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M82A1 0% (destroyed)
Posted: Sun May 08, 2011 5:57 pm
by Demon
Posted: Sun May 08, 2011 7:00 pm
by warhead052
Wowwwwwwwwwwwwwww, thats nice! Very cool.
Posted: Sun May 08, 2011 7:17 pm
by Gaderelguitarist
Very nice. Can't wait until it is 100%
Posted: Sun May 08, 2011 7:44 pm
by saefroch
That looks pretty amazing... care to enlighten us as to the sabot discarding system?
Posted: Sun May 08, 2011 8:00 pm
by mark.f
Looking good! It seems that friction would keep the CPVC part from sliding forward... Works great nonetheless.
Posted: Mon May 09, 2011 6:04 am
by Demon
That looks pretty amazing... care to enlighten us as to the sabot discarding system?
It's very simple: At he end of the barrel, there is a reducor with an I.D. just over the size of the projectile. That way, the sabot is stopped, but the projectile continues.
Posted: Mon May 09, 2011 6:20 pm
by saefroch
*facepalmheaddesk*
Brilliant!
Posted: Mon May 09, 2011 7:15 pm
by Demon
It seems I have accuracy problems ...
No matter the front barrel ejected sabot, discarding sabot or plain simple paper wadding, the 2.5 gram projectile can't stop curving to the sides
(approx 2 meters at 40 m eters). If it curves, it implies that it spins. But why ?
With my .43 gram airsoft carbine with a shorter barrel I got at 500 (same speed) much better accuracy (somewhere ten centimeters at 40 meters).
Any reason, solution ?
The projectile is spheric enough. Spinning is the problem.
Posted: Mon May 09, 2011 11:43 pm
by jackssmirkingrevenge
Sexy indeed, good job!
I think the fact that you're using soft wadding material means that accuracy isn't going to be that great. Have you thought of adding a short sub-barrel at the muzzle that is exactly the same diameter as the projectile to guide the projectile correctly?
Posted: Mon May 09, 2011 11:49 pm
by Zeus
I didn't think of this whilst we were in the chat but whay JSR said prompted me to think of it.
The sabot isn't releasing the projectile evenly thous it's trajectory is being altered. The fix JSR suggested would fix you're problem.
Posted: Mon May 09, 2011 11:54 pm
by jackssmirkingrevenge
Have a look at
these ideas, you may be able to use a more rigid projectile without actually tearing the thing apart
Posted: Tue May 10, 2011 6:02 am
by Demon
I think the fact that you're using soft wadding material means that accuracy isn't going to be that great.
The blue foam sabot fits rather snug, I dont think to problems comes from there.
The problem is the projectile spinning on itself, causing a curve to the sides.
Would rifling the copper barrel help controling how it spins ?
Posted: Tue May 10, 2011 6:06 am
by jackssmirkingrevenge
Demon wrote:The blue foam sabot fits rather snug
... yet it's very soft material and I can assure you it deforms considerably when pressure is applied.
Posted: Tue May 10, 2011 7:08 am
by Demon
But It cannot impart spin along the vertical axis on it, can it ?
Rifled barrel, good or bad ?
Posted: Tue May 10, 2011 7:39 am
by jackssmirkingrevenge
Demon wrote:But It cannot impart spin along the vertical axis on it, can it ?
I think your problem lies with the reducer - how close is the internal diameter to the projectile diameter?
Remember, golf ball in a drain pipe - if your projectile is free to bounce around, there's no telling at what angle it will leave the muzzle.
Rifling will not help if the projectile hits one side of the reducer and not the other.