363mm/ 407mm barrel

[Pewpewpetie]

Hi guys, currently running a standard plastic rotary from specna arms in my specna bo3 dmr with 363mm 6.02 zci barrel firing at 415fps. I read some articles and discussions that a 400mm+barrel with 6.03 Inner diameter is best for a dmr for accuracy/range so I bought a madbull python 2, 6.03 407mm with a prowin hop and prommy purple, bb is dropping 25ft shorter then before. Is this theory true that I've seen around?

P.s I'm using .36g asg 

[Adolf Hamster]

Not enough hop by the sounds.

 

As a general rule apart from the extremes the length doesnt do much for accuracy.

 

As for nominal diameter its kinda secondary to quality of the bore, although i tend to preferr the tight side, after all why fight air leaks everywhere else in the gun only to let it out the front.

[Asomodai]

1 hour ago, Pewpewpetie said:

Hi guys, currently running a standard plastic rotary from specna arms in my specna bo3 dmr with 363mm 6.02 zci barrel firing at 415fps. I read some articles and discussions that a 400mm+barrel with 6.03 Inner diameter is best for a dmr for accuracy/range so I bought a madbull python 2, 6.03 407mm with a prowin hop and prommy purple, bb is dropping 25ft shorter then before. Is this theory true that I've seen around?

P.s I'm using .36g asg 

Have you got a full or ported Cylinder?

 

 

[Pewpewpetie]

11 hours ago, Asomodai said:

Have you got a full or ported Cylinder?

 

 

I have a full cylinder, internally I upgraded cylinder, piston and head, air nozzle. From what I have read I was under the assumption that slightly wider bore aloows less friction keeping a small cushion of air around bb allowing a straighter flight path and slightly further range

[ak2m4]

Did you try with the original hop and bucking?  Lot of theories floating around in Airsoft, but so many different variations of products what works well for one setup may not work well for another setup.  Trial and error, you've just hit an error 🙂

[Iceni]

On 26/12/2019 at 18:42, Pewpewpetie said:

madbull python 2, 6.03 407mm

Never had any luck with those barrels.

I have a 509mm one that seems to have an uneven inner coating. It doesn't jam, but it does like to drop short and throw BB's to the right all the time. I tried all sorts of tricks to get it right, nothing sorted it. Swapping to any other barrel corrected the issue. You can actually see the poor internal finish when you inspect it internally with a light source (it's pitted).

Typically my go-to barrel is the ZCI 6.02, It's cheap, and takes a decent finish if you lap them.

The main things to look for in a barrel are straightness and internal finish. Bare metal brass and stainless barrels are the best. Those metals are hard enough to not wear and scratch with clean BB's, The surface will polish and can be polished.

Coated barrels, on the other hand, are an exercise in cost savings by manufacturers. They use softer materials like aluminium and apply a coating over a rougher finish. The coating also wears out.


 

[Adolf Hamster]

5 hours ago, Iceni said:

You can actually see the poor internal finish when you inspect it internally with a light source (it's pitted).

 

Thats shockingly bad, note to self- their barrels are as bad as their hop units.

[Iceni]

11 minutes ago, Adolf Hamster said:

Thats shockingly bad, note to self- their barrels are as bad as their hop units.

I can't say that all or even most of those barrels are bad. Mine was.

I do shoot at max range a good percentage of the time, If I were only shooting at max 40 meters you would not be able to tell there was a problem. It's only when I try to dial it in for range it shows. If I only shot CQB and short field sites it would be fine.

That's also not saying ZCI are perfect either. Out of the box, they work well, but only get good if you put time into them. Polish the insides, Deburr the hop windows ect. I put at least a couple of hours into a new barrel with micron diamond lapping pastes to get them where I want them, You can't go all out with a coarse grit paste either as you will oval the cross-section. You have to work slowly with fine pastes over time.

You need to start at about 3 microns (3,000 grit naniwa) and work in steps down to about 0.5 microns (30,000 grit). To put that into perspective most house knives are sharpened at 11 microns (1000 grit) with Japanese knives getting the extra edge going to about 3 microns (3000 grit). It's the difference in a smooth surface and a lapped surface.

[Adolf Hamster]

10 hours ago, Iceni said:

I can't say that all or even most of those barrels are bad. Mine was.

I do shoot at max range a good percentage of the time, If I were only shooting at max 40 meters you would not be able to tell there was a problem. It's only when I try to dial it in for range it shows. If I only shot CQB and short field sites it would be fine.

That's also not saying ZCI are perfect either. Out of the box, they work well, but only get good if you put time into them. Polish the insides, Deburr the hop windows ect. I put at least a couple of hours into a new barrel with micron diamond lapping pastes to get them where I want them, You can't go all out with a coarse grit paste either as you will oval the cross-section. You have to work slowly with fine pastes over time.

You need to start at about 3 microns (3,000 grit naniwa) and work in steps down to about 0.5 microns (30,000 grit). To put that into perspective most house knives are sharpened at 11 microns (1000 grit) with Japanese knives getting the extra edge going to about 3 microns (3000 grit). It's the difference in a smooth surface and a lapped surface.

 

 

yeah, i have a zci in the e&l but i havent got it shooting well enough for the barrel to play too much of a role in accuracy.

 

lapping is something i do plan on giving a go at some point, suppose i'll maybe give it a go on the zci see what results i can get, worst case i'm planning on maybe going edgi for the m4 so can donate it's pdi to the cause if i screw up.

[PopRocket123]

ZCI is my go to inner barrel. My dad and I have them in most of our guns and have never had an issue. As others have said they're not flawless and need polishing but I run my primary with a 310mm R hopped ZCI with an old ASG hop until I can afford a MAXX and it puts .28s accurately out to around 60-70m at 1.1J