I've regged my FAC Rapid 7; short inlet chamber.
Buils pecs are....
mk2 spec top port, was 5mm ..only gave 26ft, 5.5mm 28ft
The block was already ported between inlet and valve chambers and is not blocked by the reg.
6mm valve,
Hammer spring is relatively short
pre-chamber,
short-core reg
22" barrel c/w 3.5x5.5 oval port. 16.5sq mm Not massive but told it should be good up to 40ft (dependant on other specs)
(https://i.imgur.com/B9zPccc.png)
Making 935fps with 16s, 2-4fps shot to shot, 10fps extreme spread.
You would like to think the jobs a goodun.
Admittedly I'm down to 180bar in my dive cylinder but I'm only getting 23 shots from 30bar in a 480cc c/f bottle.
Reg is set at 150, recharges quickly with no great differential after rushed follow-up.
Backing off doesn't improve the shot count and the off reg drop is 10fps per shot
Quite a blast at the business end, lots of wasted air..no ooomph
you tryed shot count on a 220 bar fill.even when reged they use different amounts of air per shot.seam to use les at beginning of fill than lower down.as a guide a standard fac mk2 reged does around 70 shots at around 910 fps with 16 grn.on a 19 inch barrel
KevG
Short hammer spring could make hammer bounce worse as the hammer preload is low...
Quote from: KevG on April 17, 2021, 03:13:58 PM
you tryed shot count on a 220 bar fill.even when reged they use different amounts of air per shot.seam to use les at beginning of fill than lower down.as a guide a standard fac mk2 reged does around 70 shots at around 910 fps with 16 grn.on a 19 inch barrel
KevG
Cylinder is in for a refill tomorrow but will have to leave it until Tuesday.
Was hoping for more shots than the fast-flow even at the bottom end of the bottle. As is ..not even close.
Quote from: Daztilley on April 17, 2021, 03:51:25 PM
Short hammer spring could make hammer bounce worse as the hammer preload is low...
it's not a full length spring, couple of coils off. I have a couple of spares, this is the first shakedown perhaps I'm being too conservative with the springs.
Not aiming for massive power levels 950-ish with 16s...maybe a case of increasing preload and backing off the reg?
I would try it with a full size spring with the reg as it is .... go from there 👍
to be sure you need reg set so its capable of giving around 20 fps more than you want.that way you are not thrashing the reg which can also magnify hammer bounce..I would also try and get the pre chamber to later mk1 spec.
KevG
That was part of the plan with the valve extension, would guess that I'm benefiting from barely half of the extra volume.
More drilling ? Don't think there's much in them 8mm on the safe side ?
from memory short pre chamber is 45mm and 60 mm for later deeper type.
KevG
I'll trust your memory ;D
Got a bare mk1 block that I measured a little while ago, 64mm to the bottom of the bull nose...or 2.5" which would be more in keeping with the imperial.
Bore...9/16" 14.27mm ?
Could be interesting with a Parkside bench-top pillar drill
black and decker should do it m8😁
not much room for clearing the threads in the action
What pip length are you running it with??
Quote from: Daztilley on April 17, 2021, 09:05:14 PM
What pip length are you running it with??
6mm, I have a couple with different length pips that I could try if needed
Quote from: KevG on April 17, 2021, 08:45:37 PM
black and decker should do it m8😁
not much room for clearing the threads in the action
yeah...run-out on the Lidl pillar isn't too much of a worry with a stub but I'm not sure about a long 14mm bit. ;)
Be interesting to see how the build comes along ....
Quote from: Daztilley on April 17, 2021, 09:56:18 PM
Be interesting to see how the build comes along ....
Full length spring...straight in a 965 >968fps over 12 shots with the adjuster backed out to the stock!
But..... only 15 shots from 30 bar, shot # 16 955 #17 950
Will pick my dive cylinder up later to try running on a full fill.
Quote from: KevG on April 17, 2021, 03:13:58 PM
you tryed shot count on a 220 bar fill.even when reged they use different amounts of air per shot.seam to use les at beginning of fill than lower down.as a guide a standard fac mk2 reged does around 70 shots at around 910 fps with 16 grn.on a 19 inch barrel
KevG
(https://i.imgur.com/idlsEJ9.jpg)
Still not sure exactly what was going on to start with besides what you said about there being more shots from the top-end of the fill.
I have been genuinely thinking that I screwed up big-time with this conversion so not wishing to waste more air emptying 480cc bottles I used a 400cc aluminium at 200bar, Either it came good or I would be stuck with an over-ported bodge.
Anyway the chrono results were 55 shots 945fps +/- 5fps 31.75ft/lbs from a 200bar fill.
20bar increase ...35 shots extra
whats confusing me (again) .....I took the full length spring out as was rather rather hot, put the shorter spring back in and its making an extra 20fps with the adjuster still backed out to the stock
some times to much hammer spring can lower power.its caused by hitting stem so hard the stem spring can coil bind and in turn throws back faster so in theory less valve time.
KevG
whoops, a close shave!
I took it apart again before the latest trial, double-double checked the valve and habitually changed the o-rings.
Appears to be undamaged.
If that's the case the short stem-spring you supplied with the valve and pre-chamber extension is right on its compression limit?
Stiil not sure how/why I'm getting a different output from the same hammer spring tho, before it was wound in fully and dropped on backing off...now its 4mm further out.
should be a standard length around 19 mm
KevG
I'm not picking fault Kev, brain was fried on this one, I had a mk2 fast-flow and valve on the table waiting
I don't want to take it apart again to check it :D :'( :'( :'(
that looks very good now.480cc bottle with 220 bar fill will give outstanding numbers i should think.
KevG
My 500cc carbon fibre bottle is rated to 300bar and a theoben reg should handle 250bar- might be worth trying 240bar to increase the shot count further....... you would get less fills from your charging cylinder though....
Just a thought .....
I have Inocom 480cc bottles (DS - FX ect), rated 250 bar, didn't plan on going over 220-230 to be honest.
Hopefully the 80-90 shots will free up the spare I carried when it was fast-flow.
Although I now have three custom high-flow bottle valves that are overkill for a reg.... :-X