BAD CROWN?????

[CajunHoss240]

 I am having an issue with accuracy at 10 yds with my modified 1377 in .22 cal. I was able to hold down same hole groups with my stock .177 barrel self recrowned and lead in polished. Yesterday I received my order for a .22 flow thru bolt, sold pivot pin, and 23.5", recess target crowned 2260 barrel. I inspected the barrel with a Q-tip and there were burrs on the inside edge of the crown and the second inner diameter isn't centeredto the O.D.. The inside edge isn't 11 degree as it should be, but flat. And the finishing looks like it was only machined. There is no sign of anything higher than a 200 grit on this crown. I have included a picture of the crown. I locked the barrel in good with three set screws on my free floated highly modded 1377 carbine and shot some Crosman HP couldn't get them to group in any kind of pattern. Picture also included. Next I tried some destroyers, again erratic. Then I tried some Crosman pointed, again horrible. I am frustrated because I have been waiting so long and now this is just disappointing. I have a TKO 6.5 and when it is on it shoots even worse. Anyone have their TKO mess up acccuracy? I mean this is only 10 yds...

I am not going to say who did this job, but i will say I am convinced this is not his/her best work. My question to everyone is,
1. Have you ever had a bad crown job by a custom supplier?
2. Who does good crown jobs?
3. What type of crown is best for 2260 barrel?
4. Have any of you had a problem with a 2260 barrel?
5. What pellets have y'all had luck with in a 2260 barrel for long range accuracy?

[CajunHoss240]

 I am having an issue with accuracy at 10 yds with my modified 1377 in .22 cal. I was able to hold down same hole groups with my stock .177 barrel self recrowned and lead in polished. Yesterday I received my order for a .22 flow thru bolt, sold pivot pin, and 23.5", recess target crowned 2260 barrel. I inspected the barrel with a Q-tip and there were burrs on the inside edge of the crown and the second inner diameter isn't centeredto the O.D.. The inside edge isn't 11 degree as it should be, but flat. And the finishing looks like it was only machined. There is no sign of anything higher than a 200 grit on this crown. I have included a picture of the crown. I locked the barrel in good with three set screws on my free floated highly modded 1377 carbine and shot some Crosman HP couldn't get them to group in any kind of pattern. Picture also included. Next I tried some destroyers, again erratic. Then I tried some Crosman pointed, again horrible. I am frustrated because I have been waiting so long and now this is just disappointing. I have a TKO 6.5 and when it is on it shoots even worse. Anyone have their TKO mess up acccuracy? I mean this is only 10 yds...

I am not going to say who did this job, but i will say I am convinced this is not his/her best work. My question to everyone is,
1. Have you ever had a bad crown job by a custom supplier?
2. Who does good crown jobs?
3. What type of crown is best for 2260 barrel?
4. Have any of you had a problem with a 2260 barrel?
5. What pellets have y'all had luck with in a 2260 barrel for long range accuracy?

[JEBert]

Maybe they forgot to lap the inside edge of the crown?

[1377x]

well i dont see any target pics!???
1. yes
2.if you are looking for a target crown you can try to convince muzzlemack aka yourdaddyjoe aka hpa sports to do one for you he had the best target crowns i have seen.mac-1 is another that comes to mind.i get my barrels cut and crowned locally but he is so busy he isnt taking any work like that.air gun repairs only now and sales
3. the crown that has no flaws! im serious.a concentrically square cut barrel needs no crown to be accurate all a crown does is protects the muzzle
4. there has been many reports of bad barrels 2260 and others crosman barrels are a crap shoot.lucky for me i get to inspect all my barrels before i buy.just got a 2260 barrel on saturday picked through 8 found the one i liked best
5.try a jsb pellet they seem to be the most consistent when it comes to a good pellet out of a crosman or the boxed cp's.there is a certain lot you want if you get cp's hopefully someone will chime in with the lot number

[1377x]

why are you using a breech band?

[CajunHoss240]

1377x your right but you forgot to mention a concentrically,square cut crown "without internal burrs" Although I do not believe the crown to be concentrically cut. I should have just asked for a normal rounded crown and I would be  much happier. So what did you/ supplier do about your bad crown job, 1377x?

I really need to order some JSBs, I wish I knew someone here that sold them so I didn't have to pay shipping. I mean I could buy a whole new tin for what pyramid air wants to ship one tin. I think they do that to get you to buy 3 tins at once! So what weight seems to work for people in JSB exact? I was thinking of the 16grs since this isn't a PCP.

How much do muzzle mack and Mack 1 charge for a barrel and crown and maybe a lead in polish? might need to just PM them... 

Also, 1377 I am using a breech band because I am free floating the 23.5 incher. I am trying to attain maximum accuracy and FPE for fall and spring squirrel hunting. the breech screw is just wimpy and with the rear screw locked down tight the barrel raises up because of the wimpy breech screw. The breech band is ugly but it helps seal my valve perfectly and it keeps my barrel parallel with the main tube. Finally, I am a poor college kid and I can't afford a metal barrel band which may or may not be as accurate as a full floated barrel.  I saw the Uber pumper had it and I copied except I mounted it straight to the main tube for a more flush look.

