Rotek for 449

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Who_needs_powder

Who_needs_powder

Member
Apr 7, 2019
172
25
PA, United States
Umarex has the Walther Rotek for $449 and free shipping. One heck of a sub $500 deal! Only in .177 though.

Screenshot 57.1598964012.png

 
Something doesn't quite sound right 24 shots per fill from a Rotex 200cc bottle in 177.

The 177 Umarex Gauntlet 213cc has a lot more shots than that.
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Yes, I was unimpressed with the apparent number of initial shots with the rifle, so I refilled to 232 Bar and chrono'd from first to last. Didn't save the strings but saw FPS start to tail off pretty significantly around shot #22-23.

Will repeat just to make sure. Seems to me that reg is set to about 160 Bar. So far I have fewer than 50 shots through this rifle - maybe things need to break in.
 
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Rotex has a 19.69" vs 23.5" Gauntlet barrel and the Gauntlet is set at 1100psi 75.8bar IIRC or maybe 1300psi 89.6 bar I forget but I think 90 or 100bar maybe 80bar if you don't need high power and get a lot more shots with the shorter barrel would do just fine for a 177. I would first try backing down the power adjuster via lessening the hammer spring tension because you are probably wasting a lot of air right now.


 
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Well, out-of-the-box I have confirmed that my .177 Rotek gets maybe 25-27 consistent shots. I have not made any changes to the gun, like backing off the hammer spring as suggested above. I just wanted to confirm what I thought I had seen in my first shooting session with it yesterday.

Started off with a full bottle per the higher resolution gauge on my compressor. 232 Bar on the compressor gauge was closer to maybe 245 Bar on the gun's gauge, if I had to guesstimate. Bottle values were: 220 Bar after 8 shots, 200 Bar after 16 shots, 180 Bar after 24 shots, 155 Bar after 32 shots, 150 Bar after 40 shots, 140 Bar after 48 shots. Was shooting JSB Exact Diabolo, 8.44 gn pellets, straight from the tin.

Following is the chart of pellet speed in FPS from the string of 48 shots. Waited at least 5 seconds between shots in case the regulator needed to 'recover'.

Rotek.1598996325.jpg


Maybe not how they all are, but this is how mine is out of the box (purchased directly from Umarex).
 
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Well, out-of-the-box I have confirmed that my .177 Rotek gets maybe 25-27 consistent shots. I have not made any changes to the gun, like backing off the hammer spring as suggested above. I just wanted to confirm what I thought I had seen in my first shooting session with it yesterday.

Started off with a full bottle per the higher resolution gauge on my compressor. 232 Bar on the compressor gauge was closer to maybe 245 Bar on the gun's gauge, if I had to guesstimate. Bottle values were: 220 Bar after 8 shots, 200 Bar after 16 shots, 180 Bar after 24 shots, 155 Bar after 32 shots, 150 Bar after 40 shots, 140 Bar after 48 shots. Was shooting JSB Exact Diabolo, 8.44 gn pellets, straight from the tin.

Following is the chart of pellet speed in FPS from the string of 48 shots. Waited at least 5 seconds between shots in case the regulator needed to 'recover'.

Rotek.1598996325.jpg


Maybe not how they all are, but this is how mine is out of the box (purchased directly from Umarex).
Click to expand...

I would back it down to shoot 860-880fps. Should get a lot of shots. 
 
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...I know it’s a truck gun but with some tuning it might be a real nice gun.
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It is the ability to tune (beyond varying pellet weight) which will seemingly be an issue here. Aftermarket regulators (generally for more power) are available - for 2/3 the price I paid for the whole gun. Apparently the OEM regulator is locked out from adjustment. Even replacement parts (for the Walthers) seem to have a very limited availability through Umarex in the U.S. So if I start cutting coils off the hammer spring and screw up...

The gun generally seemed pretty accurate for what it is even when shooting pellets at pretty hot speeds. Maybe heavier pellets will be even more accurate, and then I will just accept that it is a 3-magazine-then-refill gun.
 
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If you can be happy with a bottle gun that only gets 24 shots, that’s great. I wish I could but I’m cursed. If you don’t want to get into major surgery, and I completely understand, I would at least take a peek at the hammer spring. If it’s not adjustable, I would measure it’s diameter, length and wire thickness. Take those measurements to a good hardware store that has springs and look for one or a couple you can play with. If you find a shorter one or one with thinner wire that brings your velocity down where it needs to be, it may be a slightly jacked up tune with that reg still at 160b, but you will have way more shots. And the gun will sound waaaay better.
 
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Worst case scenario is you go to ACE Hardware and match couple spare an equal and others less strength springs like AHEM! "VETMX" said and longer is fine just trim then heat that chopped end with a torch or gas stove then press that hot end on a flat surface make perfect.

I would try to lessen the hammer spring tension as-is first over a crony and see how it does first.

I wouldn't try to adjust the factory regulator and negate their lifetime warranty.

Screenshot_2020-09-01-20-54-132.1599029761.png



 
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