Where is that air coming from?

[3Crows]

IMO, the puff of air from the hammer adjustment hole is normal. The air is leaking past the poppet stem and the ID of the hole in the valve face. The poppet stem fits closely but there is no O-ring there and thus some small amount of air can pass through the space between the poppet stem and the ID of the poppet stem hole in the valve face. A poor seal at the TP to valve interface could also result in a puff of air through the hammer adjustment hole and that would result in a loss of velocity and needs to be addressed.

 

[Vetmx]

Now you guys made me think I need to check mine for that puff of air. Have only shot it a few magazines full since I bought it used. That was about three years ago. I bought an M-rod and a P-rod used, from the same guy and he gave me the info on the tune for both. I need to learn more about tuning with the various mods and parts out there. A carbine stock should be in my future for the p-rod. It wears the factory buttstock now. Be Well Brothers, Bandito.

Concerning the puff of air. Read the last reply I sent you in a PM about the SSG. Your hammer is a piston. Your tube is a cylinder. When it flies forward, that air has to go somewhere. The faster you make the piston go, the worse it is. So you have to make sure it vents or you’ll get erratic hammer strikes.

 

[Twinkees_n_Pb]

Concerning the puff of air. Read the last reply I sent you in a PM about the SSG. Your hammer is a piston. Your tube is a cylinder. When it flies forward, that air has to go somewhere. The faster you make the piston go, the worse it is. So you have to make sure it vents or you’ll get erratic hammer strikes.

Ha.. ok. Makes sense. I guess nothing to worry about then. Thanks for sharing. Here I am thinking something is broken and/or looking see perfection. Lol.

 

[Twinkees_n_Pb]

Alright, issue identified and problem solved (was really not a problem, lol). Thank you, all for sharing and teaching me a thing or two. What a wonderful hobby… and expensive.

 

[Vetmx]

P-rods are fun little guns. Especially when you keep them in their lane. Regulated or unregulated. When I had mine, I called it a Wee-rod. Stock my goal was always three mags. Then it spent about a year with a SS valve in it, still three mags. Then I finally regulated it when a guy over on GTA wanted my SS valve. Regulated it required some more refinements but it was still a three mag and refill gun.

When I first built it I posted some pics here. But at the time, this was not a builders forum so it got minimal attention. Glad to see there are guys still tweaking on this wonderfully educational platform.

 

[Vetmx]

Dug up a pic of how I had to vent mine after I built a SSG. If you wrap the grub screw in the center of the plug on a stock gun with Teflon tape, you’ll get erratic hammer strikes. It’s because now the hammer tube is sealed. It needs to breath. And prepare us for the optometrist glaucoma test.

 

[Twinkees_n_Pb]

Dug up a pic of how I had to vent mine after I built a SSG. If you wrap the grub screw in the center of the plug on a stock gun with Teflon tape, you’ll get erratic hammer strikes. It’s because now the hammer tube is sealed. It needs to breath. And prepare us for the optometrist glaucoma test.

View attachment 542334

Yessir. Makes absolute sense… the displaced air in the space where that hammer resides has to go somewhere. And that hammer is a good size relative to the space. For every action there’s a re-action as they say… a free glaucoma test is the result.

Btw is that an FX Impact on the side there? Oh the addiction. Lol.

 

[Vetmx]

Yessir. Makes absolute sense… the displaced air in the space where that hammer resides has to go somewhere. And that hammer is a good size relative to the space. For every action there’s a re-action as they say… a free glaucoma test is the result.

Btw is that an FX Impact on the side there? Oh the addiction. Lol.

Back when that pic was taken I would imagine it was one of my MKll power plenum Impacts. Like the Prod, some other member here now owns it.

 

[3Crows]

The volume in the space behind the valve face and the tube end piece is fixed. If the hammer adjuster hole is plugged the volume is unchanged. Some hammers are vented and even if not vented they are not a tight fit in the ID of the air tube. When the hammer is cocked the air that was behind the hammer moves in front of the hammer as the hammer displaces that air. When the hammer is released it flies forward quickly and that air that was in front is displaced around the hammer or if the hammer is vented through it, it is net, net. The amount of air residing in that space is unchanged. With a completely discharged rifle, dry firing it, I do feel a tiny, tiny, puff of air through the hammer adjustment hole, not very much.

 

[SteveV]

The puff is just air being displaced by the hammer. Perfectly normal, both of mine do the same, carry on.

 

[Airgun-Revisions]

Yes this is very normal as well as the long gun. It’s just the hammer in action.