Rohm Twinmaster - velocity adjustment?

Mike S-J · Post by **Mike S-J** » Sun Oct 22, 2006 7:15 am

Hi all,

My club has just unearthed a Rohm Twinmaster Top in the bowels of the armoury. A useful bit of kit for junior shooters, so I thought I would clean it up.
Perfect working order, apart from the fact that it tears holes in the target - suggesting its a bit slow (or?).

The operators manual gives no clue as to how to adjust the velocity.

So my questions are:

Is it better to send it off for adjustment because its just too hard to change? or

Is there a screw behind the grip somewhere that can be easily adjusted?

Any advice gratefully received.

Mike

JulianY · Post by **JulianY** » Sun Oct 22, 2006 9:52 am

Check it on a chronograph
Dont know if it will help but the manuals are available at http://www.roehm-rg.de/

page 18 of the manual does say;

"The TWINMASTER can be used as a single loader using the single-shotmagazine. The loss of propellant is minimised by using a smaller gap size. This increases the projectile speed."

J

Fred · Post by **Fred** » Sun Oct 22, 2006 10:48 am

Mike,

The following is based on my (sometimes faulty) memory, but FWIW, I do remember seeing two radically different velocities listed in ads for the Twinmaster Top. They were on the order of 400 and 480 fps, as I remember. The one I tested was definitely closer to the 480 mark. I wonder if there might not be two different variants? At the 400 fps level, you are getting close to paper tearing speed. Or, it's possible the ads were wrong.

HTH,
FredB

JulianY · Post by **JulianY** » Mon Oct 23, 2006 4:05 am

Just a thought but what pellets did you put down it, they wernt rifle pellets were they? Are you firing it with a co2 conversion ?

Try some nice light rws r10 pistol you may find that solves the problem, but chronograph is the real way to go

J

Mike S-J · Post by **Mike S-J** » Mon Oct 23, 2006 9:24 am

Good thinking Julian,

Unfortunately I had that base covered - albeit unwittingly - they were 4.5mm R10s.

I think you may have hit the nail on the head with your earlier posting though - the single pellet cassette design is such that a fair amount of air must be pushed out of the gaps - and there is nothing that can be done about that vis-a-vis the cassette.

I am going to try firing slightly less snug (4.48mm), light pellets tonight in the hope that less air is lost.

If that doesn't work then the beginers are just going to have to put up with less-than-perfect holes.

I guess there is no way to fine tune the velocity on these budget guns.

JulianY · Post by **JulianY** » Mon Oct 23, 2006 1:47 pm

Mike S-J wrote: If that doesn't work then the beginers are just going to have to put up with less-than-perfect holes.

I dont think they will notice :)

as long as it is consistant they have a great learning tool

J