Barrels with choke to increase barrel life and reduced need to clean in long shooting sessions

[TorF]

Some European barrels are made with choke towards the muzzle.
Choke prevents increased gas blow by as the bullet passes through the barrel getting more and more worn. Reduced gas blow by towards the muzzle reduce barrel wear due to the "blow torch effect". This is scientifically proved by GIAT and the French FRF1 and FRF2 have choked barrels.

Choked barrels are also less affected by fouling in front of the chamber, that can "damage" the bullet, because the bullet is "resized" towards the muzzle". Choked CF barrels will not win any high end BR comps but will usually outperform "straight" barrels in long shooting sessions between cleaning and in "dirty" field conditions, especially as total barrel round count goes up.

In addition, my personal experience, is that choked barrels "resize" bullets and increases accuracy with "poor" ammo like milsurp.

Schultz&Larsen match and hunting barrels, with cut rifling, are choked during lapping. S&L has a stellar reputation in Europe and in Scandinavia S&L outsells LW by at least 100-1 in match barrels.
Other makers I think have choked barrels are Anschutz match 22lr and Steyr(SSG).

Are there any US barrels with choke?

 

[ClamHammer747]

 

[WeiserBucks]

Some European barrels are made with choke towards the muzzle.
Choke prevents increased gas blow by as the bullet passes through the barrel getting more and more worn. Reduced gas blow by towards the muzzle reduce barrel wear due to the "blow torch effect". This is scientifically proved by GIAT and the French FRF1 and FRF2 have choked barrels.

Choked barrels are also less affected by fouling in front of the chamber, that can "damage" the bullet, because the bullet is "resized" towards the muzzle". Choked CF barrels will not win any high end BR comps but will usually outperform "straight" barrels in long shooting sessions between cleaning and in "dirty" field conditions, especially as total barrel round count goes up.

In addition, my personal experience, is that choked barrels "resize" bullets and increases accuracy with "poor" ammo like milsurp.

Schultz&Larsen match and hunting barrels, with cut rifling, are choked during lapping. S&L has a stellar reputation in Europe and in Scandinavia S&L outsells LW by at least 100-1 in match barrels.
Other makers I think have choked barrels are Anschutz match 22lr and Steyr(SSG).

Are there any US barrels with choke?

Did you spend your stimulus check on a bag of meth?

 

[Just Macca]

Seeing photos of recovered bullets I haven’t seen evidence they get “more and more worn” as they proceed down the bore.
It doesn’t seem to be an issue worth trying to negate with the increased complexity of a tapered bore (or choke as you put it).

 

[THEIS]

Hi,

Crazy timing for this to be posted, lol.

We were just discussing last week about the pros and cons of tapered bore barrels; specifically with monolithics.
It would reduce the torque imparted onto the projectile at throat the same way gain twist does.

The pros are pretty straightforward and legitimate.

The cons are pretty much just the amount of time and energy it would take to educate the non EU market.

The firearms industry as a whole lives in the motto of "Don't change what isn't broken".

Sincerely,
Theis

 

[THEIS]

Did you spend your stimulus check on a bag of meth?

Hi,

Can you please explain as to why you would think he is high?
Do you have any experience and/or theory that contradicts his and all the other EU experiences?

Sincerely,
Theis

 

[lash]

So, would your approach be both gain twist and taper? Or just one or the other?

It seems as if both would net the maximum benefit. Also, why would the same benefits not be useful with clad lead? It certainly seems as if certain modern convention projectiles could benefit (<cough> looking at you, Hornady <cough>).

The next questions are:
What cost penalty comes with this option?
And if offering a premium product and the cost penalty is not extreme, then how much does it matter if the rest of the western world are slow adopters?

The majority of people purchasing rifles still don’t really know nor care about high end products and premium performance anyway. That’s obvious. Those that really care about these things are usually more likely to be early adopters and sometimes the only market for premium performance.

 

[Newbie2020]

Not a hater, just ignorant. @THEIS What “problem” is the choke solving? Barrel wear? Accuracy (precision)? Other?

 

[brianf]

When you say not winning and BR contests

is that just opinion it have guys tried it etc.

Thanks

 

[THEIS]

So, would your approach be both gain twist and taper? Or just one or the other?

It seems as if both would net the maximum benefit. Also, why would the same benefits not be useful with clad lead? It certainly seems as if certain modern convention projectiles could benefit (<cough> looking at you, Hornady <cough>).

The next questions are:
What cost penalty comes with this option?
And if offering a premium product and the cost penalty is not extreme, then how much does it matter if the rest of the western world are slow adopters?

The majority of people purchasing rifles still don’t really know nor care about high end products and premium performance anyway. That’s obvious. Those that really care about these things are usually more likely to be early adopters and sometimes the only market for premium performance.

Not a hater, just ignorant. @THEIS What “problem” is the choke solving? Barrel wear? Accuracy (precision)? Other?

Hi,

LOLOL in my attempt to not sugar coat this and be crystal clear, lol....

At this very minute I do not know enough about the sum of all parts in order to answer your questions directly without just repeating someone else's knowledge.

We literally just started this conversation last Wednesday because the break between Holidays had us waiting on coating company.

I have some meetings this week with people much smarter than myself and I will get back to this thread or make another one.

Sincerely,
Theis

 

[Supersubes]

I thought this was somewhat common across many types of barrels, and goes back to the earliest barrels. I’ve also heard it stated that it was a simple measure to avoid a bore that opened slightly towards the muzzle, which is bad for accuracy. A similar thing has been done with twist rate. A very slight amount of gain was put into the rifling by some makers, simply because a slowing of twist was bad for accuracy. I think Obermeyer and Rock Creek did this.

