Falling short

[MDC]

Hi there. After some advice please. M4 with Ultimate/Lonex gearbox, ultimate hop-up, Maple Leaf barrel, Prometheus purple hop rubber..365 on .20 . I’ve been using.28 ammo but range not brilliant and seems to curve off to the left. Should I be using a heavier weight ammo? Thanks.

 

[Haru]

check if your hop rubber and barrel is attached properly

 

[MDC]

check if your hop rubber and barrel is attached properly

It’s correctly fitted, I’ve even wrapped ptfe tape around hop unit to barrel for a proper air seal.

 

[MrTea]

Curve to the left could be something as simple as you holding the gun canted. A lot of people make this mistake. It's possible you twisted the barrel in the hop when reinstalling so it's not applying hop evenly to the BB.

As for range, how short are we talking? A lot of people expect their AEG to be shooting 100m+ when they should be expecting about 50-60m for a well tuned, well maintained AEG. I always use 0.28G BBs when playing outdoors and have no issues with range.

 

[Lozart]

365 FPS? I take it you're locked to semi then?

Check the barrel is properly in line in the hop unit (take it out and look down it - check the hop mound is actually central and not lopsided), make sure the barrel is, in fact, straight along its length as well (roll it on a flat surface and check it lays flat.

Clean your barrel

Use better ammo.

 

[Skara]

Is the hop rubber new? Or have you used it already?

Prommy purples *were* good hop rubbers but now I think there is no point in using them anymore, Maple Leaf ones are much better at lifting 0.28g+ BBs and are cheaper.

 

[The_Lord_Poncho]

Check the barrel is properly in line in the hop unit (take it out and look down it - check the hop mound is actually central and not lopsided), make sure the barrel is, in fact, straight along its length as well (roll it on a flat surface and check it lays flat.

To add to this - you mention that you have applied PTFE to the hop rubber - I've needed to be careful when doing this myself in the past, as you keep the tension on the tape as you wrap, it can pull the rubber around the barrel so that the mound is not sitting centrally in the window. End result, more hop applied to one side of the BB, meaning it curves off during its flight.

 

[Adolf Hamster]

To add to this - you mention that you have applied PTFE to the hop rubber - I've needed to be careful when doing this myself in the past, as you keep the tension on the tape as you wrap, it can pull the rubber around the barrel so that the mound is not sitting centrally in the window. End result, more hop applied to one side of the BB, meaning it curves off during its flight.

To add to this adding to this.

When adding anything on the outside of the hop bucking when pushing the barrel into the hop unit it can create too much pressure on the bucking pulling it forward on the barrel.

It will be hop unit dependant, some buckings eg maple leaf have intentional ridges to provide a bit more pressure, and some hop units are intentionally tight, even too much so (looking squarely at you madbull).

 

[Skara]

Also, make sure you have the correct length nozzle, sometimes they can feed/seal fine while still being off spec (meaning they'll seat the BB in the wrong place, leading to inconsistencies and weird trajectories).

 

[MDC]

365 FPS? I take it you're locked to semi then?

Check the barrel is properly in line in the hop unit (take it out and look down it - check the hop mound is actually central and not lopsided), make sure the barrel is, in fact, straight along its length as well (roll it on a flat surface and check it lays flat.

Clean your barrel

Use better ammo.

I built this gun 25 plus years ago, guns weren’t chrono’d back then, and long before UKARA existed. 

 

[Colin Allen]

I built this gun 25 plus years ago, guns weren’t chrono’d back then, and long before UKARA existed. 

This is now, not 25+ years ago.  If you are playing at AP and the vast majority of sites, it needs to be running at or below 350fps on a 0.20g BB.  Regardless of the weight you are using, you need to be at or below 1.13J.

 

[MDC]

This is now, not 25+ years ago.  If you are playing at AP and the vast majority of sites, it needs to be running at or below 350fps on a 0.20g BB.  Regardless of the weight you are using, you need to be at or below 1.13J.

Yes, I am aware it’s running hot hence not used it at AP. 

 

[Rogerborg]

It's possible you twisted the barrel in the hop when reinstalling so it's not applying hop evenly to the BB

I'd go with that as a working assumption, or the PTFE shenanigans has skewed it.  Pull it apart and put it back together before assuming anything is seriously wrong.

 

[Leo Greer]

First off, if you built this RIF 25+ years ago, have you checked inside it for any issues? Is the hop rubber still fresh and soft?

Second, what ammunition are you using? BB quality is a big deal.

Third, you shouldn't ever need PTFE tape on an AEG. That mod originated for VSR cut barrels and hop rubbers, where the design allows air to balloon the hop packing and cause a leak. If the hop unit is loose on the rubber, then yes, you should wrap the rubber/barrel in layers of tape for stability, but that's a spec issue at heart, and I would suggest finding a rubber or unit that fits better.

Fourth, this issue could be something as simple as the nub or hop arm having shifted, putting more pressure on one side of the rubber. In order for us to give you better advice, I'd suggest disassembling your barrel group, testing and feeling everything, and post pictures! Give us the details and the nitty gritty.