Stoeger How low can a PCP regulator be set

[slugdug]

New PCP shooter with a Stoeger XM1 scout .22. I'm having a lot of fun with this guy but have been asked to help a friend out with pests in her barn. I'm wondering if there is a limit to just how low a regulator can be set on this carbine? I don't want to ventilate her barn and will be testing with some scrap material but I've never adjusted a regulator before. Not sure if it's even possible to get down to what I need to be at. My guess would be under 400fps.

 

[Avator]

Be sure to degas the gun before making lower adjustments to a regulator. You can increase them under pressure but don't reduce them.

 

[Hobbyman2007]

I’d leave the regulator pressure where it is and use a weaker hammer spring. Then if you want to return to high power it’s just a spring swap.

Most regulators if not all have an operating range, I’d say between 75 and 180 bar. Check with the manufacturer for their specs.

 

[Motorhead]

How low ... so low "NO AIR" even makes it into plenum

 

[slugdug]

Be sure to degas the gun before making lower adjustments to a regulator. You can increase them under pressure but don't reduce them.

Good point, will do if I try it.

 

[slugdug]

I’d leave the regulator pressure where it is and use a weaker hammer spring. Then if you want to return to high power it’s just a spring swap.

Most regulators if not all have an operating range, I’d say between 75 and 180 bar. Check with the manufacturer for their specs.

This was my first thought, and it would be the easiest. You think there is that much adjustment?

 

[slugdug]

How low ... so low "NO AIR" even makes it into plenum

Can the hammer spring be adjusted to the point of not allowing any air? Are there any physical stops or will the screw just back all the way out? Can damage be done approaching full spring pressure or no spring pressure?

 

[coastal drifter]

I have mine set at 70bar and get a good SD and shoot count. .22 cal 600mm barrel 18gr. pellets 900fps

 

[Motorhead]

Can the hammer spring be adjusted to the point of not allowing any air? Are there any physical stops or will the screw just back all the way out? Can damage be done approaching full spring pressure or no spring pressure?

You always want "Ideally" to have a swift and quick hammer strike onto valve poppet.
Now said .... generally if set up running at lower pressure/s the weight of hammer also becoming lighter as well.

A lazy / weak hammer strike won't work worth a hoot ... FYI

 

[Hobbyman2007]

I forgot to mention. If wanting to shoot any living creature, there should be thought on being humane. If shooting mice or larger rodents, this still applies. Dropping velocity below 400 FPS so as to not damage a barn. I would suggest you more than likely don’t have the energy to dispatch a pest. I’ve shot at many pests with Canadian sub 500 FPS pistols. I don’t any longer.

 

[slugdug]

I forgot to mention. If wanting to shoot any living creature, there should be thought on being humane. If shooting mice or larger rodents, this still applies. Dropping velocity below 400 FPS so as to not damage a barn. I would suggest you more than likely don’t have the energy to dispatch a pest. I’ve shot at many pests with Canadian sub 500 FPS pistols. I don’t any longer.

I'm at 30fpe now with an 18gr. I'm sure there is room to drop that and do both. I don't think tweaking the hammer spring is going to have enough effect though. The way all is set now, I'm pushing that 18gr pellet at just over 900 fps.

 

[beerthief]

Where does everyone get the idea that one NEEDs 20 FPE and 800 FPS to kill a mouse or rat or pigeon in a berm ? MY friends and i would kill any of these targets with Daisy BB guns . We shot them watch a short dance and they were dead .
OK rant over

 

[Hobbyman2007]

Where does everyone get the idea that one NEEDs 20 FPE and 800 FPS to kill a mouse or rat or pigeon in a berm ? MY friends and i would kill any of these targets with Daisy BB guns . We shot them watch a short dance and they were dead .
OK rant over

You are correct, you don’t need 20 ft lbs for that. Let’s say you’re shooting a 8.4 grain pellet at 500fps. At the muzzle you’re looking at 4.7 ft lbs. at 20 yards that’s dropped to 3.7 ft lbs. that really isn’t a whole lot of energy. More than likely enough for a pass through on a mouse, a big barn rat not likely. To each their own, I know I won’t shoot at an animal with less than 10ft lbs.

Back to the original posters question. I suggested he REPLACE the hammer spring with a weaker spring. Only because it’s a much simpler way of dropping the velocity. Not because it’s the correct way to get the best efficiency or a way to get the best consistency. It’s the simplest way and easily reversible without risking damage to the regulator. OK rant over.

 

[Ezana4CE]

This tangential discussion is funny. Using some of your ”rationale” I guess the bulk of the UK airgun community is functioning off of flawed physics and ethics. Ratting is pretty big in their community with sub-12 fpe restrictions.

@slugdug The member advising you to follow the regulator manufacturer’s recommended operating range provided sound advice. Operating within the recommended range making adjustments to the reg, and hammer spring, while chronographing shots, and testing penetration on the same or similar materials that will be behind your intended targets is probably a sufficient exercise to know whether you will risk damaging anything on pass throughs or misses. Keep in mind that you’re not monitoring the regulator adjustment in terms of fps of a given projectile (velocity can change by switching projectiles or projectile weights without altering any settings. Even temperature changes), but by psi/bar setting of the regulator. The velocity can change with a hammer spring adjustment leaving the regulator set pressure the same. I’ve killed rodents with a Crosman Punpmaster and bbs. I wojldnt be concerned about power. If you can penetrate cardboard, the rodent should be dead within a reasonable distance.