Tuning New Veradium Air 750 Fine Tuning....

Received the gun in fine condition and fired a few test shots. The fps and trigger let-off were not to my liking, so I made a few adjustments. The pictures below will show what I did.

Starting with mounting the optics:

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One technique you can use, if you don't have milling ability to cut new stop groves in the sliding steel bars, is to simply purchase an extended picatinny rail and mount it as far back as possible. The extended rail I had on hand has a 4" extension which turned out to work just fine with the handle fully extended.

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The extended picatinny rail gives me about 9 1/2" from butt plate to my scope lens. For me personally this turned out to work just fine as I was now able to get a full picture from my scope without straining my neck or suffering from excessive length of pull. Your mileage may vary, if so, consider buying an extended picatinny rail with a longer/shorter extension to meet your personal needs.

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My next adjustment was to the trigger. Veradium Air did not adjust the trigger to ounces of pull. This would be dangerous for some shooters, but adjustment is simple. The front top of the trigger has a hole and a tiny hex screw that adjusts let-off pressure. (the hex wrench that fit measured 0.056mm) Personally, I didn't adjust mine too far because after a few hundred shots the trigger will smooth out and trigger pressure may get lighter. I did move it 1/16th", twice, and found a crisp release that I can live with until I get the gun broken in...then I may lighten up the trigger a bit more. After I made my adjustments, I cocked the gun and slapped it hard from all angles to see if it would discharge. It didn't, so I felt the safety factor involved was just fine.

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Next up was velocity. Mine was shooting in the mid 500 fps range with 14.5gr pellets. Too slow for my tastes. The hammer spring adjustment in the back is open access and all you need is a flat blade screw driver. Brian at Veradium Air advised me to go a couple of turns clockwise and use a chrono to measure when I hit max speed before it began to drop off. My gun needed a hair over two turns clock-wise to bring the fps up to 695 fps (15.5 fpe) Considering this gun has an eight inch barrel, you can probably squeeze some more out of it, but until I break it in I'm going to let it stay where it is. Brian advised that 700 fps is likely top end for this gun and I believe he is right, However, I'm happy to say it dropped a raccoon with a head shot at 20 yards later that evening. With a 3X fixed power scope, this is definitely a 25 to 30 yard gun for ground and tree vermin.

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Powered up to near 700 fps, it has a moderate bark to it. I put a DonnyFL KOI on it and at full power it made a "pffftttttttt..." sound about as loud as a whispered comment. That's Donny's KOI 1.22" X 7" @ $145.00 and it was a good investment. I do believe you could get by with his Tanto for $99.00 and still have a neighbor friendly report.

This is what it is. An extremely compact gun at an unbelievable price that produces enough power to clear any urban back yard of critters you don't like having around. Veradium Air did a find job of cleaning up the grit, shavings, and industrial sludge inside and the gun is a smooth working piece of equipment.

Accuracy? Well, I'm not the guy to report on that. I'm 77 with not so sharp eyes these days, but I can still shoot minute of squirrel at 40 yards with a clear scope. Someone else needs to show how it groups with various pellets and slugs. Yes...I did shoot a number of NSA 18gr slugs in the gun and they work just fine!

A note of caution I picked up from earlier posts. When you cock the gun, the cocking lever is sufficient for normal cocking pressure, but if you slam it back hard when cocking, you will end up bending/breaking the cocking lever. It's thin to fit flush with the breech. I found by putting my thumb on the rear of the lever, and using two fingers to grasp the far end of the lever, that I could ease it back smoothly (thanks Veradium Air) allowing it to cock and cycle quickly and with very little effort.



Regards,

Kindly 'Ol Uncle Hoot
 
 

Hi Dingfinger...

That initial fps I experienced was because I was testing some assorted18+gr heavy pellets and slugs I had on hand. I finally switched to the 14.5gr pellets to dial in a consistent fps to my preferences. With an 8" barrel, this gun favors the lighter ammo for max performance. Recall that I didn't adjust the regulator and that could make quite a difference, but this gun is brand new to me and I don't want to dig too deep. It's doing what I want within the ranges I shoot at.

The SPA700 has a 10" barrel and that's an entirely different story! 



