Are barrels unidirectional? Which end should we chamber?

S

spencer313

Guest
Which end of a barrel blank should be chambered, and which should be crowned?

Does it follow that the bullet path should follow the direction of the barrel drilling, or is there a case for the opposite?
 
Without ever thinking about it ,Ive always chambered the stamped end? Good question.
 
As far as I know the stamped end is the end to chamber and the other end requires cutting off at least an inch... I have never seen anything stated either way... but I agree with Butch...
 
Um, I kinda meant the barrel blanks that aren't pointy on one end, eh?

:)
 
spencer313 said:
Um, I kinda meant the barrel blanks that aren't pointy on one end, eh?

:)
Click to expand...

I was and I think Butch was.. just pulling your leg a little...;)


I don't have a clear memory of it but back in 1966 I believe one of my gun smithing instructors (who also made barrels on some of Ackley's old machines) told me to alway use the stamped end for the chamber as the rifling was cut from that end to the muzzle... and I believe in the case of buttoned barrels the button is pulled from that end to the muzzle...
 
spencer

I think the guys were pulling you leg a little (or maybe a lot). :cool:

I think most barrel butchers will mark the chamber end. If in doubt, pick up the phone and call them. If the blank is not marked and you don't know who the maker is - it probably won't make much difference which end you chamber (high quality barrel blanks are marked).

Most makers will say that their barrels are good for the entire length. But, off the record they will advise you to cut an inch or so off the muzzle end. Unless they have already done that themselves - another good reason to call and talk to them.

Ray
 
Like it was stated the stamped end is the breach end. Most barrelmakers who lap there bores insert there lapping rod from this end. When they lap the barrels some will lap to ensure that the bore dia. dose not increase toward the muzzle end. Thus they will stroke the rod less at the muzzle and slightly more at the breach, we're only talking differences in the <.0002

alf beat me to the punch!
 
Even so, I've seen a couple of straight tubes swopped end for end & rechambered when the throat was shot out.
 
A top barrelmaker told me that the stamped end is always the chamber end. If the rifling should vary (on a button rifled barrel) it would probably be a slightly slower twist on the muzzle end. And I've heard about barrels being lapped with a small amount of "choke".
Makes sense to me.
 
Met a shooter at a match recently that had a 1.250 dia. barrel that had a long section in the center "swamped" or turned to a reduced diameter. He had threaded both ends of the barrel with the proper thread for the receiver. He had a large brake on the muzzle end, utilizing the large thread. He stated that he was probably going to cut a chamber in the "muzzle" end and mount the barrel reversed of the original install. I hope to see him at a match in the future and hear how it worked.
 
Barrel Grain

Spencer313,
Your query is relevant. Back in the early 1980's, I was involved in barrel manufacture and testing, downunder. The barrel maker was encountering some fouling problems. An old smith advised me that the manufacturing processes imparted a grain into the barrel with reaming and cut rifling and that it was important to chamber with the grain to reduce copper fouling. Lapping does not cure the problem if fouling occurs. His analogy was the final finish on a gunstock with steel wool, which cuts the surface clean. Although it appears smooth, the grain resistance can still be felt particulary about the pores in the wood. He also felt that the button process which we used could not iron out the grain completely and it induced its own metal flow issues which turns up as a dimensional problem when a taper was turned and heat treatment.

Your query about drilling direction is not as relevant as the reamer direction, which if rough, exacerbates the problem of fouling. The reaming operation opposed the drill direction, and the button method, followed the direction of the reamer. It was a pull method in the belief it reduced barrel stress.

It was the belief that if a barrel was tapered before buttoning it would distort less. In fact, reverse taper barrels could take advantage of tightening the choke at the muzzle without having to induce one through lapping. A straight taper did not present the same problems. If a barrel is tapered and then pull buttoned, it should be chucked in a reverse fashion, to work with the grain if that is desirable. So depending on the operation, whether the barrels are push or pulled buttoned, the barrel stamping is no guarantee that it is the end to chamber, running with the grain. Fouling problems may be minimal anyway, and the may not outweigh methods of controlling internal dimensions and cost effectiveness, depending on the quality you are seeking. I do not know what manufacturers are doing now and technologies have moved on.

These days, I chamber for personal use only, and cut both ends of the barrel back to take out the lapping induced enlargement caused by the lap stopping and reversing. I feel a better bore alignment can be achieved with the chamber reamer when indicating off the bore that has less enlargement. Similarly, I crown at the minimal bore size at the muzzle. Hope this helps.
Willy
 
I remember someone telling me that the button should be pulled in the same direction as the reamer and that the button takes a short distance to stabalise the twist rate. So the chamber is cut at the end the button starts from so any uneven twist rate is cut out.
Seems to fit with what others have said .
 
Provided that it's physically possible chambering with the grain makes more sense than anything else. Try to stroke a cat against the fur and see how long it will last to sit still. Rad
 
Rad, what kind of reasoning is that?? Go to a barrel shop and watch the process. They ain't no hair laying down in a barrel.
Butch
 
Kriegers

Kriegers have no choke. They are rifled and lapped dead straight.

The chamber end is always the one with the stamp, which of course is only a concern if it happens to be a straight profile, such as a Unlimited Blank.

I have always heard that Krieger stamps that end because that is the end the hook rifling tool starts in, and the direction of the cut. Aside from that, I am just carefull that when I cut a unlimited barrel to length, I always re-mark the chamber end.........jackie
 
Jackie...

John Krieger told me that a small "choke" was lapped into their barrels. The barrels should be chambered on the end that is marked for best results. James
 
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