Tuner contour

H

Hal D.

New member
In one of the tuner threads it was mentioned that Bartlien and Shilen have agreed to make a "tuner contour" barrel profile. I just called Frank Green to order a few barrels but he doesn't have the contour as yet. Has this special contour been drawn up yet? How much weight will be shed as opposed to a standard LV contour? For the tuners being made commercially now, .900" is the minimum at probably 23", so a Hunter class barrel wont work. I already have to chop off most of the shank on a LV barrel, so shortening the shank wouldn't help either. Are we looking at something other than a straight taper to get down the weight needed?
 
Some time ago I needed to take off about 5.5 oz from a used barrel to compensate for a tuner that I was adding. I stepped the barrel, ending up with the front being the diameter that I needed for a 15/16" fine thread, coming back a little over 6" from the muzzle and then stepping up (90 deg.) to about .100 larger in diameter. I carried that diameter back a similar length and then stepped up to the original contour. The barrel was button rifled, and there were no problems. With the tuner and Deresonator, it shot better than ever, and had a broader sweet spot. BTW, we took light cuts, with a sharp HS tool, and did not try for a smooth finish, but instead used a fairly fast feed. After the desired diameter was reached, the unthreaded portion that had been cut was filed and then smoothed with abrasive paper. The caliber was 6PPC.
 
The contour has been modeled and drawn. It should be in Frank's hand by Monday. It should allow a 4lb 8oz barrel at 22". The last 11.5" will be .900.
Butch
 
Boyd Allen said:
Some time ago I needed to take off about 5.5 oz from a used barrel to compensate for a tuner that I was adding. I stepped the barrel, ending up with the front being the diameter that I needed for a 15/16" fine thread, coming back a little over 6" from the muzzle and then stepping up (90 deg.) to about .100 larger in diameter. I carried that diameter back a similar length and then stepped up to the original contour. The barrel was button rifled, and there were no problems. With the tuner and Deresonator, it shot better than ever, and had a broader sweet spot. BTW, we took light cuts, with a sharp HS tool, and did not try for a smooth finish, but instead used a fairly fast feed. After the desired diameter was reached, the unthreaded portion that had been cut was filed and then smoothed with abrasive paper. The caliber was 6PPC.
Click to expand...

bolt025.jpg


Boyd, I've been there but I don't like spending my spare time stepping barrels down:D.
 
Hal,
What did it weigh when you started, and how much did the steps take off?
How did it shoot? Were there any problems?
 
Boyd Allen said:
Hal,
What did it weigh when you started, and how much did the steps take off?
How did it shoot? Were there any problems?
Click to expand...

The steps took just short of 5ozs off the barrel. The barrel with the 6.5oz tuner weighs 5lbs on the nose, and the rifle with a locked up 36X and a Bukys mount is 10lb 7.5ozs. I did it before I ever shot the barrel, so I can't say how it shot without a tuner, but it shoots great as you see it. I have another light gun with a 30PPC barrel and similar stepping that I put this tuner on, and it seems to have improved that barrel. I think it will agg better than it did before I put the tuner on it, although it only has one match on it since the conversion. Time will tell..
 
I may be wrong but I think the tuner works best on a barrel that is not too stiff. I think you can get the widest tuning window with a smaller contour. On the other hand I'm not sure what effect the extra heating of a lighter contour barrel might have. For example will it copper foul, etc.
 
J.

I kind of hope to find this out with what I am putting together. I have contoured a barrel down to a flat 4 pounds.
I have never seen any better agging capability in the barrels on my HV, which go about 96 ounces, and the barrels on my Sporter, which weigh an average 76 ounces.
In fact, the best agging barrels I have ever had, (non-Unlimited), were Sporter weight.......jackie
 
A Request for Jackie

Jackie,

If you get a chance will you please test whether a 100 yard tune with your new tuner will work at 200 as well?

Thanks,
Joel
 
Joel

I have always found that a load that is tune at 100 yards, will be in tune at 200 yards.
I really have never bought into the concept that there is a difference. Aside from conditions, there is nothing "mystical" that happens between 100 and 200.........jackie
 
looks like a MAUSER barrel steps

interesting that the Germans knew somthing about stepping a barrel 60 years ago.
 
