Discovery .22 accuracy

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Hey just got out the ole Disco.  Just wondering what kind of accuracy I should expect from her..  Been playing with her just a bit but don't know what to expect.  So far I wouldn't say she was a tack driver but again not sure what it is capable of.  I saw a video the other night where a very well known youtube guy was shooting at 140? yards with his.  I guess maybe 2" groups.  I personally dont believe that for a second. 

I will probably take her out again today and see what she does at 50 yards but would like to know what you guys are getting
.  I want to do some squirrel hunting this year. 

thanks

[north country gal]

We have an early 22 Disco that we bought used. Don't know how it compares to the current versions, but using a variety of pellets, I typically get half inch groups at 30 yards and with decent shooting conditions, I can reliably keep groups under an inch at 50 yards, now and then down around half inch, but three-quarters of an inch is what I would expect on a day with little or no wind, assuming, of course, that I am shooting in the sweet zone of 1200 to 1900 psi. Okay, not on a par with our Daystates, but considering the price, pretty darn good and plenty adequate for squirrel hunting. Ours came with an add on LDC and I've recently done a Baker trigger job, but otherwise just a stock Disco.

[thumbs]

Hey thanks.  This is about 5 or 6 years old.  Most of the time in the cabinet but just got back  into PCP again.  Just five minutes ago got back from the range.  At 50 yards with JSB 18gr I am getting about 1" groups.  Not all the time but around there.  When shooting little stones and chips of wood no problems at 50 yards.  The wood and stones were about the size of a squirrel head.  I can get just about down to 1000psi before she drops off.  Yes the sweet spot is just about where your is running.  I want to try some JSB 25gr next to see how it goes.  The Crosman 14.3 ?? shoot like &^^&.  LOL  At least in my rifle.  Like you say not a tack drive but should be interesting for squirrel this fall.

Oh what pellets are you shooting?

I'll have to crony it this afternoon to see where i have it set.

[Ribbonstone]

Never did get great accuracy with my Disco.

But, that’s MY Disco.  Mine won’t do that.

Given a win in the barrel lottery,  a well adjusted rifle, and shooting only in the sweet spot of a Disco, don’t see anything that could keep it from happening with HIS Disco.

Could be a BS-feast...or it could be real….unless you are right there when it happens, hard to say.

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This is with the JSB 18 grain.  Both were at 50 yards and both targets photographed sideways I guess. LOL


If you click to make it bigger the target will have the right orientation

Take out the flier on the left and it's 1"  That's about as good as I cnn get so far.
Again I'll try some JSB 25's in the next day or so.

[crazyhorse1]

Bought my Disco .22 in 2008 from MAC 1 air guns with Tim's accuracy prep and tune. Chrono data Average 906.3  ES 25  SD 6.93 shooting JSB Express 14.3 GR. Have taken many squirrels most around 45 yards.
Accurate enough to compete in air rifle bench rest events finishing in the middle of the group.

https://u.cubeupload.com/crazyhorse4/Discovsgroundsquirre.jpg

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This is with the Crosmans
Of course both targets are sideways. LOL



/Users/Owner/Desktop/IMG_0209.jpg

[Van]

  I have a couple of .22 Discos that I put together using various parts.  I got the barrels cut and crowned from Mellon Air at 20" & 15" long with shortened Disco tubes and they are what I would call tack drivers at the 25-35 yard ranges I usually shoot squirrels and other pests at.  Never tried long range target groups with them though.  I think the crowns are much better than stock Crosman barrels which I have on other guns.

[mobilemail]

My disco isn’t my most accurate airgun, but accurate enough for squirrel hunting and target popping. It really likes AA 15.9 gr pellets.

[CableStop]

I don't have a disco so I'm just talking out of my donkey here but I would be suspicious of a 140 yard accuracy claim.  At the very least I think you'd have to either know the exact hold over or adjust your scope massively high in order to compensate for the drop.  I mean a disco tube and valve are pretty small diameter and don't let a huge amount of air through so getting the kind of muzzle velocity you'd need seems unlikely without major modifications.  I think even cheap barrels can be very accurate with a good crown and the right pellets but at those distances you need to have some power behind it just to deal with air resistance since pellets are less aerodynamic than slugs and slow down much more rapidly. 

