Underlevers and Gas Rams

[ColinH]

I have a PCP and a break barrel, but have no understanding of underlever or gas ram rifles.
Is there an explanation or can someone explain, how they work, and operate, where do you load the pellet etc. as interest in a purchase?

 

[That hurts]

A gas ram is a sealed pneumatic strut that replaces a spring. Underlevers are cocked with a rod under the rifle rather than breaking the barrel to compress the spring and have a rotating tap or breech to load the pellet into, or an opening breech that allows the pellet to be barrel loaded.

 

[Bighit]

There is rifles that use the piston as part of the ram and there is struts that fit in a piston like a spring.

This is the Theoben System Gas Ram from a HW90.
It uses the piston as part of the Ram.

VORTEK made a Ram that used the Piston also . It was not in production long though I believe they were trying it again.

This is a Gas Strut . Fitted to a lot of rifles under the Nitro Piston system as they use Nitrogen in the struts , in break barrel and underlever airguns.

Struts in airguns are mostlybsealed units though some are adjustable and rebuildable though .sealed units can only be adjusted with specialist equipment but many won't do it as they won't know the pressure it needs to be.

 

[Varminter]

Nearly all gas rams are break barrels, unless an underlever has been converted - it’s just a sealed cartridge of air you compress to act as a spring rather than a coil spring.

But there are rams and rams, all modern offerings other than the Weihrauch HW90 are not serviceable and are generally regarded as being a bit crap. The ram in the HW90 is adjustable/tuneable and an evolution of the old Theoben rams.

Underlevers use a lever under the action/barrel to cock the action rather than using the barrel with a linkage - the clue is in the name. They have some form of breech opening to load the pellet directly into the barrel. This supposedly increases accuracy over a break barrel, but with good quality modern break barrels the gains are probably negligible. Some breeches slide open (HW77/97, TX200) some pop up (HW57), some have a tap or similar (Webley Eclipse).

 

[ColinH]

Ok thanks all for the replies, seems like the gas rams could be a bit troublesome and perhaps unreliable if purchased secondhand?

So are underlever springers easier to cock than break barrels?

 

[Bighit]

Ok thanks all for the replies, seems like the gas rams could be a bit troublesome and perhaps unreliable if purchased secondhand?

So are underlever springers easier to cock than break barrels?

The strut type can be problematic where as the HW90 or the Theobem ones can be serviced though the Theoben ones can be tricky to get parts for as they are no longer in production.

 

[Rich79]

Ok thanks all for the replies, seems like the gas rams could be a bit troublesome and perhaps unreliable if purchased secondhand?

So are underlever springers easier to cock than break barrels?

They're about the same as it's entirely dependent on how long the barrel/underlever is, if you get a really short underlever like an Airarms TX200HC it can be a bit arduous on extended range trips, but that's not because it's an underlever it's because it's short.

Underlevers are a bit more muzzle heavy for obvious reasons but a lot of people like the stability this offers, also the felt recoil reduction.

 

[ColinH]

They're about the same as it's entirely dependent on how long the barrel/underlever is, if you get a really short underlever like an Airarms TX200HC it can be a bit arduous on extended range trips, but that's not because it's an underlever it's because it's short.

Underlevers are a bit more muzzle heavy for obvious reasons but a lot of people like the stability this offers, also the felt recoil reduction.

thanks and understood

 

[martin st ledger]

Ok thanks all for the replies, seems like the gas rams could be a bit troublesome and perhaps unreliable if purchased secondhand?

So are underlever springers easier to cock than break barrels?

Definitely avoid a second hand sealed gas strut gun, a classic such as a Theoben that has a chargeable gas ram holds substantial residule value, even as a cabinet gun,
underlevers and break barrels each require close enough effort to cock so as to not make any difference whatsoever

 

[bflat7]

Any system that relies purely on stored air has leak potential , whearas a mechanical
system eg. spring, does not.

 

[ColinH]

Definitely avoid a second hand sealed gas strut gun, a classic such as a Theoben that has a chargeable gas ram holds substantial residule value, even as a cabinet gun,
underlevers and break barrels each require close enough effort to cock so as to not make any difference whatsoever

Thanks and understood