Stepped barrels

primerate2 said:
interesting that the Germans knew somthing about stepping a barrel 60 years ago.
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Try over 100 years ago. Peter Paul Mauser had stepped barrels in the 19th century.

Look at the second and third barrels from the botton.
(I think I've posted this picture in an earlier thread)
or01ls.jpg
 
jackie schmidt said:
I have always found that a load that is tune at 100 yards, will be in tune at 200 yards.
I really have never bought into the concept that there is a difference. Aside from conditions, there is nothing "mystical" that happens between 100 and 200.........jackie
Click to expand...

Shooting in the high pressure window like you do I'm thinking your velocity deviation is very low. On paper if there is enough velocity deviation and what some are calling compensation brings bullets of different velocity together at 100 yards it might require different compensation to bring them together at 200 yards. As you have stated many times what happens on the firing line and in real match conditions is what really matters. Thanks
 
It all comes down

Quoted from the IBS Rulebook: "a barrel not less than 18 inches long, a diameter at and not more than 5 inches ahead of the boltface of not more than 1.250 inches and a diameter at any point between the muzzle and 5 inches in front of the boltface not greater than would be defined by a straight taper between such point 5 inches in front of the boltface at 1.250 inches diameter and the muzzle at .9 inch diameter at 29 inches".


to interpretation of the rule of barrel contour. Could a reverse taper be used? The rule book states: the shank of the barrel cannot be more than 1.250" in diameter for the first 5" from the boltface. From that point forward, to a point of 29", the diameter of the barrel cannot exceed what would be constituted as a straight line taper from 5" in from of the bolt face to the 29" mark. At the 29" mark the barrel cannot exceed .900".

I would say that a reverse taper barrel fits into this picture. The rule states that it "cannot be greater" than what would be a straight line taper between the 2 points.

This would definately make a barrel that would have no problem meeting weight requirements for the Sporter/LV Class with a heavy tuner attached.

Thoughts?????????
 
CYanchycki said:
Quoted from the IBS Rulebook: "a barrel not less than 18 inches long, a diameter at and not more than 5 inches ahead of the boltface of not more than 1.250 inches and a diameter at any point between the muzzle and 5 inches in front of the boltface not greater than would be defined by a straight taper between such point 5 inches in front of the boltface at 1.250 inches diameter and the muzzle at .9 inch diameter at 29 inches".


to interpretation of the rule of barrel contour. Could a reverse taper be used? The rule book states: the shank of the barrel cannot be more than 1.250" in diameter for the first 5" from the boltface. From that point forward, to a point of 29", the diameter of the barrel cannot exceed what would be constituted as a straight line taper from 5" in from of the bolt face to the 29" mark. At the 29" mark the barrel cannot exceed .900".

I would say that a reverse taper barrel fits into this picture. The rule states that it "cannot be greater" than what would be a straight line taper between the 2 points.

This would definately make a barrel that would have no problem meeting weight requirements for the Sporter/LV Class with a heavy tuner attached.

Thoughts?????????
Click to expand...
Read the "not more than's and cannot exceeds" one more time.

Reading the IBS and NBRSA barrel taper rule kind of leads one to think the tapered Varmint Class barrel profile is a fixed dimension. It isn't.

A reverse taper is just as legal as a traditional taper.
 
So then

would it not be worth trying making a barrel around the 21"-22" mark in a reverse taper that weighs around 64-70 oz?

This would then give a lot of room for a tuner of some weight to try and get the results of a tuner that the rimfire folk talk about.

Typically short and stiff was the way to go. Would not something slightly not as rigid with a tuner that is supposed to do what is claimed to do by the rimfire folk possibly be wortha try? Maybe it has been tried?????????????

I wish I was able to try this out or had more experience.
 
The reverse taper

Hopefully someone is working on a reverse taper for centerfire right now.

I'm going back to regular barrels and no tuners. I think tuners like television and airplanes are just fads of the day and they too will pass.
 
I think I would rather look into fluting, than step turning to reduce weight. It's quite easy to take 6 ounces off a barrel this way, it that's enough. You'll end up with a stiffer barrel. Maybe that's bad with a tuner, but I always thought we wanted to be stiff. Come to think of it, that has advantages in other areas, also.
 
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