[Nvreloader]

With my Disco, shooting at HS at 40 yds, using OEM CMHP ammo, = 850-900fps,
there is a 90.0 % average that 9 out of 10 HS will ground loop, = DRT,
if I do my part shooting from the bench rest................

Still tinkering with her to get the best accuracy possible,
right now testing hammer weights -vs- flat wire hammer springs etc.

HTH's
Don

[thumbs]

Sounds to me like I may be trying to stretch this thing out a bit to far.  To tell ya the truth I am pretty happy, considering, With the ability to hit ball park squirrel sized head targets at 50 yards.  Not overly happy with the paper target results but it really isn't a target rifle.  Would I take a head shot at 50 yards with her, probably not.  I will see what she does at 40 yards in the next day or so.  Heck around here you dont see to many squirrels at 50 yards anyway. I've made mods to quite her down and to receive rotary magazines but nothin to make it more accurate.  I even have the stock trigger with no mods.

Oh for the 140 yead shot........ I would have to be there and see it to believe it.  Not saying maybe it can be done but with a stock Disco pretty dough full at least in my mind.

[crazyhorse1]

Sounds to me like I may be trying to stretch this thing out a bit to far.  To tell ya the truth I am pretty happy, considering, With the ability to hit ball park squirrel sized head targets at 50 yards.  Not overly happy with the paper target results but it really isn't a target rifle.  Would I take a head shot at 50 yards with her, probably not.  I will see what she does at 40 yards in the next day or so.  Heck around here you dont see to many squirrels at 50 yards anyway. I've made mods to quite her down and to receive rotary magazines but nothin to make it more accurate.  I even have the stock trigger with no mods.

Oh for the 140 yead shot........ I would have to be there and see it to believe it.  Not saying maybe it can be done but with a stock Disco pretty dough full at least in my mind.

I got away from head shooting squirrels because I want more wiggle room on elevation so I shoot for the shoulder...pellet then goes thru heart/lungs....no jitterbug dancing when hit.

[K.O.]

The Disco .22 well they called it the barrel lottery for a few reasons... some that did not shoot well benefited from some simple barrel work...such as some had burrs at the port... leade work sometimes really helped... sometimes would reduce pellet pickiness....some had rifling damage near the muzzle... Me I only used the disco barrels  for my 1322 carbines... the worst I get is ~.75 at ~35 yards with CPHP... mostly .5 and .6 groups...this is at 800 fps and down... There seemed to be variation in how tight/loose barrels were and that would help explain crowning tool damage at the muzzle in my mind... I think consensus was that they are 1:16 twist

Now even if after work you are not satisfied or it does not help... the New in house Maximus .22 barrels will fit... and are less of a lottery and well it seems quite a few like the CPHP... the Maxi Barrels are 2" longer... I personally think they are 1:20 twist.   I feel that the slower twist provides a small improvement at distance with most pellets... as Bob says less dynamic instability at longer ranges...

https://www.gatewaytoairguns.org/GTA/index.php?topic=130537.0

1:20 twist is enough twist for the 30g BBT I send out of my Ported 45 fpe Max... My goal is not 200 yard hunting shots or even 100 yards... I would have fun at 2 moa at 100 yards... of course would love to get better time will tell...   

My main goal is for handling less favorable conditions... wind bucking...

was floating right  around  moa at 50 yards in initial testing but barrel was being pulled down a bit by barrel band and when I fixxed that well harmonics changed... It is now in a 160 stock with 3 barrel bands to help tune the harmonics a bit... testing again with heavy pellets and the BBT 30g soon... 

So my point is... If you have never inspected your barrel you might want to... it is possible it can be tuned/improved... If not well a Maximus barrel is not that expensive... and If you want 100 yard accuracy fpe and B.C. matter...

[K.O.]

oh when you get to reading the above link... click on Jason's guide in reply #5 for his approach to barrel tuning..

[Ribbonstone]

Sometime in 2008, bought a .22 Disco.  Was looking for something less powerful and easy to pump fill for general use, the Disco did that.


