How many shots to break in a (regulated) PCP?

[DrGunner]

So, I picked up a 25 caliber Artemis M11 a little over a month ago. I haven’t had time to shoot it much, maybe 100 rounds or less. I started out zeroing at 25 yards shooting 31 Grain H&N Grizzlies, which it shot VERY well. I shot both flavors of JSBs, and it also likes the heavy 33.98 grain heavies. I shot 2 groups right around 1/2-5/8” at 50 yards with the 33.98s.
This was off of a Protektor 13B tall bunny ear rear bag used as a front rest, shouldered with no rear bag- in 32-35F weather.
This morning I shot 2 groups, using Wayne’s amazing 34.5gr cast pellets. Both groups were ragged holes at 50, around 1/2”. More than sufficient for the purpose of the rifle- pest control.

Tonight I had time to actually set up a backstop, and get started with my Competition Electronics ProChronoDLX. I bought the indoor lighting kit and the chrony was flawless with one exception- the Bluetooth was sending, but my phone would not link with it. Time to contact CE & see why... It is a new production iPhone 11  Pro Max Plus, so it may just be that they have not updated their app for that phone model yet.

Onto the confusing data. All 3 strings started with the rifle topped off @ 250bar.

String 1- JSB Diabolo Exact 25.39

Shot 1- 906
2- 912
3-918
4-916
5-921
6-918
7-916
8-917
9-914

String 2- JSB Diabolo Exact 33.98gr

1- 796
2-806
3-812
4-814
5-818
6-821
7-818
8-815
9-817

String 3- Wayne’s Wonders 34.5gr

1-805
2-823
3-829
4-831
5-833
6-831
7-834
8-832
9-835


I guess I was expecting more power, especially after reading Wayne’s thread, “My M11 is turning out to be a powerhouse.”
I was hoping to be in the 900-920 range with the heavier pellets. Out of curiosity, I checked the screw on the hammer spring and it is set at three full turns from fully seated. I put it back to where it started, 3 turns out from seated, not wanting to change anything just yet before I understand more.

Is this normal behavior?

Can I expect velocities to increase with break-in?

Please be gentle- I am new to PCPs and really don’t know what to expect.
Pressure at the regulator reads right around 150.

Should I be making any adjustments at this point or is it a matter of more shots before it’s broken in?

About how many shots in general would you all consider adequate to say the rifles sufficiently broken in, and it’s time to start tweaking the hammer spring screw or changing anything at the regulator?

Accuracy is outstanding so I’m not worried about that, although I do know it will change somewhat with velocity.

DrGunner

[RDB]

I don't think there's a hard fast rule for break in. In my experience, most of the ones ive owned actually settled down about 10fps from new. But ive heard of them coming up some after break in.

Your strings look pretty good. If your looking for a little more speed,  go ahead and turn the hammer spring in another turn and see where that gets you. If velocity doesn't raise, that means your already running at the peek of your pressure range and reg pressure would need to be bumped up.

We like to tune our guns 3-5% below max velocity for the most efficient tune. That just means running the hammer spring in until velocity quits rising, and back it off 3-5% for the most efficient air use.

[DrGunner]

RDB- thanks for weighing in. I scoped it again, just to double check the transfer port & look for shavings. The bore looked pretty dull so I cleaned it & shot 2 more strings.
After some mental math, I figured I’ve only got about 70-80 shots through it.
I shot these after I cleaned it- I still haven’t touched the hammer spring. It came up some in velocity, so I’m going to just shoot it for a while, clean when it looks dingy and keep going as long as it looks like it’s gaining velocity. Once it levels off, I’ll start with adjustments.

Strings

JSB 25.39gr

1-687
2-720
3-761
4-788
5-809
6-906
7-912
8-904
9-898
10-907
11-912
12-918
13-919
14-900

String 2- Wayne’s 34.5

1-846
2-848
3-847
4-844
5-848
6-849
7-846
8-848
9-842

 DrGunner

[WesBob]

Looks like it had a bit of creep in the reg on that first string you last reported. You are switching Ammo but not refilling the gun each time , am I correct?
Adjusting the hammer spring is pretty easy with a small flat screwdriver, no need to remove the stock. Wouldn't hurt to turn it one full turn and see how it does. Easy to turn back again.
If that doesn't increase the velocity you may have to turn up the regulator pressure a bit.
It has a nice big plenum and fairly large ports so there should be fairly goid power available.

