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#46 – Project Cold Bore – Phase 1

Project Cold Bore - Phase 1

00:55:29  | Project Cold Bore is planned to be an ongoing exploration of variables affecting first shot accuracy. Bryan and Mitch discuss Phase 1 of this project which is to simply track the cold bore shot, and group center of a single 5-shot group fired from each of 4 rifles each day for 5 days. Muzzle velocity is also recorded and all variables are analyzed. There is a series of blog articles on The Science of Accuracy Academy which accompany this podcast which documents everything with tables and data plots.

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  • William Larrabee says:

    Great podcast on a very interesting subject but the entire time I was waiting for the conclusion to be linked in some way to the individual rifles contruction since they all behaved slightly different in some aspects. For example not every cold bore shot was fast or slow on every rifle or shift left or right but some individual rifles did have some consistency on how they behaved within that one system. So could this be due to that rifles construction. You are comparing and testing between rifles that are full custom, low quantity more expensive production, to more mass produced rifles. They are all going to have different quality of construction. Could there have been more stress built into one rifle vs the other leading it to have more of a shift in POI between the first shots. I would think in theory if there is zero stress in the rifle and the barrel is already fouled there should be almost no shift in POI vs one that has lots of stress could have a lot and I would imagine very repeatable POI shift. I know the purpose on these podcast is more geared towards external ballistics but I would like to see more of a focus on the rifle itself. How does the straightness of the bore in relation to the rifle affect the consistency, free floating vs not free floating, issue such as Borden bumps to fix bolt alignment and trigger issues. There is a lot that goes on within a rifle that can keep people from chasing their tail and while I believe all of these things make a difference, I would like to know through actual testing how much of a difference is it? Is the difference worth purchasing a BAT or Borden action instead of just “accurizing” a 700 action that may have some of these issues?

    • Mitchell Fitzpatrick says:

      Thanks for your comment William! We are doing more cold-bore testing and will be able to draw better conclusions with more data. This was just phase one of the cold-bore testing, and while we gained some good insights, we can’t draw any distinct conclusions about cold bore effects for a given rifle type. We will also be doing more rifle specific testing as well! I think people will find it very interesting what does, and does not, matter when it comes to how precise a rifle is.

  • Mark Lanphear says:

    Great talk. In the .308 heat soaked test with the ambient ammo, one thing you might consider is heat transfer. The heat from the rifle will move toward/into the cooler ammo. Not sure how much time would be required to make a difference, but it could be a variable in the outcome.
    Keep the info coming. Great learning opportunity.
    Mark Lanphear

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