Gunsmithing Why taper a barrel?

[csbkmartino]

I don't think I have ever heard a solid explaination for tapering a barrel other than "to reduce weight".

Is there a quantifiable reason to taper a rifle barrel other than weight savings?

 

[BOLTRIPPER]

Re: Why taper a barrel?

have you ever lifted one of them bench-rest weenie riflez....?

 

[palma]

Re: Why taper a barrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 80sParatrooper</div><div class="ubbcode-body">I don't think I have ever heard a solid explaination for tapering a barrel other than "to reduce weight".</div></div>

Why isn't that a good enough reason?

 

[MontanaMarine]

Re: Why taper a barrel?

Balance, and handling characteristics.

Heavy isn't so bad if it's balanced. Get too front heavy and not so good.

 

[long-shot]

Re: Why taper a barrel?

If you're getting theoretical then maybe to minimize vibration or customize vibration along a sine curve for a specific bullet weight, but honestly who cares?

 

[BobinNC]

Re: Why taper a barrel?

You don't need a tapered barrel on your gun if you have Wheels.....

 

[DMann]

Re: Why taper a barrel?

Tapering will also affect the distribution of the weight. For example, to move the point of balance more toward the shooter or receiver, the barrel would be made thicker at the breech end and taper to the muzzle. If balance is not an issue (such as benchrest), then the barrel could be a straight cylinder.

So, not only weight savings, but handling characteristics could be altered or customized with certain tapered contours.

 

[nashlaw]

Re: Why taper a barrel?

I have had a couple or three HEAVY rifles built with straight, no taper tubes. Gosh, those guys were a job to tote. Also, when you have so much barrel hanging out there 22" from the muzzle, it really throws the balance off. Even shooting from a bench with bags, you are having to make sure the rifle does not tilt forward and go over the bench and make a big "THUD!"

Trust the experience of those who have been there. Unless you have a special purpose(shooting varmints off a concrete bench or paper punching) and do not intend to haul it, get a taper. The MTU contour is plenty heavy and I am now leaning toward the varmint/sendero contours.

 

[bohem]

Re: Why taper a barrel?

I have an untapered, 27.75" finished length Shilen on a Savage 12 which started as an FV. It's in a Choate Sniper stock, which even with the factory barrel on it, was heavy. Now it's an enormously heavy stick that is really only practical to carry from safe to car to bench.

Tapering it changes the vibration characteristics, overall stiffness, balance and total weight.

Tapering it can allow you to tune for a specific bullet weight and target velocity to make the muzzle sit as still as possible but it requires a bit of math and some decent capabilities as a lathe operator, it's not a linear taper. I thought about doing this and also setting up the crown with a counter bore to act as a tuning collar. It's a decent amount of work though and it's only good for the original barrel and bullet/velocity. If you set it back, you're screwed. If you make a mistake cutting the barrel and have to set it back 50 thou, you're screwed, if you decided to calculate everything based on the 174 Amax by Hornady you're screwed because they quit making it and only make the 178 now. It's an effort in futility unless you get it absolutely right on the first shot, you're a machinist that never F's up (which I'm certainly not) and you can afford to throw away a match barrel if a bullet maker decides to change their product line.

OK, I'm done. I didn't mean this as a sarcastic or snide response to your question, I'm just trying to explain why given the proper academic consideration I never tried cutting a barrel contour like that.

 

[csbkmartino]

Re: Why taper a barrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">I have an untapered, 27.75" finished length Shilen on a Savage 12 which started as an FV. It's in a Choate Sniper stock, which even with the factory barrel on it, was heavy. Now it's an enormously heavy stick that is really only practical to carry from safe to car to bench.

Tapering it changes the vibration characteristics, overall stiffness, balance and total weight.

Tapering it can allow you to tune for a specific bullet weight and target velocity to make the muzzle sit as still as possible but it requires a bit of math and some decent capabilities as a lathe operator, it's not a linear taper. I thought about doing this and also setting up the crown with a counter bore to act as a tuning collar. It's a decent amount of work though and it's only good for the original barrel and bullet/velocity. If you set it back, you're screwed. If you make a mistake cutting the barrel and have to set it back 50 thou, you're screwed, if you decided to calculate everything based on the 174 Amax by Hornady you're screwed because they quit making it and only make the 178 now. It's an effort in futility unless you get it absolutely right on the first shot, you're a machinist that never F's up (which I'm certainly not) and you can afford to throw away a match barrel if a bullet maker decides to change their product line.

