Standard measurement for accuracy
 

I was trying to find out where my Kraken stood in terms of its accuracy, and what barrel I could switch to. I found that most of the stuff on accuracy of various barrels is very subjective, based on the guy shooting by hand and the terms describing groupings and distance are pretty variable.

I also found that it's rather hit and miss with tightbores and stock barrels: the accuracy depends ultimately on the barrel itself, not the make of barrel. Some stock TM barrels outshot some tighbores in terms of accuracy, and some tighbores turn out to be lemons. Some other airsoft site said that the very used (many tens of thousands of bbs) stock barrels of any make are the most accurate, when they are highly cleaned.

I was wondering if there is some kind of standard measurement for accuracy for barrel/hop-up combinations? For example, a gun held on a vice or stand can shoot a grouping of X inches at X feet, with X brand of bbs. Such a standard would be useful. Then we would know if we have a duff barrel or if we got lucky and it's not worth switching to a tighbore, for example.

another question:
What grouping do stock Tokyo Marui AKs manage at 60 feet, gun held fixed firmly as possible, with good bbs? I am assuming TM barrels and hopups are at least fairly consistent in terms of QC, so they can reliably post results with a low standard deviation?

None exists as far as I know. Airsoft guns are so inherently innaccurate that it would almost be pointless. So many factors can screw with accuracy -weight of BB, hop-up, slight wind, etc. There are too many variables to try and compansate for to make a proper baseline. Add to that the fact that a certain barrel type might perform great in a stock gun but really shitty in the same gun with certain mods... it's just too much data you can't account for.

I think what we need to do is to formulate a standard whereby all accuracy tests are performed under. ie: distance, fps, performed indoors, bench rested, parts used in the setup, bb used, accurately measured groupings, etc... Then whack it into a spreadsheet and start overlapping the similarities between the tests. After a boatload of tests, data should start emerging where we can actually point to parts that are consistantly better than others. Wouldn't be too difficult, as it would only take a little while to do a gun with different bb's and/or weights. If enough people participated we'd have a ton of info really quick.

I agree. There must be enough people with access to an indoor range of up to 100 feet to make it possible to generate data. The data management would be a bit labour intensive, though.

Off the top of my head,
I would say 100' for most AEGs is getting toward the end of your effective range. 230' for most bolt rifles and semi-only upgraded AEGs. 300' for highly tuned bolt guns and this requires a fair amount of know how. A man sized target should be considered for these estimations. I am also assuming that hopup and BB weight is also correct.

TBBs can make a difference but hopup is where its at. TM, Prometheus and Firefly make great AEG hopups. TBBs can also be used to increase velocity as an alternative to upgrading a spring. Of course a spring will give you more control in obtaining a target FPS.

mateba

Yes, I forgot to mention weight of bbs. Or did you mean the bbs themselves vary?

If tests are performed indoors wind can be eliminated.

So you are suggesting it is better to just experiment with various parts combinations until you maximise the accuracy of your setup? It's hard to know what to upgrade to when a particular barrel that worked great for some guy does not do much for another.

Really, though, I think we can create a benchmark against which to measure your set up - some kind of golden standard - if a load of people did a 60 foot grouping test with a benched gun indoors with KSC 0.2s, we could see what individual gun had the best accuracy and what gun was the worst, and where our setup falls in the grand scheme.... sort of like a league table.

Also, some guns are inherently more accurate by design than others. A stock TM MP5 will always outshoot a stock TM Armalite, simply by the design and the way the inner barrel is held. Armalite is "held" at the hop up unit, between a spring in front of it, rails at the sides and the mechbox at the rear. And that's about it. MP5 is screwed to the body, is helf by a clamp in front of the body, then also held inside the muzzle, so it has three points of security vs. the single point of an Armalite.

Accuracy, I do it all at 30ft in my basement, is a pretty damn good way to do it too. If there is a tight group at 30ft, that will give an idea of tightness of your BBs at 100ft (remember, small things become large things). Some guns will make a CD sized grouping at 30ft (new G&P SPR for example) and others will put 5-6 semi shots into a 1" hole at that distance (my MP5s are an example, and a SIG 552 I recently installed a tightbore into).

And heavier BBs will always be more accurate too, even at said 30ft.