Did everything I could to that Disco (still have it) BUT spend money on it.  Probably two-three years of pharting around with it.

All the DIY “tricks” (undid some when they didn’t work out).  Really smoothed out and gave great chronograph numbers. Was launching the pellets impressively uniformly over the sweet spot, so figure the power plant was doing all it could do.


Also pretty well convinced that the barrel is at best a 1.5-1.6 MOA barrel even after a trim/recrown and smoothing.  Accurate enough for field use, never going to be really impressive from a bench.

Also tends to stay where you left it….gave equal time to getting a stable POA/POI.


Still about as “plain jane” a disco as any….wasn’t doing cosmetic surgery.

DSCN3055 by Robert Dean, on Flickr

Tried going away from power, adjusting it down to more like 19-20 foot pounds to see if that helped.  Didn’t help accuracy, but the sweet spot eventually adjusted great... long shot counts for a non regulated PCP….staying in the short range of best of the best may be slow, but is regulated type variation.

c85a175c-7963-4cf9-9eee-67e88e006d84 by Robert Dean, on Flickr

If anything, the lower launch speed started to balanced out….power limit and accuracy limit getting closer to the same. Even at this energy level, it’s a reasonable 11-12 foot pounds at 50 yards.

This is as good as it got with that Disco. On Ľ” graph paper if you want to self measure.

d3aff6d1-5cfe-4fc0-855b-0010556cde21 by Robert Dean, on Flickr


Junk shooting:

1. Could impress the locals by shooting 5 soda cans  with 5 shots at 100 yards on a calm day (and already knowing where to hold). 

Consider that a typical soda can is something like 6” tall and 2.6” wide; that’s not really impressive accuracy even when you knock them over and only have that 2.6” base to shoot at.  It’s not like anything you’d hunt with a Discovery’s power would have a 2.6” kill zone.

2. MOA would be more like shooting bottle caps at 100 yards.  Go 5 for 5 shots, and I’m impressed.

[SILENT SQUIRREL]

Sometime in 2008, bought a .22 Disco.  Was looking for something less powerful and easy to pump fill for general use, the Disco did that.


Did everything I could to that Disco (still have it) BUT spend money on it.  Probably two-three years of pharting around with it.

All the DIY “tricks” (undid some when they didn’t work out).  Really smoothed out and gave great chronograph numbers. Was launching the pellets impressively uniformly over the sweet spot, so figure the power plant was doing all it could do.


Also pretty well convinced that the barrel is at best a 1.5-1.6 MOA barrel even after a trim/recrown and smoothing.  Accurate enough for field use, never going to be really impressive from a bench.

Also tends to stay where you left it….gave equal time to getting a stable POA/POI.


Still about as “plain jane” a disco as any….wasn’t doing cosmetic surgery.


Tried going away from power, adjusting it down to more like 19-20 foot pounds to see if that helped.  Didn’t help accuracy, but the sweet spot eventually adjusted great... long shot counts for a non regulated PCP….staying in the short range of best of the best may be slow, but is regulated type variation.

c85a175c-7963-4cf9-9eee-67e88e006d84 by Robert Dean, on Flickr

If anything, the lower launch speed started to balanced out….power limit and accuracy limit getting closer to the same. Even at this energy level, it’s a reasonable 11-12 foot pounds at 50 yards.

This is as good as it got with that Disco. On Ľ” graph paper if you want to self measure.

d3aff6d1-5cfe-4fc0-855b-0010556cde21 by Robert Dean, on Flickr

Kirby
With your Disco you have accomplished exactly what I've been hoping to do with mine
Modest power & a great shot string.
With my favorite pellet no less.
Although its not apparent in the photo  I assume you did install a hammer spring adjuster.
Do you recall the wire diameter of hammer spring you used?
Any other changes?
Looking very forward to your reply
Thanks
Ed

[Ribbonstone]

Not Kirby….but I’ll run though what I found inside.  Been years, lost track of the things done/undone/redone so just looked at what was in there.

Basically nothing that cost  real money...just time and basic tools.

Just got it resealed (they do leak after years of use)….not going to take it apart again, but did look at it had while it was apart.