[DrGunner]

Looks like it had a bit of creep in the reg on that first string you last reported. You are switching Ammo but not refilling the gun each time , am I correct?
Adjusting the hammer spring is pretty easy with a small flat screwdriver, no need to remove the stock. Wouldn't hurt to turn it one full turn and see how it does. Easy to turn back again.
If that doesn't increase the velocity you may have to turn up the regulator pressure a bit.
It has a nice big plenum and fairly large ports so there should be fairly goid power available.

I don’t recall what the gun was filled to before the first string, but I know it was topped off before the second string.

Still learning here- creep?
As in it was not functioning properly and slowly increased pressure from shot to shot?
Remember, total noob here.
 Is that a function of fill pressure? Break-in? Or possibly a problem?

It’s late & my daughter is having friends stay over, so I’ll get back to testing tomorrow, I’ll shoot a couple strings over the chrony, then give the hammer spring a full turn & see what’s what.

How hard is it to access and adjust the regulator? I’m handy and have plenty of tools.

This is that point where I realize I’m treading water, it’s getting over my head, and I need to learn more.

I wish there was a “PCPs-R-US” on the corner & I could just drop it off & pay a professional to tune it. I work a LOT, so I’m hoping I can resolve this easily by my onesies without a long, drawn out downward spiral for a learning curve.

DrGunner

[Pelletjunkie]

If you look at your first shot, it’s slow for a reason and it’s reg creep. Let’s say your reg is set at 130 bar. Your hammer spring is adjusted to hit the valve with 130b of air pressure behind it and give you 900fps. Now your gun sits for a while and a creepy/leaky reg, that is set at 130b starts letting more air into the plenum. Now by the time you go to shoot it your plenum pressure has crept up from 130b to 150b. Your hammer hits the valve with the first shot and doesn’t move it as much because there is more pressure in the plenum. After a couple shots everything is back to normal until you let the gun sit long enough for old Mr Creepy to his thing again. On some guns, it can correct itself after shooting and refills. But don’t bank on it. Yes it can be fixed. You either buy a good reg or get your feet wet learning how to fix yours. I hear from time to time the “I fire two shots into the ground” before I start shooting. Personally, there is no sense in having a regulated PCP if your first shot isn’t spot on.

[DrGunner]

If you look at your first shot, it’s slow for a reason and it’s reg creep. Let’s say your reg is set at 130 bar. Your hammer spring is adjusted to hit the valve with 130b of air pressure behind it and give you 900fps. Now your gun sits for a while and a creepy/leaky reg, that is set at 130b starts letting more air into the plenum. Now by the time you go to shoot it your plenum pressure has crept up from 130b to 150b. Your hammer hits the valve with the first shot and doesn’t move it as much because there is more pressure in the plenum. After a couple shots everything is back to normal until you let the gun sit long enough for old Mr Creepy to his thing again. On some guns, it can correct itself after shooting and refills. But don’t bank on it. Yes it can be fixed. You either buy a good reg or get your feet wet learning how to fix yours. I hear from time to time the “I fire two shots into the ground” before I start shooting. Personally, there is no sense in having a regulated PCP if your first shot isn’t spot on.

I agree. So- if I understand you correctly, I should be on the lookout for low velocity initial shots any time the gun sits for a while?

If it is creep, and does not self correct, I’d rather  replace it with a better regulator than try to fix it, provided a replacement doesn’t cost too much.

IE: https://www.huma-air.com/Artemis-M11-Replacement-Tuning-Regulator

DrG

[Pelletjunkie]

Yes low velocity first shots. If you are happy with the guns accuracy, velocity and ergonomics, get a Huma reg and live happily ever after. Cost you around $100.

