DAR... We Have A Problem...

[Firewalker]

Glad you got your leak worked out.
I have to do that with mine now. It's leaking 1000psi a night.
Still shoots great but its leaking pretty bad now.

I'm hoping to get a section of Ti rod ground to the same dimensions as the poppet rod and will mount a delrin seat in it so I can get a better seal. The shavings indicate the poppet in the gun is delrin but the design is awful. The poppet edge was so small (sharp) that dust or a hair could block it open and I think swarf got into the face giving it the half circle dent.

The seat appears to be brass but I could not remove it as the ball bearing for the bleed screw, degassing post was over tightened and crimped the housing.

Funny but that was the only right screw on the gun.

Yes, the .25 is brand new, new orings and coming from DAR.

[crazyhorse1]

I shoot Exact Kings in my Marauder .25 cal...25.39 GR...they also work good in the wind. Think they work well in most rifles...

[Firewalker]

I shoot Exact Kings in my Marauder .25 cal...25.39 GR...they also work good in the wind. Think they work well in most rifles...

I have my first pellet mold from NOE that drops 25gr pellets, I hope they shoot well but with a full .25 meplat,  I think distance will be an issue.

[crazyhorse1]

Make some as long as you can even if you must handload without magazine...think you will need about 860 FPS for 100 yds..

[Firewalker]

Make some as long as you can even if you must handload without magazine...think you will need about 860 FPS for 100 yds..

The NOE mold only allows for skirt depth, not overall length.

I'll be watching for the domed version of the 30gr pellet.

[Firewalker]

The NEW DAR .25 Eats a lot of air, I start at 200 bar and shoot until 100 bar and refill. I get exactly 20 shots or 2 magazines for every top-up.

I get 900 fps with the 25gr for 45 fpe. That is a nice number for pesting as the .22, 14.3gr flying at 850 fps make 22.9 fpe and that is OK for most of my needs but other critters really need 45 fpe for a quick kill. I would like 50 fpe for yotes and other same sized critters but dont know what this gun has in it still since it feels pretty wide open at this point.

I removed the barrel and popped out the probe o ring, gave it a good scrub with Ed's Red then followed up with Goo-Gone. Greased up the o ring and replaced it, pulled the trigger and sear, polished them up hit the contact points with moly grease, reassembled and started running pellets through it.

Nothing fantastic as its seasoning, minute of yote head at 50y to start then I changed gears, replace the pins in the mold, went from the 22gr pellets to the 25gr pellets and the groups started to close up. I would say I ma closing to minute of ground hog now and I think another tin will bring me down to squirrel head at 50y.

With the new compressor, fills are simple, both of the guns are holding air with no drop. The next thing is a scope. I am looking at a 4-24x50, FFP for wet work.

[crazyhorse1]

My Marauder .25 cal .25.3 gr is hitting at 42 ft lbs  from the Green Mountain barrel. It was the first time I heard a squirrel squeal when hit and I have shot a bunch of squirrels in .22 cal.

[Firewalker]

My Marauder .25 cal .25.3 gr is hitting at 42 ft lbs  from the Green Mountain barrel. It was the first time I heard a squirrel squeal when hit and I have shot a bunch of squirrels in .22 cal.

How many shots before falling off the reg? I did some chrony work today and my DAR drops off at 18 shots. 

[RDB]

My Marauder .25 cal .25.3 gr is hitting at 42 ft lbs  from the Green Mountain barrel. It was the first time I heard a squirrel squeal when hit and I have shot a bunch of squirrels in .22 cal.

How many shots before falling off the reg? I did some chrony work today and my DAR drops off at 18 shots. 

Time to start tuning it then. Reg pressure is most likely set too high hogging air.

I believe Jason has his tuned at 40 fpe for something like 30 shots? Maybe he'll chime in.

[nervoustrigger]

My gen1 turned in 31 shots at just under 45fpe inside a 4% ES


Nothing special done to improve efficiency. Just adjusted hammer spring tension to the velocity knee.

[RDB]

There you go David.  Thats with the heavies. They usually run 80-100 fps slower than the 25 grain jsb. So you should be able to get close to 30 shots at 850 with some tuning.

[crazyhorse1]

My Marauder .25 cal .25.3 gr is hitting at 42 ft lbs  from the Green Mountain barrel. It was the first time I heard a squirrel squeal when hit and I have shot a bunch of squirrels in .22 cal.

How many shots before falling off the reg? I did some chrony work today and my DAR drops off at 18 shots. 

My Marauder is not regulated...but averages  860 FPS.....across 20 shots.

[Firewalker]

Since I am a rank n00b with PCP's, I need some help with figuring out where to start with tuning the .25 DAR.

I have read Knifemakers, Bob's posts and others threads but they all seem to have a different starting point and none speak of the DAR platform specifically. I also need to find a 1 sentence synopsis of what the "velocity knee" is.

Chrony is set up and ready for testing, I have a bottle filled and ready to overcome a leaky poppet should that arise and the time to work all day on it if necessary.

Step 1 is to do the same as the DAR .22, take it apart and see what they have written on the reg body and adjust the screw to be level with the body, adjust the hammer spring cap to be even with the body, reassemble and shoot a string.

Trigger work is done, feels very nice, barrel was cleaned, cocking arm has been lubed, moves freely now. Lets get started!

[nervoustrigger]

The velocity knee is simply 95 - 97% of the maximum velocity, by way of adjusting the hammer spring tension.  It is favorable for consistency and produces good but not great efficiency. 

[crazyhorse1]

Read this David...


https://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0

[Firewalker]

Read this David...


https://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0

Rich, I have read that thread by Bob  a few times and it seems that my starting place with the hammer spring preload is not the issue as that is what I did when I got the gun but nothing changed at all. I may have to find a softer spring but first, I am tearing the gun down to the reg and adjust it like I did the .22.

Here is the chrony string from this morning, 25.5g WC, chrony at 1 foot, 65F, starting pressure 210 bar, ending pressure 100 bar, 20 shots. Looks like it fell off on shot #14. BTW- the speed is right where I want it at 860.

1-862
2-861
3-862
4-860
5-860
6-858
7-859
8-865
9-862
10-864
11-862
12-849
13-862
14-861
15-853
16-837
17-831
18-815
19-802
20-798

[crazyhorse1]

When I got my Marauder .25 10 years ago it came from factory shooting 820 or so...I made adjustments to get it to 860 and left it and have not touched it since. Very accurate  and just 1.25" group at 100 yards...Just received my new compressor yesterday and now I can get things done a little quicker and get off the hand pump. It is the Umarex Readyair....$529 from AOA.

[RDB]

If you screw the hammer spring all the way in or all the way out,  it stays in the 860's?

Here. Do this.

Back the hammer spring all the way out. Take a shot over the chrono. Record the fps. Turn it in one half turn, shoot it over the chrony. Record the fps. Keep going half turns and recording until the hammer spring is maxed out. Post the numbers up for us. And the pressure in the tube when it falls off the reg.

[Firewalker]

I disassembled the gun and turned in the regulator screw two full turns, it is now shooting approximately 802 FPS. The DAR does not allow for hammer spring adjustments while in the stock, I will have to naked frame shoot it while messing with the hammer spring. The good news is that I was able to get two full magazines down range without falling off the regulator.

Be right back....

[Firewalker]

OK, 3-1/2 turns from all the way out to all the way in and it would no longer cock.

1-819
2-812
3-814
4-805
5-809
6-810
7-808

Higher velocity the further out the hammer spring was.... Hmmmmm. 

Is shot #4 with 805 significant?

Never came off the reg.