Tuning Artemis PP750 - time to start modding

[bigHUN]

Anybody successfully converted the .22 to .25?

I am just trying to clear my drawers from all .177 and possibly .22 (pellets, cleaning/polishing and tools) and hopefully bring all my barrels to a single calibre size.

The pistol is in parts now (deburring, polishing internals) and I am designing a new plenum block, not a simple machining it will be a two side operation so need to make a jig as well.

My best guess to

- extend the block from 10 mm to 25 mm thickness (so the plenum would be 15mm longer) and,

- incorporate a reg gauge as well, also,

- it would be nice to have a picatinny or arca mounting hole from underneath as well, I still need to research for a shortest possible rail.

I have no machines (lathe or mill) I will ask my old friend for a favour.

Anybody made something similar and want to share the costs I am interested to get a larger plenum anyhow.

 

[bigHUN]

My PP750 came with a 8" barrel but the shroud can fit about 11.2".

What brand/model blank barrel you would recommend in .22? eventually some link where I could order?

 

[boscoebrea]

Mountain air air guns does....google it...

 

[UncleHoot]

Mountain air air guns does....google it...

Here is the web site... mountainaircustomairguns.com

I want to beef up my 750 and a longer barrel is the first step towards that goal.



Hoot

UPDATE...Here's the response I got when I inquired about a longer barrel for the 750....



"No sorry I know nothing about this gun

Thanks, Roy



www.mountainaircustomairguns.com"

 

[bigHUN]

So far I asked 3 US stores and 2 UK stores, no one is hipping out to Canada. This is getting pathetic, I guess I go look around in EU again.

My best guess to put LW or Weihrauch on my list.

 

[bigHUN]

Prototype #1

plenum length increase from 15 to 35 mm and added a reg gauge

 

[Pale_Rider]

Looking good man! Curious to see the results

 

[kkarmical]

Prototype #1

plenum length increase from 15 to 35 mm and added a reg gauge

Man, you do excellent work. Can't wait to see what performance you get with the additional plenum.

Are you going to use a huma regulator or stick to the stock one?

 

[B.Guns.]

Your plenum looks sweet.

 

[bigHUN]

No testing further until I finish all the modifications/debugging I had in my mind. I can say only I need to change the barrel to a longer one.

I polished the original regulator bevel washers no need to spend extra bucks for Huma, also minimized the friction between all moving parts, for now looks promising.

Waiting for my orders, need more .22 pellets and orings from oringsandmore (in the mail) and then I shall experiment with the hammer weight, right now it is way to heavy and makes a sound like "bumphf" instead of "thing", probably bouncing/rattling on a replaced weaker spring, maybe that will stop ones I pressurize the chamber.

As per Canadian laws no air pistol can exceed 500 fps = becomes prohibited...

but

a pistol is considered a one hand shooting device.

If I jump to the longer barrel 18" + length which is "intend" to use with two hands (pistol vs carbine). Only then I can give you numbers,

but be prepared for eye opening numbers

 

[thane]

Your going to make some serious power with an 18" barrel and the increased volume plenum.

With a 19" barrel my stock plenum volume PP750 was making 32FPE for 20 shots using 18.13 gr pellets at 890 FPS. Flip up was substantial and group size suffered.

 

[bigHUN]

Your going to make some serious power with an 18" barrel and the increased volume plenum.

Yes I know that, but I cannot expose my numbers (these CA lawmakers just looking for any excuse to make more cuts) until I secure my new longer barrel (which actually converts the pistol to carbine).

I have a problem locating more .22 pellets and I will make a test run for max number of shots in sub 500 with lower reg pressure.

 

[thane]

Of course, following all local regulations... could be a south of the boarder airgun stored at a friends house... the context is myriad and unknown to us.

 

[bigHUN]

This will be a new plenum block, so far I got to a rev.6 and looks like a final number

now only remains to figure out how to machine this thing (6 sides setup)

 

[bigHUN]

No bueno, every time I open my CAD software I get a new idea again. And a Canadian winter is just knocking at the door, only -7C outside.

 

[bigHUN]

From debugging to rev.6

I had only one Picatinny Keymod Rail Section in 35mm in my drawers, but for a picture I just positioned one longer:

just in case...for future upgrades

 

[bigHUN]

...........

With a 19" barrel my stock plenum volume PP750 ... group size suffered.

Did you figure out a cure?

 

[Smudgerii]

From debugging to rev.6

I had only one Picatinny Keymod Rail Section in 35mm in my drawers, but for a picture I just positioned one longer:

just in case...for future upgrades

Damn fine piece of kit

 

[bigHUN]

Guess what is coming next

 

[thane]

Most excellent work!

Looking forward to lower assembly...