Muzzle threading diameter and accuracy
- Thread starter Gil P.
- Start date
a1712
Gold $$ Contributor
Referring to soft lead bullets. Brian.
ELR LVR
Silver $$ Contributor
1/2-28's def Bell Mouth over time
Even an AR-15 will,
For this reason I will not thread anything larger than .224 cal for 1/2-28
even if a customer requests it...Unless they are absolutely sure they understand
IT WILL HAPPEN if enough rounds are sent through the barrel
Some guys argue with it and say they have even seen 7 mm Mags threaded for 1/2-28
Just because you CAN, does not mean it's a good idea.
----------
With 5/8-24 I think theres too many variables to be CERTAIN. it will happen over time.
I've not experienced it or had problems with 5/8-24 though (SS Barrels only)
With this logic wouldn't the exact same off center force exist once the bullet passes the crown of the barrel? If the rifling is even all the way around to get an even force at the crown one would assume that force is therefore even through the entire barrel?
I think it's indisputable that the bore gets larger, but it'd be interesting to see a test showing 20 barrels with groups before threading and groups after. Trouble is no one has deep enough pockets for a test like that. 1 barrel test or just showing a pin in the end with no groups just leads to conjecture.
Go with the larger threading if you can obviously, there is no benefit to take the risk.
TAJ45
Silver $$ Contributor
Per my apprentice instructor and to me, obvious logic, "anytime you lay a tool to metal, stress is induced".
If magnified videos of metal being peeled off w a tool, (tool steel, carbide, ceramic etc) the ragged edges leave no doubt.
Now, how much, how bad......Hard to quantify.
L.Sherm
Silver $$ Contributor
My point in this is if you have a button barrel and a cut one both have zero stress before threading do they both have stres after? Processes matter.
ELR LVR
Silver $$ Contributor
3 shots wont show until it heats up enough and the stresses start relieving themselves to show up in the barrel walking.
A factory pencil barrel can shoot good for 3 shots, Just FYI
If a piece of steel is properly stress relieved, there should be no stress. In a best case, there really is no stress. Stress may be induced by stock removal but dimensional change we see when turning down a muzzle, for instance, is the result of stress being removed with the material, or stress being able to make itself known for the same reason.
For some time, I worked as a machinist and much of what I did was the manufacture of hydraulic parts and bushings. For the production of large bushings (6 to 12 inches in diameter) I would usually start out with heavy walled tubing or DOM (drawn on mandrel) tubing. The DOM especially was loaded with stress. If I bored the diameter first, it would grow when I turned the outside. If I turned the outside, it would shrink when I bored the inside. I started throwing the pieces in the oven and cooking them at 1100 degrees and the problem was largely eliminated. Mind you, we're not talking tenths here. On a six inch bushing, I would have a .006 tolerance (6.010 +or- .003). Without stress relief, it was almost impossible to stay round and within tolerance. So, stress relief is important.
When it comes to barrels, I believe any barrel should be stress relieved, regardless of the method of manufacture. In general, most of the steel used by barrelmakers is stress relieved as purchased, but not always. I have had cut rifled barrels which warped visibly when contoured. Plainly, the stress was in the material prior to drilling, reaming and rifling. This is different than the stress which is induced by cold forming of the rifling via a button. The latter is the stress which will cause the bore to grow when material is removed from the outside. By the way, if you want to see a great example of the displacement of metal by the button rifling process, have a look at a Redmond barrel liner for a 22.
When the barrel blank is stress relieved, the induced stress is not necessarily removed but is dissipated throughout the blank (normalized). This allows the barrel to retain its shape while the stress is essentially eaten up by the whole mass. (I'm taking some metallurgical liberties here. Nothing gets eaten). So, the effect of the stress is minimized as the grain structure is, once again, homogenous (mostly). You know, I had a point I was moving toward here, but I may have sidetracked just a little.
The point is this; there is always the possibility of some residual stress regardless of the method of manufacture. Whether or not there is a significant effect on the barrel dimensions due to the removal of stock probably depends on a lot of things, not the least of which is the amount of stock removed.
About twenty years ago, I undertook to make some tuners for a couple of "F" class guns. The barrel were about .9 at the muzzle so I decided to go with a 7/8"x48tpi thread for attachment and adjustment. I never checked for muzzle distortion simply because I figured there probably wasn't any! If I decide to install a tuner on my Tack Driver gun, I think I'll mount a sleeve with a 24 tpi square thread ID and thread the OD to 48tpi for the "Will Henry's Special" tuner (Pat. Pending). So far, from the comfort of my recliner and in the virtual world, it works great! WH
For some time, I worked as a machinist and much of what I did was the manufacture of hydraulic parts and bushings. For the production of large bushings (6 to 12 inches in diameter) I would usually start out with heavy walled tubing or DOM (drawn on mandrel) tubing. The DOM especially was loaded with stress. If I bored the diameter first, it would grow when I turned the outside. If I turned the outside, it would shrink when I bored the inside. I started throwing the pieces in the oven and cooking them at 1100 degrees and the problem was largely eliminated. Mind you, we're not talking tenths here. On a six inch bushing, I would have a .006 tolerance (6.010 +or- .003). Without stress relief, it was almost impossible to stay round and within tolerance. So, stress relief is important.
