Can't leave the Discovery alone.

[shearload]

I really wanted a .22 Discovery, but when one of the chain sporting goods stores marked almost everything down 25%  on Cyber Monday, I couldn't pass it up.  But they only had the Discovery in .177.  I figured that I could order a .22 barrel and bolt from Crosman, if I really needed a .22.

The gun arrived via UPS in early December, and lived up to the reviews.  The Centerpoint 3X9 scope, from another chain at 25% off (Cyber Monday, again) arrived a couple of days later.  Everything worked great, but the gun was LOUD!  Much louder than my springer.

Time to rummage around for moderator parts.  The Discovery's muzzle brake is precisely 0.750 OD.  Hmm.  Copper 3/4 water pipe on hand.  Loose fit, though.  Lined the pipe with PET from a Mountain Dew bottle; nice friction fit.  Now for baffles.  Countersunk washers from my aircraft mechanic days; OD slightly over 3/4", ID a little over 1/4".  Perfect.  More PET from the Mountain Dew bottle for spacers.  Assemble and install; no joy.  The muzzle blast blows the whole assembly off and about four feet down range.  

I do not want more friction.  I want the moderator to be as easy to remove as the filler cover is; I will have to remove it each time I fill the gun.  Hmm.  Magnet?  But the muzzle brake is aluminum.  Aluminum magnet?  I don't have one.  But I do have rare earth magnets; five are cylindrical, 3/4" L, 3/4" OD, 5/16" ID.  I try one.  Again, a loose fit in the copper pipe, but the plastic from the Mountain Dew bottle as a shim makes a perfect fit.  I glue a cadmium-plated steel flat washer to the end of the Discovery's muzzle brake with JB Weld and trim to match with a Dremel.  Reassemble, reinstall, and test.  Success!  Now the gun sounds like a Daisy BB gun.  The whole assembly is about 4" long, and not very heavy.  It slides over the muzzle brake about 3/4", which seems to be plenty to maintain alignment.  A little o-ring lube on the plastic liner makes it easy to remove.

Life is good.  One-hole groups at 10 yds, cloverleafs at 20 yds. with CPHPs from Wal-Mart.  Four squirrels intent upon invading my attic meet their maker.

So what's the problem?  

The gun is good.  Now I'm thinking of taking it hunting for real, out in the woods, for wild squirrels and rabbits.  I worry about the .177 pellets being marginal at 40 yards or so; I don't have confidence that I can make head shots at that range consistently.  So I order the .22 barrel and bolt, an extra  barrel band, spare o-rings for both bolts, spare transfer port and seal (in case I damage either one).  With shipping, less than $35 total.  Bargain.

The parts arrive and I install them.  The accuracy is poor.  Check the crown; a little rough, so deburr and lap it.  The accuracy improves a bit, but still not great (1.5" c to c at 20 yards).  The best .22 pellets I have are Benjamin Discovery HPs from Sports Academy.  I pull the barrel off and push the Discovery pellet through with a cleaning rod.  The skirt shows nice, even contact all around.  There are no marks at all on the forward part of the pellet.  I try another type pellet; Benjamin domed 14.3 gr. that Sports Academy had on clearance ($2 for a 250 ct. tin).  the result is the same.  I suspect these pellets are the same as Crosman Premiers, and probably have identical dimensions.  Either type pellet will easily insert into the muzzle up to the skirt with no resistance.

In comparison, a .177 CPHP pellet pushed through the .177 barrel will be marked both on the skirt and the forward ball.  The markings on the ball are light, but there.  And the initial push required to deform the pellet as it moves from the breech into the barrel proper is harder for the .177 than for the .22.

So do I need bigger pellets?  The .22 barrel looks fine inside.  If the pellets I have were 0.0005 larger, I suspect they would make contact with the rifling both forward and aft.  I suspect that if I order .22 Crosman Premiers, I will get pellets the same as those I have.  I could order one of the variety packs that one of the on-line retailers offer, but I really don't need the wad-cutters, or pointy pellets.  I need hunting pellets; hollow points at 14 gr. or above.

Anyone have suggestions?

Oh, and the 4" moderator works fine with the .22 barrel, even with the small holes in the baffles.  But the pellets clip the baffles in the 7" Mark II model I made last week.  The Mark II is a bit quieter, but not enough to justify the precise alignment it needs for the .22.

Shearload
No sig. line yet

[sigsr]

JSB Exact 5.52mm was the solution for me.  Shot both 14.3g and 15.8g, both pellets group quite well, but my gun seems to like the 15.8g a little more.

[normal]

I've had a rash of bad .22 barrels from Crosman lately.  The rifling has been a wavy, rippled mess from one end to the other.  I sent them all back.  All eight of them.  Make sure your barrel has good rifling.  The ripply stuff won't shoot straight. Slows the pellets down, too.   A good Crosman .22 barrel is not fussy about what you feed it.  Jan in Crosman parts is a sweetheart and will try very hard to get things right for you.

[shearload]

I think I will call Crosman tomorrow.  After reading your reply, I pulled the barrel out and looked at it again.  My eyesight isn't what it once was (especially at close range), so I really can't tell.  I dropped a pellet in the muzzle end, and it falls to the skirt edge.  And I can rotate the pellet easily.  I tried the same thing with the .177 barrel; I have to "help" the pellet in a bit, and cannot rotate it.

For $15 or so, it doesn't seem worth it to ship this one back.  Maybe I'll just order another.  If the new one is as bad, then it'll be worth it to ship two back ;-).

Shearload
No sig. line yet ...

[shearload]

I'll try them.  It seems that they're often out of stock, though, at the on-line stores.  And no one carries them locally.

Thanks,

Shearload
No sig. line yet...

[melloroadman]

Dale with the un choked crosman barrels it is very important that the pellet seat snug. If the head is not snug in the chamber it will not stay true in the barrel when the blast of air hits it . Even with a choke on the barrel it will not straighten out a pellet that is not true in the barrel . If you can mic the barrel and pellets and see if you can get pellets that will seat better for you . Here is a chart that might help .Marvin
http://straightshooters.com/documents/pelletcomparison.html
http://www.gatewaytoairguns.com/airguns/forums/thread-view.asp?tid=12313&posts=5&highlight=propellent%20&highlightmode=1#M96691

[shearload]

Thanks for the link to the pellet dimension table.  I got around to measuring pellet diameters last night; both the Benjamin pellets I have measure .217 at the head.  The Discovery hollow points slightly over that (maybe .2172) and the domed measure a little under (maybe .2168).  Both are a bit larger than the table shows for the Crossman Premiers.  The only hollow-point pellets that I saw in the table that had a significantly larger head was the Beeman Crow Magnums.

As I noted earlier, the heads of the pellets I have do not fit the rifle lands in the barrel I have.  I wouldn't want to be tied to one brand and one type of pellet.  The article you linked is interesting and very informative; however, it makes one observation that I don't think applies to air guns.  It says that bore size isn't super critical, since, in a firearm, the bullet will distort to conform to the bore.  Pellet skirts may expand to fit the bore, but not the pellet heads.

I'm going to send the barrel back and hope for a better one.

Dale