It's RiDAQulously Beautiful

[Tofazfou]

Bob,

What is the recommended fill pressure for your gun by DAQ?  Is it 3000 psi or higher?  Without touching your springs, a 3200 psi fill would tighten up your shot spread.  i'm confused on the fill pressure though cause you stated that you filled to 3000 and that THEY were filling to 3200 psi

[rsterne]

The instructions that came with the rifle say 3000 psi maximum.... The article I am referring to is on the DAQ website....

http://www.quackenbushairguns.com/308_exile.html

They were filling the gun to 3200 psi but from what I can determine, either the first or second shot was still the fastest.... I agree that filling to a higher pressure would likely give me 3 shots with a tighter spread, as the first shot would not likely be much faster.... What concerns me is the drastic air usuage.... In the article, the first string they shot was 5 shots starting from 3000 and they still have 2000 at the end.... My rifle is down to 1800 psi after just 3 shots, starting from 3000.... That is twice the air consumption, and something I am not prepared to live with....

Bob

[Norm_m]

Nice, very very very NICE! Now let the hunting stories begin
Norm

[Tofazfou]

Ok, i gotcha now.  Then yes, your thinking is on the right track then.  You would need a "SLIGHTLY LIGHTER" main spring then.  A "LITTLE" (less spring compression) goes a long way with springs. Something that would drop your 1st shot to somewhere in the 800 to 820 FPS range.  

But yes, as you stated, Dennis said ONCE that he makes his guns for the 1st shot to be THE KILL SHOT kinda thing.  In other words the 1st shot is the most powerful.  But, that is the standard for EVERY BB maker.

And that 3200 psi fill thing with the guys in the artical getting a faster 2nd shot but slower than yours now makes sense.  That just prooves that the gun IS setup for a 3000 psi fill.  That extra 200 psi changes the game..lol

McMaster Carr has a nice supply of springs.

PS....and oh yeah, i forgot to say, "that gun is very nice looking"....lol.  

[rsterne]

I will remove the rear spring cap and see if it's possible to install a power adjuster (I still call them RVAs - rear velocity adjusters).... That is a typical mod for the DAQs so that people can tune them to their own preference and bullet weight.... I've been doing this for a while, BTW.... Here is a link to one of my projects....

http://www.gatewaytoairguns.org/GTA/index.php/topic,9588.0.html

You can see one of my RVAs in the third photo, sitting just behind the hammer (no spring installed)....

Bob

[Tofazfou]

Ohhhhh shucks......SORRY MAN......lol.  you know your stuff then.  Lol, i'm new around here so i didn't know.  Would be cool if all Big Bores and Small Bores came with power adjusters.

Looking forward to your next shooting session with her (DAQ)

[rsterne]

NO problem.... I saw you only had a few posts.... Nice to meet you, BTW....

I can't shoot this thing at home (too loud), even though I live in a town with only 85 residents.... About a mile away I have a camp on my Placer Claim where we go gold panning and it's on Crown land.... I have target boards setup at 35, 50, 75 and 100 yards, and can set one up at 125 or so.... There is a picnic table there to shoot from, so it makes a great range.... and you can't even hear the DAQ from town.... 

Bob

[Tofazfou]

Nice to meet you also Bob.  And yeah, them big bores are NOT backyard friendly or neighbor friendly or kid friendly nor animal friendly.....lol.  I have a few myself so i know the feelin......

Talk to ya later and good luck

[rsterne]

I got out to the camp today and got the DAQ sighted in at 50 yards.... that will put me about 1" high at 25 yards.... Before sighting it in, I tried the first couple of shots across the Chrony starting at 3200 psi and it ran 855 and 808 with the ending pressure about 2400 psi.... This compares to 836 fps at 3000 so the gun is still gaining speed at 3200 psi.... Definitely gonna have to back down the hammer spring preload a bit.... it's still using 400 psi per shot, even at 3200 psi.... 

I tried a shot at 2700 psi at two pieces of fir 2x6 stacked together at 50 yards.... The muzzle velocity would have been about 795 fps, and the remaining velocity about 765 fps (155 FPE).... It blew through the first one and imbedded in the second, stopping about 1/2" from going through.... ie 2.5" of penetration at 50 yards.... I'm pretty sure a maximum power shot would penetrate both pieces of wood at point blank range.... Here are the pics....