[Back_Roads]

 The nice thing about the M11 is there is a gauge on the regulator, keep a close eye on the bottom gauge " Reg. gauge" and the front gauge fill pressure,. I have been watching mine with no signs of creap, I also have not filled the gun to max PSI as of yet but am filling to 3200 psi as that is the most my tanks fill to, but sometimes the creep may only happen at max fill pressures.
 I will top my M11 off with my 12 v portable to full fill pressures today for further testing.

[DrGunner]

The nice thing about the M11 is there is a gauge on the regulator, keep a close eye on the bottom gauge " Reg. gauge" and the front gauge fill pressure,. I have been watching mine with no signs of creap, I also have not filled the gun to max PSI as of yet but am filling to 3200 psi as that is the most my tanks fill to, but sometimes the creep may only happen at max fill pressures.
 I will top my M11 off with my 12 v portable to full fill pressures today for further testing.

Will do. I filled to 3000 for the first 3 outings/about 80 shots; I’ve had precious little time to shoot since I received my M11.
I reread Wayne52’s thread yesterday @ work, and noted that he’d been filling to 250bar.
Yesterday I started filling to 3600psi, which might have been enough to cause the reg to creep if that’s what’s happening.
Unfortunately, I did not top off the gun last night before locking it in the safe.
I just filled it to around 3200psi. I’ll check on it periodically throughout the day to see if the pressure at the reg drops. Right now it’s at 150.
If there’s no creep in 24 hours, I will fill to 250bar/3600 and monitor it again.
If the reg won’t hold at 3600, it will be replaced by a Huma as that will be my final working pressure.

Is it a difficult task to either adjust or swap out the regulator on this rifle?

I noted in Wayne’s thread that his regulator is set at 160. I’d like to be in the 900 block of JSB lane when I meet my first feral invader.
I know 840 will do the job, but I’m hoping to be able to test & shoot this one @ 75, 100 yards and beyond.

Thanks for your input.

DrG

[DrGunner]

Just so I’m clear- on the M11, the hammer screw is turned IN to increase velocity, right?

DrG

[WesBob]

It may very well be the higher pressure showing up the creep more. I haven't pulled the reg out but have taken the gun apart and it's pretty simple, with the tube unscrewing and the other two sections come apart with the side screws after taking breech off. I like the simplicity of how Snowpeak builds their guns, fairly easy to work on.
The front of the reg has a flat head screw. I believe this is the adjustment and so if it's like lane regs or altaros regs you would turn that screw counter clockwise for more power/higher pressure.
If your gun is at 150 bar after shooting a few shots then yours is set a bit higher than some of these, so you may be able to get your desired power as is just turning up the hammer spring tension. The creep causes the reg pressure to slowly rise, so if you see it at 160 after it's been sitting a day for example, shoot ten shots then check it again. If it's dropped to 150 or 140 that's the true reg setting, not what you saw after sitting.

Yep turn in to increase power on the hammer

[DrGunner]

WesBob- Perfect, exactly the answers I was looking for. I watched a 2 part vid of a guy disassembling an M10, and it looked really simple, but that was an unregulated gun.
I’ll keep testing for creep, and if I can rule that out I may well set the reg a little higher, 155 or 160. I’ve been watching the progress of 2 other M11 .25 owners and the regulator on mine came from the factory with the reg set at the lowest of the three, with the others at 155 & 160.
I don’t want to end up over pushing the hammer and risk losing all kinds of air to get the velocity I want; I’d rather bump up the reg and reduce the hammer spring a tad to keep it running efficiently, at least in theory? Please, tell me if my thinking is wrong here.

If the reg shows me any signs of creep, it’s gone. I have no problem whatsoever spending $100 plus shipping for a Huma. The gun has already shown me that it’s accurate enough, and I like it enough to warrant the investment to get it shooting how I want.

Does anyone know if there’s a US distributor that would carry the M11 Huma regulator?

All the sources I’ve seen are in the UK. I’d rather order here to save money and time.

