338-378 Weatherby Questions

[bearpaw]

All my other dies are rcbs and seem to have been pretty accurate, but I want fairly good performance from this gun, not sure if there would be a difference or not between loads from rcbs or redding?

[yorketransport]

I like the hornady dies. You can get a replacement micrometer adjustment for the seater die too if you wanted one. The micrometer is only a couple bucks and just screws on to the regular seating did.

[Magnum_Willys]

I got the Redding Deluxe Neck Die and Seater Die ($100) and ordered the $35 VLD micrometer for the seating die.   It doesn't have the interior sliding tube like the Competition Dies.  (Have those for my Lapua but $$$$)  Not sure it matters we will see.  Just started developing loads for it today:

338-378 Accumark, 26" Barrel w brake, 300 Grain Berger Elite Hunter - 3.880 COAL  (EDITED said 3.800)
RL33
106gr - 2588
110gr - 2669
112gr - 2773
114gr - 2823 @3.880    ( 2885 @ 3.800 )
116.5 - 2934

No pressure signs yet, will get to 3000 and then go back and search for accuracy.

Update - Gotta drop to 3.800 for proper magazine operation ( mag 3.86 but extractor without touchup is 3.800)

I don't think I'm going any higher than 114gr at 3.800 COAL with RL33 - not enough room with Bergers:
112 GR = 100% full
114 Gr = 102% 
116.5 = 104%  ( I don't like this much compression )

Going to Try SMK's which look better based on Yorke's terminal performance test.   Can get almost 3 more grains in case with SMK'S vs Bergers due to COAL limit. 

Update:
COAL 3.80 , RL33
300 Gr. SMK'S

114gr - 2870   
115gr - 2929      ( Too Hot !  slight ejector mark, slight stiff bolt )  100% full

Accuracy test next 112 to 114 grains with both SMK & Berger

[bearpaw]

Magnum_Willys that's really great info, thanks so much for posting, anxious to hear more about your dies. 

How's the recoil been so far, I haven't mounted a scope or shot my rifle yet, still trying to decide on scope and rings to use?

Yorke I'll check into the Hornady dies, do you think the loaded rounds will be much more accurate than RCBS loaded ammo? I've had good luck with RCBS so trying to determine whether to get something different or not?

I want to shoot a 300 grain bullet, has anyone been able to compare performance on game between the limited choices of bullets?

[Magnum_Willys]

Mine has the factory break so with 225 grain factory loads it kicks quite a bit less than my unbraked 300 wm or 338 wm .  At max load with the 300 grain it is going to be almost as much as the unbraked 300 or 338 with synthetic stocks.    My buddy shoots his unbraked with factory 225 grains and says it not bad.  I haven't tried it.  I've heard 300 grains without a brake are not good. 

[idaho guy]

I have always used the rcbs dies on my 30-378(same case) and have never felt like I needed anything else the results have been great

[bearpaw]

Mine has the factory break so with 225 grain factory loads it kicks quite a bit less than my unbraked 300 wm or 338 wm .  At max load with the 300 grain it is going to be almost as much as the unbraked 300 or 338 with synthetic stocks.    My buddy shoots his unbraked with factory 225 grains and says it not bad.  I haven't tried it.  I've heard 300 grains without a brake are not good.

I have numerous magnum guns and none have a break, my 340 wtby didn't have a break and was just fine. I hate breaks, however, I too have heard the 300 gr bullets are brutal, not sure if I'm man enough try the 300's without the break? 

[yorketransport]

Yorke I'll check into the Hornady dies, do you think the loaded rounds will be much more accurate than RCBS loaded ammo? I've had good luck with RCBS so trying to determine whether to get something different or not?

I want to shoot a 300 grain bullet, has anyone been able to compare performance on game between the limited choices of bullets?

I like the Hornady dies better because of the elliptical expander on the sizing die and the floating "sleeve" on the seating dies. I don't know that the load more accurate ammo but I do think that they're an improvement over the RCBS dies, especially the bullet alignment on the hornady seating die.

I tested the 300gr SMK in my bullet trap and it performed great. I tried the 300gr OTM and 300gr Scenars but they didn't do well at low velocity; I'll try them again going a little faster. The 304gr Hammer bullets would be worth looking at too but they may not stabilize in your 1:10" twist barrel. I'll double check the length and see if they're too long or not.

[mountainman]

Mine has the factory break so with 225 grain factory loads it kicks quite a bit less than my unbraked 300 wm or 338 wm .  At max load with the 300 grain it is going to be almost as much as the unbraked 300 or 338 with synthetic stocks.    My buddy shoots his unbraked with factory 225 grains and says it not bad.  I haven't tried it.  I've heard 300 grains without a brake are not good.

I have numerous magnum guns and none have a break, my 340 wtby didn't have a break and was just fine. I hate breaks, however, I too have heard the 300 gr bullets are brutal, not sure if I'm man enough try the 300's without the break? 

Bet you'll be just fine👍
Just keep sessions to tolerable round counts. Hate breaks on hunting rifles also..

[bearpaw]

Yorke I'll check into the Hornady dies, do you think the loaded rounds will be much more accurate than RCBS loaded ammo? I've had good luck with RCBS so trying to determine whether to get something different or not?

I want to shoot a 300 grain bullet, has anyone been able to compare performance on game between the limited choices of bullets?

I like the Hornady dies better because of the elliptical expander on the sizing die and the floating "sleeve" on the seating dies. I don't know that the load more accurate ammo but I do think that they're an improvement over the RCBS dies, especially the bullet alignment on the hornady seating die.

I tested the 300gr SMK in my bullet trap and it performed great. I tried the 300gr OTM and 300gr Scenars but they didn't do well at low velocity; I'll try them again going a little faster. The 304gr Hammer bullets would be worth looking at too but they may not stabilize in your 1:10" twist barrel. I'll double check the length and see if they're too long or not.

Did the 300 SMK's expand good?

[yorketransport]

Did the 300 SMK's expand good?

The 300gr SMK  did great. I shot the 300gr Berger Hybrid, 300gr Scenar and the 300 SMK from the same gun, with the same load, at the same velocity and at the same range and this is what I got.




These were all impacts velocities of about 1760 fps.

[Magnum_Willys]

SMK's have .088 less jump to the lands compared to bergers.  Not sure it matters in the Weatherby.  Seems to give the Berger another 50fps maybe velocity potential.   I'm hoping SMK's at 2850 are accurate in this rifle  - hope to test a batch next week.  Hard to Ignore Yorke's results !

[mountainman]

Seemed to work good on the 1 elk, 2 bears (1 coastal, one black) since they all didn't move at the shot..

[bearpaw]

great info, i've had good performance with other sierra bullets, i'll have to order some 

i wonder if they will hold together at higher velocities/close range shots?

[Magnum_Willys]

Got a chance to shoot some more 300 gr SMK's today.  113 gr. RL 33 at an average of 2860 seemed to group the best ( was my starting load today) and only 22 fps max spread, 7fps average.  3.800 coal .   At  114 was starting to show a lil ejector mark and groups spread.  Not tack driving yet by any means need to keep playing with it.  Was hoping for something stable in the 2900's but didn't see it.   Have some more loads ready for next week.  So far it doesn't shoot the 300 gr smk nearly as well as the barnes 225 but we will see.   
Did wake the guys at the range up tho !