Question about TC Round Ball Twist Barrels

[BruceHH]

Do the Thompson Center "Round Ball Twist" barrels have the same shallow depth of the grooves as their standard barrels? Thanks in advance.

 

[Phil Coffins]

I don’t know, but in my youth I bought one of those nasty shallow 1 in 48” twist TC Hawkens. Shot many matches from 25 to 100 yards and side matches like snuffing candles and splitting the ball on an ax blade. Won with some regularity despite not having a slow twist deep groove barrel. Lately at our local club matches there are at least a couple of guys shooting TCs with us. They do alright against a number of fellows shooting custom hand built rifles.

 

[necchi]

Do the Thompson Center "Round Ball Twist" barrels have the same shallow depth of the grooves as their standard barrels? Thanks in advance.

I've never owned one but I have handled two with close inspection, (they're rare in these parts), and both of those showed a distinct difference from the common barrels.
I never layed tools on'm too measure, but I'll say no, they have a different more robust rifling pattern.
That's the only way I can say it,,

 

[dragnetbill]

According to the T/C catalogs that I have the round ball twist barrels have .010" deep cut rifling.

 

[BruceHH]

Thanks very much. I have never had one in my hands either.

 

[ETipp]

Do the Thompson Center "Round Ball Twist" barrels have the same shallow depth of the grooves as their standard barrels? Thanks in advance.

I do not have a definitive answer for you. However, I can add this.

In terms of TC and whatever rifling they used back then, I had a .54 Renegade that shot patch and round ball very well. It was not finicky and would stack them in there at 50-60 yards nicely. Then I had another Renegade in .50 caliber. That thing would throw RB all over the place. Try as I did, I could not find a good combination that would shoot RB. But it was a very accurate Maxi Ball shooter.

My next TC was a New Englander. It too, throws RB all over the place but is a superb conical shooter.

With that said, there may or may not be an accurate combination for the latter two but I gave up on RB out of those ML. Some folks out there claim that they will shoot RB just fine but you have to find the correct combination. Well, my answer to that is, I find it very interesting that the .54 Renegade was such and awesome RB shooter and the later two are not. My thoughts are the .54 (being an older model TC) either had a slower twist or deeper grooves.

 

[COTNTOP]

I think that a member here said the larger the caliber the better a 1/48 twist TC would shoot RB.

 

[ETipp]

I think that a member here said the larger the caliber the better a 1/48 twist TC would shoot RB.

If that is true, it may have been the issue.

 

[Scota@4570]

According to the T/C catalogs that I have the round ball twist barrels have .010" deep cut rifling.

That sound like a great set up. Excessively deep grooves are detrimental to fine accuracy.

And, btw, the 1:48 TC barrels are capable of great patched ball accuracy. Just do not expect to feed it loose loads and skip cleaning between shots.

 

[ETipp]

That sound like a great set up. Excessively deep grooves are detrimental to fine accuracy.

And, btw, the 1:48 TC barrels are capable of great patched ball accuracy. Just do not expect to feed it loose loads and skip cleaning between shots.

Ya know, with one of my .50 TC's, I tried thicker patches, thinner patches, .490 round ball, .495 round ball, different powder charges, different powders, swabbing between shots, not swabbing between shots, and none of that helped. Not saying that there isn't/wasn't a magic load for them, but I didn't find it. It was much easier to give in and shoot conicals, which they liked very much. Very accurate with Maxi Balls and Great Plains conicals.

And again, I had two TC Renegades. One in .54 and one in .50 caliber. The .54 shot RB very well and was not finicky. The .50 would throw them all over the place. Same with my TC New Englander. But boy howdy did those last two like conical, especially Maxi Balls. Many of critter met their match with those two setups.

With that said, perhaps I was unlucky enough to get two TC's in a row that I personally was not able to get to like RB. And I have no reason to doubt what a few of the posters in this thread contends, in terms of obtaining great accuracy out of their 1:48 TC's. It simply did not happen for me personally, but I did find a very lethal alternative. However, that will not change my thoughts on 1:48 TC's. If I ever buy another one I will not expect it to shoot RB accurately.

 

[zimmerstutzen]

That sound like a great set up. Excessively deep grooves are detrimental to fine accuracy.

And, btw, the 1:48 TC barrels are capable of great patched ball accuracy. Just do not expect to feed it loose loads and skip cleaning between shots.

LOL, great round ball accuracy? Accuracy is so many different things to so many people. MY TC Hawken off a bench at 50 yfs could make ragged one hole 5 shot groups. (with different sights than the crappy stock sights) So could my 50 caliber smooth bore. At 75 yds, the TC group would open up to 1.5 inches. The smooth bore could still do better at about 1.25 inch 5 shot groups. At 100 yds, the TC was at best a 4 inch 5 shot group. The smooth bore opened up to just a fraction over the TC group. My H&H target barrel on the TC stock with the same lock off the bench in similar calm weather could shoot 1 inch 5 shot 45 caliber groups with open sights at 100yds.. My heavy barrel Hopkins and Allen underhammer with stock 45 caliber barrel and open sights could do 2 inch groups off the bench at 100yds. With diopter rear and globe front sights, the group shrank below 1 inch. My 19th century heavy bench rifle with open sights and 3 inch ACF barrel could shot ragged one hole 5 shot 62 caliber holes. that could be covered with a 50 cent piece. None of my guns could shoot as well as the cross patch slug guns they shoot up at Blue Mountain Muzzle loaders outside of Shartlesville, PA Those 100yd matches are determined by the number of x's not the number of tens. Nearly every one of those guns can shoot caliber size 5 shot groups at 100 yds. Matches are lost by what fraction of an inch a shooter throws a shot or two out.

