are well past that expiration date.

[Yogi]

Paul,

How long a period are those 3-5000 shots over?
Years or months?
If years, maybe you should change the spring, breech/piston seals, and reapply a little lubricant?

-Y
PS Motorhead does great work and is not to far away...

[HectorMedina]

I am at around 4 - 5000 pellets on the .22 and .177.  I noticed the velocity on the .22 dropped (can actually see the pellet hit home), along with penetration into the pine board backing.  So, I shelved it for the time being.

The .177 displayed the same this past weekend, I could actually see the pellet thru the scope arch toward the target.  It is also no longer penetrating a soup can at 20 meters. Some of the pellets I picked up from the dirt by the can were in really good shape with no or little deformities.

I am thinking the breech seal and maybe pistol seal are due for replacement?  Does this sound about right?

Spring fatigue or breakage.
At around $10 DIANA OEM springs are "consumables" and they do develop the power they are supposed to.
They would last a lot longer with a good hard guide.

Get new springs, if possible, get new guides turned to dimension, and be happy.







HM

[Bladebum]

There are three power points on springers- piston seal, chamber seal and mainspring. If any of these fails power and accuracy mpst times will go. Replace piston and chamber seals and check mainspring for straightness...when you open up the gun, you wont need to check if the spring is broke, you will know right away

[Mark 611]

If u got 5k on a factory spring u got ur moneys worth!

[Allen Rice]

Paul,
As mentioned by others here, springs gradually fatigue and eventually break with normal use.  In my experience, the piston seal usually outlasts the spring unless the seal has been damaged by extreme detonation, or was damaged during the assembly process.  Again, these parts are inexpensive consumable. Most Diana rifles are fairly easy to work on, and you may even be able to replace the spring without removing the piston.  Replacing the piston seal is a little more involved.  I any case, for safety, you will need to use a spring compressor.  Good Luck.

ar

[photrod2000]

Thanks for the info, will add some oil of the proper type and needle that I have, it may work.  But looks like I'll be taking them down for some replacement parts.

[HectorMedina]

Paul;

Do NOT add oil. That was necessary when seals were leather. Nowadays seals are synthetic and oil just increases the possibility of a detonation. It also increases the bounce-back of the piston, and so, for every shot, the spring gets double or triple use. That reduces the number of shots you can get out of a spring.

HTH





HM

[Madd Hatter]

My m48 was made in 1987 and the first time it had any work done to it was a year and a half ago. Main spring was getting a little tired but never broke. I bought it in 1993.