Hoot
 
Thanks, Hoot

Great write up.

I also like the way you are laying out the hard case.

Mine (22 cal) arrived from Brian today, but I did not get home to unbox until after 10p

Too late to shoot!

It's now sitting at 240 Bar (after 325 strokes from near empty on 4 stage hand pump) and will sit overnight.

The fun begins tomorrow.

I'll let you know how a Tanto sounds.

Ed
 
Adding a 3.5 brass slug into the hammer and setting reg to 2,180 PSI brought my .22 PP750 ( with porting as brian did) to 22 FPE (737 FPS with 18.13 grain) for 18 shots.

14.5 grain would be closer to 800 FPS.

I did not care for the shooting balance at this power, but it is easy to break 700 FPS and make 22 FPE.


Any impact on accuracy, thane?
 
Wow...if only Thane could show some pics of how he made these two changes!

Whenever I take a pcp apart I usually hear a "Thannnggggg!" and parts fly across the room...then the only way I can control squirrels is throw the gun at them!!!



Kindly 'Ol Uncle Hoot


Careful Hoot

Throw enough guns and parts at those varmints and they build a gun and shoot at you
 
Brian, for Veridian tuned guns, already opened up the transfer port, see comparisons, and port between regulator and poppet which is the largest bottleneck. If not, 4mm is all that is needed photos show it opened up 5mm, without it regulator changes would net next to nothing. The spring really blocks this port

Reg setting is simple, air down by slowly unscrewing air gauge with tool provided in gun kit. Unscrew air tube to reveal brass slot head regulator adjustment. Mark it with punch on brass head and body to identify factory setting. Factory settings seem to be close to 1700 psi, at least on both of my PP750s. Counter Clockwise (CCW) increases pressure, Clockwise decreases pressure set point. 1/2 turn in either direction will take you past the regulator's range. I would start with a quarter turn CCW, close it up, relube airtube ring.

Two screws release handle assembly, keep an eye on the sear spring when removing handle, it won't shoot out, just small and loose fit in holes top and bottom. I turned a brass hammer plug on a lathe, but a brass bolt sized just loose to the interior of spring would work just as well. Cut to make 3.5 to 5.5 grams, keep head to rest spring against inside hammer, it will also act as a bit of a spacer increasing spring tension.

Test the spring range 1-5 turns, see where the velocity increase begins to fade and thats the peak.

More extensive discusion on GTA: https://www.gatewaytoairguns.org/GTA/index.php?topic=170095.msg156015113#msg156015113

Very fun gun to work on.

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Adding a 3.5 brass slug into the hammer and setting reg to 2,180 PSI brought my .22 PP750 ( with porting as brian did) to 22 FPE (737 FPS with 18.13 grain) for 18 shots.

14.5 grain would be closer to 800 FPS.

I did not care for the shooting balance at this power, but it is easy to break 700 FPS and make 22 FPE.


Any impact on accuracy, thane?

Accuracy suffers at higher powers in all pistols for me. Better shooters may be able to mitigate the flip up that occurs. Some added mass in the LDC can go a long way towards balancing the power increase.

When shooting from a mechanical/clamping rest it delivered the same 1/4" 25 yard groupings with stock 8" barrel at higher powers, off bags it begins to open up.
 
So I have the 177 and just put a few pellets though it. Trigger sucks!!!!!! Very gritty...Using the JSB 8 grainers I just shot this short string for now. I screwed in the hammer screw 2 turns in.

Shot count: 5
Low: 721
Hi: 724
Avg: 723
Spread: 3
STD Dev: 1.6
721
724
724
721
724

I will take it to the range with me tomorrow and try to sight in at 20 yards.....What are folks shooting their 177's at?

Tony P.
 
Just finally shot the pistol today, but it is a 177...It likes the H&N Baracuda match 10.65, but not the JSB 8.44 so far.

Shot count: 5
Low: 670
Hi: 680
Avg: 675
Spread: 10
STD Dev: 3.9
680
670
677
677
673

Just a short shot string with the H&R after 10 pellets had already been shot..this was 5 rounds at just 10 yards off a bag using a red dot sight.

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