Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
- 941
It's been oooohhhh so long since I actually started a topic, but I think I have reason to today.
A while ago now I bought a custom made L129A1 based on an A&K SR25 URX, and since then I have wanted to put a Polarstar into it, because it only came shooting at 300fps and it was a pile of cack.
I have skirmished it once and with it only firing at 300fps, the obscene weight of it was just too much considering it's immeasurable crapness.
Well today, the dream became a reality and I finally got a Polarstar into it.
A long time ago I started a topic regarding whether or not fitting a Polarstar into an SR25 was even possible, due to Polarstar Fusion Engines all being standard sizes, but SR25s using longer, 7.62mm style receivers; and obviously a standard V2 and hop configuration would only fill the same space as a regular 5.56mm receiver.
So to get it to actually fit, I had to a buy a G&G SR25 hop unit, and the Polarstar G&G SR25 air nozzle. The G&G SR25 uses a standard V2 gearbox and long hop and nozzle configuration; so that made up the gap you get from using a standard V2 size Polarstar in a longer receiver.
However, the G&G hop didn't fit properly, so I had to remove 4mm from the back of it, which also meant I had to remove 4mm from the front of the nozzle (the highly accurate digital callipers came out).
So with the power of a Dremel tool me and my mate Joe managed to get the length PERFECT on the first attempt, we crowned off the nozzle, rounded the edges to get rid of any sharpness, and voilà.
With a black nozzle we're getting about 425fps at 120psi, meaning it's firing nicely at 350fps on .30s, it may actually be more due to the barrel being a .01mm tightbore, so there'll likely be a degree of joule creep, but we've only chrono'd on .20s so far.
But shooting nicely it is, nicely, for at least 60m with a respectable, rough 1.5ft grouping.
1.5ft actually sounds terrible now I've put it on paper, or internet space...? But without looking through an optic you'd watch the shots going down range and be thinking, "Well, being on the wrong end of that would be shit" because it's only once you see it through a scope that it looks as bad as it sounds, and don't forget, 1.5ft is about as wide as your average person, and most of the grouping was out along the vertical axis, which means it's pretty much down to hop inconsistency.
But! The target was a 6x4" metal plate and mounted about 10m higher than the firing position, so a man ought to be a doddle to hit at around 70m I reckon. But we'll have to wait until the weekend to see how it actually performs in a game situation, the true test will be when there's only an arm visible around a tree at those sort of extended ranges.
Personally I think it'll be better once the hop's had a chance to better bed in, I'm using a Madbull red rubber with the stock nub at the moment, but R-hopping it with an expensive Prommy barrel is very much on the cards at some point down the line.
Before I get the funds for that I'll be trying a much more rigid H nub though I think, since the stock nub is squidgy as all hell, which I don't imagine is great for consistency, and almost definitely the cause of all the fliers.
Not been this excited about using a gun since my first ever purchase
Oh, and here's a reference photo of the real one it's based on:
A while ago now I bought a custom made L129A1 based on an A&K SR25 URX, and since then I have wanted to put a Polarstar into it, because it only came shooting at 300fps and it was a pile of cack.
I have skirmished it once and with it only firing at 300fps, the obscene weight of it was just too much considering it's immeasurable crapness.
Well today, the dream became a reality and I finally got a Polarstar into it.
A long time ago I started a topic regarding whether or not fitting a Polarstar into an SR25 was even possible, due to Polarstar Fusion Engines all being standard sizes, but SR25s using longer, 7.62mm style receivers; and obviously a standard V2 and hop configuration would only fill the same space as a regular 5.56mm receiver.
So to get it to actually fit, I had to a buy a G&G SR25 hop unit, and the Polarstar G&G SR25 air nozzle. The G&G SR25 uses a standard V2 gearbox and long hop and nozzle configuration; so that made up the gap you get from using a standard V2 size Polarstar in a longer receiver.
However, the G&G hop didn't fit properly, so I had to remove 4mm from the back of it, which also meant I had to remove 4mm from the front of the nozzle (the highly accurate digital callipers came out).
So with the power of a Dremel tool me and my mate Joe managed to get the length PERFECT on the first attempt, we crowned off the nozzle, rounded the edges to get rid of any sharpness, and voilà.
With a black nozzle we're getting about 425fps at 120psi, meaning it's firing nicely at 350fps on .30s, it may actually be more due to the barrel being a .01mm tightbore, so there'll likely be a degree of joule creep, but we've only chrono'd on .20s so far.
But shooting nicely it is, nicely, for at least 60m with a respectable, rough 1.5ft grouping.
1.5ft actually sounds terrible now I've put it on paper, or internet space...? But without looking through an optic you'd watch the shots going down range and be thinking, "Well, being on the wrong end of that would be shit" because it's only once you see it through a scope that it looks as bad as it sounds, and don't forget, 1.5ft is about as wide as your average person, and most of the grouping was out along the vertical axis, which means it's pretty much down to hop inconsistency.
But! The target was a 6x4" metal plate and mounted about 10m higher than the firing position, so a man ought to be a doddle to hit at around 70m I reckon. But we'll have to wait until the weekend to see how it actually performs in a game situation, the true test will be when there's only an arm visible around a tree at those sort of extended ranges.
Personally I think it'll be better once the hop's had a chance to better bed in, I'm using a Madbull red rubber with the stock nub at the moment, but R-hopping it with an expensive Prommy barrel is very much on the cards at some point down the line.
Before I get the funds for that I'll be trying a much more rigid H nub though I think, since the stock nub is squidgy as all hell, which I don't imagine is great for consistency, and almost definitely the cause of all the fliers.
Not been this excited about using a gun since my first ever purchase
Oh, and here's a reference photo of the real one it's based on:
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Gonna get the tank filled and have a play over the next few weeks getting my M700 running on air before sorting HPA for my G5 with a hi-cap 