OK, I'm done. I didn't mean this as a sarcastic or snide response to your question, I'm just trying to explain why given the proper academic consideration I never tried cutting a barrel contour like that.</div></div>

Not taken as either snide or sarcastic! I appreciate the response!

 

[csbkmartino]

Re: Why taper a barrel?

Thanks all (most)!

Even though I've been shooting for decades, harmonics are not something I hear a great deal about. I know the effects on pencil barrels but hadn't really considered it as it relates to tactical field guns. I'll have to look into this more.

I have a bit more perspective now.

Again Thanks

 

[eddieharren]

Re: Why taper a barrel?

A little insight from a "benchrest weenie" here. In all classes of short range BR except Unlimited or Heavy Bench, there are rules restricting barrel taper, length and contour. Light Varmint rifles are limited to a total weight of 10.5 lbs, Sporter class has the same weight limit and Heavy Varmint rifles are limited to 13.5 lbs. Minimum barrel length is 18".

 

[csbkmartino]

Re: Why taper a barrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocEd</div><div class="ubbcode-body">A little insight from a "benchrest weenie" here. In all classes of short range BR except Unlimited or Heavy Bench, there are rules restricting barrel taper, length and contour. Light Varmint rifles are limited to a total weight of 10.5 lbs, Sporter class has the same weight limit and Heavy Varmint rifles are limited to 13.5 lbs. Minimum barrel length is 18".</div></div>

Benchrest weenie

Length I understand and weight, possibly. In this instance I'm not sure I understand why contour is regulated other than directly effecting weight?

 

[former naval person]

Re: Why taper a barrel?

I read an article not too long ago from the BR crowd...it appears that part of the reason is balance, but not just between the hands. If the barrel is long and straight...read heavy... you need a really long fore end to balance over the bags. Otherwise the recoil pattern is off...not to mention that if you let go of the butt it would hit you in the nose. I firget where I read it but you might search Bench Rest Central or 6mm BR.

 

[LRangepro]

Re: Why taper a barrel?

Contour isnt regulated at all but you have to have a barrel longer than 18" but still under the weight limit. It kind of forces you to have a tapered barrel. Most guys have seen or even used standard light and heavy varmint tapers on their tactical guns. Its still a pretty good piece of steel, taper or no.

 

[Greg Langelius *]

Re: Why taper a barrel?

For my own part, I am unclear how/if taper affects harmonics.

Some folks seem to think the main issue with harmonics is barrel length, as it relates to bore transit time, and very little else.

My own view relates more to issues like the effect of the taper on bending forces; and I think that taper therefore affects harmonic frequencies, so it has a real bearing.

But I don't have any definitive conclusions yet.

For distances of 200yd and under, I think short and wide is preferable.

Greg

 

[cdmurphy]

Re: Why taper a barrel?

I don't have the article at hand, but in a recent issue of "Precision Shooting", there was a great writeup of the effects of barrel vibration on bullet impact. Apparently the main harmonic of concern was the 3rd order vibration, where the barrel vibrated about a node approx 1/3 of the way back from the barrel, with the muzzle whipping about that point. This harmonic was about 1250 Hz for a typical barrel. The 1st order vibration, where the barrel whipped about the breach was apparently two low a frequency to be of concern, along with the 2nd order where the barrel whips between the breach and muzzle like two kids with a jump rope. Any higher order vibrations apparently didn't have enough amplitude to have much effect on accuracy. The good news was that these vibrations appeared to be very stable, and that for a given cartridge, the sweet spots at the high and low points in the vibration were pretty much velocity dependent. So if you can keep your loads consistent, or duplicate the velocity of a known good load, you should be getting the best accuracy out of that load.

- Cameron

 

[BLAWTON]

Re: Why taper a barrel?

Coming from my father and him testing many things, this was one he looked into real hard. What they found was a barrel with even a slight taper has more rigidity then one that was dead straight. He refused to make barrels that were no taper.

 

[x ring accuracy]

Re: Why taper a barrel?

On an unrelated note to Camerons response......
Tapered barrels look cooler, shoot faster, get more chicks, and make your man-hood larger than life, LOL
No word yet on the increase to your bank account to pay for the above chicks.
In all seriousness, the bigger the barrel, the more stable. Tapering helps in competition where weight and length are the determining factors. If I am ever in doubt, I go heavy. I have been asked to leave a few matches for that reason. Good Shooting.

 

[jetlyting]

Re: Why taper a barrel?

weight and balance.....straight tubes or MTU contour gives me more bugs nuts shots in a row when things heat up after a few rounds. contour and length for weight limits when shooting competitively. the bigger diameter barrels with less taper also help to soak up recoil from their sheer weight.