Author Topic: converted my plinkster co2 to 25 caliber (Read 4738 times))

Rob M · « **on:** April 11, 2017, 05:29:57 PM »

I bought a 25 caliber NPXL barrel from crosman, under 20 shipped.. Removed the breech block from the barrel and started machining// No one wants those pics, so heres a few of the complete gun

just enough room to load co2 carts ( for those interested in the barrels , the muzzle thread is m12 )

ANYWAY , the high with 19.9s was 538fps or 12.8fpe , my goal was 500 fps so im pretty happy.. I dont hunt so for plinking , it simply hits harder and louder.. speaking of loud lol , heres a test shot before the shroud ,..

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oneshot61 · « **Reply #1 on:** April 11, 2017, 05:49:27 PM »

Sweet!! I like it!!

Ribbonstone · « **Reply #2 on:** April 11, 2017, 07:06:25 PM »

Nicely done.

Will be interested in following this one's progress.

Pretty loud bare-barreled, that long LDC will likely tone it down (but they do start to have a kind of odd hollow "thunk" sound when they are way-big).

Not a PCP, but I've kept a .25 gas-ram for several years that only makes 13-14 foot pounds (and I'd not complain if it were 12-13). It's slow, but as a short range rat-shooter, it's one of my favorites. Whole lot of "thump" without a blowing through shed walls/fences at exit.

CraigH · « **Reply #3 on:** April 11, 2017, 07:11:55 PM »

Very nice! Some of us like machining pictures.

39M · « **Reply #4 on:** April 11, 2017, 07:16:22 PM »

Wow! That's kinda neat!

I never thought I'd want a .25, but what an intimidating can killer that should make!!

Rob M · « **Reply #5 on:** April 11, 2017, 07:18:11 PM »

thanks Dan , its the poor mans FX lol..
Criag , here ya go , this was the first step, get the springer block off the barrel ,and match the factory shank for the breech

Rob M · « **Reply #6 on:** April 11, 2017, 07:19:43 PM »

Quote from: Ribbonstone on April 11, 2017, 07:06:25 PM

Nicely done.

Will be interested in following this one's progress.

Pretty loud bare-barreled, that long LDC will likely tone it down (but they do start to have a kind of odd hollow "thunk" sound when they are way-big).

Not a PCP, but I've kept a .25 gas-ram for several years that only makes 13-14 foot pounds (and I'd not complain if it were 12-13). It's slow, but as a short range rat-shooter, it's one of my favorites. Whole lot of "thump" without a blowing through shed walls/fences at exit.

The shroud has some serious internals , when friends are over , thats coming off for the noise " effect " lol.. Also , in the UK , wed be breaking the law ! (-'

39M , im gonna hang some pots and pans in the woods, been meaning too for a while

Back_Roads · « **Reply #7 on:** April 11, 2017, 07:28:10 PM »

Might make a nice squirrel / bunny gun , I did take a rabbit @ 22 yards with a .25 springer that had a bad piston seal, it was shooting crow magnums @ 450 FPS and maybe hit the rabbit with 4.5 LBS of energy. Sounds like a fun plinker for sure.

Ribbonstone · « **Reply #8 on:** April 11, 2017, 07:37:03 PM »

Know we all like speed...but with co2 conversions made for sporting use, have always found the heavier pellets end up earning a lot more energy...they do shoot slower, but not so much slower that they don't end up making more energy.

Those 20gr. at about 540fps might turn into 31gr at 463fps...but that's 12.9 foot pounds vs 14.6 foot pounds...which isn't a "carp load" more, but you might even end up with a few more shots per fill. Almost all my "ratting" is inside of 25 yards, so the real world difference in trajectory is nothing.

When I am "ratting", will use the bluntest nosed .25 I can find that shoots well. If .25WC's were more commonly available (and they once were), I'd use them...want that immediate transfer of energy (the "smack") without a whole lot of energy on exit. At this velocity level, forget HP's...there is just not enough speed to activate the expansion features.