DrG

[Wayne52]

A couple days ago I was out with mine and I checked the regulator gauge after the gun had warmed up and the reg pressure was way more than it normally is so I shot it without a pellet then checked the reg pressure a few hours later and it was right where it should be.  Coming in doors from the cold the air in the plenum will increase when it warms up.  There's been several people that immediately replaced the regulator in SPA guns and some of them came to the realization that there was never anything wrong with the original reg to begin with.  I have had really good luck with the regulators in my SPA guns.  I got me a raccoon yesterday with my M16, the reg in that always does a really good job.

[DrGunner]

The post below by Wayne52 and others in his “My M11 is Turning Out to be a Beast” thread have me thinking I should wait and put a lot more shots through this gun before messing with the regulator set point. I’ve noticed that my velocities with my desired load, the 33.98 JSBs have been creeping up with my shot count-slowly, but very definitely and rather steadily.
Once I either rule out or confirm regulator creep, I can keep working.
I’d really like to know how much more velocity increase I can expect with break in- that would help immensely. Would it be beneficial to do some fine lapping of the bore, or is it better to shoot it through break in?
Wayne’s rifle is shooting at the velocity I want from mine, with his reg set at 160; but he came to the conclusion that his reg is probably set a bit too high, as he adjusted his hammer spring to coil bind and was still not getting efficient filling of the plenum. If I do adjust, I’ll likely only bump up 1/2 turn to 155.

I know no 2 PCPs are the same, but comparing Wayne’s shot strings to mine, and our regulator pressures, I can’t help but think my set point is the reason I’m still 60-70fps behind where Wayne is & where I want to be.
I certainly don’t want mine operating at coil bind on the hammer (possible hammer bounce and air loss?)- Id rather up the regulator a tad and then have the ability to tweak the hammer up or down as needed.

Again, I’m new to all this and I’m thinking out loud with my posts, so if my thinking is in error, please educate me!

DrGunner

Wayne52-

This is what I'm getting right now with the 34.5 grainers, once I had a thousand rounds through my SPAM16 in .22 my velocity had increased considerably, from out of the box it was doing 28.5 fpe for 55 shots and by the time I hit 1000 rounds through it I was getting 60 shots at 32fpe.  It's hard to say what the M11 will be doing after it has a thousand rounds through it but it only stands to reason it will increase I've no doubt.  My regulator gauge is reading 160bar the way it came.

                                             

[DrGunner]

A couple days ago I was out with mine and I checked the regulator gauge after the gun had warmed up and the reg pressure was way more than it normally is so I shot it without a pellet then checked the reg pressure a few hours later and it was right where it should be.  Coming in doors from the cold the air in the plenum will increase when it warms up.  There's been several people that immediately replaced the regulator in SPA guns and some of them came to the realization that there was never anything wrong with the original reg to begin with.  I have had really good luck with the regulators in my SPA guns.  I got me a raccoon yesterday with my M16, the reg in that always does a really good job.

Wayne -good point on cold to warm air, but all the shot strings that I posted in this thread were shot indoors, room temperature. So I still have a job of watching mine for creep, but given everything I know so far I am not going to plan on replacing the regulator unless I can prove that it’s consistently creeping, and that it does not go away after a healthy number of pellets, perhaps 1000 shots.

DrG

[RDB]

Dr, all your strings look good except the fourth one you posted. Sometimes if the rifle is filled when the reg is below it's set point, it takes a couple shots to level it back out.

On your other strings. The first shot is about 10 fps slower than the rest. Which indicates a wee bit of creep. Nothing id worry about,but may very well get better with a tin of pellets through it. Creep is when the pressure rises in the plenum, so look for it to ceep up above 150 bar.

Now, the little bit of creep is causing your first shot to be slower. That means your hammer doesn't have enough force to open the valve at higher pressure. So turning up your reg will only make you have to lean on the hammer spring harder to open the valve to get a higher fps. 

With your first shot being slow from a bit of pressure rise leads me to believe you need more hammer strike at the state of tune the gun is currently set at. It should get rid of the first slow shot and bump your fps up.

