I am not sure how many barrel manufacturers are putting the holes in their barrels these days. Perhaps the norm for many is to use some of the new exotic HSS or Carbide deep-hole drill bits or inserted drill blanks - But I seriously doubt that; Because where I work we are pushing the envelope at what can be done using both of the above to the maximum depth possible at the highest rate of feed achievable thru tool steels over 62 Rc.
Having said that , I seriously doubt barrel manufacturers have invested the money required to keep up with what we can do. They almost have to be using gun drills, which
are by far the best way available to put deep, straight, precise, & smooth holes thru long distances. Nothing else can come close to what a gun drill can do, especially on a cost scale.
A gun drill is not really a "drill", as one would think of when they look at a common drill bit as seen on the shelf at Lowes or Homeless Depot. Yes, it is a "drill" in the sense of how it rotates & advances thru the material, removing it as it goes. But, they look nothing like a common drill bit. The secret of a gun drills performance is in the end geometry of the cutting portion of the bit. If this geometry is off in any way, or dull to a certain degree, all bets are off as to how good of a hole you will get. Back in the early '80s, we routinely gun drilled 0.5000" diameter holes 10 feet deep with less than 0.0007" circular runout & concentricity from end to end thru stainless steel in less than 20 minutes.
Perhaps you just got a bad barrel, or when the barrel extension was put on it, someone forgot to indicate it concentric to the bore or vise-versa.
Having said that , I seriously doubt barrel manufacturers have invested the money required to keep up with what we can do. They almost have to be using gun drills, which
are by far the best way available to put deep, straight, precise, & smooth holes thru long distances. Nothing else can come close to what a gun drill can do, especially on a cost scale.
A gun drill is not really a "drill", as one would think of when they look at a common drill bit as seen on the shelf at Lowes or Homeless Depot. Yes, it is a "drill" in the sense of how it rotates & advances thru the material, removing it as it goes. But, they look nothing like a common drill bit. The secret of a gun drills performance is in the end geometry of the cutting portion of the bit. If this geometry is off in any way, or dull to a certain degree, all bets are off as to how good of a hole you will get. Back in the early '80s, we routinely gun drilled 0.5000" diameter holes 10 feet deep with less than 0.0007" circular runout & concentricity from end to end thru stainless steel in less than 20 minutes.
Perhaps you just got a bad barrel, or when the barrel extension was put on it, someone forgot to indicate it concentric to the bore or vise-versa.
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