porting hammer forged barrels?
Has anyone ever tried porting a Vanguard, Howa 1500, or other rifle with a cold hammer forged barrel? I am concerned residual stresses from the hammer forging might cause it to go out of round.
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Magnaport uses EDM=Electro Discharge Machining to cut the holes in the barrels. They have been doing it for years. Never was aware that they ever had problems with barrel warping due to the removal of metal for the muzzle brake holes. 0 -
quote:Originally posted by rufe-snow
Magnaport uses EDM=Electro Discharge Machining to cut the holes in the barrels. They have been doing it for years. Never was aware that they ever had problems with barrel warping due to the removal of metal for the muzzle brake holes.
Not all barrels are created the same; some have residual stresses and some don't. In fact, I think the wear resistance of a hammer forged barrel may be caused by the outer metal pressing in on the inner metal, leaving it in a state of compresive residual stress. I don't think the cutting tool will cause the distortion. I think hammer forging leaves residual stresses in the barrel. The inside is under compression and the outside is compensating with tension.
EDIT: Imagine a steel bar about 1/4"x1/2"x1foot which is bent into a hoop and the ends are bolted together to form a 1/2" long tube with 1/4" thick walls, with a 1' circumference.
Now make an imaginary tube by gluing 50 of them end to end.
Now port the tube by drilling 1" ports with a distortion free edm machine so that at least one of the hoops is cut completely through. It would spread out like a bow after you released the string. I am concerned a barrel with residual stresses may go out of round from porting. It's not glued together so it wouldn't come apart, but it may warp a little.
Some authors speak of reducing the contour of a barrel only to find the muzzle end opens up like a blunderbuss because after forging the inner layers were pushing outward, and the outer layers were pushing inward, and you cut away the outer layers.0 -
You bring up two interesting questions . I hope Nononsense gives us his opinion on these two questions . I don't know if he has ever used hammer forged barrels. I personally would not be happy with no gas guard on a bolt action I will have to go to a gun shop and look at one of those rifles. I have only had 2 bad primers in 50 + years of shooting but with out gas protection one would be one too many. 0 -
Send it to Magna-Port. EDM uses no heat and won't hurt blueing. I had a Redhawk 44 mag done and the cuts are clean, no burrs at all. 0 -
SoreShoulder,
quote:EDIT: Imagine a steel bar about 1/4"x1/2"x1foot which is bent into a hoop and the ends are bolted together to form a 1/2" long tube with 1/4" thick walls, with a 1' circumference.
Now make an imaginary tube by gluing 50 of them end to end.
Now port the tube by drilling 1" ports with a distortion free edm machine so that at least one of the hoops is cut completely through. It would spread out like a bow after you released the string. I am concerned a barrel with residual stresses may go out of round from porting. It's not glued together so it wouldn't come apart, but it may warp a little.
I am afraid that you have the definition of Damascus barrels, confused with the definition of hammer forged barrels. Hammer forging uses an arbor with rifling on it, with a barrel blank with no fifling(like a thick walled pipe) slid down over it, then hammered down onto the arbor, using a orbital hammer machine. The Damascus twist barrel, is not cold forged either.
Furthermore, I think you will find that the rifles you mentioned, have Criterion barrels on them, which have buttoned rifling, not hammer forged.
Either rate I dont think that you have to worry about this
quote:Some authors speak of reducing the contour of a barrel only to find the muzzle end opens up like a blunderbuss because after forging the inner layers were pushing outward, and the outer layers were pushing inward, and you cut away the outer layers..
ever happening.
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I've had a 300WM MkV and and two Browning Citori 12 gauges Magnaport and Proported and have seen no problems all all with either. There were no burrs, no discoloring of the bluing, no warping of barrels. In fact, if you didn't know the rifle porting was there, you probably wouldn't notice it until you examined it closely.
Accuracy was not affected. POI did not change.0 -
SoreShoulder,
VANGUARDr SERIES 2
New for 2012
"Cold Hammer Forged 24" Barrel maximizes velocity and produces SUB-MOA Guaranteed Accuracy when used with specified premium (non-Weatherby calibers) or Weatherbyr factory ammunition. 20" and 22" barrels available on some models."
"All HOWA M-1500's feature: One piece, forged steel receivers with flat bottom and integral recoil lug for strength Hammer-forged barrels for precision rifling - and tack-driving accuracy"
Your description of what you think is hammer-forged, is incorrect.
This is the article I often suggest for reading about hammer forged barrels:
http://technology.calumet.purdue.edu/met/higley/NotesOnHammerForgedBarrels.pdf
Criterion (Krieger button barrels) used to be the barrel of choice for the Vanguard but that seems to have changed. I've worked with hammer-forged barrels a lot, considering Remington's factory sporter barrels are hammer-forged. I wouldn't get real excited about removing a bunch of material from the muzzle but you can certainly have someone add some ports if that's what you want for some reason.
I suggest, as the others have, sending it off to Magnaport to get the best job done for just porting. I would not suggest letting anyone get near a rifle barrel with a drill in order to add ports. This is not for the amateur unless you have lots of experience.
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quote:Originally posted by tsr1965
I am afraid that you have the definition of Damascus barrels, confused with the definition of hammer forged barrels.
