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Problems with 340 weatherby accumark accuracy
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I am reloading with 250 grain Sierra Gamekings and Imr 7828SSC and am shooting three shot groups (cold barrel) of 2 1/2" to 4 3/4" groups at 100 yds. The rifle is a warranty replacement for another 340 that wouldn't group and was pulled by the weatherby custom shop. The rifle is an accumark that grouped at the factory sub-moa, actually sub 1/2 moa with 200 grain spire points. I had the rifle checked over by the local weatherby dealer gunsmith, who checked the crown, trigger guard screw setting, etc. and pronounced it fine. Weatherby stated they had their worst groupings in the over 30 calibers with Boat tails and told me to try the factory loads. Tomorrow I will try the factory 200 and 225 spire points, but would like any advice from jorge and company for any pointers in loading boat tail or any thing else I am overlooking. The 340 is very hard on scopes and is currently wearing its fourth new Leupold VARI II/ VX-2 3x9x40 replaced by Leupold this year, so I think (hope) the scope is not the culprit this time.
 
Posts: 5 | Registered: 13 January 2007Reply With Quote
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I am not a 340 Wby expert by any measure. But only one bullet and one powder is not a sufficient test. Especially when the gun apparently shoots well with a relatively lightweight bullet, and you are trying a rather heavy one.

I suggest trying some factory ammo. Then, if you want to use the 250 GK try different powders. If that doesn't work and you still want a heavy bullet, try different bullets.

LWD
 
Posts: 2104 | Location: Fort Worth, Texas | Registered: 16 April 2006Reply With Quote
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Donald; I'd try a different powder. My 340 LOVES RL-22 or MRP (same powder) and I've also had good luck with IMR4350 & H4831. I just finished working up loads with the 210 TSX which is a BT (I think, I'm not home during the week). I've tried factory 250gr & 225gr Hornadys and they were both MOA shooters. Also the 240 North Forks & 250 Partitions all grouped very well for me with RL22 & MRP. The 340 so far has been a pleasure to load for. I've had no scope issues. I originally had a Leupold 2.5X8, but the rifle now sports a Swarovski PH 1.75X6X42.

I've never tried Sierra bullets as I am allergic to "tin foil" Smiler . LEt me know if there's anything else you'd like to know. I'll be home by tomorrow eve so I can give you specific loads. jorge

PS: Jsut found these from another post:

Load 1: 81.5gr IMR 4350 MV: 3125,3147,3120 & 1.25"
Load#2: 83.5gr IMR 4350 MV: 3185, 3165,3175 & 1.00"
Load#3: 90.0gr RL-22 MV: 3230, 3220, 3205 &.55"


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Posts: 7113 | Location: Orange Park, Florida. USA | Registered: 22 March 2001Reply With Quote
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Donald, you might also try here --> http://www.weatherby.dk ... Not a large forum but very knowledgeable folks on the Weatherby rifles....

Ken....


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Posts: 5386 | Location: Phoenix Arizona | Registered: 16 May 2006Reply With Quote
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I'm sort of having similar problems (.308 though) and have come to suspect the bullets. My rifle shoots .4 MOA with AMAX but nothing under an inch with anything else (usually 1.5 to 2 inches, not what I was expecting with a .308 varmint rifle).
This may sound weird but try some match bullets (hornady 250 gr.) and see what they do. If you still can't get the groups you want it may be the rifle/scope not the load.
 
Posts: 209 | Registered: 27 July 2007Reply With Quote
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Donald, I am curious about your rifle being hard on scopes. I have a friend that had a Wby 7 mag with same issues, and his accuracy was always pretty poor with the rifle. He went through 5 Leupy scopes, which are usually pretty durable IME.

Long story short, at the range one day my friend showed up with his rig. I ended up asking him where he was in the scopes adjustment, and he didn't know, they had just bore-sighted it at the dealer for him when his new scope came in, and he tweaked it from there. Upon checking it, he wasn't at the end of adjustment, but really far into the windage adjustment one direction.

