338-378 weatherby load data

[speeders]

My buddy dropped off his 338-378 with me to develop a load. I'm thinking of loading 300 grain bergers. I can't get my hands on a berger manual. Anyone have one and willing to share the data. I was thinking of H1000 or Retumbo.

Alternatively I was thinking of 250 grain accubonds or 250 grain bergers.

Any info would be appreciated.

Thanks

 

[speeders]

Anyone? Anyone willing to share the load Data from the Berger manual for 250 and 300 grain hybrids?

I bought the new Nosler book and have the info for the Accubonds. I just cant find a Berger manual.

thanks.

 

[idaho elk hunter]

All that I have worked on with the factory freebore have digested the Barnes LRH or ttsx whichever you want to call them very accurately. The 265gr does great as well as the new 280 gr. Do not get this confused with the old 285gr. RL 25 so far will give the best accuracy and velocity. I have not used the new RL 33. Waiting for warmer weather to get out to work up loads. MRP-2 was the best until it was discontinued and I can not get its replacement due to the democrats. Use the Winchester Magnum Primer. Not the 215 that everyone states is the best. Load to 3.8 coal and work the rl 25 from 109 gr up until pressure signs. Only go 1 gr at a time 109 is starting within a few grains that you will be ending at. RL 25 is temp sensitive . The new RL33 is not. I hope it can improve upon the 25 but it is going to be hard. let us know how this works for you. It will outpound any 338 edge that all have made famous and is running on the heals of the other wildcats in factory form. If you really want to pump up the power then HEX coat the bullets and bore. The 250 Accubond did ok and I can not wait to try the new 285 a max. All 300 gr bullets seat to deep and the ogive distorts due to powder capacity. Its taken thousands of dollars and hundreds of hours to figure this out. Hope this helps. Yes Bergers shoot like **** out of this caliber as well as Sierras. Why go less than 250 gr is beyond me why people even do this. If you want a 338-06 then buy one.
lightbulb

 

[speeders]

I actually got this beast to shoot really well. 300 grain bergers on top of 101 gr of h1000. I
Have only shot it to 500 yards and .5 moa all the way to 500. Once the weather warms up we are gonna stretch it out.

 

[wby mag]

I run mine with 101.7 grains of h1000 behind the 300 Berger. Or 110 grains of reloader 33

 

[longrangebo]

I havn,t tried either of those powders yet, but mine realy likes h 50 bmg it shoots so good I,am not trying anything else started at 108 and ended up at 112.5 My 338 big baer also like it at 141.5 gr. I went and got 3 8# jugs of it It should out last me HaHaHa

 

[idaho elk hunter]

I am amazed that you and others have good luck with the Bergers in this caliber. I have never had anything shoot with SUBSTANTIAL velocity in this caliber. It goes into compaction in the case and distorts the bullet. RL 25 is the ticket to be fast enough but it ripps the Bergers apart. Nose slump and ogive distortion is the issue. Are you using a true chronograph? Load books are so far off I do not think your getting over 2700 to 2800 on your loads. I built no less than 23 of these and in a 26 in tube they are not reaching the velocity that people think they are. I hope the new Hornady might hold up but I would be willing to bet not. The 250 accubond and Barnes ore the only ones I can get to do the job with velocity.

 

[longrangebo]

I have to agree on the Bergers, when I first got the 338-378 I tried them but they were the first ones out. I gave them to a buddy that has a 338 Laupa, they work good in it. I myself found that the smk,s work great in both guns, the 338-378 at 3080fps and 3250 in the 338 BigBaer! I have changed to the 252 gr. CE in the 338-378 to get more speed 3180 works great I think to get good preformance out of these calibers you have to get over 3100 The CE,s are pricey, but do a great job! Everything is pricey in this game! HaHa

 

[dig]

300 grain Berger OTM, 104.0 grains Retumbo, CCI mag rifle, seated to fit in a Weatherby box/action. 2860 out of a 27 inch tube. Be very careful and work up, in hot weather tends to spike a bit.