   
The first pic shows the two pieces stacked and the bullet in place.... The black line indicates where the wood was crumbled and fell apart when I cut the piece of wood in half, ie the damage zone.... The bullet curved over in the second piece of wood, rotating almost 45 degrees from the entry line.... The second photo shows the exit hole from the first piece of wood, and the bullet after I removed it from the second piece of wood (above it).... You can see where it stopped, about 1/2" from going through....  Crazy Power.... 

Bob

[ronbeaux]

When I fill the 308 to 3000 the first shot is always high and to the left about 1/2". Dennis suggested I charge it to 2850 and I should get 3 pretty normal shots. Shot 2 and 3 are always almost in the same hole at 50 so I am going to give it a try. I don't have a way to go above 3200 lbs so I have them max out my tank to give me more fills.

Now I just need to know how to get on the list because I want a 50!!!

[rsterne]

How much pressure do you use for three shots?.... My gun drops 1200 psi....

Bob

[lloyd-ss]

Bob,
These are certainly very nice shooting guns right out of the box, with some fairly straightforward adjustability.  BUT.... I am going to be watching this to see what you come up with for an RVA (based on previous projects, you have set the bar pretty high ). 
With the visitor season winding down, I know you need something to occupy yourself this winter.   

Lloyd

[rsterne]

I would a lot sooner have 5 shots within 10% (or less) of 800 fps maximum than 3 shots starting at 835 and dropping 100 fps.... It seems pretty clear to me that the DAQ is currently set up for a "dump shot" where the valve is still open after "Elvis has left the building".... There is no other way for the gun to use 400 psi per shot AFAIK.... I'm wondering if Dennis fitted a stronger hammer spring for some reason.... All I know is that my gun is using about twice the amount of air compared to the article posted on his website.... It's tempting to try 3500 psi, but that seems pretty risky without knowing the dimensions of everything and doing the math.... too risky!.... 

Bob

[Butcher45]

I agree.....a balanced shot string is much more preferable than a 30-50+fps drop with each shot.  I think it makes for a more balanced/efficient rifle that you can actually shoot a group with while using the same POA.  Dennis feels that the extra fps for the first shot is worth sacrificing the rest of the shot string in his .458's.

Wait a minute.....this is the .308 Exile?  I thought the .308 Exiles had a fairly tight shot-to-shot variance for 4 shots or so.......at least the one I have seen shoot/hunt did if I recall correctly.

[rsterne]

YUP, it's a .308 Exile.... That's why I'm surprised at the 400 psi (and 50 fps) drop per shot.... since the article on the DAQ website says about 200 psi per shot....

I can see setting up a .458 for two shots of roughly equal velocity.... but on a .308?.... Makes no sense to me....

Bob

[Butcher45]

YUP, it's a .308 Exile.... That's why I'm surprised at the 400 psi (and 50 fps) drop per shot.... since the article on the DAQ website says about 200 psi per shot....

I can see setting up a .458 for two shots of roughly equal velocity.... but on a .308?.... Makes no sense to me....

Bob

Yea something is amiss there.....I think the Exile I saw may have used about 200psi per shot as well, rather than 400psi.

[0351_Vet]

What a sweet rifle Bob........Congrats
I'll be following this thread for sure.

[rsterne]

OK, so here's what I found out when I pulled the DAQ hammer out today.... First, some dimensions....

Hammer
Weight: 177 gr. + cocking lever (15 gr.) = 192 grams total
OD: 0.995"
Length: 2.36"
Bore for spring: 0.516"
Depth of bore: 2.10"
Stroke: 1.62"

There is a flat milled along the bottom of the hammer for the sear to slide on.... The sear catches on the square front end of the hammer (which is hardened) when cocked.... There is a milled notch for the sear to catch on to keep the hammer from sitting on the end of the valve stem, providing a "safety catch" to allow filling the gun without fully cocking it.... The aft end of that notch is showing wear from hitting the sear already, in about 100 shots....  