There is so much more than "excessively deep grooves" to accurate rifling. width of lands and grooves, shape of the grooves. (round, oval, or square/rectangular) then of the round bottom rifling, most round bottom rifling is too narrow. Wide round bottom rifling, or wide oval bottom rifling is better. Rifling can be fairly shallow and still have a better bite on the patched round ball than most cut rifling. Then we get into progressive rifling, choke rifling and gain twist rifling. .

 

[Scota@4570]

There is so much more than "excessively deep grooves" to accurate rifling. Of course there is. The discussion was about TC button barrels.

I wore the muzzle down to the grooves on a TC Flintlock 50 cal in the 1970. When new, it was capable of tennis ball sized 5-shot groups at 100 yards. That is off the bench (of course) and a Lyman 57 rear and a 17A up front. Not every barrel of the same make is a winner. I would not expect all TC barrels to be great, they were made as cheaply as possible.

I doubt many here are interested in the details of what makes an accurate ML barrel so I did not get into the weeds. The question was about TC barrels. TCs are disrespected by some and I do not see that as fair.

Some people think super deep grooves and round bottoms are great. I suspect their accuracy expectations are different than mine. You will not see any such barrels in serious target shoots, like Friendship. No serious accuracy bug cares about shooting all day without cleaning. A person who recommends a deep round groove barrel based on lack of cleaning required and off hand accuracy is not setting the accuracy bar very high.

I had a barrel made to my specs recently. 40 cal, 0.008 deep, the grooves follow the bore (square bottom) 70% groove and 30% lands. The bore is smooth based on slugging, there are no big tool marks, based on a borescope exam. The diameter is nice and uniform based on the feel of the slug. IT shoots around 1" @50 yards. No single barrel proves anything.

With that same barrel, I did reject the first attempt by the barrel maker because the bore was rough and the diameter was not uniform. IT was not accurate as I expected. He made it right, all is well.

The barrel started as a 32 from a different maker. It had narrow groves and wide lands. The grooves were 0.014" deep. IT was a tomato stake, as I expected based on my initial observations. The maker sincerely believes it does not matter. That puts that barrel maker in the "never buy from" category for me.

Bottom line, easy button, get a Green Mountain barrel, if you can.

 

[Fastleo]

The factory round ball barrels have deep rifling, but I get great rb accuracy with standard barrels as well.

 

[Dale Allen Raby]

I have only one slow-twist barrelled gun; a Jonathan Browning Mountain Rifle in .54 caliber with a 1:66 twist. It shoots round balls very well. Some of my 1:48 T/C guns will shoot round balls well, a few will throw them all over the map. I just use those for conicals/unmentionables. Never had any experience with things like the Pennsylvania Hunter. They were not made for too many years and are still pretty rare in these parts.

 

[kansas_volunteer]

Fifty years ago nobody bitched about TC barrels we just shot the heck out of them and won matches with them. Everyone shot round balls. We didn't know we had to clean after every shot. We shot all day and cleaned once when we got home. The 1:48 twist was never questioned. Apparently Jake and Sam's customers felt the same as all original Hawkens of all calibers were rifled 1:48.

 

[Mulemauler]

The factory round ball barrels have deep cut rifling. There is so much confusion over rate of twist. 1-48 vs 1-56 or 1-66. The amount of powder burned and velocity have more effect on accuracy than many other factors. A 1-48 shoots very well with light target loads but will get erratic with heavy hunting loads. A 1-72 will stabilize a larger diameter ball with higher velocity loads but won't do as well with light loads. All will do well if you take the time to find the "sweet" spot load for a given barrel.

 

[Muddly]

Have 2 T/C Pennsylvania Hunters, 32 inch 1-66 and the rifling is deep enough to constitute a trip hazard. .010 to be exact.
Oddly, I'm having quite a time getting consistent accuracy with ball.
Hornady Pa. conicals and Lee 250 grain R.E.A.Ls do quite well though.

 

[ETipp]

Fifty years ago nobody bitched about TC barrels we just shot the heck out of them and won matches with them. Everyone shot round balls. We didn't know we had to clean after every shot. We shot all day and cleaned once when we got home. The 1:48 twist was never questioned. Apparently Jake and Sam's customers felt the same as all original Hawkens of all calibers were rifled 1:48.

Its not necessarily the rate of twists 1:48 that can be the issue. Its the dimensions and depth the rifling is that makes the difference as well. Either way, there is no denying a slower twist is superior for RB and a faster twist is optimal for longer, conical projectiles. Generally speaking, a 1:48 twist does shoot conical well when inside there proper powder charge range. And I can tell you for a fact that some of the very same 1:48 twist ML can be problematic trying to get them to shoot RB accurately.

 

[ohiochuck]

When I owed a TC Hawken in .50 cal back in 1970s, I found a drop in barrel (1-66) for RB shooting. My memory of it was that it shot RBs accurately
if I did my part and it easily harvested Ohio deer.
It shot better than my TC barrel.

 

[Albert53]

Do the Thompson Center "Round Ball Twist" barrels have the same shallow depth of the grooves as their standard barrels? Thanks in advance.

I have one of their rifles with their 1 turn in 66 inches barrel that is longer that is marked for round ball