DBoys SPR tech advice needed

[Babyalien]

Well, the long and short of it is that I (eventually) received a DBoys SPR Mod 0 I purchased on here. The listing stated "the range and accuracy are amazing and has never let me down" as well as "near perfect condition never seen a skirmish or any real use". I found another post from some time ago started by the seller describing a jamming/double feed issue he needed to sort which after contacting him, he assured me this issue was fixed so purchased it in good-faith as I had wanted one for ages,but not so. Test fire results are that the double feed issue is still present, every 5-10 shots or so and shots seem slightly to the left and down no matter how much the scope I bought is adjusted to compensate. I have cleaned inside the barrel and inside the hop chamber (via the magwell/down the barrel) with a cleaning rod+cloth+ silicone spray and no massive change really.

I have read the hop can be an issue with double feeds and so intend to strip the hop unit and replace the hop rubber at the same time as I want it to be an effective DMR rifle, not to just look on the bi-pod in the Safe Zone. I have looked at the Madbull Shark Hopup Bucking (Black): Rubber + Silicon + "X" Type Spacing set which from the description seems like a good purchase but hop rubbers/nubs are something I have no knowledge/experience of so need some help or advice on these please.

Also, not sure if this is inherent with the DBoys or not (presumably not) but when looking down on the front handguard/barrel, the gas tube/flash-hider appear to be very slightly off-centre, would this suggest the gas tube style outer barrel has been bent slightly or it this something that can be straightened up with an adjustment (I have already tightened down the lock-ring which threads on to the receiver body) which solves the barrel wobble but now means the rod from the front sight no longer locates correctly in to the hole in the top of the upper receiver front. Though I am not certain of this, it doesn't look like it will cause any issues, correct me if I'm wrong, but I have removed the front sight at present anyway.

I will eventually go with a 6.03mm tight-bore barrel amongst other things but at this time I want to iron out the issues I have before pumping money in to bigger upgrades and if needed, can I buy a replacement gas tube/outer barrel part from another manufacture as can seem to locate the DBoys spare I may need. Any advise will be greatly appreciated.

[steven seagull]

Hi, I had the same rifle only the A&K version, the hop unit and rubber were terrible. I fitted an element airseal m4 hop unit and an shs white rubber and the fps increased by 30, the range was amazing. Still to this day i haven't had a rifle with that kind of range. I also recommend fitting an element h nub with this set up(2 in a pack, use the white one). Regret selling this gun, once you fix the hop they are brilliant!

[Babyalien]

Re: DBoys SPR tech advice needed

OK, sounds good, thanks. Is this polycarb Element Hop Unit not a step back as it is poly instead of metal like the standard one or is it a case that the poly unit is so good, being polycarb is not an issue? Also, as for hop rubbers, what is the difference/effect of a hard or soft rubber and in the event of not being able to get hold of a SHS white rubber what alternatives should I consider. Do you think these upgrades will held straighten the shots that are currently off to the left?

[cannon_fodder]

Re: DBoys SPR tech advice needed

I have worked on 2 of these, Both DBoys SPR Mod0,

First of all don't panic, its not a complete lemon, In fact they are nice guns once you get used to the wieght (too heavy for me )

The parts are OK but the build is terrible. Both mine and my mates SPR were put together wrong and had screws missing. (EG my barrel was inserted incorrectly and was on the piss causing the hop to be crooked causing miss feeds + jammed mags
The hop unit and rubber is shit (yes I know its nice shiny metal but its still shit )
The gearbox, gears, piston and spring are great but the gearbox has been assembled and shimmed by blind chimp with the shakes.... Ill-fitting nylon bushings don't help so the gearbox will lock up at some stage.

Take it apart and put it together properly. A new hop + rubber . Rebuild the gearbox with 7mm bearings and your done

We both bought these new so the shop supplied some of the repair bits free and it didn't take long to get great performance out of these guns.

[steven seagull]

re-shim and grease is a must and some new bearings 7 mm i think check out you tube for a step by step guide, this was the first v2 gearbox i worked on. The plastic hop is no step backwards it gives a far better seal than the original.I will probably. Pm you some info :-)

[Babyalien]

Re: DBoys SPR tech advice needed

Guys, I just want to say a massive thank you for your help and advice (no homo though) so I think I have a selection of parts I may go with following what you have said.

1. Element Air-Seal Hop-Up Chamber
2. Element H-Hop
3. ***** Airsoft White Hop rubber as apparently similar to silicone hop rubbers but harder compound (*****=certain manufacturer who is also a trader but can't mention name ;0)
4. Shim set (not sure which yet)
5. 7mm Bearing Set (not sure which yet but maybe Systema OILLESS Bushings/SHS/G&P)

6. 6.03 Tight-Bore barrel eventually (most likely a Prommy or Systema).


Any thoughts on the above? As for shimming- this is something I have never done and after searching for shim sets, I am slightly bewildered as there are many different brands and sizes available. Does anyone know what I will need for a V2 M4 gearbox?

[steven seagull]

Sounds good, you can buy shim sets with various thickness, then just follow one of the you tube guides it's not as hard as you may think, if your technically minded at all you will be fine

[Babyalien]

Re: DBoys SPR tech advice needed

Well I certainly like to think I'm pretty technically minded so after watching some video's on YouTube (now I get it) I think I should be able to manage shimming. Gonna go with a set that has 0.1mm and 0.2mm shims as these seem to give good sizes which allow minor adjustments due to the thin measurements. Think I will try these: ULTIMATE SHIM SET from a certain retailer as you get 10 of each size.

Think I will hold out on buying a new outer barrel for now until I have stripped and rebuilt everything to see how it all sits and fires.

[steven seagull]

Make it so! :D

[steven seagull]

Spr pic's

[Babyalien]

Re: DBoys SPR tech advice needed

Nice, liking that! Love the silencer. This is a future external upgrade I have considered. What sling are you using there and does it attach via the scope towards the front? Funnily enough, it doesn't look too dissimilar to mine, until I lay some paint down on it at least. You even have roughly the same eye relief position of the scope. See pics below. Excuse the slight grain to the images, these are all I have at the moment and they were taken on my HTC Desire instead of the missuses DSLR which I normally use.

[steven seagull]

Nice! Think it was a viper 3 point sling, it attaches to the stock and i used the forward scope mount and it was pretty well balanced

[steven seagull]

Just got a new toy sr25k