Longer barrel did not produce velocity increases suggested

[arkmaker †]

Here were the numbers I got over my chrony. This was a bulk filled tank drop system, smoking hot valve and a 14.5" .22 barrel.


The guy I traded it to, brought it over to Mac 1's shop and it was hitting in the high 590's over Tim's chrony. He said Tim did nothing to the gun other than look it over. So......I still say you are in the right ballpark for numbers.

The last picture is of the original Transformer.....it had basically the same valve and 24" .177 barrel. I was tickling 650/660 fps as long as the gas held out.

[wahoowad]

Actually, your numbers sound about right. Most 2240's start off around 425 to 450 out of the box. So if you are averaging 520' that makes 10 fps x 7" =70 fps putting you in the right ballpark.


1377x is right, I thought I had numbers for my Transformer build, but can not find them. At one point I was running a 14.5" barrel, but bulk filled. Also, the Transformer 2 build was 14.5". I know I have some number from that. Let me figure out where they are and I will post them for you.

This is a 2300kt that started at ~ 500 fps, the longer barrel moved it to ~ 515 fps

[K.O.]

Hi I just realized maybe I did not explain myself enough and my comment could be mistaken as a flippant response...

Did not mean it that way...

I do not know a lot about co2 systems but do know they are conditions sensitive,

If first string the fresh cartridge pierced had sat long enough to warm, and after mods not (pierce and shoot sooner) that could cost some fps,

I posted the link to show that it could be about 20- 25 or so dependent on temp.

Just some thought to try and help not offend,

new here and do not know if it was a measured  temp difference or,

weather report because  to me with co2 when doing comparisons  it would seem that you have to be just a touch anal  about consistency of conditions and procedure...

I am also one who believes a new barrel need to get some  pellets through it,

as a final polish helping it be slicker and gain a few fps...

Just some thoughts.

Sorry if I seamed (seemed, darn spell check) flippant earlier.

[ped]

as previously mentioned two guns with the same mods give different results ,i wonder if some of this is down to the bore  diameter?
maybe testing with different pellets will show an improvement of the order you were expecting, you would have to retest the old barrel with the different pellets to keep the same results
ped

[arkmaker †]

This is a 2300kt that started at ~ 500 fps, the longer barrel moved it to ~ 515 fps

I get that.....



Still, basically the same gun as far as power levels as the 2240 with a 10" barrel. Same valve, same tp, same breech. Only the barrels change and the tube (which means nothing on a cart gun).
So, if you can think about it that way, his 10" barrel set up was more efficient than most or at least we can say running on the high end. In fact, perfect fps for pistol target shooting. Adding the extra 4.5" just put him back to the average. The way it goes. There are so many variables, that I have pulled hair out more than once over the same issue. That said, its not bad.


Rich

[wahoowad]

well, at least it is accurate. I don't usually shoot groups as this is a rat buster but I shot a sweet 30 yard cloverleaf group. 

[arkmaker †]

I love accuracy! If you can't hit the broad side of a barn, then speed means nothing.
Keep working on it. If you have an accurate barrel, then it will always be accurate unless you modify or damage it. So hang on to that barrel, but go back inside and mess with the valve springs and transfer port a little. If you screw up the valve, it can be replaced from Crosman pretty cheaply. That's the beauty of the 22xx based shooters 


If you have the chrony, you will fast be able to tell what works and doesn't. Need for Speed gets us all 


Rich

[K.O.]

well, at least it is accurate. I don't usually shoot groups as this is a rat buster but I shot a sweet 30 yard cloverleaf group. 

sweet 30 yard cloverleaf group.    that is what I am hoping for from my pumpers and would be extremely happy to get

NOT there yet...

[T191032]

wahoowad,


"In another thread I received advice about increasing power and I went with installing a longer barrel. Today I swapped out my 10" barrel and installed a 14.5" barrel in my 2300kt (.22). I just shot my first 30 shot string and can tell I didn't get anywhere the +/- 15 fps per inch folks thought I would get. 

My 10" barrel averaged 500 fps for the first 10 shots (max = 508 fps)

My 14.5" barrel averaged 515 fps (max = 520 fps)

So what gives? I was expecting 4 * 15 = 60 fps increase. The temperature was only 2 degrees warmer the day I shot the 10" barrel string. The gun reassembly was very easy and everything looked and felt good. "



Temperature does play a major factor in the CO2 game!  And honestly, I wouldn't exactly say that the last couple days have been "warm" (which favor the CO2 systems), at least not like those days back in June or there abouts here in VA. 

As has been previously stated, more "ommph" is going to come from "Power Mods".  And barrel length, based upon the geez I've forgotten how many posts I've read over the last, what 7 years???   The .22, which I have more limited experience with, I can't speak much about, I mostly shoot the .177 at paper, not those nasty little furry rats.   Accuracy with that .22 Wadcutter sounding pretty good with the barrel swap, but we're getting towards the winter seasons, might be interesting to see how the ratting goes if you're gonna use "RatBuster 2300" on them.   

[targettgii]

If you want more power put a boss valve in it from B&A that will give you more power.I don't know what the longer barrel will add but it definitely won't hurt your numbers.

[WyoMan]

^^^ Agree with Tom...barrel length (volume really) needs to be balanced with valve volume (or volume on deck).
Just a possibility here, your limited gains from the longer barrel are due to insufficient valve volume release 
One quick and easy (not so precise) way to get an idea is in the report of the gun....real loud means it wants a longer barrel
Of course velocity isn't everything, if you get lots of shots, its accurate, you like the look and feel, 515 fps ain't bad at all 

[hogrider04]

FWIW I was going to put a 14" barrel on my stock 2240. Crosman was slow in shipping the barrel so I got bored and put my 12" 2289 barrel on it. The stock barrel produced around 430 fps, the 14" bumped that to around 510 fps. That's 80 fps divided by 7 which is 11.4 fps per inch of barrel. I'm happy with that and think I'll put the 14" on the 2289. When I get it installed it'll be interesting to see what 2 more inches will do on that gun. I'm guessing not much.