 

[idaho elk hunter]

I must admit the OTM is one I have not tried. It does have thicker jackets on it but is not intended for hunting. I for this reason will not use it. I do not know if it would open up at longer ranges. The Hunting bullet I have found has severe problems when pushed to the velocity that the 338-378 can achieve. The 300s that I have ran have gone into the 3100 range, You can do this and the case last 3 loads. The bullet and barrel needs to be hex coated as well as my lands are at a 1 degree 30 entrance. You have to shoot these one at a time like a single shot due to the fact the powder is a compressed charge to the point at a 3.8 coal it will distort the bullet upon pressing into the case. Retumbo is good but there are better powders for velocity. Accuracy depends on the rifle but I have found Rl 25 is hard to beat. RL 33 is great and N570 is ok, All HAVE to be ignited by a WN MAG PRIMER. They are hotter than the famed old 215. Your fps will go up as much as 40 fps. RL 25 loads should be worked up for pressure at the temp that you think you will be using them at, it is not extruded, therefore not temp stable. One could keep it close the 98.6 degrees areas on there bodys and eliminate this issue. Can someone reply with facts and actual pictures of the OTM hunting abilities at close and long ranges. I would like pictures due to the internet has made to many people experts overnight. Pictures are fact not internet talk

 

[dig]

I must admit the OTM is one I have not tried. It does have thicker jackets on it but is not intended for hunting. I for this reason will not use it. I do not know if it would open up at longer ranges. The Hunting bullet I have found has severe problems when pushed to the velocity that the 338-378 can achieve. The 300s that I have ran have gone into the 3100 range, You can do this and the case last 3 loads. The bullet and barrel needs to be hex coated as well as my lands are at a 1 degree 30 entrance. You have to shoot these one at a time like a single shot due to the fact the powder is a compressed charge to the point at a 3.8 coal it will distort the bullet upon pressing into the case. Retumbo is good but there are better powders for velocity. Accuracy depends on the rifle but I have found Rl 25 is hard to beat. RL 33 is great and N570 is ok, All HAVE to be ignited by a WN MAG PRIMER. They are hotter than the famed old 215. Your fps will go up as much as 40 fps. RL 25 loads should be worked up for pressure at the temp that you think you will be using them at, it is not extruded, therefore not temp stable. One could keep it close the 98.6 degrees areas on there bodys and eliminate this issue. Can someone reply with facts and actual pictures of the OTM hunting abilities at close and long ranges. I would like pictures due to the internet has made to many people experts overnight. Pictures are fact not internet talk

3100 is smoking for the caliber, what elevation? I load for a stock Weatherby with 26 inch barrel and custom with a 27 inch tube, never got close to that velocity with H-1000, Retumbo or Reloader. Reloader powders spike big time in heat (I live in the desert). Not fond of single loading cartridges in a hunting rifle, on the bench sure, carrying in the Feild no thanks. Best accuracy/least extreme has been with CCI. Have used Winchesters on older cases for practice on occasion as they seat tighter, work fine, have not chronoed any increase in velocity. I'm getting 8 loads out of brass. Started with the Elite Hunters now they are hard to come by. Will see how the OTMs work on Elk, Mulies and Nilgi this fall.

Longtimelongranger has done a ton of work with the caliber using the now unavailable 870, learned a lot from his posts/messages.

 

[idaho elk hunter]

3100 fps is achievable with a 3 groove r rifling barrel with hex coat on the bullet and barrel. It works better with nitride coating the barrel and hex coat the bullets with the 27 in tube. Again the shells have to be kept in the area that keeps them 98.6 degrees. Free bore has a lot to do with this also. One better have a trued bolt and tight neck. as well as the action be perfectly aligned with the bore of the tube. Only expect 2 to 3 loading out of these loads before the primer pockets go south. Norma brass is EXPENSIVE! 4500 feet in elevation.