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Rob Allen 120 railgun band / shaft configurations

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Nicholas1986

Member
Oct 27, 2016
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Hi Guys,

I have a 120 RA railgun. 2 x 14mm green bands cut to 70cm each. 160cm x 7mm shaft (0.49kg). I am interested in playing around with different configs and I'd like to know if anyone out there has done the same or has any opinions/advice:

Option 1: Switch to 7.5mm x 150cm shaft (0.515kg) - I think the shaft will be Can I use the same 14mm rubbers with good performance? Or would I need to change to 16mm bands.

Option 2: Switch to 7mm x 150cm shaft - Can I use the same 14mm rubbers as is? Or will the shorter lighter shaft be overpowered?

Option 3: Install Meandros Reverse Trigger mech - Will I have to change the length of bands (using same shaft)? Can I use the same rubbers without overpowering (as there will be some more band stretch)?
 
I shoot a RA 110 with 140x7 shaft and 2 14mm bands. It's very accurate and is not overpowered. If you go up to a 7.5 shaft, you might need the 16mm bands.
 
Reactions: mariusshobo
NicholasCLF said:
I have a 120 RA railgun. 2 x 14mm green bands cut to 70cm each. 160cm x 7mm shaft
Click to expand...
Looks good as it is, even if the shaft is a little long for 7 mil dia. But if it is accureate, then ... good.

hteas said:
I shoot a RA 110 with 140x7 shaft and 2 14mm bands. It's very accurate and is not overpowered. If you go up to a 7.5 shaft, you might need the 16mm bands.
Click to expand...
This setup loks perfect.

My setup : gun 120cm, 150cm 7mil shaft + 2 x 14 mil Primeline bands. The 14 mil primeline's works better then 14.5mil Sigalsub Reactive on this shaft.

NicholasCLF said:
Option 1: Switch to 7.5mm x 150cm shaft (0.515kg) - I think the shaft will be Can I use the same 14mm rubbers with good performance? Or would I need to change to 16mm bands.
Click to expand...
I would try 14mm rubbers, but considering also 14.5mil Sigalsub Reactive (the brown ones). Even the diameter is almost the same, the Sigals are somehow stronger ...

NicholasCLF said:
Option 2: Switch to 7mm x 150cm shaft - Can I use the same 14mm rubbers as is? Or will the shorter lighter shaft be overpowered?
Click to expand...
14 mil mands shoud be ok.

NicholasCLF said:
Option 3: Install Meandros Reverse Trigger mech - Will I have to change the length of bands (using same shaft)? Can I use the same rubbers without overpowering (as there will be some more band stretch)?
Click to expand...
? I do not know. You have to try it. Just make longer dineema wishbones and adjust them till you find the sweetspot.

Make a target for the water, spend a morning trying different setups and see what works. That is the best way to figure it out.
 

I have a 110cm with a 150cm x 7mm shaft. I think I'll put it on the 120cm gun and play around with it. I heard that sometimes it is harder to aim with a shorter shaft...
As for the rubber, its RA rubber and if I'm not mistaken, he uses primeline rubber.
 
If I could make a suggestion...

How you chose to set your gun up generally depends on how you use it... and what your loading abilities are.

For the Rob Allen 1.2M with a 160cm 7.5mm shaft I would run either twin 16mm rubbers or if you don't have loading difficulties a tight 20mm or 18mm single rubber would be fine also... the advantage of runing a single larger diameter rubber is reasonable power and a much faster reload.

DM
 

I'm using 7mm shafts. I just bought some small id 14mm to try out. I also have a piece of 18mm as well that I could try.
 
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