I took his rifle to a smith I knew at the time, and he determined that the scope base holes were well out of alignment with the bore of the barrel. He welded up one or two of them and re-drilled and tapped to larger (8x40) screws, and from that point on, this rifle has worn the same scope. It functions very close to the middle of it's adjustment range for windage now.

Shooting with the same factory ammo, the rifle now groups better, although one may have nothing to do with the other, maybe my friends rifle just needed some more rounds through it. I will say that I helped him clean it, and he admitted he hadn't ever really cleaned it like I did--on 4 different occasions--this alone may have helped a lot. He only has shot factory ammo through it--he had bought a couple of cases, so that's all he shot in it.

Just FYI, maybe not relative--but maybe......
 
Posts: 3563 | Location: GA, USA | Registered: 02 August 2004Reply With Quote
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Very good observation there Fish... My 338-378 doesn't bother my Leupold VXIII at all... I bought the Leupy basically because of there reputation for standing up to hard kickers... I adjusted the scope to it's center first and then mounted it... My first shot was only a few inches high so I still have alot of adjustment room... I'll be keeping the alignment with the bore in mind the next time I purchase a new rifle... Never really thought of it so I guess I've been lucky so far...

Ken....


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Posts: 5386 | Location: Phoenix Arizona | Registered: 16 May 2006Reply With Quote
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Barnes 225 gr TSX which is flat base shoots great in one of our Wbys over 91grs RL-22. Assume from your post its doesn't have a brake, ever consider one. Reducing the recoil may help alot.


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Posts: 665 | Location: Western NY- Steuben County | Registered: 02 February 2007Reply With Quote
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I'm not sure why your rifle is having such a hard time grouping. Literally, shots 3,4, and 5 out of my then new Accumark went into one inch at 200 yards! This was with Weatherby factory fodder, 200gr spire points I believe. Since then, I've found the rifle to be stupidly accurate no matter what the conditions. Handloads with 7828SSC and either 200 or 250gr Hornady interlocks yielded similar performance.

The part of your post that raises the most curiosity is the scope issue. The 340 is no harder on scopes than any other 338, let alone larger calibers like 375's. I've got a Zeiss Conquest 3-9 on mine, and it's rock solid. Another significant advantage is the dual-dovetail bases and Burris signature rings I used to keep things in check. Methinks the scope and/or mounts are the culprit. A Leupold VX-II should not even be fazed by a 340. Perhaps there's a problem with the way it's mounted (misaligned mounting holes, unnecessary torsion on the scope would throw groups way off. Maybe removing and rechecking the scope would make some difference. Alternatively, you could swap the scope with another in your safe (if you have one) and see if that affects anything. Good luck in your diagnosis.
 
Posts: 1164 | Location: Gilbertsville, PA | Registered: 08 December 2005Reply With Quote
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Thank you everyone for your respones. Jorge, I would appreciate any information on your loads when you have the chance. As to the accuracy first. I went to the range very early this morning before work and was able to fire two 3 shot groups of factory 200 SP and 225 SP ammo, waiting 7-10 minutes between shots and cleaning between the groups. Both groups were 1" ctc, with initially less than full effort on my part. I couldn't believe the rifle was really going to shoot after the groupings with the Sierras. I am going to back to the dealer and by the 250 spire points and give them a try. As to the Leupolds breaking, the first Leupold did fail on the first 340 Synthetic and the adjustments on windage were close to the limit. The next two times however were on the accumark and were essentially centered on the adjustments. The rings and bases are Talley for Weatherby and did not seem off in alignment in respect to the separate bases. I have to go take my 14 year old for father-son time now, but I must add that both Leupold and Weatherby have been exemplary in their warranty work with my accuracy issues. It would seem that having a bad rifle, scope and bullet choice can sometime come simultaneously.
 
Posts: 5 | Registered: 13 January 2007Reply With Quote
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My 340 Accumark will print 1/2"-3/4" 4 shot groups at 100 yds all day with factory 225 gr SP. Here is what I would check...

