Turning Hop up Reduces FPS Too Much!

Asomodai

Asomodai

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Heya gents. 

Issue with my Real Sword T97s hop unit. I can actually see my shots being very slow. 

Stock barrel, stock hop unit. ML Macaron 50 degree bucking and Shore 70 ohm nub copy. 

Fires at 330 FPS on .2s

280FPS on .28's - > 330FPS on .2s

Add enough hop to lift .28's = 230FPS on .28's = 272 FPS on .2's. 

Losing that much FPS doesn't seem right to me. Range is not their either. Hop rubber is seated correctly and looks good. My T97b has the same Hop combination and doesn't have this problem. Ideas?

 
Why such a hard compound at a low FPS?

To gain your backspin (friction) using a harder compound means you need more pressure (hop applied) to achieve the same hop as a softer compound.

 
Davegolf said:
Why such a hard compound at a low FPS?

To gain your backspin (friction) using a harder compound means you need more pressure (hop applied) to achieve the same hop as a softer compound.
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the nub is hard but the bucking is a nice soft 50°

bit of a weird one, can't say i've noticed it on any of my guns, although granted i start at .3's and work up from there.

 
Further, are you chrono'ing the 28s with the chrono still on 2s?

If so your FPS reading is not all bad from a joule creep POV, obv you still don't want to lose that much FPS to your hop setting.

Adolf Hamster said:
the nub is hard but the bucking is a nice soft 50°

bit of a weird one, can't say i've noticed it on any of my guns, although granted i start at .3's and work up from there.
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Read the wrong way around!! FAIL!

I would still say something's not happy with that combo.

PS still don't like Macarons or Crazy Jets, don't get the hype or the results

 
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Davegolf said:
Why such a hard compound at a low FPS?
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50 is as soft as they go in that range actually and that should be the appropriate level for that fps level.

One thing you could try is experimenting with different nub options.. the two that come to mind are:

- an original ML omega if you have one handy.

- but before that I would try a little cut square of eraser/rubber in the nubs place; no need to round out the contact half of it either, just allow a flat contact patch which will push the base of the bucking slightly further down on to the BB than an omega, which might mean you could use a little less hop for the same result and get that fps up a bit.

 
Adolf Hamster said:
the nub is hard but the bucking is a nice soft 50°

bit of a weird one, can't say i've noticed it on any of my guns, although granted i start at .3's and work up from there.
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The nub is actually the softest possible. It's the AK2M4 copy made specifically because the stock ML nub is too hard for a macaron 50 degree. 

 
Asomodai said:
The nub is actually the softest possible. It's the AK2M4 copy made specifically because the stock ML nub is too hard for a macaron 50 degree. 
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i use ml's own nub in everything bar me m4 which is running the maxx r-block

possibly are you maybe adjusting past the sweet spot? i've had that happen where you kind of have 2 points of hop where the second is much more restricted.

 
Adolf Hamster said:
i use ml's own nub in everything bar me m4 which is running the maxx r-block

possibly are you maybe adjusting past the sweet spot? i've had that happen where you kind of have 2 points of hop where the second is much more restricted.
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I have tested it extensively with my chrono and a range. Unfortunately as soon as there is an obvious bit of hop the FPS is down to 230. It gets worse the heavier the bb you use of course.

I usually use .3s as well. 

 
Dumb theory:

There is an air leak that only shows up with heavier weights and the tiny bit of resistance the hop is creating.

Since a heavier BB requires more pressure to get moving, and the hop rubber has to protrude more than what it would be with a 0.2, I suspect there is something that holds air with the lower weight (low pressure) but then shits the bed when more pressure is required.

Maybe the nozzle isn't quite right for the new rubber.

Have you tried reverting to the standard rubber?

Heard ML macarons need a bit of modding.

I did have a similar problem on my ares m4 (was clocking at 1J on 0.2s and dropped to 0.6J on 0.25/0.28s, piston head wasn't sealing properly and it was leaking air with the heavier weights, should've been the opposite as the thing was massively overvolumed)

 
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Asomodai said:
I have tested it extensively with my chrono and a range. Unfortunately as soon as there is an obvious bit of hop the FPS is down to 230. It gets worse the heavier the bb you use of course.

I usually use .3s as well. 
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hmm, strange. it's defo not catching anything as it's being activated?

Skara said:
Since a heavier BB requires more pressure to get moving, and the hop rubber has to protrude more than what it would be with a 0.2, I suspect there is something that holds air with the lower weight (low pressure) but then shits the bed when more pressure is required.
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it's a decent theory, but 1j seems too low an energy and that setup should be good for even .48's with enough push behind it (admittedly all my .48 lifting guns are hpa's so a different pressure curve)

the ml macaron feed lips tend to be marginally longer than most other hops, but normally that'll be bad fps and awful feeding regardless of ammo weight.

 
Adolf Hamster said:
hmm, strange. it's defo not catching anything as it's being activated?
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Nothing that I can tell. I'm going to order a spare hop unit, new barrel and put in a Prommy purple I have spare. See if I can work it out. Have also ordered a Guarder clear and G&G green just in case the Prommy purple doesnt do the trick. 

 
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@Asomodai give me a shout if you want a want a spare nub for nowt, have some softer and harder ones you can try ?

 
@Asomodai - Stop having the same problems as me! First it was your M9 not hopping. Now this, which I experienced on a KWA RM4 which went from pretty much 350fps to barely 300 with hop applied.

 
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