1377 Accuracy Problem Solved

[Tad]

I picked up a re-manufactured 1377 for $36.  Didn't really expect too much, just looking for a fun plinker.  With CPHPs, tin can accurate at 10 yards, but not much better.  Tried some other pellets.  I found Daisy Precision Max Flat Heads to be pretty accurate, along with Gamo match not being too bad.  Still, I was not too impressed, with about 1" groups at 10 yds.  Beyond 10 yds., the group really opened up.

There was not enough adjustment on the open sights, so I ended up getting the barrel rings and a $7 Crosman scope.

I had some fun, but some frustration too.  Some days it would shoot OK, other days not so much.  Spent a couple of days chasing POI, even with open sights.  It would shoot at 1 POI for a few groups, then shift to another "stable" POI for a while, then shift back.  A real pain.

After a while it seemed to hold a POI, but accuracy was erratic.

I figured maybe I hadn't found the right pellet, so I ordered a variety pack of about 25 different types of pellets.  More frustration!  At first, many pellets shot about the same, about 1.25", at 20 yds. with some much worse.  Sometimes, a pellet would give me a good .5" group, then give me a +2" group another day.  No clear winner was emerging.

I tried recrowning.  It looks nicer, but no real help. 

My pellet tests showed a few pellets that were always bad, but some that gave occasional great groups, but sometimes really bad groups as well.

I tried shimming the barrel with a wedge of wood.  This gave me stringing, sometimes vertical, sometimes horizontal.  Hmm. 

I was about to give up on the gun, figuring it would always be just a plinker.  I decided to take it apart.

The barrel seemed like a pretty loose fit in the breech.  I wrapped Teflon tape around the barrel, and tried to get it a tight as possible.  The barrel really does not engage the breech very much, particularly since I had to avoid the transfer port when taping.  But, I think I got it pretty tight.  I put the gun back together, and tightened things down as much as I could.

Wow, what a difference!  Unfortunately, I had pretty much run through all my pellets, But I had a few left, ones that I did not think were good candidates.  I tried a group of Baracuda Hunters, which at 10.3 gr I had thought too heavy.  I got a less than .5" group at 10 yds.  Consistently.  Other pellets I had rejected gave consistent groups as well.  Looks like my problem is solved! 

I still find it strange that my gun hates Premiers, both lite and heavy.  I mean a POI a couple of inches away from where most other pellets group, and +2" groups.

I've ordered R-10 lites, JSB Exacts and Baracuda Hunters, which showed some promise in my pellet test, so I'll need to see if it stays consistent.

Anyway, I hope this helps folks that may have the same symptoms.   

[0351_Vet]

Do you think Teflon Paste might work as good?

[Tad]

I don't know about teflon paste.  The object is to get the barrel snug in the breech so that it doesn't move around.  If it doesn't dry hard, I would think that a slippery paste would make things worse.

[Smaug]

Thanks for sharing that solution.

It sounds like you should think about a steel breech in the meantime.

[Tad]

I hear you.  But this was going to be my $36 gun.  I certainly see the attraction of modding these guns, but I convinced myself that I was not going to put $200 into a $36 gun.  It was going to stay stock.

But, so far I've got the $11 rings (well might as well use the red dot that I had) and the $7 scope (it's only $7 and better than the red dot), the $25 stock is on order (well now that it's accurate, it deserves to be steady). I've spent over $50 looking for the right pellet, and I've got $50 more pellets on the way.  I find myself looking at breeches and barrels.

No, must stay strong!

[MountainMan126]

When I got mine the air space under the barrel was uneven and is on most. Looks like it has a slant, muzzle end downward. After the steel breech and new barrel band to accomodate the longer barrel it is nice and even all the way across. This should change your sight angle a little but also align the loading port and air inlet on the barrel with better positioning.

[0351_Vet]

Mountain Man......What kind of air stripper is on your pictured above. Pretty cool.

[MountainMan126]

AC Customs muzzle brake , awesome addition, good place to deal with.

http://accustomparts.com/Shrouds.aspx