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Old December 4, 2012, 11:48 PM   #1
tahunua001
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hot bore PIO change in weatherby?

hello all,
I have no idea why I am just getting bothered by this now but about a month ago I was sighting in my 300 weatherby vanguard to get ready for elk season and had serious POI changes between hot and cold bore. now this is not a question about it walking an inch in the other direction after 5 shots. the first shot was hitting straight inline and 2 inches high at 100 yards, just where I want it but after that very first shot it was hitting directly center bullseye. leaving the bore for a good 15-25 minutes cooled it enough that the first shots were predictably hitting SUB MOA groups 2 inches high but the hot bore shots all dropped a full 2 inches and landing just at MOA.

is this normal for first gen vanguards or is my rifle just wonky?
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Old December 5, 2012, 04:10 AM   #2
bacardisteve
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Im sure you know most guns will change poi when hot some more so then others. You could check to see if the stock is free floated that may help. Still a 300wby is a pretty flat shooting round and i would try and shoot the rifle at further distances to see how bad the diffrence is at those ranges. Im guessing you plan to use it for hunting? How far do you typically harvest game? No animal will be able to tell the diffrence in 2" and most dont allow for many follow up shots.
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Old December 5, 2012, 07:25 AM   #3
Mobuck
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Given the range capability of the 300Wby, this much change could be a real problem with a followup shot. I've seen similar variances with a cold,clean bore vs second shot dirty bore but you're saying this happens again with a clean, fouled bore. I'd look at the bedding and action screws first.
Has anyone else shot the rifle? In my experience, a harder recoiling rifle like this is very prone to vertical stringing dependant on shoulder contact and how it's held. I shot a 300 Win mag target rifle for a period of time and can assure you that it takes very little difference in recoil attenuation or shoulder contact to throw the shots several inches.
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Old December 5, 2012, 11:56 AM   #4
old roper
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I enjoy shooting groups in my deer/elk rifles but my main concern is first shot out of cold bore for hunting and maybe 2nd or 3rd fast followup shots just to see how they print to first shot.

My varmint partner has 300mag Vanguard it's first gen like your. He shoot factory and he can do pretty good 3/4 shots and he'll let it cool some but shots start moving. I talked to him about having it bedded etc he said heck with it shot good on cold barrel. He took pretty nice 5x6 bull this year got him down on first shot took 2nd shot to finish he was good bull.
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Old December 5, 2012, 12:03 PM   #5
tahunua001
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the average range for elk in the unit I hunt is generally around 300 yards but then there are some closer and some farther. I usually opt out of the 300 for deer as I prefer to have some meat leftover when I'm done so I tend to go for my 243 or smaller for the closer 100-200 yard deer. at 300 yards the bullet drop, even with a flat shooting round like 300 wbymag is pretty big and the difference of 2 inches at 100 can mean the difference of 6 at 300 which can easily mean the difference between a wounded animal and a dead one.
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Old December 5, 2012, 01:43 PM   #6
kahrguy
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2" between 2 shoots is not good. Have you tried different ammo? It would help to know what it does at 300 yards or 400 yards more than just 100 yards. You need to shoot at the longer distances just to know know what it does. Some companies barrels are cryogenicly treated to help to keep them stable and relieve stress , some aren't. The howas tend to be better than average shooters. You may also talk to weatherby CS folks about it.
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Old December 5, 2012, 02:42 PM   #7
tahunua001
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home loads and factory weatherby ammo performed identically. same hot to cold bore POI. as this is a discontinued model I don't know if weatherby would have much helpful advice or inclination to help. they obviously can't replace it unless I wanted to trade it for a 2nd generation which may or may not be a good deal.
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Old December 5, 2012, 03:43 PM   #8
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tahunua001, I may of misunderstood. did you shoot one group then shoot another after barrel cool down?
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Old December 5, 2012, 07:34 PM   #9
tahunua001
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actually it was 3 sets of 2 shot groups. the cold bore shots all went into a 3 hole, sub MOA group 2 inches high, the hot bore group was just barely MOA inside the bullseye.
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Old December 5, 2012, 11:49 PM   #10
big al hunter
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Slide a piece of paper between the barrel and stock. If it slides all the way to the action, shoot it twice and check for float again. I will bet my favorite rifle that the barrel is currently touching the stock somewhere. If it is touching float the barrel and shoot it again.

Sounds to me like the barrel is moving with the heat and pushing against the stock. Free floating and bedding the action should help. You can free float the barrel first and see if it helps. Bed the action if it needs more improvement.

Let us know if it is floating already or if it contacts.
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Old December 6, 2012, 06:00 PM   #11
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Point Impact Of ?
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Old December 7, 2012, 01:50 PM   #12
Bart B.
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Any barrel that's not fit correctly to a reciver or not stress relieved after profiling, boring and rifling will bend as it heats up. Factory rifles are norious for this. Good quality match rifles will shoot to the same POI for 40 plus shots fired 30 seconds apart. Well, within 1/4 MOA anyway, 'cause barrel fouling and heat sometimes causes a few fps faster bullets that end up at the top of your group.

Lake City Arsenal's match ammo is fired for dozens of shots per test group. Group center doesn't change as their barrels heat up.
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Old December 7, 2012, 03:10 PM   #13
old roper
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tahunua001, I post about my friends Vanguard like yours and I put scope on for him also got box rifle came in. I check packet that came with rifle in side was letter from Wby on what they call proof of performance which is rifle guarantee to shoot 1 1/2" 3 shot group from a cold barrel @ 100yds using Wby ammo.

I never open that packet till now I was seeing if they put test target in etc is how I found it. I think my friend paid less than $400 on close out for his and looking at that letter my friend got what he paid for. He'll clean that rifle next time it come out be elk season next year and may fire 1/2rd before hunting then go hunting with it for elk.
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