300 Weatherby Load Help

Discussion in 'Reloading' started by Rymart, Feb 17, 2006.

  1. Rymart

    Rymart Well-Known Member

    Jan 26, 2005
    I'm going to give my troublesome 300 Weatherby Mark V one more try to shoot accurately (by that I mean under 1 moa) and I really need some help with working up an accurate load for it.

    Here is what I have to work with:

    175 gr SGK's
    180 gr SGK spbt's
    190 gr SMK's
    185 gr Berger VLD's

    20 pieces of new Weatherby brand brass that I have BR prep'd.

    Federal 215 primers.

    1 lb of RL19 powder

    I'd also consider purchasing a lb of IMR4350, RL22, RL25, or H4831 powder if any one of these came highly recommended for this caliber.

    I would really appreciate any 'pet' load recommendations. My main emphasis, for now, is accuracy, not velocity. I would also appreciate recommendations on a powder that will excel with this caliber. I do not have any load data on the berger VLD's (as they were given to me), and would like some help on where to find load data or starting points for these.

    I'm a careful reloader and would start low and work up to any recommended loads. And I would consult the books.

    The past accuracy problems with this rifle are a whole other story. At this point, the action and the first inch of the barrel are bedded. The rest of the barrel is free floated. The action screws have been torqued. The scope and mounts have been swapped, just in case they were part of the problem.
  2. Mysticplayer

    Mysticplayer Writers Guild

    Jul 27, 2001
    Confirm that your throat is not too long ie bullet must engrave the lands before leaving the case neck. If there is a jump, accuracy will always be poor.

    H1000, Retumbo would be my choices for the heavies. I have shot h4831SC with light 155/168gr bullets and this was really good. However, would go slower powder for the weights you are thinking about.

    Use Fed 215M primers. collet or bushing size your brass and monitor runout. Work up load.

    Make sure that the bedding was done right and that the action is not bending. You don't need to torque a stock down. if the bedding is done properly, firm hand tight is plenty.

    The use of so called torque is a bandaid to other stock problems.


  3. kraky2

    kraky2 Well-Known Member

    Jan 6, 2005
    I have to politely disagree with some of the above. First of all...for some reason Hodgdon doesn't recomend retumbo for the 300 wby till you get to 200 grain bullets. Another poster had called them and was told by a tech it had something to do with inconsistant ignition on bullets lighter than 200 grain. (Which surpirsed me)
    Secondly Weatherby rifles with freebore can be VERY ACCURATE. I know because I own 5 of them. While they aren't benchrest quality all but one of them will do MOA to 400 yds which is my personal limit. AND you might actually get BETTER accuracy out of you rifle by seating the bullet shorter (not longer) in the case.
    It would be my recomendations:
    * For powder try RE22 or I7828--personally I'd give the nod
    to 7828.
    *84-85 is usually a max load for 180's with 7828. TRy working up in 1 grain increments from say 81 or 82 and see if you find a sweet spot.
    You could also try and "hang the bullet out" as much as your clip will let you....or seat it deeper like the factory and see if that "jump" makes the barrel "sing".
    If none of these work I'd take it to someone with a good reputation and a borescope.
  4. WunderDog

    WunderDog Well-Known Member

    Feb 11, 2005
    I have to agree with kraky on the bullet seating depth issue. With the freebore in the Weatherby, it is likely not possible to seat the bullets very close to, or on the lands so you may as well keep them short. Another point of concern is that you have the barrel floated. It has been noted and discussed on other threads here, that the Weatherbys actually have a designed pressure point at the front of the stock. I don't know which Mark V you have but in my ULW, I had to remve a little bit of that pressure point to decrease the pressure on the barrel. It shot near MOA prior to this and with a little trial and error of filing down those pressure points, I improved that by about 50%. I do think that perhaps the very thin profile of the lightweight barrel is a bit more susceptible to these changes than a standard barrel.

