I like the speed of the .177

[DBOdude]

confidence goes a long way to aiding accuracy , if you're more confident with .177 stick with it . proportionally hitting a squirrel head with .177 is like hitting a elephants head with a bullet the size of a milk jug .

[mudduck48]

.22 is better.

[K.O.]

With all my 13xxs I am more accurate as a .22 especially in the wind...

My 14.5" barreled 2289 clone does 660fps with the Discovery .22 hollow point on 22 pumps it has been hogged out to .13 ci and still uses a pump cup...

FPE used right means accuracy at further range... now then a 14.3g  .177 at the same speed would have better ballistics but have 50% markup on energy needed to get it to that speed...

[beerhippy]

I'm liking my pumpers more than my 22xx builds these days.  Because of the difficulties I've had with Crosman's .177 barrels I think my next build may be a 1320.  The LW barrels are just short of 24" so I could get two 11.5" tubes out of one of their blanks.  With the volume reduction and spring mods they should really smoke.  Solid hammer and power adjuster,  1701P trigger group and enough off the end for a small effective ldc.  Maybe some Woods n Water furniture. ..........

[CO2Freak]

For some reason I like .22 for CO2 powered airguns more, while a spring powered airguns shines more in .177.

I really fancy the .20 caliber btw, unfortunately any standard offering from manufacturers in this caliber is really getting scarce these days...

[39M]

Some weeks back I tried increasing the volume by removing some threads on the male side of a valve.  Actually lost speed with 10 pumps on the same 14" .22 barrel.   With an 18" .177 barrel on 10 pumps it gained about 30 fps if I recall.  Try it for yourself.  None of the changes are permanent and can be reversed.  If you are math inclined you could calculate the ideal valve volume for a given  barrel length and bore.

So Beerhippy,
You lost me when you said you gained 30 fps with the .177.
Was that with the reduced volume valve?

I'm new here and putting together ideas before I order parts for my phase 2 1377 that I'm going to mod into a rifle. I've pretty much decided on an 18" .177 barrel as the best compromise for my needs. I have the old style long(about 1/2") check valve in a brass valve body. And I had to grind a fraction off the front part of the valve to get the transfer port to line up correct. So I'm guessing I already have reduced volume over a new stock valve. But my old brass valve stem needs to be replaced, and I'm guessing that I'll get a new plastic?delrin? valve stem that I'll radius, therefore slightly increasing volume. So just trying to see if I should order the small check valve?
Of course power and speed are my main concerns since I'm planning to use it as a small game getter.

[beerhippy]

No, that was with the increased volume (but lower pressure).  It is too complex for me to dope out other than dead reckoning.  What I got out of it was that higher pressure serves you well with less bore area but a longer barrel, particularly in .22 can use the extra volume.

I want the most speed from the least number of pumps which is different than just going for ultimate speed but with high pump count.  I think a 12" .177 barrel on a reduced volume valve is probably near optimal for speed on 10 pumps.  I have an 18" 1377 and it smokes with some extra volume.  15 pumps gets me to 700 fps, but 10 gets me close to 650 which is plenty good for pidgeons and squirrels.

[beerhippy]

If you want to try reducing the volume I think an airsoft bb or two nested in the valve spring might work well.

[39M]

Thanks for the replies beerhippy.
I have one new 1377, and one old. So one of them will stay as a pistol and might get the long check valve for plinking. And the other will get a slightly increased volume for the rifle configuration.
I'm learning towards making the old Phase 2 into the rifle because it has a really nice light trigger that I'd prefer for hunting. This will be the one where power will be a main concern. I would consider going with .22 caliber, but here in Texas an air rifle must be rated for 600 fps to be legal for squirrel.

Also, I'm not lookin to pump 50 time either. I'd like to build the rifle for maximum efficiency with 15 pumps or less. So it might require more tinkerin than I had originally planned.
I'll be keeping an eye out for a medium or long tube donor rifle in the future.
 

[agninja]

I never pump over 15 times either. With the mods I do, the velocities I get at 15 pumps is about 640 for .177 and 540 for .22, with standard length barrels. If I need more power than that I can always grab the springer rifles or my Talon instead.

[1377x]

Thanks for the replies beerhippy.
I have one new 1377, and one old. So one of them will stay as a pistol and might get the long check valve for plinking. And the other will get a slightly increased volume for the rifle configuration.
I'm learning towards making the old Phase 2 into the rifle because it has a really nice light trigger that I'd prefer for hunting. This will be the one where power will be a main concern. I would consider going with .22 caliber, but here in Texas an air rifle must be rated for 600 fps to be legal for squirrel.

Also, I'm not lookin to pump 50 time either. I'd like to build the rifle for maximum efficiency with 15 pumps or less. So it might require more tinkerin than I had originally planned.
I'll be keeping an eye out for a medium or long tube donor rifle in the future.
 

flat top valve and piston adds up to 100fps with a 10" barrel .177 same with a .22
In my experience with a flat top set up my guns gained 100fps in both calibers, the least I've seen is a 70fps increase. I like using accustoms piston and valves. Read up on some of wyoman's builds and look at the stickys in the pumper board

[39M]

1377x,
Thanks for the heads up. I've been battling with the idea of stuffed piston and matched valve head/pump cup idea, but an adjustable flat top piston certainly seems like the easy way out.
But I can't locate AC Customs website. First thing that pops up is a British company, GMAC.

I have been looking at some old threads with the search feture, and will look at the tech section for more info. I'm thinking the hollow probe is the one for me, if for no other reason than it might give a little more space for loading pellets than an extended probe. But also have ideas of modding my magnetic bolt to a flow through design. Will look to see if it's been done.

I don't mean to load you up with questions, but curiosity has the best of me. I should probably just use the search function, but not sure what words to search.
Anyway I've been considering the leade? and wondered if guys have been getting more velocity with a jump to the rifling or if that's even worth considering on something that I hope to get 700 or 750 fps with an 8 or 9 grain pellet.

[39M]

Found a link for AC Customs on Air Gun Artisans.

[beerhippy]

Never considered the leade in terms of speed, more for accuracy (getting the pellet past the port without forcing it with the bolt).

[beerhippy]

For some reason I like .22 for CO2 powered airguns more, while a spring powered airguns shines more in .177.

I really fancy the .20 caliber btw, unfortunately any standard offering from manufacturers in this caliber is really getting scarce these days...

The German springers are still offering the 20 cal chambering.  I think it will be viable for some time yet.