See that you avoided barrel shank O-rings. Have done that in rifles that uses this system of barrel sealing. So long as the fit is really good, there is minimal leaking (usually at the front,,,where the barrel enters the breech). Odd as it seems, one good cure for me was basic good old old-school rubber cement. Not super aggressive, if you need to remove the barrel, can defeat its weak hold.

Rob M · « **Reply #9 on:** April 11, 2017, 07:41:47 PM »

agreed Rob.might try some 25 grains.. What i did to avoid the rings , and have a floated barrel was machine the barrel into .400 .. then to get to the .397 breech hole i sanded.. tried again, sanded , etc etc.. It was super snug, insane, then i painted which added another .001.. So , Its airtight.. Atleast no blowby at my face or fingers I can feel..ALSO , being in LA , you know the armadillo issue , but i use my 22 rimfire for those.. Thats not really hunting, just eliminating a nuisance.

Ribbonstone · « **Reply #10 on:** April 11, 2017, 07:50:37 PM »

Just check the front...it's a sneaky leak that happens to the o-ring barrels too (when the front of the two O-rings goes bad) and often goes in-noticed as it doesn't blow back...it blows forward along the top of the gas tube where you can't normally feel it.

As you aren't using the barrel band, would (but this might just be me) want that barrel tight to the breech...those little set screws aren't the worlds strongest fitting and there is only like (by eyeball) 8/10ths of an inch of barrel insertion into the breech. Free float can certainly work, but it needs a solid anchor.

Rob M · « **Reply #11 on:** April 11, 2017, 07:53:24 PM »

YEp, I added an 8-32 set screw in the sidewall of the breech where its thickest, I dont even use the top set screws anymore, Like you said , theyre more or less useless.

39M · « **Reply #12 on:** April 11, 2017, 08:07:35 PM »

Yeah! Pots and pans should make a good racket!

And get a trash can lid or an old cymbal and hang it waaaay out there.

Rob M · « **Reply #13 on:** April 11, 2017, 08:10:11 PM »

everyone in the neighborhood will know when my aim is true

Ribbonstone · « **Reply #14 on:** April 11, 2017, 08:12:53 PM »

Two rifles (varmint and plinkster)..odd as it may seem, actually found the tapped holes (for the little set screws) to be good, the little set screws to be bad. Opinion was that the screws were a little undersize, but the holes looked fine.

Swapped set screws for better ones, have had no problems with stripping. BUT, if you crank down on the issue set screws, stripping is pretty likely.

Yeah..it's one of those things you're likely to find out "after the fact"...so not a lot of help.

Rob M · « **Reply #15 on:** April 11, 2017, 08:18:20 PM »

that actually makes perfect sense. I lost 2 of the lil buggers over time just shooting the gun stock lol

Horatio · « **Reply #16 on:** April 11, 2017, 10:03:13 PM »

Pretty neato. Thanks for sharing.

Rob M · « **Reply #17 on:** April 12, 2017, 01:43:22 PM »

hit 583 fps today, no major changes , just shortened the probe so the pellet sits right at the blast.. 15 fpe , not to shabby from a 129.00 dollar co2 gun and a 20 dollar barrel

Bentong · « **Reply #18 on:** April 12, 2017, 02:48:02 PM »

Quote from: Rob M on April 12, 2017, 01:43:22 PM

hit 583 fps today, no major changes , just shortened the probe so the pellet sits right at the blast.. 15 fpe , not to shabby from a 129.00 dollar co2 gun and a 20 dollar barrel

Cool, $129 plinker, $20 barrel + $$$ w/o your diy craftsmanship.

Rob M · « **Reply #19 on:** April 12, 2017, 03:05:34 PM »

thank you sir.. Yes , were I paying someone , it would be cheaper to just buy a 25 cal gun lol

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converted my plinkster co2 to 25 caliber

Author Topic: converted my plinkster co2 to 25 caliber (Read 4738 times))