Thanks! so if you can land most shots at 100 feet into a man sized target I guess that's good enough.

Now I'm getting somewhere! that data is golden, thanks Stalker. I did some tests at 30 feet in my basement, and found a 1 inch grouping was easy to achieve even aiming by hand, not benched. I don't think I need to upgrade, then.

My only reservation is that with my gas/spring pistols I notice they can be incredibly accurate at around 25 feet, but beyond 80 or so they veer off to one direction - so I was not so sure accuracy at 30 = accuracy at 100.

EDIT: offhand exaggeration. it was more like 2 inches, I just measured.

Taken from modern firearms here
There is a technical measurement of accuracy, but in airsoft the MOA will be much larger, tightbores will decrease that value, as would longer barrels.

When it comes to GBBs the ammo weight is key. I've gotten kills at 140ft with my G19, propane and 0.43g BBs. yes I had to aim for the head to hit th echest, but those AEGs users were embarrassed to run AEG vs. GBB with me. List is long and dignified actually. Lol

Mostly I use 0.28g to 0.30g for my GBBs, have outlined the many reasons why, and many have benefitted from it and follow it themselves.

Regarding the above post, is rather pointless to compare real steel ballistics with airsoft ballistics. for most airsoft guns, 100ft would be less than similar to 300 yards with real steel. My 500fps tuned sniper rifle with good ammo and no wind conditions (like indoors) can hit a piece of paper 8 times out of 10 using 0.30g BBs. No lie, airsoft sniper rifles tend to have greater "shit luck factor" than AEGs do, simply because you are shooting one shot. Mother Nature largely decides where the BB hits, nothing you can do changes that, and that gap increases with the range. 300ft kill? Shit luck, period, unless you are using a 700fps rifle. Others will argue with me, but I have little to brag about (way I am) I prefer to tell it like it is.

Do rifled barrels exist for Airsoft?

They have proven worthy in the paintball world...

It does not matter if you have the best barrel on the market , it has to do with the play or user behind the AEG. MasterGoa You are refering to a company call Armson bast in South Africa then moved to the UK and now owned by Pro Team Products., I was involve in the development of the 3 types of barrels, that were made, over the yrs we had done tests and tests, what we found was that Paintballs in there nature were bad due to them having a seem and that there were 2 types of fluid base that effected the ball flight , so to control the flght we tried different thing in the end and by pure chance we discoverd that if you start with a gentel rifling moving to the end of the barrel ending in arresive twist we could control the ball, this we improved in late 2002 with the tight bore and venting.Also the 3rd barrel was we call straight Rifling barrel with a 2 piece step tight barrel .
hope that helps :D

but that deals with a vortex

Closest we have to a rifled barrel though.

The reason I brought up rifled barrels if that in target shooting,
bullet spin is of utmost importance. Since the projectile revolving
around itself will create it's own gravitational field, it can move
inside a pocket of air that will give it better down field velocity and
less sensitivity to cross winds.

Having said this, the factor in paint ball or paint soft is that the
projectile is filled with liquid. That liquid will resist the projectile spin
and can actually start wobbling which is worst than if it was not
turning at all...

So I was inquiring in what ways can bullet spin can be attained in Airsoft...

This is also a very interesting thread by M76 because Cartridge Overall Length
is an important factor in target shooting. If the bullet is too close to the rifling,
pressure buildup could cause mechanical failure. However, to much clearance
will cause the bullet to accumulate sufficient velocity to cause excessive
bullet shear.

In paintball, the outer shell of the ball is very thin, so bullet shear can very
well cause bullet failure in the barrel. This is why variable rate of twist
in the barrel will cause a softer rotational acceleration and will prevent
the balls from ripping their outer shell trough bullet shear...

Very interesting discussion...

Pierre

Our projectiles are very sub-sonic, and not usually prone to material failure during discharge or flight, unless you use cheap crap BBs.

The BB is lightweight enough and slow enough that gravity and air resistance affect it's trajectory more that anything else. That's why backspin is employed, to help overcome gravity and allow extra energy to overcome it as much as possible. Then, a polished BB will do as much as possible to cut through the air smoothly. Dimpling like a golf ball may help, but good luck making them in the billions needed, with good QC and still be as cheap as we pay now.

