Author Topic: 200FPE Disco Build .357 (Read 5164 times))

Fullblown · « **on:** October 24, 2016, 10:05:35 PM »

Using .35 caliber 82 grain JSBs. 3 power shots over 200fpe or 10 shots at around 70fpe. Still working out the kinks though. Stay tuned

oldpro · « **Reply #1 on:** October 24, 2016, 10:18:33 PM »

Only part of a disco left was fill nipple LOL

Tofazfou · « **Reply #2 on:** October 24, 2016, 10:57:49 PM »

I would back up quite a ways from the chrony. hope your not reading the High Pressure Air flying over those screens.

Big bores have a problem with this phenomenom and require at least 6-10' of spacing from the chrono

rsterne · « **Reply #3 on:** October 24, 2016, 11:06:51 PM »

Certainly not impossible.... I have managed 192 FPE with my Disco Double in .357 with a 28" barrel on 3000 psi with ports that were 0.219", for one shot.... although it was with a 132 gr. bullet, not an 82 gr. pellet.... Impressive to say the least.... We need more details to properly evaluate this accomplishment....

Bob

Fullblown · « **Reply #4 on:** October 24, 2016, 11:34:05 PM »

The build has a Disco tube, Cothran Powerhouse valve with .250 transfer hole, a 21 inch barrel and upgraded valve and breech screws. Got around 10 consistent shots at 70 fpe when filled to 3000psi. The power adjuster helped out with balancing that shot string. The first time it was shot, it was filled to 2500psi and went from 120fpe up to 240fpe.

The chrony is reading as it should. Just got to get this thing sorted out to about 5 good shots.

rsterne · « **Reply #5 on:** October 24, 2016, 11:41:21 PM »

I just want to make sure I got that right.... You got 240 FPE at 2500 psi with a 21" barrel and 1/4" ports?....

Bob

45Bravo · « **Reply #6 on:** October 24, 2016, 11:48:02 PM »

Ooohhh.....

Monkeydad1969 · « **Reply #7 on:** October 24, 2016, 11:51:46 PM »

Any pics of the rifle?

Joe

Fullblown · « **Reply #8 on:** October 24, 2016, 11:57:08 PM »

733, 1048, 1153, 683

rsterne · « **Reply #9 on:** October 25, 2016, 12:03:41 AM »

I assume those are velocities.... without a fill pressure and an ending pressure, I still have no idea what is going on.... but I would sure like to....

Bob

Fullblown · « **Reply #10 on:** October 25, 2016, 12:16:31 AM »

Those are velocities RSTRNE. No fill pressures because there is no gauge on the tube. Replaced it with a block. Will try to get a better video with a shot string on the gun. That was the first time the gun was shot. The goal is 150 fpe with pellets.

Hopefully someone will tell me what that acronym stands for.

oldpro · « **Reply #11 on:** October 25, 2016, 12:49:15 AM »

Quote from: rsterne on October 24, 2016, 11:41:21 PM

I just want to make sure I got that right.... You got 240 FPE at 2500 psi with a 21" barrel and 1/4" ports?....

Bob

Didnt happen with those specs. No chance no way. 120fpe yes but 240 is out of the question there simply isnt enough stored energy thats useful in that short of a barrel to hit 240 fpe at 2500psi.

MJP · « **Reply #12 on:** October 25, 2016, 12:50:36 AM »

Looks interesting, but I would really like to see the numbers with the chrony further away from the muzzle.
Sound of the discharge bothers me somewhat or is it just the mic not picking it up. Or does it have ldc on it?
Do test more and more details please.
Marko

oneshot61 · « **Reply #13 on:** October 25, 2016, 09:14:32 PM »

Congratulations on the build brother! The cothran valve definitely puts out some power. Looks like from the video that you have a sleeved barrel? Also, what others have said, may want to back up about 6 feet or so. I see the grass being hit hard right behind your chrony. Honestly I've done the same thing, then moved it back on someone else's suggestion, and had my own... uh oh...moment

. Please continue to post results, everyone is here to cheer you on and help!

dmeguy · « **Reply #14 on:** October 26, 2016, 04:05:46 PM »

Andre - Are you working with Troy on this? I've been following his posts on the Facebook groups.

Fullblown · « **Reply #15 on:** October 26, 2016, 07:19:45 PM »

DMEGUY, Yes I'm working with Troy. In fact, trying to get a good video in right now before it gets too dark. I actually spoke to a few shops today about some new parts for a 45 build since this build looks extremely promising.

Fullblown · « **Reply #16 on:** October 26, 2016, 07:35:41 PM »

Well you guys were right! A little too close to the chrony. Got 5 shots ranging from 715 down to 685. Shucks!! Back to the drawing board.

oldpro · « **Reply #17 on:** October 26, 2016, 08:14:33 PM »

Quote from: Fullblown on October 26, 2016, 07:35:41 PM

Well you guys were right! A little too close to the chrony. Got 5 shots ranging from 715 down to 685. Shucks!! Back to the drawing board.

Thats what I come up with using my spread sheet. Up the barrel length and those numbers will climb a lot partner.

rsterne · « **Reply #18 on:** October 26, 2016, 10:33:05 PM »

Glad to see you got it sorted out.... For a while I was thinking the spreadsheet I have been using to calculate ballpark numbers was in the wrong ballpark.... Actually, those numbers seem pretty low.... The real potential probably lies between the two extremes.... My .357 Disco Double can do three shot strings at 170 FPE, starting from 3000 psi, ending at 2100, with 127 gr. bullets in a 24" barrel, and 0.219" ports.... You should be able to get about the same FPE with a 21" barrel with your larger ports.... but I still have 250 cc of reservoir available with the double tube setup, instead of only 135 cc.... With pellets I can get 10 shots at 125 FPE, so half that many with a single tube Disco should be attainable....

Bob

TroyHammer · « **Reply #19 on:** October 26, 2016, 11:00:54 PM »

Rsterne,

What valve are you using in your double to get those numbers?

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200FPE Disco Build .357

Author Topic: 200FPE Disco Build .357 (Read 5164 times))