Substandard Disco ?

[John A]

 I am losing hope for this .22 Disco. I have done all the necessary mods to get some accuracy out of her. But this airgun has never been better than a low mediocre airgun for the last two years that I have owned it. Its got a 1 1/2 lbs. trigger, I did a valve mod and bumped it up to around 950 fps. (no quiet, weak shots anymore) (Crossman Prem HP), Heavy hitting hammer spring, lapped and recrowned the barrel (stock peeshooter) . Tried at least 5 different scopes thinking I had a string of junk scopes (its happened before to me). It just won't shoot a group under 2 inches with a flyer ofcoarse at 27 yrds no matter how hard I try to sort this mess out. Is it absolutly necessary to put a Walther barrel on them ? It is an easy PCP to figure out and work on but is it a piece of junk at heart ? I hate to admit this is the first airgun to beat me. For God sake, I have Magnum springers that will out shoot this thing ! Is there something I don't know about Discos ?     Please help !

[Air Rifle Hunter]

 Have you tried ordering some JSB 15.9 grain .22 caliber pellets and shooting those in your .22 Disco? Have you shot any other "good" pellet through your Discovery other than the CPHP's?

 The reason I ask is that you have to shoot different pellets and different pellet weights in your Disco to find the one that your gun likes the best. The CPHP's won't always be the best pellet for that gun, especially at longer distances and if your gun is shooting more than 900FPS with the CPHP those pellets will not be accurate at all. CPHP's are best around 850FPS or so (at least in my air guns). If I shoot them at 915FPS or greater I get a shotgun pattern because the increased velocity causes the pellets to become unstable during flight. You would think that faster would be better, but that isn't true. It is like speed wobbles. The faster the pellet goes, it changes the air flow over the pellet shape. At faster speeds some pellets (in some barrels) begin to lose stability and tumble or wobble extremely in the air.

 Using JSB 18.1 grain pellets I get 3/8" groups or less at 20 yards all day with my .22 Discovery. However, if I use the CPHP's the groups open up to 1" to 1 1/2" from time to time. I just ordered some of the 15.9 grain JSB's and they should arrive tomorrow. I ordered them because they are a more consistant pellet diameter and weight, and a heavier pellet will help the accuracy out (typically).

 Don't give up on that Discovery. Get some JSB's, clean the barrel (don't use a metal brush! Only use nylon or patches) and shoot those JSB's through your Discovery. You should see much better groupings.

[MustangMike]

Ya before doing valve mods and a heavy hammer spring you should have gotten some quality pellets to try out

Almost every crosman out there loves em some jsb's.. get some 15.9's and 18.1's and retest the accuracy

[grumpy]

Have you tried another Crosman barrel ?

[rsterne]

If you can't get it to shoot with ANY pellets, then I would replace the barrel.... The original one on my .22 cal Disco wasn't great, the rifling was VERY shallow.... I'm guessing the broach was worn out when they made it.... New barrel and the problem disappeared....

Bob

[Bryan21184]

Yes yes I agree. Pellet selection and good pellet brands like jsb will almost always improve accuracy. As my disco .22 would not group at all till I tried jsb 18.1 and 15.9   
Bryan

[Plekto]

Every barrel is a little different. A pellet sampler should help you decide if the barrel is junk or not.  That said, the barrel in a Discovery is no better than a typical Crosman rifle (say like the stock 18 inch barrel you get from the Crosman Custom shop).  To get real accuracy at long range, you need a good barrel.

The best replacement option, if it comes to that, IMO, is actually to get a replacement barrel for/from a .25 Marauder.   These appear to be U.S. made and firearm-grade (much better than typical airgun barrels).  You would get better accuracy and a bit more power. 

http://www.mountainaircustomairguns.com/
This company also has ready-to-go LW (German) barrels.  Just crazy accurate.  This barrel is essentially the entire difference between a German match rifle and a budget one.  A lot of people who have put a LW barrel on their gun have reported amazing improvements.  $160 is a bit steep, though, and the replacement Marauder barrel is less money.

[MustangMike]

ok first off a mrod barrel will not work on a standard crosman steel breech like the disco's

2ndly a lothar barrel is not needed, unless you want the best barrel you can get. also you will need a riser block or a multi shot breech from sergio inorder to run a lothar barrel on a disco. the lothar barrel would have to be machined so skinny for a standard disco setup that it will bow like a bananna on the lathe

ive seen standardx crosman barrelled disco's shooting half inch groups at 50yrds.. so crosman barrels can get the job done, but yes every now and again a bad barrel or 2 makes it out the door. simple fix, contact crosman and get a new barrel for a disco, i think their right around 20 with shipping. or order a barrel from mellonair.com for 30 shipped for a 24" barrel.. charels mellon will cut the barrel and recrown it then polish the cut face of the barrel and the crown a picture perfect mirror shine, all thats left then is to touch up the lead if it looks like it needs it

[rsterne]

Actually, you can purchase a LW barrel blank with a 12mm OD that is 23.8" long and choked.... That is only 0.040" larger than a Disco barrel.... You have to turn the breech end down to fit, and the rest of the barrel still clears the main tube.... Mountain Air supply them in .20 and .25 cal already turned to fit, and complete with a bolt that fits into the stock Disco breech.... LW have them in .177 and .22 cal as well, although they may be special order (6-8 weeks)....

