EVOL Does BETH have a sick regulator

[mr007s]

Been gathering data for a couple weeks, sorting out performance of 5 pellets, group sizes at 50 yards, and lots of chrony print outs to help decide 2 or 3 choices of ammo for Beth.
I have found a disturbing problem during all the testing. My very first shot with 18.2 JTS was 965 fps. The next 9 shots were in the 1015-1020 fps range. No problem, the gun is new and things need to be broken in. After the initial shot the rest of the days strings have no wild spread changes but I am NOT getting single digit numbers for my extreme spread, even when throwing out the low first shot. This happens every day so I just fire a couple rounds before the testing begins.
Is this what REG CREEP is? Do I have a sick reg or some other thing going on that isnt allowing my ES to be single digit?
Hope some of you have a fix for this as it is very annoying.

 

[CTAirgunner]

Been gathering data for a couple weeks, sorting out performance of 5 pellets, group sizes at 50 yards, and lots of chrony print outs to help decide 2 or 3 choices of ammo for Beth.
I have found a disturbing problem during all the testing. My very first shot with 18.2 JTS was 965 fps. The next 9 shots were in the 1015-1020 fps range. No problem, the gun is new and things need to be broken in. After the initial shot the rest of the days strings have no wild spread changes but I am NOT getting single digit numbers for my extreme spread, even when throwing out the low first shot. This happens every day so I just fire a couple rounds before the testing begins.
Is this what REG CREEP is? Do I have a sick reg or some other thing going on that isnt allowing my ES to be single digit?
Hope some of you have a fix for this as it is very annoying.

Next time you fill the rifle up, look at your reg pressure on the gauge, leave it for a few days, check the gauge again. It should indeed go up if it is creeping.

 

[mr007s]

Next time you fill the rifle up, look at your reg pressure on the gauge, leave it for a few days, check the gauge again. It should indeed go up if it is creeping.

I should mention that I have read that the regs come set t0 1950-2000 psi.
My reg gauge reads 2200, but how accurate are these gauges? I dont always trust the small gauges.

 

[CTAirgunner]

I should mention that I have read that the regs come set t0 1950-2000 psi.
My reg gauge reads 2200, but how accurate are these gauges? I dont always trust the small gauges.

Don't pay attention to the numbers just yet, what I would do is just shoot it down, refill it. Look at it after it cools down , then check it each day, see if the regular gauge creeps up.

 

[mr007s]

Don't pay attention to the numbers just yet, what I would do is just shoot it down, refill it. Look at it after it cools down , then check it each day, see if the regular gauge creeps up.

Will do, thanks. It will be hard waiting a few days to fondle BETH.

 

[Dairyboy]

What is your ES currently? Minus first slow shot. Also where is your adjustment at for hammer spring. What you need to do is fond the max speed and then back off 15-20fps. Being you have the 18" barrel version I'm guessing the hammer spring is backed off too much for only shooting at 1020fps with the 18gr with them. I also don't know if my reg does single digit ES. I don't stress about that. If its over 15fps then I get concerned alittle but nothing before that.

 

[CTAirgunner]

What is your ES currently? Minus first slow shot. Also where is your adjustment at for hammer spring. What you need to do is fond the max speed and then back off 15-20fps. Being you have the 18" barrel version I'm guessing the hammer spring is backed off too much for only shooting at 1020fps with the 18gr with them. I also don't know if my reg does single digit ES. I don't stress about that. If its over 15fps then I get concerned alittle but nothing before that.

I didn't even think of that, if you go by the 15 fps per inch of barrel rule he could 100% turn his regulator down as well, I am thinking this may definitely be a tune thing considering he is shooting the 18s.

When I had my original hps with a 3 inch longer barrel, I was at 1200 psi on the reg shooting them at 890 for like 145 shots lol.

 

[mr007s]

What is your ES currently? Minus first slow shot. Also where is your adjustment at for hammer spring. What you need to do is fond the max speed and then back off 15-20fps. Being you have the 18" barrel version I'm guessing the hammer spring is backed off too much for only shooting at 1020fps with the 18gr with them. I also don't know if my reg does single digit ES. I don't stress about that. If its over 15fps then I get concerned alittle but nothing before that.

I will go thru my notes and report back. ES varies with the different pellet weights. I am testing JTS 18.1, 21.53, 22.07, NSA 20.02 in .2165 and JSB 18.1

 

[Dairyboy]

I didn't even think of that, if you go by the 15 fps per inch of barrel rule he could 100% turn his regulator down as well, I am thinking this may definitely be a tune thing considering he is shooting the 18s.

When I had my original hps with a 3 inch longer barrel, I was at 1200 psi on the reg shooting them at 890 for like 145 shots lol.

Yeah my 15" I had at 1600psi with I think 110shots in that 880fps range also lol very impressive actually

 

[Bladebum]

Been gathering data for a couple weeks, sorting out performance of 5 pellets, group sizes at 50 yards, and lots of chrony print outs to help decide 2 or 3 choices of ammo for Beth.
I have found a disturbing problem during all the testing. My very first shot with 18.2 JTS was 965 fps. The next 9 shots were in the 1015-1020 fps range. No problem, the gun is new and things need to be broken in. After the initial shot the rest of the days strings have no wild spread changes but I am NOT getting single digit numbers for my extreme spread, even when throwing out the low first shot. This happens every day so I just fire a couple rounds before the testing begins.
Is this what REG CREEP is? Do I have a sick reg or some other thing going on that isnt allowing my ES to be single digit?
Hope some of you have a fix for this as it is very annoying.

