300 RUM First Shot High?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Engineering101, May 11, 2013.

  1. Engineering101

    Engineering101 Well-Known Member

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    I’ve got a new stainless Savage M114 that was a 270 Win. I took off the toothpick they call a rifle barrel and put on a new “factory” standard shank stainless 300 RUM barrel, 26”, varmit contour. I hogged out the barrel channel in the walnut stock so the barrel floats with good clearance. It came steel pillar bedded from the factory. I swapped out the factory recoil lug for a thicker precision recoil lug, epoxy bedded but with the epoxy removed under the bottom of the lug so there is no upward pressure on the lug when the action is bolted in the stock. Headspace was set to near minimum by screwing the barrel in on a PTG go gage. The torque on the barrel nut was set not with a torque wrench (I don't own one) but "a good hard pull" which I'm guessing is ~ 80 ft lbs. A 4-port Muscle brake is installed on the barrel.

    Initial loads out of this rig have grouped 1” to 1.5” at 200 yards depending on bullet and load but cold bore (dirty or clean) the first shot is always about 4 inches high, then it groups. If I let it cool 10 - 15 minutes between shots which is not as cool as cold bore, it will walk down the paper an inch at a time. I’ve swapped between 3 different scopes which doesn’t change the results. Except for the cold bore shot, I was somewhat surprised how good this thing shoots since it isn’t a custom barrel and it is just the factory stock tweaked up a little. So all you Savage rifle tuners – what do I change to get it to put them all in the same spot?
     
  2. rinodods

    rinodods Well-Known Member

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    Is the whole action bedded or just the recoil lug area? I've heard a thousand times that Savages don't like to have the tang bedded and it should float. I would think though that if it was just a bedding issue it wouldn't be so consistent. Haven't seen any of this in my Savages but I don't shoot them until I've been over them pretty good. If you take enough time between shots can you actually keep a decent group with the cold bore shots?
     

  3. rinodods

    rinodods Well-Known Member

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    Oops! Did a double.
     
  4. Engineering101

    Engineering101 Well-Known Member

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    rinodods

    First let me say thanks for taking the time to help out. The action is not epoxy bedded, just the lug. The factory steel pillars looked pretty good so I figured that I would give them a try before bedding any more of the action. It will shoot a good group if every shot in the group is truly cold bore.

    Since the impact point always comes down and stays down (if I don’t let it cool down) even from just one shot something must be pushing on something as it all warms up. I’m hoping that the something is between barreled action and stock as that is pretty easy to fix but I suppose it could be internal to the chamber/barrel.

    I have seen a barrel that was reamed where the chamber was 0.005” misaligned with the bore and it would actually bend perfect ammo so it was no longer concentric but I haven’t gotten into checking the more esoteric stuff yet. I was hoping that someone had seen this problem before and could give me a shortcut as what to check but it looks like I may be in for another “learning experience”.
     
  5. rinodods

    rinodods Well-Known Member

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    Sounds like you've checked most of it out. You might still take a real close look at those pillars. Sometimes you will get stock material in the way and you won't actually be making very good contact with the pillar. With any luck yours isn't that way but it is pretty easy to fix.