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PostPosted: Thu Jun 09, 2016 8:47 am 
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Location: New Brunswick
One of my recent purchases was a Hastan Junior break barrel. It was an impulse purchase while visiting a gun store in a remote town and I hadn't yet had a Hatsan in my collection.

It's designed for "junior" so it's not that long. I have done some shooting with it and surprisingly it shoots just below 500 fps.
But there's a problem with the breech, it's difficult to set the pellets into it. I find I have to use a tool or a BIC pen to "seat" the pellets into the breech.

My question is this, can I use a mild abrasive Dremel tool bit to increase the breech opening? I've never done it before, I'm guessing it will be like "crowning" the barrel except at the other end. I will probably hand polish the opening and not actually use the Dremel tool so I don't remove too much material.

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PostPosted: Thu Jun 09, 2016 10:54 am 
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By hand sounds right, but I'll let the experts chime in.


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PostPosted: Thu Jun 09, 2016 11:58 am 
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Location: Alberta Canada
My suggestion is as follows.
Insert a pellet bass ackwards into the breech. Press it in aprox 2/3rds the depth of your choosen ammo. Using a Q'tip upon a hand drill under 350rpm. Load Q'tip with (my chioce) Autosol metal polish. But good ole tooth paste will do the same just take much longer. Polish in both directions. Clean test fit pellet/ redo until your happy with the seating results.

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PostPosted: Thu Jun 09, 2016 12:03 pm 
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Try a few different pellets. Some seem to have bigger skirts. I think I would try removing a few skirts to see if that is the part that needs polishing.


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PostPosted: Thu Jun 09, 2016 7:14 pm 
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So the head goes right in but not the skirt? That's normal and imo the way it should be. So basically after pressing firmly with your finger the skirt is still sticking out a few thou, or however much it want to stick out as long as the skirt isn't hitting the receiver when closed.
If the head catches a bit or the edge is sharp enough that it cuts the skirt, then you have the option of beveling the sharp edge until the prob is solved, which usually takes very little metal removal to make happen. Too much beveling is a drawback imo so just enough is all.


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PostPosted: Thu Jun 09, 2016 8:07 pm 
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Chevota wrote:
So the head goes right in but not the skirt? That's normal and imo the way it should be. So basically after pressing firmly with your finger the skirt is still sticking out a few thou, or however much it want to stick out as long as the skirt isn't hitting the receiver when closed.
If the head catches a bit or the edge is sharp enough that it cuts the skirt, then you have the option of beveling the sharp edge until the prob is solved, which usually takes very little metal removal to make happen. Too much beveling is a drawback imo so just enough is all.

If I press the pellet into the breech flush and try to fire the air rifle the pellet fails to launch, fails to move.
But if I seat the pellet about 1/8" into the breech it does launch.

I have some air rifles where the pellets don't seat flush in the breech and when I close the barrel I squish the skirt. This isn't happening with the Hatsan Junior.


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PostPosted: Thu Jun 09, 2016 9:17 pm 
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SureShot wrote:
Chevota wrote:
So the head goes right in but not the skirt? That's normal and imo the way it should be. So basically after pressing firmly with your finger the skirt is still sticking out a few thou, or however much it want to stick out as long as the skirt isn't hitting the receiver when closed.
If the head catches a bit or the edge is sharp enough that it cuts the skirt, then you have the option of beveling the sharp edge until the prob is solved, which usually takes very little metal removal to make happen. Too much beveling is a drawback imo so just enough is all.

If I press the pellet into the breech flush and try to fire the air rifle the pellet fails to launch, fails to move.
But if I seat the pellet about 1/8" into the breech it does launch.

I have some air rifles where the pellets don't seat flush in the breech and when I close the barrel I squish the skirt. This isn't happening with the Hatsan Junior.


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Have you tried other brands, and do they seat the same? If so a bit of polishing will not hurt you, only aid in seat the pellet better. From your desription if the rifling cuts thru the skirt the pellet then leaves the barrel as its suppose to.

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PostPosted: Fri Jun 10, 2016 9:12 pm 
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Won't budge? Wow. My first thought would be it's defective, like a major air leak, but if it's at the claimed 500fps when it does work then I guess not. I don't have any guns in that power range but apparently it's true that too tight a fit can cork it up.
So I guess that kinda forces you to do something since I doubt you want to deep seat it each time?
Are they Crosman Premier pellets? Those are kinda stiff/sturdy pellets so maybe try some JSB Exact which are probably as soft and delicate as they come. I'd be sure any sharp edge at the breech catching the skirt is removed, which obviously will hang it up, and I'd probably sand down the rifling in the chamber so the pellet isn't wedged on the lands so much. Picture how a firearm chamber/rifling is setup, if you're into that. It's generally a bad idea to allow the bullet to touch, and especially be pressed into the rifling because it's harder for the bullet to start moving which raises pressure. Point being it's harder to get moving and in your case no moving at all :o So I'd probably sand the lands in the breech half way down and see how it works? Like sanded half way down right at the breach edge and tapering smoothly to full lands ~7mm in.
I sand bores with a dowel that has a piece of fine sandpaper scotch taped to it. I do it to smooth the typically rough bores and open up tight spots, but same deal if just doing the breech. If interested I can post some pix of my setup.
I also push a pellet thru thru by hand with a dowel to see the bores condition. It'll show what the bore surface is doing to the pellet and tell you if/where the tight spots are.


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