    I have actually never shot nor loaded any bullets as heavy as you are looking at for this caliber. I usually shoot 165 gr. I have used the both the Swift Scirroco and the Nosler BT with great accuracy success. With how the Swifts have performed on elk, I have not considered looking to heavier bullets. The two best powders I have used are H4831SC and H1000. Both loaded to near the top of typical recommended loading have been good (under .75 MOA). I have played a little with a couple of the VV powders as they have tended to be very good for me but haven't gotten too serious about getting the best loads out of them yet. With as much more expensive as it is for me to get the VV powders, if I can stick to Hodgdon I would prefer that. Though I do consider the expense well worth it if they are the best for getting a particularly finicky gun to shoot well. Good luck - I do think your gun is capable of more than you have seen out of it to this point.
  5. jb1

    jb1 Member

    Jan 27, 2006
    here is my load data I have found that works great for me. I have found that my 300 weatherby really likes 200 grain bullets. I have played around with speers swift and many others. I finally found that the 200 accubonds 81.5 imr7828 have given me the best results. By far not a bench rest gun but I am satisfied. I worked the load up and got better accuracy at 83 grains (I believe this is the top book load) but the pressure was a little high for my likeing. Every gun will shoot a little different but 7828 brought my groups down to my likeing. just at 1 moa at 100 yards.
  6. cdhunt

    cdhunt Active Member

    Jul 23, 2004
    my 300 works well with the following--

    180 gr. nosler part.
    federal gm215m primers
    80 gr, h4831sc powder

    3005 fps on my chronograph

    saami oal used
  7. kfrye

    kfrye Well-Known Member

    Jan 17, 2006
    My Jap MKV recipe is 88.0 grains of H4831 and 150gr. Hornady Spire Point. If I do my job, the first two are in the same hole at 100 and the third just pulls slightly to 1 o'clock. I still need to work on heavier bullets.
  8. 30-06 boy

    30-06 boy Well-Known Member

    Nov 17, 2005
    i have shot a 300 weatherby in 1000 yard br competition.reloader 22/h4831 is what shot well in my rifle.it was chambered with a standard freebore reamer.i shot a variety of bullets.most were 220/200 smk's.so a freebore chamber can shoot very well if you "find"its nich or sweet spot.
  9. Delta Hunter

    Delta Hunter Well-Known Member

    Feb 18, 2002
    IMR 7828 seems to work the best for me. It works well with just about every 180 gr. bullet I've ever tried. I've also had pretty good luck with RL22.
  10. Varmint Hunter

    Varmint Hunter Well-Known Member

    Dec 26, 2001
    I have owned several older Mark V rifles and have struggled to maintain accuracy in all of them. The foward bedding points and wood stocks are a big issue. At least they were in my rifles. Since you are shooting a factory barrel I have two bits of information that might help.

    I had a well known gunsmith re-bed my Mark V action and float the factory barrel. The gun shot worse. No load combinations would return the accuracy. I eventually sent the rifle back to Weatherby and they insisted on restocking the rifle. They claimed that hogging out wood and floating barrels was inconsistent with attaining accuracy in their rifles.

    The rifle was returned with a new stock and new pressure pads near the foreend. It shot MUCH better for a year or two. Eventually the same accuracy problem returned and I got rid of the rifle. Wood stocks warp, move or whatever over time.

    Weatherby also advised that 95% of the rifles that are returned to the factory for accuracy problems had badly fouled bores and that they only needed a substancial cleaning. Most of the shooters who owned those rifles claimed to have been cleaning the bores regularely, according to Weatherby. IMO before you do any more testing I would strip that bore throughly with Foul Out (or similar) and them follow up with JB Bore Paste. Testing for a complete removal of copper fouling by leaving Barnes CR-10 in the bore for 5-10 minutes is a good idea too.
  11. Rymart

    Rymart Well-Known Member

    Jan 26, 2005
    Thank's everyone for the information. It was exactly what I was looking for. It looks like I should give IMR7828 and RL22 a try (Does anyone know how well these powders perform in the 338 Lapua, my next project?).

    Here is some more background on the rifle:

    I bought the rifle when I was in college. It originally shot 2-3" groups. I left it with my dad to work up some loads for me (before I was equipped to reload myself). He couldn't get it to shoot any better, so as a surprise for me, he had it bedded and free-floated. So there went the factory 1.5" guarantee, at least without replacing the stock. The action and the first inch of the barrel were bedded. This did not help, nor hurt, the rifles accuracy. At one point I backed out the front action screw, inserted some folded business cards between the stock and the barrel, and shot groups while tightening the front action screw. Doing this I was able to get a 3/4" group, but didn't like the upwards pressure on the barrel.

