SpudFiles

I have been working on ball bearing and marble accuracy and preliminary tests suggest blowby improves accuracy with hard spherical projectiles in hard barrels. I was surprised.

Then I'll try one of these wide bores and see if it's true.

My general opinion is that while a hop-up system makes airsoft playable in terms of handguns and assault rifles, there are too many variables in the way the spin is imparted for it to lead to meaningful accuracy at long range. Apart from that, inducing the spin robs the BB of energy that reduces its impact even if it does manage to connect with the target. The ultimate sniper system would combine accurate range estimation along with appropriate drop compensation.

The Airsoft Trajectory Project is also an interesting link.

I'm almost certain a straight barrel with no hop up would be more consistent down range, but for airsoft BB the drop would be very significant. I have read that too, however the articule is rather old and many new things came up. The old airguns I made with ~6mm ID aluminum extrusion tubes were very accurate, however I never attempt long shots because the bb drop. In order to have the same range the FPS needed would be seriously unsafe.
I think I'll cook up that rig I mentioned above to test out, once the mid-terms are over.

Tight barrel definitely gave me huge inaccuracies with my airsoft, the BBs weren't free to roll down the barrel, after I polished it out so they rolled down easily it was much better. An early construction I made used 7mm ID tube with 1/4"(6.35mm) Steel BBs, it was very accurate at short range.

Does anyone have experience casting with silicone/rubber/latex from home Depot?
I have experience casting with expanding foam but they don't have the mass I need for good (safe and far flying) projectiles.

the BBs weren't free to roll down the barrel, after I polished it out so they rolled down easily it was much better.

Could be you have improved the bore quality after polishing, doesn't necessarily because of the diameter.

Anatine Duo wrote:I don't have the physics background to comment intelligently, but I have been working on ball bearing and marble accuracy and preliminary tests suggest blowby improves accuracy with hard spherical projectiles in hard barrels.

Do you have any data comparing group sizes with different barrel diameters?

not enough barrels for that test

Jack you have talked to taofledermaus before, could you shot him a msg asking him to do a video about this? I can supply the rig, (clear barrel, hop up etc)

wyz2285 wrote:Jack you have talked to taofledermaus before, could you shot him a msg asking him to do a video about this? I can supply the rig, (clear barrel, hop up etc)

I could, however IIRC he's still limited to same 1,000 frames per second cameras that we've been using, you need someone with those 10,000 frame per second cameras to have meaningful visuals.

jackssmirkingrevenge wrote:I could, however IIRC he's still limited to same 1,000 frames per second cameras that we've been using

I'm guessing it's a while since you last watched. This is what he uses now: http://www.krontech.ca/

Ragnarok wrote:I'm guessing it's a while since you last watched

huh... they even use his clips in their promo:

[youtube][/youtube]

Too much going on online to keep up with everything!

Does anyone know if you can ruin a .22 caliber shark cannon, if you drill a hole in the middle of it? It would be this 2mm hole. My question is whether it would alter the work of the fluted ...

Done it before, didn't really mess it up. You're supposed to drill in the grooves (calculate the position of the grooves) but 2mm it's definitely wider than a .22 rifling groove. I made a brass piece that matchs the bore and just pushes it back and forth to smooth the hole and I'm still doing 1inch group at 25m

wyz2285 wrote:Done it before, didn't really mess it up. You're supposed to drill in the grooves (calculate the position of the grooves) but 2mm it's definitely wider than a .22 rifling groove. I made a brass piece that matchs the bore and just pushes it back and forth to smooth the hole and I'm still doing 1inch group at 25m

Ok, I understand what I should do. Thank you

What's the best way to install a spark plug into a hybrid made of sch. 40 black steel? Should I machine a custom coupler with NPT threads on one side and 14mm X 1.25mm threads for the other side?

Or am I better off using some other ignition source.

What mixes do you intend to go to?