Im not the best at explaining this as others, but hope it helps some.

[Wayne52]

Rod Mine is at 160bar which is too high for the hammer spring, I had it up to 1/4 turn before coil bind and it was still increasing the velocity.  I'm going to set mine at about 140bar once I get about a thousand through it, I'll tear it down, inspect it and reassemble it.  PCP's are so easy to work on IMO.

[RDB]

Rod Mine is at 160bar which is too high for the hammer spring, I had it up to 1/4 turn before coil bind and it was still increasing the velocity.  I'm going to set mine at about 140bar once I get about a thousand through it, I'll tear it down, inspect it and reassemble it.  PCP's are so easy to work on IMO.

Sounds like a good plan Wayne. Looks like there's a fair amount of plenum to work with. You guys are giving me an itchy Buy finger!

[DrGunner]

Dr, all your strings look good except the fourth one you posted. Sometimes if the rifle is filled when the reg is below it's set point, it takes a couple shots to level it back out.

On your other strings. The first shot is about 10 fps slower than the rest. Which indicates a wee bit of creep. Nothing id worry about,but may very well get better with a tin of pellets through it. Creep is when the pressure rises in the plenum, so look for it to ceep up above 150 bar.

Now, the little bit of creep is causing your first shot to be slower. That means your hammer doesn't have enough force to open the valve at higher pressure. So turning up your reg will only make you have to lean on the hammer spring harder to open the valve to get a higher fps. 

With your first shot being slow from a bit of pressure rise leads me to believe you need more hammer strike at the state of tune the gun is currently set at. It should get rid of the first slow shot and bump your fps up.

Im not the best at explaining this as others, but hope it helps some.

That makes sense- the creepy string you’re referring to was the only one shot where I didn’t check the pressure in the gun or at the reg before shooting. I filled to 3200 really early this morning, took a closeup shot of the reg gauge, and checked it again just now, over 4 hours later.

Both gauges appeared to be exactly where they were 4 hours ago.


Following y’all’s advice, I turned the hammer spring in 1 full turn.

I just now put 6 shots of JSB 33.98 over the chrony:

1-852
2-844
3-846
4-843
5-845
6-847

Question 1:
Should I have given it more time than 4 hours?

I have no frame of reference for how long it should take for creep to affect the rifle.

After I shot that mini string, I filled it to 250 and put it back in the safe.

Question 2:
How much time is sufficient to let it sit- to be reasonably certain the regulator is or is not creeping?

Of course, just to make things more fun, my CF tank hit equilibrium just as the rifle hit 250 bar, which means if I want to keep testing at that pressure, I’m going to need to make an air run today. The local paintball shop is open all weekend and it’s only a 15 minute drive so no biggie there, feeling kind a lazy so if I do shoot more today, I will probably keep shooting until my tank is down to 3200 just to get more lead through the bore for break in. I found it interesting that the velocity of the JSB heavies is noticeably higher today than yesterday, as I said earlier, the entire rifle just seems to be speeding up with use.
This has me rethinking the regulator pressure, I’m just gonna leave it alone and shoot it for a while until I am getting stable velocities out of the same ammo.

Question 3:
I asked this before, Maybe no one caught the question. Would there be any benefit to doing some light lapping of the bore, or is it best to just shoot it in?



I really do enjoy this kind of tinkering, but I kind of feel like I’m winging it here and learning as I go because I’ve never done this before. Can anyone point me to any good reference threads/stickies/videos for a noobstick like me to catch up and get a handle on knowing what I’m doing?
I really appreciate y’all taking the time to post and answer my incessant questions.
It would not surprise me in the least if several of you have rolled your eyes reading some of my retarded questions.
I feel like I am so far behind the curve of so many of you and there is so much to learn in tuning these rifles when you’re starting from the bottom.

I said this before – if I weren’t working two businesses 60 hours a week plus family time with two kids in sports, I’d probably have much more fun picking away at this slowly. I swear, if there were someone local to me that would take this rifle and tune it to my desired load and speed, fee for service, I would jump on it.

DrGunner