Here is my dilema. I am using once fired weatherby brass, federal 215m gold primers, and 180 grain barnes xfb bullets. The tightest group I shot at a 100 yards was .44". I was happy with this group, so went home to load more, next time at our range, 2", the following group was .7". Shot some more it got worse 2-3-4". Went back home cleaned gun for several hours until it was perfectly clean, reloaded again with 107,108,109,110,111 grains of H1000 and can't get the gun to group at all. One paticular issue is that out of every three shot group, 2 bullets are always close and one bullet zings off. I have been working on this rifle for five days straight and don't plan on quitting until I get it right. Sunday morning I will try the 165 gn. ballistic tip. I have also used H870 on the 180 grain. Thanks to whoever can help.

With that much case capacity to work with, why not try the 200 grain bullets. It is obvious the barrel does not like the 180 grain very much. On Deer it doesn't matter, but on the larger animals the extra weight will mean more penetration. Good shooting.

Try 106,5 grains Norma MRP 2 Primer CCI 250
180 grains Barnes X.

The rifle I own is an Accumark,what happened to you has happened to me with 3 different BOAT TAIL bullets,BST,Barnes XBT and Speer SBT.One day 1MOA,the next day 2.5",the other day 3".I tried different powders H-4831sc,H-1000,H-870,H-50BMG,different primers,playing with COL,full sizing,neck sizing,the results remained the same,the rifle doesnt like 180 BOAT TAIL bullets,may be with spitzers ,the result might be different.AS for myself I will try 150 grs,BST and 150 MK,if it doesnt work with these boat tail,I will try SP bullets.I have to find an "consistant load".(165 grs SP or 200 SP will the next step.Two shots out of three within.5",it has happened ,the third one was out of accuracy...

Put me down as another guy frustrated by this caliber. I have a sako trg-s in 30-378. I have come to find it likes 150 and lighter bullets. If you let the barrel get fouled it will like 150 barnes xbt's at 3650-3700 fps. Very flat and good enough for any elk that walks. It takes a good 12 fouling rounds and then it will settle to 3-4" round groups at 300 yds. I'm thinking this gun is a good candidate for moly only and NOT SCRUBBING the heck out of it when done.

Just an idea--but a boresnake between groups could be an interesting experiment. I've seen more people swear by them then at them. BESIDES it just isn't a fun caliber to have to foul BEFORE IT STARTS SHOOTING.

My local gunsmith said he had more people bringing him this caliber when it came out than any other in memory--they all asked him to pass his "magic wand " over it!!

Well today I went to my range with 97.5,98.5, and 99.5 grains of H1000 using a 165 grain ballistic tip. The results were 1.133" with the 99.5 grains. I also used Nosler's recommended powder (H50BMG) with 112,113,114,115, and 116 grains with same bullet and federal 215M match primers. First group 112, .734". Second Group and this is NOT a misprint 113 grains, .234" (3 shot). The third group w/114 was 1.033". The forth group the first two shots were about 2" so I quit shooting. Needless to say I was jumping up and down going nuts. I believe I have found my bullet and powder. Tomorrow I will go and double check everything and final the zero. Hope this helps anyone.

ps The rifle is Weatherby Accumark w/ accubrake, 6-24X50 Swarovski 30mm tube, shooting off a lahti company rest. I also cleaned the gun last night and so this group was shot on a barrel with 12 rounds through it over about 45 minutes.

Mike,

They seem to be very light loads.

A friend of mine in Australia did quite a lot with a 30/378 Accumark and his best loads were lower velocity loads with 180 grain Ballistic Tips.

Something else to consider. If the rifle will shoot well from low loads but not full pressure loads, this is often indicative of a bedding problem with the rifle. I have no good idea why this is the case but I know it can be the case.

Mike

Hello everyone
I have heard this problem about getting a good group and then one bullet going astray. This was happening to me also, but I found the problem to be the muzzle brake. As the rifle got hot the brake would very slightly constrict the bullet as it left the barrel causing a bullet to go astray from the group. I had a good gunsmith slightly enlarge the diameter of the break. Since then absolutely no problems. This may be the problem some of you are also having.