I think a rifled barrel for an AEG is a non-starter. The BBs themselves have too much dimensional variance to make that effective, and you'll either have under-spec BBs with no induced spin or over-spec causing a jam.

In that case, how does tight bore help Airsoft?

Do they allow greater initial pressure buildup before launch?

Yes, a bit. But the biggest difference is to keep the BB running on a strainght path after it's gained it's rotational energy from the hop-up.

In a standard 6.07-6.08mm barrel, the BB has some room to float around inside the barrel. It doesn't run perfectly centered in the barrel, as often the BB in less than 6.00mm. When you reduce the barrel ID, the BB has much less room to float around. This keeps it running as true as possible, and this translates into better accuracy.

If you go really small, like 6.01mm, you may run the risk of a jam if you use an inconsistant or oversized BB.

Can you explain the hop-up vs barrel ID?

I keep hearing about hop-up adjustments, however, I fail<
to visualise the relationship between them...

Pierre

The MOA measurement is something similar that I was thinking of... to create a reference to compare one's set up against.

I think in this way a lot of unnecessary upgrading can be avoided. I have recently discovered that you should not upgrade just because a component is *supposed* to be bad. Take the time to optimize the hop-up, and wear it in in that setup... you may be surprised. The stock barrel and hopup I now have (Kraken!!) are shooting 11 inch groups outdoors at 100 feet (measured, not guesstimated) and an incredible 6 inches if no outliers happen to come out. The outliers are decreasing in frequency (about 1 in 6 now) as the grease clears out the hopup (the first bb I ever fired was coated in thick, golden grease). I have so much confidence in the gun firing damn straight almost every time I pull the trigger. Certainly at least one out of a three round burst nails where the iron sights are centred, at 100 feet.

and to think I almost bought a tightbore and new hopup for $100, when the difference I could have obtained would have been so minimal as to be completely negated in an outdoors context with wind and foliage as factors.

I'm pretty sure that you are hoping for MUCH more than any airsoft gun (considering the nature of the gun design and the ballistics of a light BB) can produce regularly. Even at 100ft I'm 99.999% there isn't an airsoft gun out there that can even set a standard at that distance, even if "Airsoft MOA is 6" @ 100ft".

Now, consider what the airsoft guns are used for and you'd have a better chance. 5 shots at a certain distance, can you hit a guy that many times on semi? There ya go, the important part. My CA M24 shooting around 500fps, and when using 0.30g match grade ammo, can hit a 10" pie tin at 100ft maybe 6 times out of 10 shots, depending on wind. Indoors, I can improve on that to about 8 shots out of 10 on a peice of paper.

Expecting anything that can be considered a measurable standard is rather foolish when dealing with airsoft, unless usning heavy BBs (say .43g or higher) at 600+ feet per second, aka. make the airsoft gun a legitimate firearm (500fps+ and 5.7J+) and then a standard can be set for 100ft accuracy. Anything under that is impossible.

These standards can't really be followed.. mainly because most people don't know how far 10 feet is...

the ultimate test for a barrel would be, like you said, with all variables accounted for. also, tests should be done with the hop-up turned off. that way, BB accuracy will be raw and unobstructed.

sure we do, its about 5m ;):p

dont worry, i kid.

Staker, you raise good points.

Having a 1 MOA airsoft will mote make you a better
contender as strategy is by far the best tool for this game.

However, understanding Airsoft ballistics and how it all relates
does help understand the issues and concepts involved.

If for nothing else than maintenance, getting the best
of your gun add another dimension to Airsoft.

Meanwhile, here are some target shots from both mi rifles.
Note that I reload my own bullets and use Lapua 144 FMJBT
for the Swede and 168 FMJBT for the Savage.

Savage 12LVSS with Laminated stock and floating barrel, 308 cal:
http://img.photobucket.com/albums/06...ring_Front.jpg

.5 MOA at 100 yd

http://img.photobucket.com/albums/06...rget_2-870.jpg

Tikka sporter in 6.5X55, out of box:

http://img.photobucket.com/albums/06...ikka_Table.jpg

.25 MOA at 100 yd

http://img.photobucket.com/albums/06...et_3055COL.jpg

:D