Spring
OD: 0.505" +/- 0.002"
Wire: 0.062"
Coils: 25
Free length: 5.44"
Preload: 1.20" (uncocked)
Cocked length: 2.62"
Compression (cocked): 2.82"

The spring appears to be hand made.... The coils, particularly at the ends, are not perfectly spaced, and the ends of the spring are not bent down (closed) to contact the next coil, merely ground off on an angle.... There is a shouldered plastic spring guide that fits into the end cap which is drilled 0.516" to locate the spring.... The knurled end cap is threaded into the end of the main tube, and prevented from rotating by the rear breech screw.... To be frank, the quality of the machining inside the tube where the hammer slides is quite rough.... Of everything I have seen thus far, this bothers me the most.... Because of the design of the end cap, I think the easiest way to make a velocity (preload) adjuster would be to use a relatively small (1/4" or less) diameter fine thread screw and counterbore the spring guide for the end of it.... The only thing that bothers me about that is that once the shoulder on the spring guide moves very far, the spring will no longer be contained by the hole in the end cap.... In addition, there is no simple way to REDUCE the preload as the guide is already bottomed in the hole in the end cap.... Since the whole point here is to reduce the preload, I decided to look at modifying the spring....

I could have simply cut off a coil or two on the spring, but the uneveness of the coils bothered me.... This usually indicates that he spring has never been "set".... ie collapsed completely to coil bound and then allowed to spring back.... When you set a spring, the coils rebound to an even spacing, at least even enough that you can't see it with the naked eye.... I slid the spring over a piece of 3/8" threaded rod with a nut and washer on each end and proceeded to collapse it.... I first wound the nuts in until the spring was at its "cocked" length (2.62").... The coils were pretty much all over the place for spacing.... I wound the nuts in another 4 turns (1/4") and let the spring rebound and measured it's free length.... It had just begun to collapse, the free length had shortened by about 1/32".... I repeated the operation, going 8 turns beyond the cocked length.... The spring was beginning to look better, with more even spacing between the coils as the ones that had the bigger space collapsed first.... The spring rebounded to 5.25", so it had collapsed about 0.2".... It looked MUCH better, the spacing appearing much more even.... I checked the OD, and it had only increased about 0.001".... Encouraged, I went another 4 turns, so that I had now compressed the spring 3/4" more than it's cocked length.... The distance between the coils was now becoming much more even, and the free length was now down about 0.35".... I went another 4 turns, and the spring was now looking very nice, straighter, very even coil spacing, and nearly coil bound.... When I released it and checked the length, I found that it had collapsed a full 1/2", with the free length now measuring 4.94".... It had taken a full inch of compression past the original cocked length to achieve this result.... The spring coil spacing was now very even, and the spring was also straighter than when I started, indicating that every coil was now more symmetrical....

I checked the spring rates using a web based calculator, and in both cases, it says the spring rate is 9.9 lb/in....  so now I know that "setting" a spring doesn't change the spring rate, only the free length.... Here is how the spring compares to what I started with....

Preload: 0.72" (instead of 1.22") Force = 7.1 lbs (instead of 11.9) - a reduction of 40%
Compression (cocked): 2.32" (instead of 2.82") Force = 23.0 lbs (instead of 27.9) - a reduction of 18%

Lloyd shared his hammer spring energy calculator with me, and it gives the following results:

Stock spring
Hammer Velocity = 70.4 fps
Energy = 1.63 in.lb.
Momentum = 0.72 in.lb./sec.

Set spring
Hammer Velocity = 61.0 fps
Energy = 1.23 in.lb.
Momentum = 0.62 in.lb./sec.

If I cut 3 coils from stock
Hammer Velocity = 61.9 fps
Energy = 1.27 in.lb.
Momentum = 0.63 in.lb./sec.

What do these numbers mean?.... I dunno, but I'm sure I will begin to understand them as I get more data.... I do know that setting this spring produced similar results to cutting off 3 coils in terms of the effect it should have on the hammer strike.... I don't have a backstop that I can fire the DAQ into inside as of yet.... but I decided that one test I could do was to see how much air pressure it dumped with the set spring installed but no bullet.... It now dumps 300 psi per shot.... I assume that it would dump less with a bullet in place.... and I don't have a comparison for how much pressure it would have lost with a dry fire when stock.... but my gut feeling is that I'm going to be close to what I want.... I asked my wife if she could hear me shooting in our detached garage, and she said no, which is a good sign.... That means that if I have a backstop strong enough I can at least do some Chrony readings without having to go out to our camp.... That's a good thing, because it snowed today.... so my days at the camp are likely over for the year....  The plan is to make a temporary backstop from some timbers and find out what the velocity is and the air consumption.... If it turns out I need to detune the gun more, then I'll shorten the spring a coil and try again.... If it turns out that I've already gone too far, then I'll either make a new spring guide, a spacer for the end of the spring inside the hammer, or an RVA....