1) All scope rings and bases are tight.
2) Action screws are properly torqued.
3) Try different bullets, (mostly not a big fan of game kings)I have had good results with Barnes, Partititions, and Hdy interlocks.
4) Avoid light powder charges, 340 doesn't seem to like the loads being to far away from max. Also, make sure you are using Mag primers, sometimes its easy to get them confused.
5) Use slower powders akin to RL22.

Good luck with the Accumark, I have been well satisfied with mine.

John
 
Posts: 1343 | Location: Northern California | Registered: 15 January 2006Reply With Quote
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quote:
It would seem that having a bad rifle, scope and bullet choice can sometime come simultaneously.


Murphy's law that, Murphy's law seems to apply a lot!

1" CTC seems like you are on the right track, I think you've got the scope mounts and scope spot on now from that description.

Good Luck--Don
 
Posts: 3563 | Location: GA, USA | Registered: 02 August 2004Reply With Quote
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My old 340 WBy used to love the 210 TSX and RE-22.

A lot of Wby's don't like boat tails due to their free bore.

Sounds like the factory ammo has restored your confidence in the rifle. thumb


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Posts: 8808 | Location: Sydney, Australia. | Registered: 21 March 2007Reply With Quote
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A follow up to my weatherby accumark accuracy problems. I test fired factory 250 grain spriral points with 2 1/4"+ groups. I then tried hand loads with the 250 Nosler partition bullets out to 3.67"OAL and Imr 7828SSC, 86-88 grains with average groups slightly less than 2". Better but not great. I next tested 210 grain nosler weatherby factory loads. The 210's grouped into one hole 3/8" ctc! It seems that the rifle will shoot with the lighter weight bullets. Not wanting to give up on the 250 grain weights, I again spoke to Sierra and found out that the most accurate powder they tested was Reloader 25 @ 2900+fps. I loaded the Sierra 250 SBT out from 3.562" their manual lists to 3.70" OAL and shot groups averaging 1" up to their maximum listing of 90.0 grains. The Nosler 250 grain Partitions also shot to the same average grouping of 1", although to a different POI. Nosler and Sierra techs both suggested changing the powder to set up a different barrel harmonic. Primers used were Federal 215M.

In response to Jorge's good natured jibe at Sierra Bullets. I have killed 3 very large Bull Elk with the Sierra's 250 grain boat tail. Two were shot at 385 yds and 415 yds with a .338 win mag 2700 fps and 1 at 170 yds with the 340 @ 2950fps quartering through the leg/ shoulder. All shots (one per elk) passed through putting 2" holes through the elk with no sign of jacket/core separation or weight loss. Two of the Elk were down before another step, with the 340 hit knocking the elk flat. Assuming of course you can find an accurate load with the 250 grain game kings, their retained energy at long range far exceeds any other hunting bullet. with a BC of .562 a 2900 fps a hand load will hit with more energy at 500yds than any available 338/378 factory load. I'm off in 2 1/2 weeks to Montana and hopefully will be able to report bullet performance on another big elk.
 
Posts: 5 | Registered: 13 January 2007Reply With Quote
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Donald,

7828 is about the worst powder for the 340. Slow the powder down and work on filling the case. The new Hodgdon US869 will work wonders. H5010 and Retumbo, and RL-25 also work great. But do yourself a favor and don't bet that the 340 will out run a 338-378. I am shooting 250 gr custom bullets in front of 116.5 grs of Retumbo with an average velocity of 3172. The spread is just 8fps, and for that much powder and that much case, that's un-real. That is after the factory Weatherby barrel got screwed off and a decent barrel replaced it. The factory Accumark barrels are pure junk. Until this rifle was re-barreled it would have to work to get under two inches at 100 yards. Now it shoots that at 500.

Joe


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Posts: 551 | Location: Northwestern Wisconsin | Registered: 09 April 2007Reply With Quote
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