1. Didn’t need a lot of adjustment with the standard length spring, so the adjuster is  just a short spring guide and a screw in the degassing hole. There is a detent in the guide to allow that adjusting screw’s tip to stay on center.

618596eb-f379-413f-923f-24abeac74791 by Robert Dean, on Flickr

2. Spring looks like a Crosman Disco spring, shortened a bit with an added “dead end”.  COULD be some random spring from the junk box.

58d014eb-07a8-4cf1-b9ee-d2be48b10e12 by Robert Dean, on Flickr

3. Can’t find the striker picture.  Basically a standard striker that  got “side swiped” with a grinder. Less weight,  free air passage to not allow it to act like a compression piston,  less friction.  Pin still works at the top, sear untouched at the bottom.

NOT the actual striker...the the same idea.  A little more radical on the striker, so more like a 25-30% weight reduction.

27742768-6de9-44e9-85c4-ce5909e40539 by Robert Dean, on Flickr

4. Polished (but not enlarge) the striker/air tube for less friction.

5. Valve looks like a Disco valve stem to me...a little smaller poppet diameter, but started out life as a standard poppet.

6.. Transfer port also looks standard to me...about 1/8” hole (call it .125ish). It’s a good match for a standard  valve body.

7. Along the way, when trying everything…. decided to clamp the rear of the barrel down with a rear barrel band and move the front barrel band farther forward.  Does need some stock inletting, but the idea was to make the breech end more secure (that tiny little front action screw is not trustworthy)
DSCF2469-1 by Robert Dean, on Flickr

8. Did do the old 6-screw mod to the front barrel band.  Idea here was to clamp the bottom of the band firmly to the tube (3 screws) and just barely NOT touch the barrel with the top 3 screws.  Wanted it to stay put on the tube, but leave just the barest of in-out slack on the barrel.

f1ff9300-a5e1-4d72-acc1-28c1e0979cf0 by Robert Dean, on Flickr

9. Trigger was just screw modded, not replaced.  With shims to take up some slack, it’s a nice clean break at about 1.3 pounds.  No trigger gauge, just free hanging known weights on the trigger.  LAter on, did try a "borrowed" M-Rod type trigger....no differnce.

MAYBE:

Maybe an anti bounce device...wasn’t an option back then, but might be a quicker way now.  Could speed up the process.  Did try one, but only after all the above stuff...so didn’t find anything to make me want to stick with that system.

Wasn’t looking for  more power...so maybe  a lighter striker and a stronger striker spring would keep this power.  Wasn’t going to sacrifice cocking effort to find out.


----------
Short range bias:

Disco always did LOOK good at 20-25 yards.  Nice  “one hole” clusters, 40 good shots. 

b24117ba-b8f4-4df3-ada0-7753727ab24b by Robert Dean, on Flickr

Until you put a caliper to the groups.

In comparison, another .22 PCP.  Also nice “one hole “clusters.

35d7b496-e7d7-4233-b414-25aa6f311481 by Robert Dean, on Flickr

That one still looks good, even after actually measuring.

[SILENT SQUIRREL]

Not Kirby….but I’ll run though what I found inside.  Been years, lost track of the things done/undone/redone so just looked at what was in there.

Thanks Ribbonstone
Very useful info
And,of course, sorry for getting your name wrong

The rifle is not taken apart yet
No doubt when it is apart I'll find a very stiff hammer spring accounting for the hard cocking.
I already have a Melon Air hammer spring adjuster in my parts box, along with  .038 x1.5" spring.
With that combo achieving your results seems within reach
However I do not have the proper tools to relieve the hammer.

That 6 screw mod on the barrel band is also interesting.

Thanks again
Ed

[thumbs]

Thanks for all the great info guys. 
Hey question.
I have done this before but cant remember how its done.
I want to figure say 4% spread in my fps.  Do I take the average and get 4% of that then divide that in half and go up and down that amount to get the 4% spread?  I dont go up or down the original number do I? That would give me an 8% spread right?

Example       My average is 760fps.  4% of that is 29.  Do I half that to 15 then add 15 to my average and then subtract 15 from my average?         760 + 15  = 775 fps   760 - 15 = 745  right? So the spread is 29 fps with 760 being the average.  Is that correct?

thanks