Load work up bullet spacing

Discussion in 'Long Range Hunting & Shooting' started by jrw1976, Apr 16, 2011.

  1. jrw1976

    jrw1976 Well-Known Member

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    Ok gentlemen this is an issue that vexes me when I am doing load work up. How much time do you guys wait between shots when either testing or shooting groups to maintain a cold bore? I am trying to work up a load for cold bore accuracy so I believe barrel temp matters. But, it is all I can do to be patient enough to wait 5 minutes between shots. I am pretty sure that is not enough so I am asking how long do you guys generally wait. If it matters I am shooting a 26" varmint contour savage custom in 7mm rem mag my son and I built this winter.

    Thank you, Jason
     
  2. liltank

    liltank Well-Known Member

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    I go by feel. If you can touch the area of the barrel just ahead of the chamber and it feels cool to luke warm, I'd shoot. You don't want it to feel too hot after string and start shooting again. I would say about 10 to 15 min. Take a 22LR or a pistol and do some plinking between strings.

    Tank
     

  3. jrw1976

    jrw1976 Well-Known Member

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    Tank,
    Well now I have to ask want you mean by a string. I try to leave 4-5 minutes between each and every bullet so for one, the barrel stays cool and for another to try and keep the barrel as close to the same temp as possible as the first shot. I guess my question is do I need to wait longer or am I wasting my time and waiting to long.

    Thanks Jason
     
  4. 375fan

    375fan Well-Known Member

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    My routine: 3-4 shot string at least 2 minutes between shots. Then shoot, play with other guns I have along. As other poster said , I go by feel of temp of barrel, want it to be cool. Depending on temp at the time I'm shooting also plays into things. On real hot days things go real slow, maybe only shoot 1 or 2 strings (test loads) per rifle.
    One day another gentleman at the range was shooting test loads, he was using cans of compressed air to help help cool barrel between groups. Had short piece of hose and would spray inside barrel. Don't know if it worked, he thought it did.
     
  5. liltank

    liltank Well-Known Member

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    See... I don't waste anytime. I shoot a 3-5 shots consecutively and then allow the barrel to cool. If you are keeping and even temperature between each shot, I wouldn't think waiting would be an issue. Unless your impatience:rolleyes: causes the barrel to get warmer than you like it to be. I figure if I am shooting at something, the first shot is always going to be cold bore. If for some reason you need more than one (let's face it, not all of our names start with Shawn or Kirby, J&E), than you should have an idea what consecutive shots are going to produce in rapid succession. Realistically we aren't going to get more than 3 or more shots at a live target. To each is his own.:cool: I still think if you are giving time between each shot then I wouldn't be too concerned as long as you are keeping an even temperature.

    Tank
     
  6. jrw1976

    jrw1976 Well-Known Member

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    Tank,
    That statement is exactly why I am going through all the trouble of waiting between shots. I am trying to work up the best performing, most predictable load I can for that one and only shot.

    "I figure if I am shooting at something, the first shot is always going to be cold bore."

    Maybe I am thinking about this wrong. I havent done enough testing to figure out if a good consistent warm barrel (not hot) load will be just as consistent from a cold bore. Im just not sure what is right. That is why I am looking for opinions from men with more experience than I, so I can calculate my next step in testing.

    Thanks, Jason
     
  7. 375fan

    375fan Well-Known Member

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    If you really want to do a load test of cold bore than fire one round per day. I use to have piece of property with my own 150 yard range. After working up loads that I thought were spot on I'd fire one shot a day as a test using different time of day. Using this method really gained confidence in loads and zero for rifles. Wish I hadn't sold that property.
     
  8. jrw1976

    jrw1976 Well-Known Member

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    375fan

    That is a good idea and actually very easy for me to do since my shooting bench is set up out of the back of my shop about 50 yards from my front door. I just dont have the patience to take 20 days to run a ladder test. I am wondering if anyone on here has done any barrel temp testing in relation to POI change and velocity from different barrel temps. I should really get a laser temp sensor and do the testing myself since I am so worried about it.

    Thanks Jason
     
  9. liltank

    liltank Well-Known Member

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    To be honest, my fouled shot cold (say after a day of shooting) is the same as the prior day. But my clean, cold bore shot is very low. About 3" from my POA. So I need to be very conscience that I have to have about 3 foulers shot through my barrel before I go hunting. Otherwise I am going to have to remember to come up 3MOA from what it is suppose to be initially with a shiny barrel. At that point I know it will hit where I put the cross hairs.... well I know it is suppose to go there anyway!:D

    Tank
     
  10. sp6x6

    sp6x6 Well-Known Member

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    jrw, I have several buddies that shoot 1000 yrd bench. And they have something like 10 min. for a 10 shot string, dont recall for sure,but I'll ask one. When the wind conditions are right, one guy in particular sends rounds down at a very fast rate, few seconds between shots. I asked him about this, and these are light, and heavy class with large diameter barrels, and his reply was '' I'm hard on barrels" These guys shot groups that we dream about. I think barrel contour would have a bit to do with the heat issue also, These guys get them warm but hold groups.
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Most of us are shooting sub 1/2 MOA rifles for LR work. Your cold bore shot should be irrelevant. Sight it in and you're good to go. I have found that waiting until the bore is completely cold vs warm doesn't really matter much and shouldn't matter if you're shooting a good rifle. Just a couple days ago, I shot a fairly quick 4 shot string with my 300 RUM, putting them into a .39" one ragged hole group @ 100 yds. After the 4th shot mys barrel was very warm, you could even call it hot. When I started the group, the barrel was already luke warm from shooting another load. If your group is wandering from cold shot to warm shot, then you probably have an issue you need to work out.

    Edit... now if shooting under completely different temperature conditions can have a significant affect on your POI. I like to shoot at various temps, and especially the temps I'll be hunting in, to see what my load is doing.

    -Mark
     
    Last edited: Apr 17, 2011
  12. jrw1976

    jrw1976 Well-Known Member

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    Mark,

    You are completely correct, I did have a problem going on and this morning I figured it out. For the last couple of months I have been trying to get berger 168 vld's and H1000 to shoot for me but with no luck. I would get it to shoot 1 hole groups for a couple of groups then it would blow out. I finally ran out of bergers as well as H1000 so I decided to change it up and try something completely different. So a couple of days ago my wife brought me home a box of 168 SMK's and a pound of Retumbo to run down the pipe. I loaded up a ladder test last night and this morning when I got up the wind was calm and I was out the door by 6:00 and shooting by 6:20. I took my time spacing my shots equally and by 8:00 am I was all smiles. I had 3 accuracy nodes to work with 2 of which were 1 holers and 2-6 fps seperating them. In my glee I ran back in the house and loaded up a group test so I could shoot it before I lost the calm wind. Well needless to say I am a happy camper now. All 3 group were good but one really shined it measured 3/4" and had and ES of 8 fps, I was shooting at 250 yards. The other 2 groups weren't shabby either, 1 measured 1.5" ES of 12 fps and the 3rd measured 2" and an ES of 18 fps. I am really happy with my results and now the load is worked up and I can get my drops confirmed and play the rest of the summer. Oh the magic load ended up being 168 SMK, CCI 200, OAL 3.326, 69.3gr Retumbo, WW brass running 2960 fps.

    Thanks for the help, Jason
     
  13. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Gotta love it when it all comes together :)
     
  14. liltank

    liltank Well-Known Member

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    So are you saying I have a problem if my clean barrel, cold bore shot is not up with the following shots at my POA? My first shot on a clean, cold barrel always drops 3" but is good left to right or vise versa. Once its dirty its not a problem.

    Tank