It is indeed reg creep, or off balance tune. Like @CTAirgunner said check for creep over a few days. Even if it is indeed creeping, that is WAY to hot for an 18 grain pellet, and to try and smooth things out with more HS would just drive them faster. Also, if your reg is sitting at 2200 and you want to shoot pellets I would go in and turn that down to probably 1800 or so. Woth that barrel and reg pressure your more like on a slug tune, and likely not balanced with HS like @Dairyboy stated.

Also, I know that we all strive to see single digits on the chronograph but I feel it is highly overated most times. You figure many unregulated guns swing 60-100 fps in thier shot string and accuracy is hardly affected.

 

[CTAirgunner]

Will do, thanks. It will be hard waiting a few days to fondle BETH.

Trust me bud I know that feeling!

 

[pan60]

i think if your goingig to be shooting 18 gr it will need to be turned down.
keep us posed on rather your getting creep or just the tune.

 

[Airgun-hobbyist]

A couple of things that haven't been addressed yet...

Tom's regulator is not a creeping/leaking valve like some styles in the industry. What you are seeing is actually not a regulator creeping air past it, but a simple change in atmospheric conditions from when the gun was placed out of service and picked back up layer. (And that is why it is also looked at as inconsistent creep and ES). You'll notice on the gauges that cylinder pressures fluctuate quite a bit, even just handling the gun. (Pulling from the safe or out of the gun case and fondling Beth lovingly for the next ten minutes will likely show a cylinder gauge change of 50-100psi). This pressure change is true for the plenum side of the regulator as well, but not as easily noticed. This slightly higher plenum air doesn't go backwards and so the plenum side stays somewhat over pressurized for the particular hammer spring setting. The spring setting then has to overcome the additional plenum pressure on that first shot, oftentimes at a lower fps if the tune is on the verge of the max abilities of the spring and hammer at a given reg pressure. Changes in internal atmospheric conditions are not necessarily avoidable and subject to about all regulated PCP's to some degree.

The second thing that is not addressed is stiction of moving parts from either o-rings, greases, or oils. This hammer, spring and valve system does not have sealing o-rings so it isn't stiction there, but it is susceptible to some stiction if there is an excess of oils and greases that need "warmed" with a shot or two. These lubes dragging will create a different extreme spread based on operating temperature. Tom has some of the best machined guns in the business, so his parts don't drag much and do produce very tight extreme spread. So your gun might just need cleaned of all internal "contaminants" and ran "dry" with a very light application of micro penetrating high viscosity oil.

 

[pan60]

doesnt Tom tune these gun to run the 25 gr pellets in the 880 890 range? if so and as mentioned, it is still to hot for the 18 gr or at least i would think.

 

[mr007s]

I am posting results of my testing for the last couple weeks.
I will mention a few things first and hope my approach is straight forward and will not be confusing.
Session 1, chrony shots straight from AOA, no adjustments. JTS 18.1 were over 1000 but surprised by the low ES and the 50 yard groups. This would work fine for sitting on the porch with a cool beer and plinking but not for 100 yard work,
Session 2, turned the HS 1/2 round CCW, which only slowed fps by 4 except for the 25.4 which was 10 less
Session 3, Went another full round for a total of 1 1/2 CCW
Session 4, CCW another 1/2 round for total of 2 and things really slowed down and ES got large
Session 5. Went back 1/4 turn CW for total of 1 3/4 CCW and liked the fps on the 23.51 and 22.07 but ES still in double digits.

Note: I was testing NSA 20.2 in 216.5 which fit well in my mutant. They seen loose in Beth and would the .217 be a better option?

Be sure and study my scanned report and tell what I can do to get it better. I dont have the tools to go into Beth nor want to if at all possible so that is that.
Thank each of you for helping out here, I worry too much.

 

[Woogie_man]

I should mention that I have read that the regs come set t0 1950-2000 psi.
My reg gauge reads 2200, but how accurate are these gauges? I dont always trust the small gauges.

My Paradigm came with the reg at 2200. So that is normal. I ended up lowering the reg to around 1900 to shoot the 25.4 grain 22 pellets. I am getting those single digit numbers you are looking for.

Though honestly if you are getting the groups you want...don't worry about the numbers. To often we get sucked into a number game and over think things.

 

[Airgun-hobbyist]

@mr007s As what appears to be the same with your Evol's, mine does like a medium to heavy hammer spring tension to keep extreme spread tight, even with a lighter regulator setting. It will normally be around 2-3 fps spread, with an off 5+ once in a while. If I try and go too light on the spring I get bigger spreads. If you want that tight extreme spread with light pellets then you will likely need to change the regulator to a lighter setting.

 

[mr007s]

Don't pay attention to the numbers just yet, what I would do is just shoot it down, refill it. Look at it after it cools down , then check it each day, see if the regular gauge creeps up.

I am doing that today. Rain is in the area so it will not be hard to wait a couple days and see if there is a change

 

[mr007s]

i think if your goingig to be shooting 18 gr it will need to be turned down.
keep us posed on rather your getting creep or just the tune.

I like what I am seeing with the 21.53 and 22.07 so probably wont worry with the 18.1, they still group well out to 50 or so

 

[Dairyboy]

Agreed with the above. Just simply not enough spring for the reg setting. That explains the ES. Now the real question to see is about the first shot.