Dmr Hop

[Pewpewpetie]

Hi again all, currently  having a frustrating time with my hop. Ive tried everything and i either get not enough hop or with minimal turn, over hop. Ive tried an r hop and maple leaf, still smame results. Ive also tried 2 different hops. The standard black cyma hop(dial type) and modify accurate. The gun is shooting 440/444fps on 0.2g bb. On game days i use 0.4g

 

[Skara]

A little more information would be useful.

 

[concretesnail]

With more info its a little hard to make any suggestions, but as a quick suggestion when it comes to the mapleleaf rubbers the omega nub can be a little too hard for some setups but ak2m4 had some omega nubs that were a softer durometer giving more sensitivity to the hop adjustment

 

[Pewpewpetie]

A little more information would be useful.

What info would you like?

Basically, there is no consistancy. Some bbs over hop and then the next shot may be perfectly straight, one after may swing to the right etc. I'm using a zci 455mm barrel and is clean. 

 

[BigStew]

What info would you like?

Basically, there is no consistancy. Some bbs over hop and then the next shot may be perfectly straight, one after may swing to the right etc. I'm using a zci 455mm barrel and is clean. 

Make and model of gun is probably what they are after. Though from your post I assume a cyma of some sort.

 

[Pewpewpetie]

Make and model of gun is probably what they are after. Though from your post I assume a cyma of some sort.

Yes, it's a cyma sr25.

 

[Pewpewpetie]

Here a view inside the hop. Everything seems to be seated correctly. It's a modify hop, zci barrel, omega nub. Barrel is wrapped in ptfe tape to give snug fit inside outer barrel. Also using asg precision 0.4g bbView attachment 76026

 

[Skara]

The hop window on the barrel looks to be slightly tilted and the hop arm seems to be offset to the right.

 

[Pewpewpetie]

The hop window on the barrel looks to be slightly tilted and the hop arm seems to be offset to the right.

Let me try and get a straighter view

View attachment 76028

The only shim I could fit on the right of hop arm is a 0.1mm

View attachment 76029

 

[Sneaky]

Could it be the quality of the hop rubber, might not be even which will cause deviations of the bb’s.

 

[Pewpewpetie]

Could it be the quality of the hop rubber, might not be even which will cause deviations of the bb’s.

I've tried an rhop, maple leaf macaroon with omega nub and standard Prometheus purple. The all do the same. 3 shots may fly perfectly and the next shot may curve left or over hop or curve right then straight again. I've ordered some Geoff's bbs to rule out quality issues

 

[Rogerborg]

I've never liked dial units, there's way too much slop and slack in the gears.  I'm not sure if the Modify unit is a dial or a rotary, given that it's about the worse name for a unit that you're trying to search for.

I'd agree with trying a softer nub, either the Gear Parts Omega 70 - in stock, amazingly! https://www.ak2m4.co.uk/internal-parts/hop-up-buckings-nubs/omega-nub-soft-70-gear-parts - or try a standard cylindrical nub.

You could also try a flat-hop style nub if you can find one, or make your own from sugru, RTV or plumber's silicone.

 

[Skara]

The lack of adjustment is something I've experienced a couple of times already.

Currently the maxx clone I have in my PDW goes from fuck all to skying 0.32s within one number (0 to 1) which makes adjusting the hop a bit of a chore. But it's not necessarily a bad thing

The lack of consistency is what worries me, I blame it on the hop unit, as mentioned by Borg the slack between the gears can have an impact on the pressure applied, so one shot flies fine, the next goes low because the arm managed to slightly rise, or vice versa, your first shot goes stupid high then it drops.

left to right deviation can be the hop rubber not being properly seated or just a dirty barrel (most noticeable in a tight bore of some sort).

I'd give the ZCI unit a go, it's inexpensive enough to try and the fact that it's rotary automatically makes it better than the fancy Modify you bought

 

[Pewpewpetie]

The lack of adjustment is something I've experienced a couple of times already.

Currently the maxx clone I have in my PDW goes from fuck all to skying 0.32s within one number (0 to 1) which makes adjusting the hop a bit of a chore. But it's not necessarily a bad thing

The lack of consistency is what worries me, I blame it on the hop unit, as mentioned by Borg the slack between the gears can have an impact on the pressure applied, so one shot flies fine, the next goes low because the arm managed to slightly rise, or vice versa, your first shot goes stupid high then it drops.

left to right deviation can be the hop rubber not being properly seated or just a dirty barrel (most noticeable in a tight bore of some sort).

I'd give the ZCI unit a go, it's inexpensive enough to try and the fact that it's rotary automatically makes it better than the fancy Modify you bought

I've tried a pro win rotary and a standard specna arms rotary. The modify accurate has a dial style, but the arm has teeth with connect to the adjustment area. I have. Tried marking with typex on the wheel and there was no movement. The modify also came with a flat hop arm which does the same thing. 

View attachment 76054

 

[Rogerborg]

Hmm, that is an interesting design.

If you turn the adjustment wheel by small amounts, left and right, can you see the final gear moving immediately, and directly?  What I've noticed (on a cheap stock CYMA unit) is that the turning it right, and then a fraction left, or vice versa, just initially takes up free space between the gears as they reverse, and that free space could be enough to let the hop arm move in use.  The Modify may be well enough engineered (I use that word loosely in the context of airsoft) to not have that issue though.

When adjusting a rotary, I got into the habit of ending the adjustment by adding hop, not taking it off: if I needed to reduce the hop, I took it back too far, then added more on, so that the gears were meshed and putting pressure on the hop arm, without any slack.

Then I binned it off for a ZCI rotary, and never looked back.  

 

[Pewpewpetie]

Hmm, that is an interesting design.

If you turn the adjustment wheel by small amounts, left and right, can you see the final gear moving immediately, and directly?  What I've noticed (on a cheap stock CYMA unit) is that the turning it right, and then a fraction left, or vice versa, just initially takes up free space between the gears as they reverse, and that free space could be enough to let the hop arm move in use.  The Modify may be well enough engineered (I use that word loosely in the context of airsoft) to not have that issue though.

When adjusting a rotary, I got into the habit of ending the adjustment by adding hop, not taking it off: if I needed to reduce the hop, I took it back too far, then added more on, so that the gears were meshed and putting pressure on the hop arm, without any slack.

Then I binned it off for a ZCI rotary, and never looked back.  

I'll Have to order a zci rotary unit and try