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Old 02-17-2011, 11:37 AM   #21
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Another quick question: If in fact the bbl and receiver surfaces are not mated properly, but the bbl is tightly screwed into the receiver, would that actually make the shots walk, rather than just group somewhere besides the aiming point?
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Old 02-17-2011, 12:12 PM   #22
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Another quickie: I'm only familiar with the process of cyro-treatment on knives where they heat the blades to critical temp and quench, either in a dry ice/alcohol bath or liquid nitrogen, then drawn to a temper in an oven. -Sounds sort of barbaric for a good rifle bbl, so I'm probably missing something.
Could someone elaborate a bit on the general process?
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Old 02-17-2011, 01:35 PM   #23
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You may want to talk to your gunsmith about bedding the entire stock. It appears that your barrel does not like to be free floated.

One of the reasons for free floating a barrel is that it is far easier to do than to properly bed the entire rifle, from stem to stern.
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Old 02-17-2011, 01:59 PM   #24
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Quote:
Originally Posted by cornbelt View Post
Another quick question: If in fact the bbl and receiver surfaces are not mated properly, but the bbl is tightly screwed into the receiver, would that actually make the shots walk, rather than just group somewhere besides the aiming point?
When metal heats, it expands. If a barrel and reciever are not mated square and tightened, there will be stress on the side that is mated tightest. When they heat up, that point of stress will tend to expand more than the unstressed side, causing shots to walk. The amount of expansion of the metal at that point would be un-measurable, but if in a jig, it could be measured at the muzzle. Hope this helps.


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Old 02-17-2011, 02:07 PM   #25
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Quote:
Originally Posted by cornbelt View Post
Another quickie: I'm only familiar with the process of cyro-treatment on knives where they heat the blades to critical temp and quench, either in a dry ice/alcohol bath or liquid nitrogen, then drawn to a temper in an oven. -Sounds sort of barbaric for a good rifle bbl, so I'm probably missing something.
Could someone elaborate a bit on the general process?
Cryo treating is a dry process. Metal never contacts a liquid. The barrel or barreled action is placed in a dry chamber, brought down to 300 below, one degree at a time, by computer. The piece is held at that temp for a specified period of time. The piece is then brought back up in temp one degree at a time to 300 above and held there for final tempering. It is then brought back down to room temp one degree at a time. It is a lengthly process and all done by computer. Hope this was helpfull.

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Old 02-18-2011, 12:02 AM   #26
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Quote:
Originally Posted by masterPsmith View Post
When metal heats, it expands. If a barrel and reciever are not mated square and tightened, there will be stress on the side that is mated tightest. When they heat up, that point of stress will tend to expand more than the unstressed side, causing shots to walk. The amount of expansion of the metal at that point would be un-measurable, but if in a jig, it could be measured at the muzzle. Hope this helps.


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What he said. You need a new gunsmith.
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Old 02-18-2011, 03:28 PM   #27
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Thanks for the info. Interesting process on cyro treatment.
Before I send it off though, since I'll have to pull the bbl anyhow, if I mount it between centers and check the shoulder with an indicator, that ought to tell me whether the bbl shoulder is square, should it not?
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Old 02-18-2011, 09:08 PM   #28
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Quote:
Originally Posted by cornbelt View Post
Thanks for the info. Interesting process on cyro treatment.
Before I send it off though, since I'll have to pull the bbl anyhow, if I mount it between centers and check the shoulder with an indicator, that ought to tell me whether the bbl shoulder is square, should it not?
Assuming the threads have no play in them at all you need to check both the barrel AND the receiver to make sure they are perfectly square to each other. Remember metal will expand in the direction of the path of least resistance so if it's tighter on one side it will bend to the other.
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Old 02-18-2011, 11:33 PM   #29
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O.K. Thanks.
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Old 02-22-2011, 08:39 AM   #30
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I don't understand why you're going to spend 3 figures fixing a new Douglas barrel! Has a professional gunsmith been working on it?

I bought a Douglas through a gunsmith several years ago that walked off the paper to the right every time ( he installed it). I saved the targets, he sent it back with the targets, and they replaced it at no charge.
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