Sorry if this is answered somewhere, I've searched but cannot find anything definitive.
There are fast and slow barrels, which is to say there are barrels that given the exact same length and load, can yield significantly different velocities on average. In other words, you can have one barrel that is significantly faster than the other. Looking at the Tikka thread in the bolt gun forum for example, you can see PVA Rock Creek barrels doing 100fps more than stock Tikka barrels of the same length.
As I understand it, there are three primary causes for this:
1.) Tighter chambers yield more pressure and therefore higher velocity. This is supposedly the largest factor.
2.) Tighter bores with a better seal on the bullet yield higher pressures and therefore more velocity.
3.) Slicker and more concentric bores yield lower pressure and therefore lower velocity, but generally allow for more powder to be used (all else being equal) and therefore can allow for more velocity on the top end of load development (an extreme example here being HBN or similar coated bullets).
Given that, I have two questions which I cannot seem to find answers for on google.
First question: am I missing something here? Is there any other cause for one barrel of the same basic length and dimensions to be faster than another?
Second question: Is buying for speed similar to buying for accuracy? In other words, we spend 4x on a Bartlein what it costs to buy a PSA barrel because you are way more likely to get an accurate barrel from Bartlein. Does speed work the same way? In other words, are you far more likely to get a fast barrel from a top end barrel maker? For example if you got a 16in .308 5R gain twist barrel from Bartlein and had it cut by CLE, would it perform (on average) like a run of the mill PSA or DD 18in or 20in barrel in terms of velocity?
There are fast and slow barrels, which is to say there are barrels that given the exact same length and load, can yield significantly different velocities on average. In other words, you can have one barrel that is significantly faster than the other. Looking at the Tikka thread in the bolt gun forum for example, you can see PVA Rock Creek barrels doing 100fps more than stock Tikka barrels of the same length.
As I understand it, there are three primary causes for this:
1.) Tighter chambers yield more pressure and therefore higher velocity. This is supposedly the largest factor.
2.) Tighter bores with a better seal on the bullet yield higher pressures and therefore more velocity.
3.) Slicker and more concentric bores yield lower pressure and therefore lower velocity, but generally allow for more powder to be used (all else being equal) and therefore can allow for more velocity on the top end of load development (an extreme example here being HBN or similar coated bullets).
Given that, I have two questions which I cannot seem to find answers for on google.
First question: am I missing something here? Is there any other cause for one barrel of the same basic length and dimensions to be faster than another?
Second question: Is buying for speed similar to buying for accuracy? In other words, we spend 4x on a Bartlein what it costs to buy a PSA barrel because you are way more likely to get an accurate barrel from Bartlein. Does speed work the same way? In other words, are you far more likely to get a fast barrel from a top end barrel maker? For example if you got a 16in .308 5R gain twist barrel from Bartlein and had it cut by CLE, would it perform (on average) like a run of the mill PSA or DD 18in or 20in barrel in terms of velocity?
