Author Topic: My CO2 Project (Read 6700 times))

AmBraCol · « **Reply #40 on:** June 15, 2013, 12:53:59 AM »

OK, it's bottle fed from the rear. Is the tube in front of the valve to provide stability or does it hold gas as well? It looks like you have a quick fill nipple on it.

sixshootertexan · « **Reply #41 on:** June 15, 2013, 01:05:47 AM »

The tubes have no pressure in them. The screw sticking out the front of the lower tube is the power adjuster. I still need to make a knob for it.

AmBraCol · « **Reply #42 on:** June 15, 2013, 01:08:40 AM »

Quote from: sixshootertexan on June 15, 2013, 01:05:47 AM

The tubes have no pressure in them. The screw sticking out the front of the lower tube is the power adjuster. I still need to make a knob for it.

DUH! It's obvious now.

Rear bottle - power adjuster on the other end...

sixshootertexan · « **Reply #43 on:** June 16, 2013, 11:31:29 AM »

I had used a 90g cartridge in my first testing. Had the 12oz bottle filled Saturday and did another test. The hammer was binding. After inspecting it I found the shear dragging on the hammer. This was because the Mrod trigger is designed for a tube of .095" wall thickness, I'm using .067" wall. Made some temporary shims and that's good. Got up early this mourning to beat the heat and did some more testing. The velocities fell of for some reason. I was only able to hit 400fps. I'm also not able to adjust the power adjuster to full power before cocking it. I know I missed dimension on one of the internal parts by .093" so maybe that's it. Will inspect that later this week. Not having full power the db's were only 79. That's using my android phone. I also am wondering if the 12oz bottle is holding psi back, may test with another 90g cartridge to see.

sixshootertexan · « **Reply #44 on:** June 25, 2013, 10:36:38 PM »

Did some more work on the hammer and valve. Managed to get 510fps out of it. Still got some more ideas to try out. With the increase in velocity it started blowing the guts out of the shroud. Going to have to drill and tap the end cap so I can put a screw in it.

sixshootertexan · « **Reply #45 on:** June 26, 2013, 09:51:20 PM »

Slowly getting there. managed a 530fps today before a seal come loose.

venxxxxx · « **Reply #46 on:** June 27, 2013, 02:03:33 AM »

Sounds like your dumping a lot of air with each shot but maybe low on compression. Whats the air volume of your valve?

sixshootertexan · « **Reply #47 on:** June 28, 2013, 08:03:35 PM »

Ok first I would like to thank Bruce for the suggestions. I got a heavier hammer spring. It's rated at 11.3# and is 2" long. I moved the trigger forward .350" to get a hammer stroke of .830. Put it back together and she was hitting 595fps. With the Benjamin domed pellets at 27.8g that's 21.86fpe. I'm satisfied with that out of CO2. I'll have to make a new lower tube this one looks like Swiss cheese now but I don't mind the rifle is shooting fine now. Going to do some testing either Saturday evening or Sunday mourning.

Tater · « **Reply #48 on:** June 28, 2013, 08:06:32 PM »

Nice pictures, but your kitchen is a little too clean for my tastes. Apparently, my wife likes piling up stuff on every counter.
Great thread and and even better looking shooter. Following your progress is fun!

sixshootertexan · « **Reply #49 on:** June 28, 2013, 08:24:26 PM »

Thanks. The kitchen only looks like that during the summer when the wife is out from school work.

Bruce · « **Reply #50 on:** June 28, 2013, 10:02:14 PM »

Great work Six!

Bruce

sixshootertexan · « **Reply #51 on:** June 28, 2013, 10:42:07 PM »

Made a valve adjustment and it hit 601fps. Still got some tweaking to do.

AmBraCol · « **Reply #52 on:** June 29, 2013, 12:39:36 AM »

Quote from: sixshootertexan on June 28, 2013, 10:42:07 PM

Made a valve adjustment and it hit 601fps. Still got some tweaking to do.

Sounds like a thumping good time!

It's fun watching this build progress.

sixshootertexan · « **Reply #53 on:** June 29, 2013, 09:57:31 PM »

Tested some this evening in 102 degrees weather. Set the rifle to 570fps. 25 shots with a low of 555 and a high of 280 for an average of 571fps. Most shots were between 568 and 575. Target was at 25yds. The shots in the rectangles were 5 constitutive shots in a row. Without any type of grip it's hard to hold it still.

Oh and the dbs were 87.

AmBraCol · « **Reply #54 on:** June 30, 2013, 12:52:44 AM »

Quote

Without any type of grip it's hard to hold it still.

I was wondering about that. Are you planning on putting a pistol grip on it, or???

sixshootertexan · « **Reply #55 on:** June 30, 2013, 02:00:05 AM »

Trying to find a piece of mesquite but I'm not going to make the stock until I'm sure all the mechanics are good.

sixshootertexan · « **Reply #56 on:** July 04, 2013, 02:00:09 AM »

I got a 614fps out of it today with the Benjamin 27.8's. I received my order of H&N Field Target pellets today . Websites say they are 20.06 but the tin says 19.91. Not enough to notice a difference. I managed to shoot a few of these before I ran out of CO2. They were hitting 690FPS. 7-8g makes a big difference. Anyways I have decided I need more hammer stroke. To get that I need a longer spring. I ordered some 2 1/2" long x .375" dia x .0475wire for 13.66lbs. This will allow me to have a preload and still have room for the power adjuster. As it is now if I preload the spring I only have a small amount of adjustment. I'm moving the trigger forward another .250" that will get me about 1" of stroke.

sixshootertexan · « **Reply #57 on:** July 10, 2013, 09:29:47 PM »

Got the latest mods done and CO2 bottle filled. The Benjamin 27.8gr pellets were doing 675fps and the H&N FTT 20gr pellets were hitting 750fps.

sixshootertexan · « **Reply #58 on:** July 13, 2013, 10:05:02 PM »

OK got the new lower tube made and did some tweaking. Did some shooting today and I'm going to need to test different pellets for accuracy. Get to many fliers with the Benji's. The H&N FTT only had 1 flier but accuracy was not great. I'll have to order some JSB Kings and H&N Barracuda's next. I also need to check for any pellet clipping too.

AmBraCol · « **Reply #59 on:** July 14, 2013, 12:33:07 PM »

That five shot group with Benjis looks decent, to say the least. Makes one wonder what happened between that one and the 10 shot group. Velocities are similar so that isn't the issue. If you got a group like that then it's not likely to be a pellet issue.

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My CO2 Project

Author Topic: My CO2 Project (Read 6700 times))