Anchutz Reg Pressure

[Jon]

They do vary a little for 10metre generally hover from 58 to 62bar for 600 - 650ft/sec.

First factory HP tested ran at 116bar.
Off the peg come in less than that for 750 ish ft/sec

Thought i would check a new build having seen in excess of 800 ft/sec but didnt see how fast it would go.

Untouched reg as it came from Anchutz.

[Lol Moore]

Jon

Excuse my ignorance but If I am reading this correctly you are saying you have modified the internals and with the original regulator setting of 60 Barg...ish you are achieving 12ft/lb (800ft/s with 8.4gr)?

If so that is pretty darn slick

It raises other questions to me if you are comparing to the standard factory HP - I assume it gives increased shot count, less muzzle flip and a noise reduction


Cheers mate...

[Jon]

Lol, in short yes.
A couple can achieve 800ft/sec by dropping from standard 7J reg pressure.

Best seen so far and will see it today is 48Bar for 800+ft/sec. even 50-60bar is hard to keep power down.

[Lol Moore]

48 Barg

Now that is efficient use of air

[Jon]

They will all vary.
Usually good going if can get 780 with 8.4 without touching the reg around 60bar. HP run 111 to 116bar, 100bar will see 750ft/sec.

[SDplinker]

That's why people come to you for sure.

I've got my action bored out and had the OD of the regulator reduced but only between the O-rings. Didn't go the full route of turning down the entire rear part of the reg and running a plug in the rear of the action.

Learning a lot about balance of hammer spring and valve spring. Jon, you ever shorten the factory striker at all? Noticed on some of my lighter spring tests that even at rest the striker/spring can overcome the valve spring.

So many variables can be changed.

Just for fun I turned the reg up by 1/2 turn on the Torx screw. No idea what pressure that sets it at. Velocity immediately to 825 fps with 8.4's.

So still messing with options. The machine shop did nice work on the boring of the action, machining the reg, opening the barrel holder and machining the valve seat deeper. Jon, at one point you mentioned eccentric boring of the action for more volume. Maybe that's my missing piece.

Any idea what the stroke of the striker is in the stock position?

[Jon]

1/2 turn up from around 60bar probably wouldnt shut off letting whatever pressures in the cylinder through, but at least 130bar reg pressure.

Plenty of power with standard stroke without having to resort to increasing it making it like a BSA, AA, Rapid etc 30 years out of date.
Valve should seal at very little pressure couple of psi. Max power may not be as little valve tension as possible, others aint figured that yet in 30 yrs!

Negligable turning reg away and relocating o ring might see 10ft/sec thats all, than between o rings and nowt to go wrong.

[SDplinker]

Hi Jon,

Don't mistake my experiments for any disregard for your expertise. I guess I like learning the hard way. Appreciate you taking the time to discuss these things that you have probably addressed ad nauseum over the years.

Had some time to experiment today, work call at home where I basically just had to listen, so I sat in the garage on mute and went to work - saw what you meant about striker pre-load. At points backing off the striker resulted in same or slightly higher velocity. Makes sense because you still get the striker throw and hit, but less residual pressure on the valve stem.

Right now gun running at 770-775 fps. Valve is PEEK, valve return spring far weaker than factory. Striker backed off probably 2.5-3 turns. After tearing it down 50 times I'm going to leave for now and just refine it. The parts I used for the spring support are a bit janky. But now I can measure where everything is set and use that as my baseline for power. Don't have a reg tester so no idea what I'm running at.

Next up is polish up some more things. Would like to Cerakote or Robar NP3 the striker. Make it glide, no lube. You will laugh but epoxied a small nut to the back of the striker adjuster. Now easy to turn in and out, job done.

Noticed I'm unable to rotate the barrel 360 degrees to index it. Probably burrs from the set screws or deliberate shape/machining? Or just bad machining?

Once I polish things up a bit going to run some chrony sessions and see how efficiency and consistency looks. Accuracy is important too

[Jon]

That will change in no time the valve spring compression.

Just hack saw a slot in power adjuster, easy.

Powers one thing its how it shoots and then combine and sort the temp and zero shift out.
Best of them no recoil even better no vibration.

All are different virtually no two the same in 12. By that can put front block complete with reg, valve etc along with same barrel, hammer and captivated hammer adjuster in to another and it will be quite different.
Drove me round the bend last year and another 3 months this year but thats German engineering.

[SDplinker]

That will change in no time the valve spring compression.

Just hack saw a slot in power adjuster, easy.

Powers one thing its how it shoots and then combine and sort the temp and zero shift out.
Best of them no recoil even better no vibration.

All are different virtually no two the same in 12. By that can put front block complete with reg, valve etc along with same barrel, hammer and captivated hammer adjuster in to another and it will be quite different.
Drove me round the bend last year and another 3 months this year but thats German engineering.

As far as the spring - going to look at more options. Would prefer a bit larger wire diameter. Need to rummage through the bins at the hardware store or look for spring lots online/ebay.

Will hack saw the nut

That's got to be frustrating when not consistent. Same reason I can't understand the barrel housing and the single spanner hole for the striker adjustment. WHY!?

At some point I'm going to own a Thomas - hand built, every gun tested, not shipped unless accuracy threshold reached. But you pay $$$

-Casey