300 wby help

greenejc

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Dec 26, 2012
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Colorado, currently
I didn't suggest the action screws or the scope mount screws or the scope screws because I figured that your gunsmith (Whom I assume is competent) has probably already torqued, leveled, mounted and fitted all these things. You may have him check your action and true the bolt if that's not done yet. But I think its just that the rifle may not like the accubonds and may not like the bullet weight or the type of powder you're using. I know one of my .300 Win Mags opens groups just with changes in brass manufacturers when using new brass. Not so much with fireformed brass, though.
 

Tumbleweed

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Oct 20, 2007
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Tillamook, Oregon
Lots of advice going on here...switch bullets, switch powders, hell maybe it's the primers! Lol! My first thought would be to rule out that scope with another known, solid scope if you haven't already. I'd see that as step 1. Secondly, these light barreled magnums are very whippy and need some finesse to tune. That sweet spot is also narrow. Gotta be patient. I start with a seating depth test from magazine box length on back 60-70 thousangths in .010" increments. Shoot 3 shot groups, find smallest group. Using the best seating depth, do a charge ladder test at 250-300 yards in 3/10 grain increments, find your flat spot. Now, massage your charge +/- 1/10 grain and seating depth +/- .005" to hone in on the sweet spot shooting groups of 3. If the first 2 rounds aren't what you're looking for, no need to shoot the 3rd. This "should" produce your best accuracy with the combo assuming there's nothing mechanical going on and reloading practices are good.
 

greenejc

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Dec 26, 2012
Messages
499
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Colorado, currently
Lots of advice going on here...switch bullets, switch powders, hell maybe it's the primers! Lol! My first thought would be to rule out that scope with another known, solid scope if you haven't already. I'd see that as step 1. Secondly, these light barreled magnums are very whippy and need some finesse to tune. That sweet spot is also narrow. Gotta be patient. I start with a seating depth test from magazine box length on back 60-70 thousangths in .010" increments. Shoot 3 shot groups, find smallest group. Using the best seating depth, do a charge ladder test at 250-300 yards in 3/10 grain increments, find your flat spot. Now, massage your charge +/- 1/10 grain and seating depth +/- .005" to hone in on the sweet spot shooting groups of 3. If the first 2 rounds aren't what you're looking for, no need to shoot the 3rd. This "should" produce your best accuracy with the combo assuming there's nothing mechanical going on and reloading practices are good.
There's always lots of advice. Some is good,some not so good. Yours is pretty good. I'm retired and have more time than maybe is good for me, so I could probably do all this over a couple of months. He might be limited in time, but this might work. I figure that he and his gunsmith have already verified the scope and mounts, but maybe not. I think if its shooting into the same group, even if the group is 2 inches, the scope isn't walking. Whenever I have had a scope fail in its adjustments, it has resulted in a second or third shot 5 or more inches off at 100 yards, and a complete change in impact for a subsequent shot. If his groups are consistent in the impact area(centered on point of aim) even if they are large, its probably not the scope or mounts. And its easy to check, because you just check screws for tightness. If I had a gunsmith mount a new barrel, I'd have had him check the scope, mount and rings. Actually, I did that this summer, and the gunsmith did just that. As to the other, its good advice. I'd just do .5 grain increments, because I'm basically lazy and want to shoot more than I want to do load development. Besides, I'm quite satisfied with 1" groups from any of my rifles except my Heavy Barreled 30-06, 25-06 or the varmint weight .308.
 

Almondgrower

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Jul 29, 2018
Messages
122
Location
CA
I shoot 210g NLRAB’s in my 30-378 weatherby . I normally start at max mag which is about .150 longer then nosler book says . I could not get them to group after finding a consistent node . After hunting for a accurate seating depth and having no luck , I jumped down half way to nosler oal. I hunted there .010 at a time , still would not group . Tried at nosler aol and groups shrank 75% . From what I have found ,Every 30 cal I use the NLRAB in ...... they really like a lot of jump . I’d give that a try
 

TommyBreaux

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Joined
Jul 30, 2012
Messages
14
Location
Louisiana
I have a 1:12 twist Lilja on my 300 Weatherby so it will only shoot light bullets.
Three loads that really work well in my gun are:
168gr Barnes TSX with 81.2 grs of Reloader 23 and Fed 215 Magnum Match primers for 3282fps This is right on the OBt node for my 26" barrel.
Another that is great load is:
185 gr Berger VLD Hunting bullet with 78.35 gr of Reloader 23 and Fed 215 Mag Match primers for 3150 fps right on node 4.5 and very accurate.
Also:
150 gr Hornady GMX over 77.45 gr Reloader 23 and Fed 215 Mag Match for 3305fps
Your mileage may very. I like Reloader 23.
The 168 gr load took this caribou at the great distance of 85 yards last week.
 

