Survey - Regulated or ideal pressures on your air rifles

[travelbike]

Just wondering what the regulated pressures are on the more expensive air rifles ? Or if you have an unregulated gun, what are the ideal pressure ranges  so they run a flatter fps curve ? Being a newbie,  I was too focused on fill pressures initially.  Now I think usable regulated pressure is more important and having enough air supply to achieve a good shot count for the intended use like field target.

I have an unregulated Crosman 1720T and it runs on a flat fps curve from 2100 psi to about 1700 psi. My typical FPS is about 610 fps using 10.5 gr crosman premieres - about 9 ft lbs. If I remember right, I can shoot close to 30 good shots. I've tethered a 22 ci tank to it regulated at 2100 psi and have gone  past 90 shots on it when tank pumped to about 2800 psi. Working on permanently connecting tank to the gun.

If you can let us know your gun brand model, pressure range or regulated pressure,  typical fps range,  bullet weight gr and foot pounds. Again thanks.

[Motorhead]

 A lot of the .177 Regulated guns run in the 110-125 bar range.
.22 & .25 guns in the 125-140 bar range.

Tho there is NO rule of thumb or fixed pressures by caliber being used, being more a gun by gun and how set up / power etc ... that determines optimum pressure.

[nervoustrigger]

There's really no such thing as an ideal pressure range unless you first freeze a bunch of other variables.  Within reason, there's more than one way to get a particular energy and shot count by manipulating porting, pressure, lift, and dwell. 

A common scenario is taking a traditional PCP and installing a regulator for better consistency.  If the intent is to keep the same energy level, you'll generally have to increase porting to compensate for the reduced operating pressure.

[K.O.]

right now I run my .177 Buc up at 3200 for the heavy stuff in the 13g-16g range... AA 10.3 and Cpum like it down around 2500 so regging almost would make sense down around 2000psi it starts sending the benji 7.9  domes into decent groups...

So I guess for the lights and mediums regging would work and give a nice long shot string...

Me for some reason I like shooting the heavies.. so I will live with finding each pellets sweet spot fill wise and plink at 2500-2000 psi... and re pump after a couple mags.

My wood stock mrod shoots very well...  10  50fpe  within 1% shots and then a short pump back to 3000 psi... at 2500 psi it likes the H&N FTT.

My new Mrod well it will be meant for cast... briefly will tackle trying 40gr   .25 with the choke and the stock 1:15 twist (somewhat overspun...)

then will switch to a 1:19 twist barrel  that has just a touch less rifling depth and no choke...   

then its headed for longer barrels and 25g-40g  .22   so it will be using to much air to have any benefit from regging... 

[Gerard]

I've tended towards finding the most power at the lowest practical pressure output by tuning, then setting up the regulator to a bit higher pressure output than that maximum in order to run things a bit quieter and more efficiently. So with my most recent build, a bottle-fed QB78D, I initially tuned it to shoot 18gr JSBs at about 700fps for a few shots, before connecting the bottle, my very short strings starting around 685 then climbing to around 715 at shot 5 then dropping to 685fps again by shot 9. My fill pressure max was about 1,250psi, finish pressure about 750psi. With more tweaking, reducing hammer mass and adjusting an SSG, I managed to tighten this up a little to 1,300psi dropping to 850psi for a similar string. Then when setting up the Ninja bottle's regulator I stacked spring washers until arriving at about 1,175psi regulated output. The resulting shot report is quieter than the second half of the unregulated spring and right on my desired output of just a hair under 20fpe. Efficiency is at about 1.4fpe/ci. It'd be a lot higher, but I chose to go with just a 13.4" long barrel, costing me about 10% of potential efficiency compared to the stock QB78D barrel.

With other setups I've similarly tried for lower pressure giving me my optimum velocity. My 2260 HPA conversion fills to 1,500psi, gives me 35 unregulated (but SSG assisted) shots with the 18gr JSB finishing at 500psi, with an ES of 5%, going from 585fps up to 615fps then back down to 585fps. Not very flat, but for the closer ranges I'm using it on grey squirrels it's plenty accurate. If I shoot it from 1,400psi down to 600psi the ES tightens up to 2.5% over 28 shots averaging 606fps. Again I'm looking at modest power output with this one, not a mighty hammer but sufficient for squirrels, and using relatively low pressure. It's a really quiet carbine, sipping air with an efficiency of 1.88fpe/ci.