@Frank Green has talked about this very topic in the past.

 

[bill alexander]

Barrel chokes in rifles are an oddity and in some instances are not well understood. They originate with particular calibers of machine gun and seem to benefit most when barrel life is considered when firing AP type ammunition, or exceptionally heavy jacketed projectiles. The accuracy of such barrels is not usually of great concern especially as the results are considered in the context of the condemnation of the barrel due to projectile tumbling. Notably the choke is usually is at caliber or only slightly below while the section behind is somewhat relieved in size. Again the context is to extend barrel life by reducing stress in the bore that can crack heavy chrome plating (+0.002")

The technique was developed for hammer forging machines before the advent of digital controls.

We conducted a large number of studies of the effects of choke on barrel accuracy and the technique shows certain promise for polygonal rifling forms with heavy jacketed projectiles. It does not seem to help match grade projectiles which naturally obturate in the bore if driven at the correct pressures

 

[brianf]

Barrel chokes in rifles are an oddity and in some instances are not well understood. They originate with particular calibers of machine gun and seem to benefit most when barrel life is considered when firing AP type ammunition, or exceptionally heavy jacketed projectiles. The accuracy of such barrels is not usually of great concern especially as the results are considered in the context of the condemnation of the barrel due to projectile tumbling. Notably the choke is usually is at caliber or only slightly below while the section behind is somewhat relieved in size. Again the context is to extend barrel life by reducing stress in the bore that can crack heavy chrome plating (+0.002")

The technique was developed for hammer forging machines before the advent of digital controls.

We conducted a large number of studies of the effects of choke on barrel accuracy and the technique shows certain promise for polygonal rifling forms with heavy jacketed projectiles. It does not seem to help match grade projectiles which naturally obturate in the bore if driven at the correct pressures

Makes sense

By thick jacket what do you think about the viability for solids which do not confirm as easily?

Thanks

 

[MarinePMI]

CZ rifles typically have a tapered bore (they're hammer forged that way), and their accuracy has always been generally pretty good. The rimfire rifles (especially) display a fairly aggressive reduction IIRC.

I believe (JMO) that is why their .22 Hornets shoot so well (phenomenally accurate out of the box), regardless if a .223 or .224 bullet is used. The hammer forging process also includes a rough chamber as part of the mandrel, and thus, ensures that the chamber is much more likely to be concentric to the bore.

JMTCW...

 

[Mike Casselton]

To add to this discussion, do some research on the Calfee built 22 rifles.
On his builds, he made a point to find the choke point on each barrel and that is where he would cut/crown it.

He made some fine shooting rifles.

 

[spife7980]

Thats how anschutz des it I believe, find that tight spot and then cut the length from there back instead of from the tenon forward.



I think Ive read some interesting stuff from @LongRifles Inc. on his old nesika or dakota days on the subject?

 

[brianf]

Thats how anschutz des it I believe, find that tight spot and then cut the length from there back instead of from the tenon forward.



I think Ive read some interesting stuff from @LongRifles Inc. on his old nesika or dakota days on the subject?

I know some of the big guys/bench rest smiths have done that for decades on 22lr

But have not heard of a company “policy” for center fire

 

[TorF]

Schultz&Larsen have a slight taper in all their barrels as standard.
The taper is done during the lapping process of the cut rifled barrels.

Here are drop in barrels, with test target, in 6.5X55 made in Norway for SigSauer SSG3000 from S&L blanks ("custom" = G&E and Bleiker 6mm): https://www.vapensmia.no/lop ($1US = NOK10)

Why AI is not using S&L in Europe, based on experiences from Sauer STR use in Scandinavia, is beyond me.

S&L website: http://schultzlarsen.com/home-3/
British S&L website: http://www.greatdanerifles.com/index.html

 

[THEIS]

Hi,

While it appears you are really really fond of S&L there are some very clear business and technical reasons some of those firearm manufacturers do not use them.

First one being S&L is still using old, very old Pratt & Whitney machines when the rest of the premium barrel world has upgraded to modern cnc machines that are more efficient in twist rate production and precision.

Second one being that 600 USD for a barrel from said machines when I can get a cnc cut left hand gain twist in bartlein new alloy for that price.

Sincerely,
Theis

 

[TorF]

Yes, the machinery is old but it is the end product that counts.

The cost of the SSG3000 barrels are cheap considering they are 100% finished for drop in, test fired and come with a test target from a machine rest. And the price includes 25% sales tax. (ouch..)

If one wants the most "modern" SSG3000 match barrels Blaser makes these on the latest GFM machines at 1/3 of the cost of R8 barrels. These also have the chamber hammered.

 

[spife7980]

Yes, the machinery is old but it is the end product that counts.

The cost of the SSG3000 barrels are cheap considering they are 100% finished for drop in, test fired and come with a test target from a machine rest. And the price includes 25% sales tax. (ouch..)

If one wants the most "modern" SSG3000 match barrels Blaser makes these on the latest GFM machines at 1/3 of the cost of R8 barrels. These also have the chamber hammered.

But I can get my chambered shouldered prefits for under 500 bucks to my door. Anything thats "cheap considering" is expensive.

 

[Edds]

From the Douglas Barrel Website.......... You will find that most of our basic barrels are marked for the muzzle end. In the process of air gaging we mark the tight end as being the muzzle. Some people feel that the taper should be to the muzzle, others say that it makes no difference. At any rate the barrel is marked so the choice is yours.