DAR Gen II is now available

[subscriber]

Firing it with the bolt open apparently transports the O-ring to another dimension.  I did it in my workroom and that O-ring hasn’t surfaced in 18 months

So, it works for O-ring removal; but retrieval may be a little sketchy

[HunterWhite]

Actually,  you're supposed to leave the bolt slightly open so that the oring ends up on the probe.  It might take a few tries to develop the technique.

Hunter

[subscriber]

Actually,  you're supposed to leave the bolt slightly open...

That is a better idea than having the bolt fully shut, but not latched.  Much less force applied to drive it backwards.

The DAR .177 has a very long skinny probe tip that could be well into the O-ring, with the full diameter section of the bolt 3/8" beyond the O-ring.  Don't see what harm can come from this except for the ear shattering noise.

[Nvreloader]

Will the bolt going forward strike any of the cocking pins/sear parts etc,
as they might be in the way of the bolt travel?   

Something to think about?

Don

[subscriber]

Will the bolt going forward strike any of the cocking pins/sear parts etc,
as they might be in the way of the bolt travel?   

Something to think about?

Don

Worth pondering; but as you can close the bolt with the hammer cocked, the bolt is not going to hit anything. 

The hammer will hit the bolt, if the bolt is too far back when you pull the trigger on a cocked hammer.  You can determine that point with the hammer decocked - it is the point where rearward bolt travel can be felt to start pulling the hammer back.  At that point, even the thin part of the probe is further back than would capture the O-ring. 

So, after doing this simple analysis, I am confident that the objective of sneezing out the breech O-ring can be reached, without hurting anything but your eardrums.

[cbourbeau32]

A few questions.

Any hand pumpers own this gun? If so, how many pumps to fill originally and how many to refill after shooting the 25 or so shots that Dana mentions in his video review?

What pressure is the regulator set at?

Can the hammer preload be adjusted and if so, how easily?

Thanks

[subscriber]

A few questions.

Any hand pumpers own this gun? If so, how many pumps to fill originally and how many to refill after shooting the 25 or so shots that Dana mentions in his video review?

What pressure is the regulator set at?

Can the hammer preload be adjusted and if so, how easily?

Thanks

Charlie,

I am a soon to be ex-hand pumper.   I am in the process of pumping up my DAR from flat and getting bored with it.  So, I paused to go look for a compressor to buy.  I pumped the DAR from 100 to 200 BAR in about 15 minutes, and it was hard work.

You can adjust the hammer strike easily.  Remove the stock by unscrewing the single bolt.  The cap at the back of the receiver houses the hammer spring.  I have been playing around with different springs to back off from the stock setting of about 25 ft.lb in .177.  One spring I have enabled the power to be set between 2.5 and 16.6 ft.lb. 

Indications are that you could get 100 shots between 100 and 200 BAR at 10 to 12 ft.lb.  At the very top end efficiency is lost, but your could probably get 50 shots at 20 ft.lb.

The regulators are factory adjusted (by caliber, apparently).   Judging by the bearing surfaces of pellet skirts I recovered from clay, the reg pressure is no higher than 100 BAR - probably lower.  People that have opened their guns have shown what appear to be reg settings written on the reg in indelible ink. 

Anyway, with the shooting I have done, I was happy with how slowly the DAR's pressure gauge drops in .177.  I would be happy being able to shoot on the reg between 3000 and 2000, or 1500 PSI.  I think it is closer to the latter for the .177.

What I do while adjusting the hammer spring preload, is to keep the stock off; while I shoot over the chronograph.  If you are fine tuning for accuracy, it would be better to have the stock attached.  I have not gotten there yet...

Modifying the gun to have an easier hammer spring adjustment could be done.  Rather than make a large hole in the back of the stock, I would thread in a short, much smaller capscrew - right into the cap, to lock them together.  Then use the hex of the capscrew to make adjustments, via a small channel at the back of the stock - right at the rear of the receiver.

[smythsg]

I have noticed on my DAR .25 cal that a tool is not required to adjust the hammer spring. Just place your thumb on the adjuster screw and push in easily and turn, at least it works for me... (make sure the gun is not cocked)

[subscriber]

I have noticed on my DAR .25 cal that a tool is not required to adjust the hammer spring. Just place your thumb on the adjuster screw and push in easily and turn, at least it works for me... (make sure the gun is not cocked)

With the gun fully in the wood stock?

[smythsg]

No, sorry, you do have to take the action out of the stock.

[subscriber]

Thanks Steve,

Mine moves very easily, but I use this bicycle spanner tool, because it does not always move with just my fingers:  www.amazon.com/gp/product/B001B6LNRQ

[smythsg]

I like that tool, looks simple and effective. I have a Harbor Freight version if I need it.

[NHGuide]

Haven't posted due to my wife's cancer meds being ...problematic...but I've been watching all the fun!


After four times tearing this apart, I THINK I have the leaks solved.
Cheaping out, I only replaced the o rings believed to cause the leak one at a time....ONE  lesson there is, replace them all if you have the parts available...it's not worth the time and PIA factor to keep taking  things apart 
Second lesson is... CLEAN the &^^& and dust off the bench! any little piece of crud WILL find it's way to an o ring and buggar it up.

It all boiled down to the regulator, I believe.
I replaced every o ring I could find replacements for from my supply of 70 Durometer Buna stash....so we shall see if it holds overnight.