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Richard Crain

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Oct 23, 2018
Messages
22
Location
Cloudcroft NM
Hi there, I have a Montana rifle in 300 wby, I just had a #3 Bartlien barrel installed by a very good gunsmith. It has a great tigger and is bedded in the factory Montana stock. I broke the barrel in per the instructions. H-4831, IMR 4350 and a box of factory wby 180 ammo. I can’t get the gun to shoot! It’s a 1 in 10 twist. I cleaned real well with CR-10, then ran JB Bore Paste down the barrel, then cleaned again and oiled. the bullet I’m trying to get to shoot is a 168 accubond long range. The scope is a 4.5x14 leupold, Warne bases and Leupold PRW rings. I loaded a bunch more with IMR 7828, R-19, and AA-3100. Now, by the way, during break in the barrel was very very filthy. I’m hoping that the JB Bore Paste helps. I seat the bullets so it clears the magazine for magazine clearance purposes. All bases, rings and scope are top notch and tight. I’m told that IMR 7828 is the go to powder? Any tips? Maybe takes awhile to break in? I’m letting the barrel cool after a few shots as well. Thanks for any tips at all to get this going.
I rebuilt my mark v almost like yours. Would not shoot 168s, shot 175s better, shoots Barnes 180 tsx 1/2 moa. I would stop putting all crap in my barrel.
 

Anthony Bonavia

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Joined
Jul 25, 2013
Messages
4
I feel fortunate that my old 300 Weatherby from the 70's shoots great with factory ammo, 180 gr. Some people don't like the Japanese Mark 5's but i am happy with mine, although I constantly consider putting a new barrel on mine. The barrel is 24 in and is a slender #1 contour, it heats up after 2 shots. I like the idea of a 26 in barrel with more weight, but haven't pulled the trigger on that yet.
Good luck!
 

Lenny Foffa

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Mar 6, 2017
Messages
185
In my 300 Weatherby Mag, #2 ,26 inch . I have only ever used Fed 215 Mag primers. Also going way back, Weatherby did not recommend using the long VLD bullets that we all love today, they suggested Hornady , over Sierra. Did the barrel maker add any "Free Bore," as was always done with Weatherby Rifles??? Weatherby's customer service department is very good with Questions.
 

Bearman375

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Joined
Apr 8, 2019
Messages
54
Location
Great falls Montana
In my 300 Weatherby Mag, #2 ,26 inch . I have only ever used Fed 215 Mag primers. Also going way back, Weatherby did not recommend using the long VLD bullets that we all love today, they suggested Hornady , over Sierra. Did the barrel maker add any "Free Bore," as was always done with Weatherby Rifles??? Weatherby's customer service department is very good with Questions.
No free ore added
 

nksmfamjp

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Jan 5, 2004
Messages
674
What shape are your groups? Are you stacking 2 or 3 through the same hole and 1-2 somewhere else? or is a 5 shot group 5 random holes? With some pics of groups, we might be able to understand if bedding could be an issue....Are these pillar bedded?

It sounds like you have several bullets. Can you load up 15 of each and see which gives you the most good 3 shot groups? I would load 3 x 5 powder charges from min/max at the oal shown in the bullet makers book. Do that for 3 bullets and determine which bullet gives best results.

If you are sure about your rest, scope and shooter, I think you have to start collecting data on if all bullets shoot to 2” or do some shoot much better.
 

Bearman375

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Joined
Apr 8, 2019
Messages
54
Location
Great falls Montana
What shape are your groups? Are you stacking 2 or 3 through the same hole and 1-2 somewhere else? or is a 5 shot group 5 random holes? With some pics of groups, we might be able to understand if bedding could be an issue....Are these pillar bedded?

It sounds like you have several bullets. Can you load up 15 of each and see which gives you the most good 3 shot groups? I would load 3 x 5 powder charges from min/max at the oal shown in the bullet makers book. Do that for 3 bullets and determine which bullet gives best results.

If you are sure about your rest, scope and shooter, I think you have to start collecting data on if all bullets shoot to 2” or do some shoot much better.
3 or 4 shot random, I’m thinking now it’s the powder, primers or doesn’t like the bullet type
 

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