PGP Mod Questions!

[flavordeliverer]

I'm making small modifications to my old PGP found in my ma's attic. Just purchased a dummy 12 gram (front port) from RTR and a cocker slide frame from ebay, to go the CA route.

I'm piecing together what info is out there on upgrading these brass babies. But there are still gaps I'm having issues filling. What's the easiest way for me to route an air line through the front 12g changer? Also, is HPA possible with this mod??
My main motivation for going CA is because I'm in Hawai'i and most stores are not dependable with having what you want, and I can't get 12 grams shipped out here.

I've also purchased a seal kit from PGP Junkies. Any other upgrade/mod suggestions? I realize I'm putting more $ into this marker than it's worth, but hey, I need a hobby again.

Thanks as always for being a great resource. First time I was on here was 19 years ago!

[Magageddon]

They used to make constant air adapter that if you ask around in the wtb section, someone might be willing to sell one

Option 2 is to cut a slot in the lower tube where the 12 gram goes and fit a dummy 12 gram with an air fitting port and then you can run an air line to the gun, the cut out slot would also act as a dropout fast changer for 12 grams.

both of these mods would still require drilling/tapping the pgp frame for an asa to go on or since you said you bought a cocker slide frame, you can get an adapter plate from some of the guys on here to put that slide frame on your pgp, as is without the adapter plate it will not bolt on

[Trbo323]

Hmmm. My first intention is to say drill a hole in the front plug but I'm worried whatever fitting you put into the dummy 12g will take up more space than you have available

I don't see any reason it wouldn't work on HPA. You may need a shp reg to make sure you are feeding it enough pressure though

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[JeepDVLZ45]

I have run a Sheridan based marker on HPA this way with no issues (during the winter) . I did have an RVA which made my life a little easier

To Jordan ‘s point below, I did open up the transfer port as well as run a centerfire bolt and freak bore that marker…that is probably made it possible.

[Jordan]

The short, large bore barrel, the small valve chamber, and the even smaller transfer ports in the valve and body make it a challenge to get velocity on HPA. Add in the rim-fire bolt setup and it becomes a challenge to get proper shooting speeds even on CO2 occasionally.

Like Trbo mentioned, running a SHP tank might work. I'm a big fan of several small mods that help with velocity and would recommend you dig around in this subsection, there's lots of info.

JeeperCreeper does good work, among others, if you'd rather have someone else take care of the "invasive" mods.

[flavordeliverer]

It sounds like I should stick with c02 for now. Thanks for the info

Magageddon Thanks for your input! A buddy has already 3d printed an adapter plate for the frame so I'm hoping that works.

Trbo323 I had the same feelings. I'll keep digging to see what other members have done. Thanks

[Trbo323]

A few random ideas, are there Walmarts out by you? That's how I get my co2. It's cheap through them.

Amazon?


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[flavordeliverer]

Amazon won't ship em. We have a Walmart, though they don't consistently stock. #LuckyILiveHawaii

I try not to complain.

[BrickHaus]

Look into Redrock MN for 12ies. I don't see anything on their site stating they won't ship to Hawaii, but being everything requires air, they may not. It's a source for 12 grams many MCBers use though, so it's worth an email.

As for running it on hpa. Glen palmer once told me on Facebook that brass guns should work on 850 psi hpa, or something is wrong. He claimed that using a shp reg was not the answer.

Like stated above the short barrel is the biggest factor working against you, but I've seen pgps with stock barrels work on hpa.

ideally you open the valve transfer ports up, and the hard part is opening the air transfer tube between the barrel and body. This typically required you to de solder to get to the holes in question.

At that rate you could solder a smaller bore, or even a freak barrel assembly which would make it much more usable.

As for using your dummy 12 gram. I think you would would want an extended feed plug like what is on the p68. And or pmi1 markers. Those are mainly hollow in the center, and you could drill the center and have it allow a gas line to pass through while it captures it.

Like mentioned in your wrb thread. I probably have a ca adapter for a pgp as well. If you can wait and or it's worth the shipping it'll cost.

[flavordeliverer]

Great to know! I won't give up on HPA just yet. I'm pretty limited with my tools right now so I'm not too confident on making precise mods to the body or valve. Maybe I can convince one of you fine folks to help at some point.

[JeepDVLZ45]

I wish I has some pictures of my old setup for you. It worked 100%. I had set it up exactly how Magageddon explains it “Option 2”

it made it so I could run HPA in the winter and 12grams in the warmer weather. Basically, I ran a bottom line of my side tapped dummy CO2 and put a tank on my wire stock when it was real cold. Then just removed the dummy CO2 and ran standard CO2s for the good weather.

Super similar setup to the marker I’m giving away for Walzmas.


Edit: ran to the basement and tinkered a few minutes for you….

Edit edit: I know it’s 2025, but why the hell are all my photos randomly changing their orientation when I post?!??


1 - drilled and tapped a dead 12gram for NTP fitting



2 - picture of the drop out cut I had made on the lower tube (you don’t have to go this extreme and cut and actual dropout.)



3 - installed BottomLine to duckbill ASA. I have a frame adapter in the car but it’s too cold out…I think you get the idea

[BrickHaus]

Snowpuff those levers are being robbed off of cheap stbb pistols. Splatmatic xj 40, pt extremes, ect. Honestly we should send one to doc, and have him re make them with a wider body so they fit in sheridans.

[JeepDVLZ45]

BrickHaus. It’d be great if he could thread them as well

[flavordeliverer]

Thanks JeepDVLZ45 ! I really appreciate you taking the time. It's all starting to make more sense

[Impactfour]

I got a pgp off Craigslist that came with the c/a adapter pictured below. A similar set up would allow you an hpa tank without having to cut into the body (you may still need to open up the airflow which is a whole different issue others have mentioned).

If you'd like I can get some closer photos of the adapter itself, but it's relatively simple in it's design

[flavordeliverer]

Sweet! Thanks for sharing. If you can get closer pics of the adapter, it'd be helpful for me. If no, no worries too.

[JeeperCreeper]

I feel like you can get HPA to work. It works better f you remove the pierce pin from the valve stem, allowing the proper air flow. You can also open up the ports a little bit with a drill. If you want to know exact measurements and details, pm me for details. Or like Jordan said I can do plenty of mods to make that thing a little more modern.

[Chuck E Ducky]

A lot of air gun places offer these as well. Just a dummy 12g

[Psycho91]

You would be better off buying one of these instead of drilling and tapping an empty 12 gram as the walls of the 12 gram are thinner and doesmt hold threads very well sometimes, the walls of the dummy 12 gram are thick to accommodate for the threads

[JeepDVLZ45]

Psycho91 Oh, definitely. I only drilled/tapped that empty one because I couldn’t find my side tapped dummy 12 gram. I was just trying to get an example in photo for the OP. That 12 gram might have 1-2 threads “holding” the fitting in…definitely not safe