M700 Problem

Discussion in 'Long Range Hunting & Shooting' started by 700varmint, Jul 5, 2010.

  1. 700varmint

    700varmint Member

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    Hello all, 1st post for me just found this forum the other day, anyhow I have a M700 that started life as a BDL 22-250 left hand. I have had the gun re-barreld with a shilen medium contour 26" barrel chambered in 260 rem and with a 1:9 twist. the action has been epoxy bedded, the barrel has also been bedded and free floated and the relief at the tip of the stock removed which helped some. the bolt face has been trued and lugs lapped. my best hand loads are 47.0 of Reloader 19 with GM210Match primer with OAL of 2.820" which is about .007 off the throat.

    Here is the problem, with a cold barrel my 3 shot group will always be 2 in the same hole and the 3rd shot about 1 inch out. the second and subsequent groups will be very tiny and better the hotter the barrel gets, for example yesterday I shot a .360" group with my 6th - 3 shot group all with a hot barrel are way under .500" groups. what is going on with this? I have never heard of a rifle that shoots better the hotter it gets.

    I also thought maybe I was over-doing it with cleaning and there is no difference however I have stopped cleaning after each range session, currently I have about 40 rounds since the last cleaning and notice no changes. I dont think its my components which B-tips are not matchkings but I still shoot great groups after the barrel heats up. I also check concentricity and keep it within .002".

    Can anyone help me?
     
  2. boomtube

    boomtube Well-Known Member

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    " yesterday I shot a .360" group with my 6th - 3 shot group all with a hot barrel are way under .500" groups. what is going on with this? I have never heard of a rifle that shoots better the hotter it gets."

    It's much more common to get better accuacy with max loads than many web experts seem to think. Or, stated another way, accuracy comes where it comes, it can be with hot loads just as easily as mild ones.

    It's not a match rifle, stacking the first two is as good as it gets for a working rig. Walking impacts due to heat are quite common due to residual metal stresses in the barrel. It's not common that groups will still be stable after moving but it's not unheard of. Zero for the first couple of rounds, in the field it's not often we can expect to keep shooting after the first couple rounds.
     
    Last edited: Jul 5, 2010

  3. elkaholic

    elkaholic Well-Known Member

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    This does sound a little unusual. Have you checked the torque on the screws? It's possible that it might need to be torqued a little more on the lug screw. Also, does the second group move over to where the third shot from your first group hits? I assume you probably have checked the barrel for clearance all the way to the bedding with a paper? Keep us posted.....Rich
     
  4. angus-5024

    angus-5024 Well-Known Member

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    sounds to me like theres some stress issue's. rather over tight/under tightened action screws or a bedding issue. either way two shots in one hole sounds like something is going right.:D
     
  5. 700varmint

    700varmint Member

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    going right yes however, the hotter my barrel gets the better it shoots, I have re-bedded twice and removed the stress point near the forend of the stock. the group does not move. when I Fire 2 at 1/2 inch high and the 3rd shot will be 1" out then every group thereafter is 1/2 high at 100 yards and in a cloverleaf, the faster I shoot and make the barrel hot the better groups I am shooting. I feel this rifle has some awesome potential however the only thing else I can do is get a new stock.I have the action screws at I think 60 inch pounds. I will post some pictures of my groups. ASAP. that 3rd shot is becoming predictable no doubt, I know it will be about 1" out usually high but can be high left or high right. pics on the way.

    RIght pic if cold bore and left pic is hot bore, as I said it is very predictable

    [​IMG]

    Left pic is showing another cold bore flier, on the left bull the hole on the right is 2 bullets and the hole on the left is the flier, the bull on the right is upside down but shows what my hot barrel does.

    [​IMG]

    I built this rifle as a long range deer gun (out to 500 yards) and as a semi target rifle. the target spots are 1" diameter to give scale.
     
    Last edited: Jul 5, 2010
  6. elkaholic

    elkaholic Well-Known Member

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    That's a head scratcher! The problem with shootig until your barrel getd hot is that sometimes the animals spook:D:D
     
  7. midwesthunter

    midwesthunter Well-Known Member

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    Check the bedding around the lug. Should have a little room all the way around.
     
  8. royinidaho

    royinidaho Writers Guild

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    Oops, went off half cocked. Deleted first remarks.

    Why are the groups in different places on the target except for the first one?
     
    Last edited: Jul 6, 2010
  9. 700varmint

    700varmint Member

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    my 1st - 2 cold bore shots will be nearly in the same hole, maybe not exactly 1/2 inch high but in the same hole none the less, the 3rd shot from this gun is usually 1/2 to 1 inch away from the 1st 2 shots, without adjustment every other shot will be 1/2 inch high at 100 yards. it almost seems like this gun wont shoot until at what operating temp it wants. once it is warm it falls together and shoots just fine.

    to answer your question one of the targets are posted upside down in my range book it is only for comparison and to show that this rifle will shoot quite well,,,,,once its hot.