Bob

[MustangMike]

Bob

I stand corrected, I was going off what jim gaska told me when I contacted him about maybe adding lw barrels for disco's

[John A]

Thank you for all the feedback. Some of you were talking as if I was doing 50 yrd shooting though. The way I see it it should shoot .22 Daisy wadcutters good at only 27 yds. I would think anything over an 1 1/2 group at that range with ANY uniform pellet would prove something beyond pellet selection is wrong , No ?  Please correct me if I'm wrong.  And Crossman prem hps get wild after 915 fps ?

[MustangMike]

no no no dude daisy pellets are no good avoid wallyworld pellets unless their cphp's or better yet the benjamin pcp hollow points.. the benkamin pcp hollow points are sized better and have a little better quality to them then cphp's even tho they look and weigh the same

get some jsb pellets and you will see exactly what were talking about when it comes to pellets.. i used to be just like you, a pellet is a pellet but boy was i wrong and it took me bitting the bullet and ordering a tin of jsb's

these days i use a 10% off pyramydair.com code (pyramyd-nra is the code) and combine that with pyramydair.com's buy 3 get one 1.. buy 3 tins and the 4th cheapest tin is free.. id suggest 2 tins of 15.9's and 2 tins of 18.1's

costs me 46 or 47 bucks for 4 tins of 500ct jsb pellets shipped with fedx from pyramydair.com

[Archersparadox]

....a smart man learns from his mistakes...

a genius learns from the mistakes of others....

...now I am no genius.....I did hit a 12" x 12" AR500 armour steel plate at ONE MILE once with my powder burner!!

....although I have only played the PCP game for a scant 4 months now....I did my due diligence here on GTA....used the search feature almost exclusivley for 2 weeks before my membership was approved....

....the pellet of choice?

JSB 15.9 gr. Exact Jumbos = shoot into 1/2" at 50 yards.....

..did I go through an extensive pellet test encompassing several manufacturers?....NO....I used the search feature here and went on the EXPERIENCED word of others.......

..ordered (2,000) JSB's from Pyramyd Air....and the rest..as they say is History!!

[Ribbonstone]

Just some suggestions, not that you haven't thought of them or tried them by now.

Readjust that trigger, adding in MORE back lash (over travel). Yeah..makes for a little more crappy trigger, but it might make for a more consistent striker release.

Take the barrel off and give it a good look-see.  Breech end is as important as the crown, so check it for any burrs or rughness at the transfer port.  (one good test is to chamber a pellet, then push it back out from the muzzle with a rod...if there is a burr at the transfer port, will show up on the pellet).

Do a search for a barrel crowning tutorial.. got nothing to lose.

While the barrel is off, push a pellet though the bore with a rod, feeling for any tight spots.

Dump the barrel.  Could spend the $ for an LW machined to fit.

-----------------
If the chronograph numbers don't show wild velocity changes, then can be pretty sure its the barrel.

[John A]

I went and did somore testing before nightfall. Tested the Kodiak and JSB preditor and Gamo magnums. JSBs shot best groups, Kodiak second then Crprhps . Still the best group was &^^& in my book. I think it was still 2 inches or more at 27 yrds. I was still suprised that the groups did contract and expand depending on what pellet I was using. Thanks for the info on all counts. I'm sure I will find the answer one way or another in this thread.

[bradyman1]

Mine loves JSB 18 g, but i am pretty  sure I wouldn't get a 2" group shooting rocks out of mine. My is an awesome rifle and it is completely stock. Try what was suggested above, and some of the pellets suggested. If that doesn't work it has to be the barrel. A new crosman barrel isnt that expensive.

[MustangMike]

pull the barrel and then use the bolt to seat the pellet, then find something softer then the barrel and smooth and push the pellet out then seat a pellet and push it all the way down and out of the barrel.. ur looking for any deformation other then the rifling marks which will be faint since no air expanded the skirt.

make sure to completely degas the disco tho since ur having to remove the back end. we can and we will get ur disco shooting properly.. im really starting to think the barrel is bad, a new barrel from crosman can be had for i believe 20 bucks. unless its less then a year old, if it is then just call crosman and explain the situation and im sure they will get you a new barrel

[Plekto]

The only reason I mentioned the .25 Marauder barrel is that it might be cheaper than the LW, even with a riser block added to the mix.  The .25 Marauder is only $10 more than the .22, so it might be a LOT less.

http://bnm111.hpage.co.in/riser_block_92352177.html
This is what you'd need.  The stock barrel could be fitted with proper bands, but it would also give you future potential to swap in a Marauder breech or shrouded barrel.

http://bnm111.hpage.co.in/disco_special__70723515.html
Every time I see this, I fall in love a bit more.    LW barrels are sweet, but man they are also pricey.  Try the replacement barrel from Crosman, but if it's also bad, this might be the ultimate solution.

[MustangMike]

Me and a handful or 2 of other members run the bnm breech setup and I've only found a couple of this id like to/will change. It needs a better cocking for the bolt. The long set screw that is used starts flattening out on the threads and seems to be wearing out my cocking pin. Its now loose in the hole in the hammer it sits in, so maybe the bolts cocking pin needs to be made a little longer perhasp.. other then that their golden

As for the mrod barrels, if you had said it was for a bnm breech id have said go for it, their 75 bucks for the 25cal barrel from crosman... but as for the breech that comes with the disco it cannot use mrod barrels.

[jimmie lee]

L/W barrels are sweet; I had a stock barrel issue with my disco, called Crossman and they sent me a new one , free. I haven't installed it yet as I don't have the proper size tool to remove the screw under the bolt but if it proves bad I'll probably consider a L/W. In for a penny, in for a pound.