When it comes to barrels, I believe any barrel should be stress relieved, regardless of the method of manufacture. In general, most of the steel used by barrelmakers is stress relieved as purchased, but not always. I have had cut rifled barrels which warped visibly when contoured. Plainly, the stress was in the material prior to drilling, reaming and rifling. This is different than the stress which is induced by cold forming of the rifling via a button. The latter is the stress which will cause the bore to grow when material is removed from the outside. By the way, if you want to see a great example of the displacement of metal by the button rifling process, have a look at a Redmond barrel liner for a 22.
When the barrel blank is stress relieved, the induced stress is not necessarily removed but is dissipated throughout the blank (normalized). This allows the barrel to retain its shape while the stress is essentially eaten up by the whole mass. (I'm taking some metallurgical liberties here. Nothing gets eaten). So, the effect of the stress is minimized as the grain structure is, once again, homogenous (mostly). You know, I had a point I was moving toward here, but I may have sidetracked just a little.
The point is this; there is always the possibility of some residual stress regardless of the method of manufacture. Whether or not there is a significant effect on the barrel dimensions due to the removal of stock probably depends on a lot of things, not the least of which is the amount of stock removed.
About twenty years ago, I undertook to make some tuners for a couple of "F" class guns. The barrel were about .9 at the muzzle so I decided to go with a 7/8"x48tpi thread for attachment and adjustment. I never checked for muzzle distortion simply because I figured there probably wasn't any! If I decide to install a tuner on my Tack Driver gun, I think I'll mount a sleeve with a 24 tpi square thread ID and thread the OD to 48tpi for the "Will Henry's Special" tuner (Pat. Pending). So far, from the comfort of my recliner and in the virtual world, it works great! WH
Here's a little, "Tip",..
The Tikka, T-3X's ( the NON-Fluted, Version ) CAN Be, threaded to, 1/2" x 28 tpi and my Rifle with, a PVA Back Country Brake, Shoots, Phenominal ! ( 5 shot group's, .3's to, 1/2 MOA, w/ ELD-M's ! ) Sub 8 Pound, "All Up" Rifle.
Brake, threading, Facing/ truing of, Barrel+ "Re-Crowning", Shipping 2 ways, etc. about,.. $350ish at, PVA !
Just DON'T Over tighten, the Self Timing, Back Country HUNTING Brake,.. WHEN installing !
IF, Questions Ask Josh at, PVA ! ( Threading, Up to 6.5 Creed was NO 'issue", don't know about, bigger Bores )
The Back C. "Hunting" Brake, DIVERTS, the Blast / Concussion, AWAY from the Shooter,.. BETTER !
Finally, Somebody PUT some Thought, into Brake Design ! ( Good "Ear Plug's", are enough to, get It, Done ! )
The Tikka, T-3X's ( the NON-Fluted, Version ) CAN Be, threaded to, 1/2" x 28 tpi and my Rifle with, a PVA Back Country Brake, Shoots, Phenominal ! ( 5 shot group's, .3's to, 1/2 MOA, w/ ELD-M's ! ) Sub 8 Pound, "All Up" Rifle.
Brake, threading, Facing/ truing of, Barrel+ "Re-Crowning", Shipping 2 ways, etc. about,.. $350ish at, PVA !
Just DON'T Over tighten, the Self Timing, Back Country HUNTING Brake,.. WHEN installing !
IF, Questions Ask Josh at, PVA ! ( Threading, Up to 6.5 Creed was NO 'issue", don't know about, bigger Bores )
The Back C. "Hunting" Brake, DIVERTS, the Blast / Concussion, AWAY from the Shooter,.. BETTER !
Finally, Somebody PUT some Thought, into Brake Design ! ( Good "Ear Plug's", are enough to, get It, Done ! )
Last edited:
L.Sherm
Silver $$ Contributor
I can tell you for a fact that barrel was stress relieved just like a barrel I made for a world champion who told me when he tested it that it never changed from shot 1-20 in a 20 shot string his words to me were whatever your doing dont change a thing, matter of fact it replaced a very well know cut rifle barrel makers barrel he had been using.
That same barrel won the SWN a few years ago.
Processes matter
Last edited:
ELR LVR
Silver $$ Contributor
Very impressive, a 20 shot string is a good test
L.Sherm
Silver $$ Contributor
A good barrel is a good barrel no matter if its Button or Cut.
Steel, tooling, and processes matter.
ELR LVR
Silver $$ Contributor
What brand of buttoned barrel did you use?
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.