Interesting read on the QLA i just came across
emrah wrote:
Maybe I should rephrase my title. I know what the QLA is, and I've seen the diagrams posted here by somebody (sorry, I can't remember who) that shows how the QLA is offset from the barrel rifling.
Here are my questions:
1. Are ALL T/C's with QLA's off-center? I don't understand how a barrel's rifling can be made (cut, forged, etc.), but for some reason, the QLA is off-center. I mean, it obviously goes in some sort of lathe or fixture, correct?
2. Even IF the QLA is off center, why does it affect conicals and not sabot rounds? Isn't the inside diameter of the QLA larger than the sabot or conical's diameter? In other words, isn't the QLA nothing more than a really deep recessed muzzle crown?
Thanks,
Emrah
This is copied and pasted here from another thread - see if this might help you with some of your questions..
The 'crown' at the bottom of the QLA - is exactly the problem. TC understands this and knows it. That is why they will tell that their rifles are for sabots and not conicals.
Here is what I am trying to convey...
The way TC chooses to bore and install lands and grooves is different that most other barrel manufactures. What they choose to works very well but on occasion the bore does not come out in the middle of the barrel. They have a +/- number of thousands that it can be off center. The fact that the bore might be off-center to the barrel has nothing to do with accuracy at this point. It will shoot sabots and conicals equally well. The problem is that for most consumers the cosmetics of the bore being off-center would not be acceptable. To hide this slight problem TC chose to install the QLA to cover the slight descrepency.
This does not happen in every TC bore it does in some.
Here is a picture of a cut off QLA... I believe in this picture you can see that bore is just slightly off center of the barrel.
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While on this end the QLA looks just fine at it install in the center of the bore.
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Then this is the picture of the bore recrowned and now able to shoot conicals as well as sabots, but notice it is still slightly off center...
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I talked to a TC Tech about all of this and from that conversation I created this simplistic picture as a representation of the problem.
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Again TC is aware of this and if you were to call them they would tell that their rifles are built for sabots.
I would also tell you that you do not find this in all TC/QLA rifles but enough of them to make you a little leary of the problem.
CVA uses and al lot of other companies, such a
Green Mountian Barrels choose to use a different type of boring to insure this problem does not exist. Yes CVA uses a form of QLA but the bore and the QLA are concentric - not a problem...
Keep Shooting Muzzleloaders - They are a Blast
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