Bullet shaped bb's

[Danke]

OH! You're a loaded gun ... yeah
OH! There's nowhere to run
No one can save me, the damage is done!

Shot through the heart,
And you're to blame
You give love a bad name
I play my part, and you play your game
You give love a bad name.
You give love a bad name.

 

Or alternate lyriics

 

shot in my post

press to make BBs

If can't tell how it works

You give me heebie-jeebies

[spamofthejungle]

I can't help but think that rifling on a 6mm projectile is going to be considerably less effective than on the 'rifled' paintballs already mentioned. Simply because the rifling is so much closer to the centre axis of the projectile, the larger calibre of the paintballs means more 'leverage' (i'm sure there's a proper term for this).

[cazboab]

Non spherical airsoft rounds would lose something that -like it or not- is now an integral part of a sunday skirmish, namely the hicap magazine, and they'd jam more often in a low/midcap. They'd cost more to make, and the market would be smaller, so they'd probably be an order of magnitude more expensive than regular round bbs, which would further reduce their sales, so less shops would stock them, and less manufacturers would build guns to use them. The end result is you'd have ammo that's expensive, hard to find and low ammo capacity in the single gun that actually uses them. This is why the blade bullet isn't around any more, and its why first strike paintball rounds are an oddity used by a small minority(there's also the problem of some if not most places only allowing the ammo that they sell etc, but if it was popular enough they'd sell it as well)

 

Then there's the question of how well rifling would actually work in a projectile with comparatively low velocity(even 600fps is "low" in this case) since the BB wont expand to fit the groves reliably, if you rifle the pellet they'll only be useful at a set velocity range to match the rifling on the pellet since the air will make them spin, when they go faster they'll over spin and tumble, when they go slower they'll under spin, and tumble.

 

Maybe the reason Nobody's done it commercially for 20+ years is that it doesn't really work very well, and any small benefit is far outweighed by the market saturation and ease of use the round BB has?

[renegadecow]

Hunterseeker5 had his finned bullets 3D printed, but unsure if he used them to make casts out of to control weight as I imagine the printed stuff will be very light. As mentioned above it only really works at high velocities and by high I mean ridiculously high, over 900fps as I was told, and HS5 claims to have a maximum range of a quarter mile. If a low velocity version can be made by altering the bullet design, we won't know until someone actually tries. 

[Gliderrider]

problem with 8mm bbs is the difference between them and 6mm is bigger than what some people think

 

6mm bb

Volume = 113 mm³

Area = 113 mm²

 

 

8mm bb

Volume = 268 mm³

Area = 201 mm²

 

 

It's inly 2mm difference in diameter, but that translates to over double the amount of internal volume, this means you need to go over 0.40g on an 8mm in order to get some sort of parity with a normal 0.20g 6mm bb with regards to density.

 

The proportion of volume to surface area does suggest some possible advantage for 8mm, but I would suspect that the advantage could only be exploited if you lurch into super heavyweight 8mm bb territory

The other difference is mass, the lowest weight 8mm bb is .28g, 40% heavyer than a .20g allied with greater surface area, 8mm are more suceptable to gravity and wind sheer making them less use in a normal skirmish.  On the plus side, they are kick *albatross* when they hit anything, the "thwack" is a lot  cooler than a 6mm.

[sir naggedalot]

This design concept uterlises Golden Ratio's and flies strait and true like a dart. I've had great fun turning my concepts in to working prototypes,these are pictures of the projectiles at around .45grm but they fly better when trimmed to a Golden weight of .23grm

[renegadecow]

Won't most of the air go through though or is this meant to be fired from a sabot?

[PureSilver]

This design concept uterlises Golden Ratio's and flies strait and true like a dart. I've had great fun turning my concepts in to working prototypes,these are pictures of the projectiles at around .45grm but they fly better when trimmed to a Golden weight of .23grm

 

I'd be interested to see these fired on video, preferably through a chronograph as well as on a range.

[sir naggedalot]

I have no chrono that can accommodate this projectile and no high end video but I do have a range.

 

I will get around to videoing their flight but I might post a pic of the projectile thats got the best CG and CO as far as I have ascertained first.

 

My launch method is more of a fling :0) but the projectile imparts its own spin every time very very consistently.

 

If someone wants to post me a brown envelope with a wad of £50's in it I will post them my formulas in return,not 100% sure but its looking like it must also be imparting its own lift as its gliding so far................................................................................................................................ but Im not sure if its the spirals its forming thats causing the extended range?     

[Jibbity]

If someone wants to post me a brown envelope with a wad of £50's in it I will post them my formulas in return,not 100% sure but its looking like it must also be imparting its own lift as its gliding so far................................................................................................................................ but Im not sure if its the spirals its forming thats causing the extended range?     

 

This is a known phenomenon, that has been used in toys (X-Zylo) and paper airplanes for years.

 

http://www.instructables.com/id/Flying-gyroscope-out-of-a-single-sheet-of-paper!!/

 

The trick would be getting them to actually feed and fire with any kind of efficiency.

[PureSilver]

I used to have an X-Zylo!

 

To be honest, I don't think it would be that hard to get something like an X-Zylo to fire properly; there are a few options for pushing it along and a few options for spinning it; once you'd worked out the desired spin ratio you'd just have to rifle the barrel with the correct twist and use a peg or something similar to locate the projectile within the rifling.

 

To be honest, these are quite similar (in very broad strokes) to hop-up as an answer to how to make ultralightweight and low-power projectiles fly consistently and accurately, in that they both exploit various physical and aerodynamic phenomena to increase their percieved performance. The obvious advantage of hop-up is that it works on extremely cheap and crude projectiles; these annular airfoils look much harder to make and much more fragile, too. The performance advantage would have to be significant to make those tradeoffs worthwhile.

[sir naggedalot]

Dont you hate it when you do a fekin long post only to find its not posted!

 

 

Anyway he is the short version.

With  low power and masses we need to impart spin by utilizing the airflow passing over the object if we are going to have long consistent flights,rifling is never going to achieve this.

 

Have you ever tried chucking those flying gyro's? Pain in the anal sphincter to get the knack of imparting plenty of spin but when you get it right its very rewarding.

 

Im trying to embrace drag but size 12 high heels are proving hard to find.lol Its hard to model how spiral airfoils need to be tapered for optimum performance... I

 

  

[Danke]

That projectile should still trip a chrono.

 

The bigger "flying windsock" might be a good solution for the arty folks who don't want to hunt down nerf footballs at the end of the day.

[Multicam_Pegasus]

Quick flick through this and I noticed people haven't though of those rubber bullet guns you get from like the £1 shops and stuff.. They fire these little paper thin rubber bullets (not nerf style foam rounds)

 

These things fire pretty Far if IRC

 

Granted you would either need a new barrel or smaller rounds but a magazine etc should be fairly easy to rig up with a feeding lip to act like an air cylinder/breech