Author Topic: New reg  (Read 1056 times)

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Offline Baggawind

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New reg
« on: March 31, 2020, 03:05:11 PM »
I own one of the Zbroia Kozak bullpups .  Nice rifle but , there is a well documented problem with the regs on these rifles , a fluctuation in velocity caused by the reg. Well, a couple of years back my old friend Dave Whelham of Airmasters sent me all the parts, minus body , to make one of his regs. So, given the lockdown we are having to endure , I decided to go ahead and make a new reg for the Kozak . I was also given two complete spare cylinders for the rifle by Matt at SureShot . Which meant I could afford to use one for experimental purposes. I had already modified the firing valve so all it needed was a new reg. This I have just done and what an improvement. I set the pressure at 80 bar - 10 bar lower than standard , and i,m getting superb consistency , 3 fps , and a steady 10.9fpe . Perfect.
That used up a couple of days , only six months to go  :(

Offline Gambo

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Re: New reg
« Reply #1 on: April 05, 2020, 07:20:59 PM »
That used up a couple of days , only six months to go.........

.......before it needs refilling!! ;D ;D


Is the reg giving good SPC as well as consistency Mel?

Any pics please dood?  ;)

Offline Baggawind

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Re: New reg
« Reply #2 on: April 06, 2020, 03:06:11 PM »
Sorry mate, no pics as it is inside the rifle. The only test i,ve done is over only ten shots . Seven of those recorded the same velocity , one shot was high and two slightly lower . Extreme spread was 7 fps. I ,ve yet to do a shot count . At the moment i,m busy making another pistol. Got to have something to keep the old grey matter working.

Offline Baggawind

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Re: New reg
« Reply #3 on: April 08, 2020, 11:12:18 AM »
Well i,ve just done a bit of pellet testing , firing 74 shots. It used 100 bar - around 1.3 bar per shot , not good . But this is around the same as before fitting the new reg. I figure the excessive use of air must be , in part, due to the very long throat and transfer port . The throat in particular is very large and long. Nowt I can do about that  :(

Offline Gambo

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Re: New reg
« Reply #4 on: April 08, 2020, 08:44:02 PM »
Yeah 1.3bar per shot is excessive, spesh as it is nowhere near the legal limit.

Is there the option/accessibility to sleeve the port down to reduce volume, or is it already narrow, and so making it narrower would choke the power too much?

Offline Baggawind

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Re: New reg
« Reply #5 on: April 09, 2020, 03:29:25 PM »
I can,t see any easy way of doing that . I checked the test figures just after I bought the rifle and they seem to be the same . 120 shots from 250 bar down to 100. I,ll just have to live with it. I don,t even use the thing these days. I bought it for shooting from inside my car when one of my permissions was a field full of pigs . But, not long after I bought it the pigs were moved away to another farm . Just my luck.

Offline Gambo

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Re: New reg
« Reply #6 on: April 10, 2020, 06:00:02 PM »
Yeah...... the estimated 120 shots out of 150bar is 1.25bar per shot......ever so slightly less air usage than what the reg'd rifle is giving.

So it seems the reg is doing very little to improve SPC (unless the factory figures have been widely exaggerated), but at least it is doing what it's doing well with regards to shot consistency. ;)

Offline Baggawind

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Re: New reg
« Reply #7 on: June 18, 2020, 03:19:33 PM »
I,ve been in the man cave today, trying to improve one of the regulators in the spare Zbroia cylinder.  I,ve substituted the nylon valve seat for a brass one , fitted with a tapered seat made of Delrin. As far as i know no one has tried this set up. I have a lot of testing to do as yet , namely trying to set the pressure i want which involves a load of stripping , adjusting and re-assembling but , hey , got nothing else to do. I,ll keep you posted.

Offline Gambo

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Re: New reg
« Reply #8 on: June 18, 2020, 06:48:42 PM »
Thanks Dood. ;)

Offline Baggawind

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Re: New reg
« Reply #9 on: June 19, 2020, 12:15:07 PM »
Been doing a lot of playing around with this reg. It involves a lot of stripping and adjusting and a lot of air being used but, I think I may have cracked it. At the moment it,s sitting at 75 bar . All I need to do now is test it on the rifle . But i,m giving it a rest for now. Watch this space.