Regulated FAC R7 (not mk1) low shot count

[Squinty]

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)




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

[KevG]

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

[Daztilley]

Short hammer spring could make hammer bounce worse as the hammer preload is low...

[Squinty]

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.

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?

[Daztilley]

I would try it with a full size spring with the reg as it is .... go from there 👍

[KevG]

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

[Squinty]

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 ?

[KevG]

from memory short pre chamber is 45mm and 60 mm for later deeper type.
KevG

[Squinty]

I'll trust your memory
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

[KevG]

black and decker should do it m8😁
not much room for clearing the threads in the action

[Daztilley]

What pip length are you running it with??

[Squinty]

What pip length are you running it with??

6mm, I have a couple with different length pips that I could try if needed

[Squinty]

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.

[Daztilley]

Be interesting to see how the build comes along ....

[Squinty]

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.