Quick snapshots here of the regulator and the two o rings that were likely the entire problem.
maybe NOW I can get to tweaking and tuning.

BY the by:
What tension are you all putting on the valve spring?
 since the screw-in spring seat for the valve spring is wildly adjustable....
to find the 'weight' I put the valve on a scale, tare it out, and press the valve stem.  Crude, but it gives me a rough idea what the spring is set to....a starting point, anyway. 

[nervoustrigger]

BY the by:
What tension are you all putting on the valve spring?
 since the screw-in spring seat for the valve spring is wildly adjustable....
to find the 'weight' I put the valve on a scale, tare it out, and press the valve stem.  Crude, but it gives me a rough idea what the spring is set to....a starting point, anyway.

In a regulated rifle, the valve spring tension isn't a critical parameter.  However I suggest shading toward the "more is better" side of things because it helps the self-regulation characteristics to maintain a stable velocity despite minor variations in pressure and/or hammer strike.  Self-regulation being the way in which an unregulated rifle produces a stable velocity over a wide pressure range...the same concept applies to a regulated rifle but generally gets ignored because regulators afford us the luxury of being lazy for the most part.

BTW, never apply so much preload that the valve spring is at risk of reaching coil bind when the valve is knocked open.  If that happens, the hammer may drive the stem through the poppet and destroy it.  Under normal circumstances, that's unlikely to happen because the amount of valve lift is quite small.  It's more of a concern if you ever happen to fire it at very low pressure or no pressure.

[boonez40]

Has anyone shot slugs yet ? If so how did it perform.

[subscriber]

I have not set my DAR's valve spring, but did press the stock valve (.177, as it came from the factory) open with my finger tip .  While that might actually be less significant than spending the night in a Holliday Inn Express, I was surprised by how much force was required.  It was slightly uncomfortable; probably close to 10 lb.  Yes, I used my trigger finger.

[RDB]

From the factory,  the disc was 5.5mm down in the housing on my .22 cal.

[NHGuide]

In a regulated rifle, the valve spring tension isn't a critical parameter.  However I suggest shading toward the "more is better" side of things because it helps the self-regulation characteristics to maintain a stable velocity despite minor variations in pressure and/or hammer strike.  Self-regulation being the way in which an unregulated rifle produces a stable velocity over a wide pressure range...the same concept applies to a regulated rifle but generally gets ignored because regulators afford us the luxury of being lazy for the most part.

BTW, never apply so much preload that the valve spring is at risk of reaching coil bind when the valve is knocked open.  If that happens, the hammer may drive the stem through the poppet and destroy it.  Under normal circumstances, that's unlikely to happen because the amount of valve lift is quite small.  It's more of a concern if you ever happen to fire it at very low pressure or no pressure.

First,
Thank you for the reply.
in addition, I appreciate the coil bind reminder, that's never a good thing... ( I got my coil in a bind once...wheew that hurt! but that's another story for another time) I went just 1/4 inch in with the spring seat. I figure it is just a touch further than the factory (mine measured just at .195 in before I started muddling about).

everything is back together, except for trigger work...which will wait until the first few hundred rounds before doing much with it.

We got hit with nearly 3 feet of snow last Wednesday and it was -2F yesterday morning so it might be a little bit before I do a ton of outside work ! but I will attempt to set up something in the next couple of weeks. but accuracy tests will commence as soon as I'm able.

Thanks again for all the feedback, everyone.

[Bob Pratl]

We got hit with nearly 3 feet of snow last Wednesday and it was -2F yesterday morning so it might be a little bit before I do a ton of outside work ! but I will attempt to set up something in the next couple of weeks. but accuracy tests will commence as soon as I'm able.

Thanks again for all the feedback, everyone.

Will, thanks for your DAR II resealing posting as it will save me time when my turn comes. So far so good but it's inevitable that it will leak someday.
Right now I'm in North Conway, NH and we only got 6" of snow in the Valley.

[subscriber]

Has anyone shot slugs yet ? If so how did it perform.

I believe the DAR barrels are unchocked.  That bodes well for slugs.  I have seen questions around slug use, but have not found reports.  There are people shooting their own cast pellets though.

One pertinent question is the maximum length of slug that will fit in the magazine.  This might limit the .25, but probably not the .22 and .177.  My .177 mag drum is .428" deep.   There is clearance with the mag body, such that a projectile .444" long could be feasible. The longest projectile I would try to single load would be .545"  (barrel breech face to rear of receiver mag slot - .005"). 

None of the above addresses the question of "chamber" shape or leade for slugs.  That probably would need to be made deeper, or more shallow; as the abrupt throat that works for pellets would likely have the potential to distort slugs on loading.  Nothing difficult about this.  Explained by many knowledgeable people, in many prior threads.  This is what I did to my .25 Marauder - step back to beginning of thread for "before" pictures:  https://www.gatewaytoairguns.org/GTA/index.php?topic=137096.msg1378450#msg1378450

This is not the best of pictures (it is grainy due to low light with the image gamma increased) of my DAR Gen2 .177 chamber:




DAR threads that mention potential slug use:
https://www.gatewaytoairguns.org/GTA/index.php?topic=179804.msg156041258#msg156041258
https://www.gatewaytoairguns.org/GTA/index.php?topic=179804.msg156041228#msg156041228