Stay tuned....  

Bob

[rsterne]

Well I couldn't wait to try it out.... I got a 12" log about 16" long to use as a backstop and tried a few shots with the hammer spring I modded yesterday.... At 3000 psi, the first shot was 856 fps.... 20 fps MORE than stock.... I did a shot string starting at 3300 psi (my hand slipped, really it did!) and got the following....

882 fps (206 FPE)
858
824
797

There was 2100 psi left, so the gun was still using 300 psi per shot.... Way better than stock, but the hammer spring was still too strong.... By now I'm convinced that Dennis somehow used the wrong hammer spring in my gun, so I pulled the gun apart and modded the spring some more.... This time I closed the end two coils to that they sit nice and flat....  I then fully set the spring, completely coil bound.... and then sanded the end two coils flat.... The spring is now only 4.50" long (neary an inch shorter than stock) and has 23 active coils instead of 25.... The spring rate is therefore higher, at 10.8 lb./in.... I ran the numbers through Lloyds hammer spring calculator and got the following....

Set spring, 23 active coils
Hammer Velocity = 53.6 fps
Energy = 0.95 in.lb.
Momentum = 0.55 in.lb./sec.

By now I'm wondering if I went too far.... I reassembled the gun and took a dry shot at 2500 psi (that was in the gun) and it was obviously working (not valve locked) so I filled it to 3000 and fired one over the Chrony.... 835 fps, the same as it was stock.... Now was the time to shoot some serious strings....

I filled to 3200 psi, and shot 6 shots before it fell below 800 fps.... WOW! that's 6 shots faster than the stock rifle's second shot....   .... I shot several strings, a few from 3200 and then gradually less as the tank pressure dropped, stopping at a 2900 psi fill.... In every case, the string used 950 psi for 5 shots or 1150 psi for 6 shots.... less than 200 psi per shot.... That is less than HALF the air the gun was using stock....  



The graph above also shows the stock performance.... Starting at 3000 psi I was getting only 3 shots, with the second shot under 790 fps.... With the modded hammer spring I'm getting 6 shots from a 3200 psi fill (5 shots from 3000) with the same maximum velocity and the last shot is over 790 fps.... Here is the summary....

Stock
3 shots averaging 787 fps (163 FPE) with the velocity dropping like a stone between shots
400 psi per shot (0.39 FPE/CI) - and the gun was VERY LOUD as a result

Now
5 shots averaging 825 fps (180 FPE) between 811 and 833 fps
<200 psi per shot (0.88 FPE/CI) - over twice the efficiency with the gun MUCH quieter
6th shot at 792 fps is faster than the second shot from the stock setup

Is the 3200 psi safe?.... Well, Dennis has an article about the Exile on his website that talks about using 3200 psi, so I would presume if he felt that was unsafe he would have either not used it, or put in a disclaimer.... I'm not going to worry about it.... Had I used a 3200 psi fill on the stock gun (I actually did try one string),  the shots would have been 855, 808, 760.... That gives an average of 808 fps (172 FPE).... While the first shot is stronger than the gun shoots now, the average over those three shots is less than I get over 6 shots now.... I think that's a darn good tradeoff, so the gun is going to stay the way it is for a while.... There remains one unexplained anomaly, however.... With the intermediate spring setup.... I got a shot at 882 fps (206 FPE) at 3300 psi.... and 855 fps at 3000 psi.... That is significantly stronger than the gun shot stock and I am at a loss to explain it.... unless the gun is simply wearing in a bit....

Bob

[lloyd-ss]

Bob,
That gun is responding very nicely to your tuning steps.  Regarding the higher velocities, is the hammer maybe sliding more smoothly now?