[ 11-15-2002, 11:20: Message edited by: 30-378Weatherby ]

RE THE MUZZLER BREAK!!!!--If you told that story people would think you were nuts BUT, I had a 300 wby ultrlight that I took to my gunsmith. It wouldn't shoot for shinola either. He also noticed the hole was so small you could hardly drop a bullet through it with out scrapiing somewhere. Since he got done I only had a chance to try it at 100 yds with a little ammo but, it shot good---If this is the problem wouldn't it be hard to believe a manufacturer could make such a dumb dumb mistake!!!

Here are 2 loads that worked well for me. RL-25 / 106.5 grs--Swift Sicircco 180 bullet or Nosler 180 gr Partition. Next is H-50 BMG/ 121.0 grs with same Swift bullet or Nosler-Winchester--180gr Partitions. The primers were all Fed 215 mag. The gun is a Weatherby Accumark . I also had the same problems that you and others have had. I have been working with this gun for 3 years. I have also bedded the action and 2" of the barrel. The rest of the barrel is floated. And one other thing. When I remove the barrel action from the stock. I tighten the screw in front of the mag well frist and then the one behind the trigger. Good luck with your gun. I have taken 3 Mule Deer & One Antolope with it.

Gents - It isn't often I acquire a rifle that does everthing right from the git go. So you'll have to excuse me if I gloat a little while relating my experiences. The rifle is a W'by Accumark; Weaver rings/bases and a Leupold 3X9 Vari X II that has never been off 6X. I purchased 2 boxes of factory ammo with it, Barnes 180g and Nosler 200g for break in. I noticed a decided preference for the 200g during break in, which was ok with me cause I didn't buy that much case capacity to shoot light bullets. I'm not sure how I decided upon Barnes X in 200g nor why I decided to moly coat them. I do know I used H870 cause I had a couple of $8 cans stashed and the manual showed good velocity with it. My first loading was 116g and still is. My notes show an oal of 3.750 max because of magazine length. It always shoots less than an inch. I am constantly amazed at how easy it came to be. And after reading the posts above, how lucky I got. But I've got 3 W'bys and they all like Barnes flat base and they all shoot into less than a inch. Life is good. Good luck all.

Geezer

MIKE, Here is a web you might like to see, http://inextinc.com/hunting. Good luck Let us know how its goes.

Mike I am reloading with H-870,115/116/117/118gr using 150grs Sierra HPBT Match King;I will send the results.FL Rcbs...

Mike,the best I could do was .905 MOA at 100 yards with H-870 117grs.I will play with COL.I will also try H-4831,100,101,102,103grs with the 150 MK...

Mike,150 Mk with H-870 at different COL didnt shoot well;same COL, two different days,the POI is always changing,I will enlarge the muzzle break,the thing seems too tight.Flat base bullet ;may be is another solution...

Mike your double check was it an accurate and consistant load...

Is anyone of you having problem with a muzzle break(Weatherby);the thing seems very "thight" and can be easyly put out of aligntment by "mishandling. Is it "fragile"...

Have same wthby accumark...caught a bullet on the muzzlebrake that torn pieces off the inside surface. sandpaper and dowel smoothed the jagged edges..went from 1/2 moa to 1/4 moa shooter with same ammo AFTER damaging the brake and reworking it. How about that! Also, mine works just spiffy with 180g bullets, in fact seems to prefer them, and positively hates lighter bullets. The Barnes 180g and NOsler 180g BT are its favorites. I use 122g of H870, neck sized wthby cases only, fed 215 primers. solid 3500fps.

NOTE: keep your stock screws tight! found after 50 rds that both front and rear were loose. now loctited. Also, don't underestimate the flinch factor on the third round. IN fact, after about 12-15rds total I can't shoot any further with this rifle. and its not the recoil, its the muzzle blast..even with earplugs. The blast actually etches the surface of the concrete benchrest!

WRYFOX;the max powder for mine is 117grs H_870,velocity around 3320fps.You can shoot better now with the muzzle break enlarged,seems to me the break was too tight.THE BEST Ican do is 2.5"moa.I have sent the rifle to enlarge the muzzle break(the POI was never at the same spot)..