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Better barrels, air gauging, accuracy thoughts
nononsense
Member Posts: 10,928 ✭✭✭✭
tsr1965,
"I know you love this stuff, that is why I like to bring it up."
Baiting. Nothing better on an early Sunday morning!
This is in reference to a thread started back in 2006 about air gauging:
http://forums.gunbroker.com/topic.asp?TOPIC_ID=219149
"So in theory, the better barrels from a standpoint are the hammer forged ones, that are forged around a mandrel of known dimensions?"
"but my point is, with a manderl/hammer forged barrel, one can almost litterally measure the rifling before the barrel is even made."
You're right, it has the potential of opening all sorts of cans of worms.
Yes, you could almost measure the rifling before a barrel is made by hammer forging. At least that's the theory.
The two basic parts of discussion involve:
How accurately the mandrel was made.
What the steel formula is for the slug.
Hammer forging barrels is one of those dichotomous processes, it is extremely front end expensive. The machines are well over a million dollars and the mandrels could be considered priceless in the days prior to CNC manufacturing, although they are still expensive today. But the end result product is relatively cheap when compared to the other barrel making process.
If the mandrel is as near to perfect as possible and the process is monitored and executed correctly AND consistently, you should get a consistently manufactured, quality part. Here is the rub. The problem becomes one based on the properties of the metal and what it does after removal from the mandrel. There will generally be spring back in some form. This is usually addressed in the mandrel manufacturing but is affected by the steel formula. You will get variances from batch to batch. Then there is the real downside...
Hammer forging imparts and incredible amount of stress to the steel during manufacturing. This stress can show up at the worst times. Heat in any form will generally cause the barrel to change shape or position. If we change something on these barrels, there is always the possibility of the stresses 'unloading' and causing some change or shift in the physical barrel. This can be as simple as a new crown (unlikely, please) or threading the muzzle for a muzzle brake or can. Re-shaping or changing the contour of a hammer forged barrel is never a good idea.
Yes there are always exceptions and I'm sure that some members will jump on the opportunity to point this out. My point is more simple than this though:
If the hammer forged barrels are inexpensive, yet serviceable insofar as accuracy is concerned, why not just replace them with another type of barrel if you want or need to make changes? Why spend the money modifying an inexpensive barrel when the potential for stress induced errors is so high? Remington would be stunned at the number of their brand new barrels that get pulled off from the NIB receivers even before one shot is fired. But the reality is that they don't care either. The barrels are cheap to make and they get their money upfront so the owner of the rifle can do as he or she desires with no impact on Remington at all.
The ultimate test is that Remington rifles with hammer forged barrels usually perform with reasonable accuracy when the shooter, the load, the scope, the accessories and the rest are up to the level required. Not everyone needs 1/4" groups 'all day long'. A great majority of the hunters/shooters in the U.S. would be do quite nicely when getting consistent 1" groups. The big difference is the pressure put on the average shooter by the press and manufacturers who are constantly trying to go one better than the next guy and this can involve groups size discussions.
This doesn't touch on the other barrel making processes or measurements. Hopefully some of the other members will join in with additional thoughts and observations.
I have to get some work done...
Best.
"I know you love this stuff, that is why I like to bring it up."
Baiting. Nothing better on an early Sunday morning!
This is in reference to a thread started back in 2006 about air gauging:
http://forums.gunbroker.com/topic.asp?TOPIC_ID=219149
"So in theory, the better barrels from a standpoint are the hammer forged ones, that are forged around a mandrel of known dimensions?"
"but my point is, with a manderl/hammer forged barrel, one can almost litterally measure the rifling before the barrel is even made."
You're right, it has the potential of opening all sorts of cans of worms.
Yes, you could almost measure the rifling before a barrel is made by hammer forging. At least that's the theory.
The two basic parts of discussion involve:
How accurately the mandrel was made.
What the steel formula is for the slug.
Hammer forging barrels is one of those dichotomous processes, it is extremely front end expensive. The machines are well over a million dollars and the mandrels could be considered priceless in the days prior to CNC manufacturing, although they are still expensive today. But the end result product is relatively cheap when compared to the other barrel making process.
If the mandrel is as near to perfect as possible and the process is monitored and executed correctly AND consistently, you should get a consistently manufactured, quality part. Here is the rub. The problem becomes one based on the properties of the metal and what it does after removal from the mandrel. There will generally be spring back in some form. This is usually addressed in the mandrel manufacturing but is affected by the steel formula. You will get variances from batch to batch. Then there is the real downside...
Hammer forging imparts and incredible amount of stress to the steel during manufacturing. This stress can show up at the worst times. Heat in any form will generally cause the barrel to change shape or position. If we change something on these barrels, there is always the possibility of the stresses 'unloading' and causing some change or shift in the physical barrel. This can be as simple as a new crown (unlikely, please) or threading the muzzle for a muzzle brake or can. Re-shaping or changing the contour of a hammer forged barrel is never a good idea.
Yes there are always exceptions and I'm sure that some members will jump on the opportunity to point this out. My point is more simple than this though:
If the hammer forged barrels are inexpensive, yet serviceable insofar as accuracy is concerned, why not just replace them with another type of barrel if you want or need to make changes? Why spend the money modifying an inexpensive barrel when the potential for stress induced errors is so high? Remington would be stunned at the number of their brand new barrels that get pulled off from the NIB receivers even before one shot is fired. But the reality is that they don't care either. The barrels are cheap to make and they get their money upfront so the owner of the rifle can do as he or she desires with no impact on Remington at all.
The ultimate test is that Remington rifles with hammer forged barrels usually perform with reasonable accuracy when the shooter, the load, the scope, the accessories and the rest are up to the level required. Not everyone needs 1/4" groups 'all day long'. A great majority of the hunters/shooters in the U.S. would be do quite nicely when getting consistent 1" groups. The big difference is the pressure put on the average shooter by the press and manufacturers who are constantly trying to go one better than the next guy and this can involve groups size discussions.
This doesn't touch on the other barrel making processes or measurements. Hopefully some of the other members will join in with additional thoughts and observations.
I have to get some work done...
Best.
Comments
Thank you Sir!
Always a lesson available, and always well taught!
Best