    Since then, on this last ditch effort to get it to shoot, I have done the following:

    Purchased some Weatherby brand brass instead of the Remington brass. Prepped the brass by trimming all the cases to the same length, uniforming the primer pockets, deburring/uniforming the flash holes. Opened up the barrel channel more since the original 'free float' job was poorly done, having left some high spots that may have contacted the barrel during recoil. Tightened the action screws with less torque than before. Thouroughly cleaned the barrel and the chamber with Kroil, various powder and copper solvents, and JB's Bore Paste. Purchased some heavier bullets, since all previous loading and shooting was done with bullets ranging from 150 gr. to 168 gr.

    This last weekend I worked up and shot some loads with the RL19 that I already had on hand and some 180 gr. SPBT SGK's. I tried several loads from 72.5 grains to 78.5 grains (all well below the max listed charge weight). Well Guess what!! ALL the groups were below 1.3"!! Most notable were 0.624" with 77 gr., 0.806" with 76.5 gr., and 0.907" with 78.0 gr.
  12. gator378

    gator378 Member

    Apr 23, 2005
    Fishry, just want to confirm that your final groups with your 300 Weatherby was with a free floated barrel. Good groups. I am thinking of re-bedding and free floating my 300 Weatherby.
  13. Hired Gun

    Hired Gun Well-Known Member

    Apr 21, 2003
    As far as the freebore goes. Forget about it. I have shot many groups from all 4 of my Weatherby's right under 1/2 of an inch. Only the aluminum bed blocked ones need the 65 inch pounds of torque. The wood stocked and regular synthetics only torque up to 40-45 inch pounds. If you are using windage adjustable rings make sure the windage screws are torqued up to 40-45 inch pounds or your groups may wander on a 300Wby.

    Which Mark 5 are you using? Use only in Weatherby brass, for Remington brass back off 3 grains. My sweet spot load is 88.5 grains of IMR-7828 behind a 180 grain Nosler Partition. It usually shoots 1/2 MOA and goes 3300 fps. I seat them at 3.60". This load very closely duplicates the factory round in velocity and the very slight extractor mark. At 88 grains I get no marks of any kind but haven't chronographed yet because my chronograph is at Pact at the moment. At 88 grains the groups opened up just a bit. 180 grain Barnes Triple Shocks shoot well too with the same load. I know the pressures are not too bad as I only neck size with Lee Collet dies and the pockets are still tight and the bolt handle goes down easy after 5 firings on the same brass.

    I pretty much avoid working up loads in my hunting rifles with bullets that are not suitable for hunting with. If you varmint hunt with it like I do, then I would try anything for less than deer sized animals. The target bullets and the Sierra Game Kings are a little fragile for the 300Wby on big game.
  14. Bart B

    Bart B Well-Known Member

    Dec 25, 2005
    Years ago, I used to shoot rifle matches with the guy who worked for Roy Weatherby and designed their first set of rifle stocks. He was much liked by Roy Weatherby and so he was able to get two Mark V actions made without the magazine cutout; solid bottom very stiff actions to make target rifles out of.

    My friend tried to get Roy Weatherby to use shorter throats/freebore/leade (whatever you wanna call it) but Roy said no, he wants to be able to burn as much powder as possible 'cause one can get higher muzzle velocity that way and at the close ranges most people hunt at muzzle velocity is more important than accuracy.

    Anyway, he said that Weatherby rifles like others, need to have thier barrel completely free floated; no bedding pad under it at all. And seating bullets out far enough to touch the lands usually produces best accuracy. However, some folks have shot some 6 to 7 inch many-shot groups at 1000 yards with Sierra 30 caliber 200-gr. match bullets jumping 1/4th inch before engaging the rifling.

    And be sure the cases are sized all the way back to the belt with a full-length sizing die else the step in front of the belt may cause headspacing problems.

    And hard-kickin' rifles like a Mark V .300 Wby. Mag. will probably shoot more accurate for folks if they are slung up in a traditional prone position with a sand bag under the fore end. Shooting such kickers off a bench in the traditional "hold it tight with both hands and squeeze off the round as best you can" method isn't very repeatable as recoil increases. Just be sure there's enough eye relief on the scope before you touch your's off prone or you'll be able to wear the "Weatherby" patch. That's a patch some white hunters in Africa have sometimes given clients when their scope nails them just above the eye brow; it's white with cross hairs with red blood drops on it.