M14 DMR Advice Please, Hop Issue

[Alimcd]

Good morning,

I came for the free advice but I'm staying for the banter. Now that one build is pretty much problem free, it's time to sort out another slight niggle. Just before lockdown started I thought that I had put the finishing touches to an M14 DMR build. I think it's a thing of beauty, real wood stock, huge Hawke Optic and a nice paracord sling. Internally, its running nicely and smoothly at bang on 440fps (I removed the selector plate entirely, so the cut off lever always engages. Easy M14 Semi lock). Consistency is incredibly good and at this point, on my bench, I thought it was ready to skirmish...

Out in the field, I had nothing but feeding issues and inconsistent hop. Some drooping, some hopping and lots of odd fliers going off at all angles...

The Barrel is a Modify 6.01 and it was very good at an earlier skirmish, so I don't think its the barrel. The feed issues were down to the Mid-caps having 3 different feed springs inside each mag which have now been replaced with longer stiffer springs and now feed perfectly. So we can assume that the weird trajectory is down to the Hop Up unit right?

In the last batch of bit's I bought for this gun was a TM M14 Hop, Maple Leaf Macaron 70, Omega Nub. I've used the Maple leaf combo before and it all looks aligned properly, although I've not used such a hard rubber before. Do these need bedding in? It had only had about 30 rounds put through it when I was Chrono-ing it before it was skirmished pre-lockdown, could this be the source of the issues? Am I asking too much of a TM Hop to lift 0.36 or 0.4g BB's? It's my first attempt at a low volume of fire/higher effective range build and I'm sure that I'm missing something really obvious.

Ali

 

[Adolf Hamster]

as a general rule you can get most hop units to provide enough protrusion to lift ammo, although you may need to shim it out to be suited for the weight range you're using (eg on my makarov i'd have to shim between using 0.3's and 0.48's as the adjustment range isn't wide enough)

are you still getting consistent fps with the current setup or was that based on previous testing?

also pays to make sure everythings clean and you don't have something like a suppressor that the bb's are smacking into on their way out.

normally i'd run a softer rubber (40 or 50 degree) but that's more as a nod to a 1j limit, cold weather and heavy ammo so i'm not best placed to say if 70 is too hard for the build you're running.

 

[Alimcd]

Hi Adolf,

When I sorted out the mags on Monday I ran an entire mag’s worth through the chrono and consistency was very tight. 
 

I think I’ve got a habit of being slightly eager when it comes to grease and lube so it could be that the changes to the gearbox have been shooting airseal lube down the barrel! Do you have a recommendation on cleaning out the barrel, I had been using small, alcohol sterile wipes but saw Negative Airsoft’s video on how alcohol could potentially dry out and damage the rubber.

I’m leaning towards the softer rubber. When I last skirmished pre-lockdown it was a crisp 5-10 degrees in the morning and it was going between zero hop applied to perfect to too much in between shots without any adjustment.

 

[Adolf Hamster]

normally i just use a dry microfibre for barrel cleaning, if it's really bad i'll pull the barrel which lets me see if i've got it clean enough.