We all have been wrong about the QLA

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Honestly, I've been shooting a T/C Thunderhawk in .54 cal for over 20 years. It has the QLA. Until I joined this forum, I had not heard of issues with the QLA barrels. I guess ignorance is bliss. Since no one told me it was bad, I had no idea. Getting consistent groups is a matter of fact with this rifle. I shoot full bore lead conicals.
That doesnt surprise me. My brother and I both bought identical Omegas in the 90s. His will shoot full bore conicals pretty dang well. My group was 8” at 25 yards with some going thru the target sideways. (No excuse bullets).

Sounds like your bore and QLA line up well. But there are a lot that don’t.
 
According to the foremost expert on everything Thompson, we are all dumbass shooters…

It is called DAS. Dumb ass shooter. When loading with a QLA people place the short starter on the ball which has not been set into the bore with a soft wooden ball starter and pop it down with the palm of their hand. because the QLA is larger than the bore the brass rod of the short starter can move off the ball and the palm pop results in the short starter being driven against the inner crown of the rifling eventually damaging it. The same applies to cleaning with a Jag. A damaged crown will not impact sabot rounds and patched round balls as greatly as it will a maxi or engraved bullet. When the QLA has been removed and the bore re-Crowned the flaws are removed.
Anyone who has a clear understanding of mill and lathe work will tell you the same thing it is near imposable to coin barrel incorrectly on a lathe as the barrel is turning not the cutter. I have modern rifles with coined barrels that shoot in excess of 1000 yards consistently. Likewise, I have won muzzleloader competitions on a national level shooting coined muzzles.
As far as being the local guru on T/C Not that it matters on the subject of machining. When national shooting and hunting magazines including the national muzzleloading rifle association's magazine have maters they need clarified on regarding Thompson Center side locks they call me. Telling me I am considered the nation's foremost leading expert on T/C muzzleloaders then request clarification.
I can bring millions of people who think Joe Biden is a genus. Does that make it true?
my bullshit meter just went off , as far as being the go to for NMLRA
 
I have no experience with a QLA, just a question. Is this specific to a sabot and bullet, or both the sabot and patched round ball? I'm guessing just the sabot. Have a great Christmas!

Frosty
 
I have no experience with a QLA, just a question. Is this specific to a sabot and bullet, or both the sabot and patched round ball? I'm guessing just the sabot. Have a great Christmas!

Frosty
The QLA has issues if it is not cut concentric to the bore of the barrel. This affects shooting solid conical bullets. Sabot are usually not affected, I have no experience with PRB.
 
Thank you. I guess the solid conical bullets are shaved at the base when going from the QLA to the bore if I understand correctly, unequal pressure when leaving the muzzle causing flyers, or patterns instead of groups.

I am mystified as to why TC did turning on the barrel in different setups.

Frosty
 
Thank you. I guess the solid conical bullets are shaved at the base when going from the QLA to the bore if I understand correctly, unequal pressure when leaving the muzzle causing flyers, or patterns instead of groups.

I am mystified as to why TC did turning on the barrel in different setups.

Frosty
The bullets are not shaved. The unequal distance (non concentric) QLA allowed gases to escape unevenly as the bullet left the bore. The sabot base expands to seal the uneven gas flow. The gas flow being uneven steers or throws the bullet off. The reason for the different steps is cosmetic. TC didn't want to have barrels that "looked" uneven. Most bores are not concentric to the OD of the barrel.There are threads on this with diagrams just search the board. The use of a sub base has seemed to fix the issue when using conicals.
 
Agreed! The comment above about the bores not being concentric to the OD is from my experience in chambering, crowning center fire barrels. This hold true for top end barrels as well.
 
That doesnt surprise me. My brother and I both bought identical Omegas in the 90s. His will shoot full bore conicals pretty dang well. My group was 8” at 25 yards with some going thru the target sideways. (No excuse bullets).

Sounds like your bore and QLA line up well. But there are a lot that don’t.
It seems to me that several important things are poorly understood on the various ML forums. Those things are bullet hardness, obturation (instant expansion of the bullet due to rapid peak pressure as the powder is fully ignited -- peak pressure is very rapid with BP and BH 209 powder), and good bullet contact on the rifling lands (which are often quite shallow with inline rifle barrels, compared to old time MLs).
If your own conicals were flying all over the place at 25 yds, it is extremely likely it was due to no expansion of your bullet at firing such that it was the same as shooting the conical in a smoothbore -- no spin on your bullet. I'd propose your bullets were too hard to obturate, so they got little or no spin from the rifling lands, and your inaccuracy was due to that and had little or nothing to do with a QLA muzzle. No offense, just sayin'....
Aloha, Ka'imiloa
 
It seems to me that several important things are poorly understood on the various ML forums. Those things are bullet hardness, obturation (instant expansion of the bullet due to rapid peak pressure as the powder is fully ignited -- peak pressure is very rapid with BP and BH 209 powder), and good bullet contact on the rifling lands (which are often quite shallow with inline rifle barrels, compared to old time MLs).
If your own conicals were flying all over the place at 25 yds, it is extremely likely it was due to no expansion of your bullet at firing such that it was the same as shooting the conical in a smoothbore -- no spin on your bullet. I'd propose your bullets were too hard to obturate, so they got little or no spin from the rifling lands, and your inaccuracy was due to that and had little or nothing to do with a QLA muzzle. No offense, just sayin'....
Aloha, Ka'imiloa
Interesting theory, and could possibly apply to some rifles, but that was not the problem with mine.

I cut off the QLA, problem solved. Shoots the same conicals that we’re going through the target sideways in tight groups. Mine was due to the bore being slightly off center and the QLA being dead center. Proved that when I cut off the QLA. I don’t remember the exact measurements on the bore side, but it was not in the center of the barrel.

Back when that happened (in the 90s). I believe I was shooting loose pyrodex. I have never shot pellets. 777 and BH 209 had not been invented yet.
 
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Pretty simple physics really. When bullet enters a malalligned QLA, and there is more room on one side than the other, the gas will seek the path of least resistance.

YBMV (your bore may vary)

Also FYI, the bullets in question (went thru target sideways) were No Excuse pure lead bullets. If I recall correctly they were 430 gr. I suspect they obturated just fine because they shot well when QLA went away.

But I also remember trying maxi-balls, Hornady Great Plains, and Buffalo bullets.
 
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