I'll post groups tomorrow if I get a chance to shoot.  sorry

[1377x]

hey dont get down on yourself for wanting something you like.its not your fault the supplier/vendor didnt come through.pm me the name i have a clue as to who it is
  well all the barrels i have had cut and crowned were done professionally and never a bad job done.the 2260 barrel i just got i chose because it was the best one out of eight cosmetically had the cleanest bore and a decent looking concentric muzzle/crown
when i was using a .22 14.5" barrel on my 1377 my go to pellets are jsb stratton and now predator poly mag both 16gr.look up www.straightshooters.com they sell a sampler pack not cheap but worth it when looking for the right pellet.thats another shop close to me 45 minutes away i have a friend who drives by there every weekend when i get a chance im going to go up there just to see what its about.maybe get some supplies but i get just about everything i need 10 minutes from me.
you can try going to crosmans site and look for a service station in your area.maybe you have one near by that you dont know about
as far as getting a nice target crown done muzzlemack aka yourdaddyjoe aka hpa sports had the best looking target crowns i have seen.he used to do it as a service but that was when he was muzzlemack.i would contact him and ask politely if he would be willing to make you up a target crowned barrel. the worst he do is say no and closed mouths dont get fed .it wont be cheap expect to pay $40 i think thats what his old price was.you can also try Lloyd Sikes www.airgunlab.com he is a master modder expect a long turnaround as he is one of the most sought after vendors now.probably wont be as long as mellons wait, he has a lot of work going his way and actually my first choice for custom work.i lucked out and caught him at the right time with my Oogie Boogie build.the turnaround time was short.i think mac-1 is about $40 also he does an accuracy prep on the barrels.most of the time he does good work,heard a complaint or two from unsatisfied customers but no personal experience, again a long turnaround time.workinmanva is also equiped to do the job,he's going to be doing some barrel work for me soon.i havent used any of his barrels yet but he does supply what i need.http://www.workinmanshootingaccessories.com/
ask him i dont know what style of crown he does but its worth a shot pun intended
  your in college thats important and a start, you wont be broke for to long after you graduate get that education.your not the only one to use the high tech sightly breech band about 2 years ago i used the same one
not because my barrel pointed up, that doesnt hurt anything,imo. i made a 88yd shot with my one set screw breech. the breech band was for sealing and to secure the breech to the tube, my front breech screw hole was stripped
  see my high $$ red dot it helped me make that 88yd shot. call it luck if you want but that barrel was the most accurate barrel i had and it was stock. just sold it a couple months ago after 4 years,1000's upon 1000's of pellets and many transfers to different guns


i feel bad for people everytime i see shotty work and the money used for it was hard earned and/or long saved.i dont have money trees and im not droid(no offense good buddy) so i research all my purchases and ask a lot of questions before someone gets my funds.it litterally pays to thoroughly research and ask the right questions so think about what you are going to ask and prioritize the needed details
there are many forums and peope talk. its easy to find out who to avoid and who to deal with.i saved $60 by researching 13ci hpa tanks and modding the regulator myself.out of the $60 saved, i put $30 back into hpa by building a regulator reader.now i can keep modding it and recording what every mod does instead of spending another $75 on another reg. i just spend $20 for parts and get the same thing cheaper. the next $70 tank i mod, the $60 saved is all mine to do with as i please
hope everything works out for you!! and keep your head up

[Fronzdan]

That crown does look kind of rough.  It doesn't look like a Mellon crown and I've had good experience with his work.  Never had a muzzlemack barrel but judging by the workmanship on his brakes, I'd say its probably outstanding.

[CajunHoss240]

1377x Thanks for the encouragement! But i would rather not spread his name around for his sake. I just hope he emails me back and makes it right. I have been waiting to squirrel hunt with my pellet gun since Sept. 15th... I wouldn't take a shot at one with such horrible accuracy at 10 yds. I need at least quarter inch groups at 10yds thats minimum. Nice PCP by the way! I looked at the unsafe gadget but I saw Rick Eutsler of airgun web was only getting abo 550 fps with 14.3s. So I have strayed away from that route. Also the pump is just as expensive as the gun if not more.

[Gippeto]

That crown does indeed look rough...and very poorly done IMSHO.

A recessed flat crown is my favorite for simplicity of setup and excellent results.



Aside...Terminology is an interesting thing...I consider the "crown" to be the actual point at which the bullet/pellet leaves the barrel...the rest is just "dressing" ie...11 degree, recessed, double step recessed...and so on. Setting the crown "back" with any of these methods is intended to protect the crown from damage.

Al

[CajunHoss240]

Gippeto, Those crowns look nice. You're right about what you consider to be the crown. I just use the whole design to describe it. This is what I had in mind of seeing when I go my barrel.

[Gippeto]

Certainly not what you recieved. 

Hope the fellow you dealt with makes it right for you.

Al

[1377x]

i was under the impression that the crown protected the muzzle
thats the way the videos by midway and others made it sound to me

[Gippeto]

Eh...it's terminology, which is a "learned" thing. In the end, it doesn't really matter if everyone calls it something different...as long as when they're talking to someone else, that someone else knows what they mean.

Muzzle to "me" is the whole end of the barrel.

You'll also catch me referring to a Crosman"breech" as  a "receiver"....I KNOW that with airguns (Crosman products at any rate), the common terminology is "breech"....with PB's, it's receiver, with cannon, it's again "breech".  Each is correct...depending upon whom you're talking to.

Al

[CajunHoss240]

the crown is the last circumference of metal that the projectile passes through before dynamic projectile motion begins. If the crown isn't perfectly square with respect to the bore line, the projectile will experience drag on the area of barrel still in contact with the rear of the projectile. This drag force induces a y component moment with respect to its z axis along the projectile's center of inertia. If the projectile is also subject to tangential forces ( i.e. rifling) along its diameter, the net effect of the moments and forces creates a wobbly un-stabilized projectile .