I have not attempted to define hammer forged barrels, only to illustrate a situation in which the inside is pressing outward and the outside is pressing inward. I don't think it's going to peel apart because there's a solid single piece of metal instead of several hoops glued together-but the metal corresponding to the cut hoop may bow outward and the metal corresponding to where the glue is in the analogy would flex and allow it to a little bit, making the barrel slightly out of round at that point-even though it's all one 24" long piece.
I am aware that hammer forged barrels are formed by reducing a one-piece tubular blank against a mandrel shaped like the inside of the bore, minus an allowance for springback, by hammering.
The point of the metal strips analogy was to point out that the outer metal is under tensile residual stress and the inner layer is under compressive residual stress.
I am concerned that the barrel will go slightly out of round where the ports are.
I am also aware that with Damascus barrels three or more strands of wire are twisted together and then wrapped and welded into a tube by hammering them while yellow hot against a circular anvil which is the size of the inside of the bore, also called a mandrel, typically fitting into the hardy hole of an anvil.0 -
No, the barrel will not go out of round where the ports are if you have them Magnaported.
Other types of relieving of the muzzle material will affect the dimensions slightly which is to say that it's not a good idea to mess with the circumference.
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What a great topic.
It still begs the question of what should the ultimate shooter be looking for? Which type of barrel? First to worst? Cut, button, hammer?0 -
I don't know if anybody even gets what I am saying. If a button rifled barrel opens up when you turn down the OD and a hammer forged barrel gets a bit smaller when you turn down the OD, then why won't either one go slightly out of round if you drill a hole in the metal?
Most importantly, has anyone tried it, how big were the ports, and do they know if their barrel was stress relieved prior to porting?0 -
I think they are getting what you are saying. You are asking the question, "Is the internal stress on a hammer forged barrel make it go goofy if you remove metal/heat the muzzle/turn it down?"
I think you got the answer in that at the muzzle, Magna-porting it will not take it out of round.
Sorry for my tangent on my previous post. It did not answer your question.0 -
quote:Originally posted by SoreShoulder
I don't know if anybody even gets what I am saying. If a button rifled barrel opens up when you turn down the OD and a hammer forged barrel gets a bit smaller when you turn down the OD, then why won't either one go slightly out of round if you drill a hole in the metal?
Most importantly, has anyone tried it, how big were the ports, and do they know if their barrel was stress relieved prior to porting?
The gentleman(nononsense) giving you the best advice is highly experienced. I dare say, more so than anyone in this forum. He has tried and done just about everything, and offers the best advice.
Magnaporting, is NOT drilling a hole. It is Electrical Discharged Machined, meaning that the material s electrically removed. There are no tools other than an electrode, to create stress, or out of round anything. Like has been stated, this is a job for the professional, not an amatuer, that has a drill press in his garage. This process has been used several million times over the last 3 decades for porting pistols, revolvers, rifles and shotguns. There have been just about every type of manufactured barrel done, with great success. I don't see where your case would be a special circumstance, or an exception. Unless you give it to someone with a drill press in his garage.
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Lastly, don't forget, that after your barrel was made, it had to be threaded and fitted to the reciever, after it was chambered, and crowned. You don't seem worried about the inherent stress those operations created. Is your barrel fluted too?
I believe you are stressing out too much over something that is non existant if it is done properly.
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quote:Originally posted by tsr1965Magnaporting, is NOT drilling a hole. It is Electrical Discharged Machined, meaning that the material s electrically removed. There are no tools other than an electrode, to create stress, or out of round anything.The stress is already in the barrel. It is left over from the manufacturing process. If messing with the circumference makes the barrel open up evenly, why won't cutting a slot completely through the barrel affect its roundness?
The inside is pressing inward and the outside is pressing outward but the forces are not equal and opposite because the fact that they are at different diameters means they are not equally effective at maintaining a given diameter.
Maybe I should have thought it out more before posting but I think any kind of hole, stressfully made or not, would definitely make the rest of the metal at that point along the barrel's length bow outward a little bit.
Can we pull this thread? I should have thought it through. I don't want to come off like I hid the right answer just to see what everyone would say.0 -
quote:Originally posted by tsr1965...after your barrel was made, it had to be threaded and fitted to the reciever, after it was chambered, and crowned. You don't seem worried about the inherent stress those operations created. Is your barrel fluted too?It was probably short chambered. If the chamber tightened a bit while being threaded, big deal. It was reamed to final size after barrel installation. 0 -
quote:Originally posted by SoreShoulder
quote:Originally posted by tsr1965...after your barrel was made, it had to be threaded and fitted to the reciever, after it was chambered, and crowned. You don't seem worried about the inherent stress those operations created. Is your barrel fluted too?It was probably short chambered. If the chamber tightened a bit while being threaded, big deal. It was reamed to final size after barrel installation.
That's not how it works, weather its a buttoned, cut, or forged rifling barrel, makes no difference. Reaming a finish on a chamber after the barrel is installed, is not how the factory works. They strive o make your rifle with as few operations as possible.
Hide the thread? You seem to have all of your own answer's you are looking for, that pertain to your question. Even though, you have been given the correct, and proper answer's.
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quote:Originally posted by tsr1965That's not how it works, weather its a buttoned, cut, or forged rifling barrel, makes no difference. Reaming a finish on a chamber after the barrel is installed, is not how the factory works. They strive o make your rifle with as few operations as possible.They could anticipate how much oversize to make the chamber before threading to compensate for the choking effect of cutting the threads.
The fact that some barrels change I.D. if you remove metal from the O.D. is well settled.0
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