Home Forums Reloading Big Game Rifles 300 WBY

Anyone use IMR4955 with 180, 200 & 220 grain bullets in the 300 WBY?

In my experience IMR7977 works better. But whatever....

Thanks MD.

I have good groups and velocity with H1000 and 180 grain Partitions. Good results with RE26 and 200 gr Partitions. (Both ~ 1MOA or less -4 shot groups.) For some reason my 700 does not like 200 grain Accubonds - 4 MOA, best so far -3 shot groups. (My WBY is a 700 Classic). I’ve tried most of the loads in the Gack book. My 700 probably doesn’t have the free-Bore as the WBY barrels. One load in the Gack book got excellent groups but seemed a little too warm in the 700.

I’ve ordered more 200 grain Partitions and have plenty of RE26. But I wanted to explore other possibilities. And I have no idea how you have gotten good groups with the 220 grain Hornady bullets.

I’ll get some IMR7977.

I bought a second 300 WBY. I have not received it yet. Everyone knows that animals a fellow shoots with heavy Partitions in a 300 WBY require sub MOA groups.

A factory 700 will have a SAAMI chamber, so it will have at least the minimum freebore length specified for the 300 Weatherby.

I was under the impression that free bore or distance to the rifling varied by manufacturer.

A manufacturer like Remington will adhere to the SAAMI spec so any in spec factory ammunition may be used safely. Weatherby factory ammo will be too hot in a zero freebore chamber.

Yep. But I didn’t think freebore was part of SAAMI.

Go here:

https://saami.org/wp-content/upload...CFR-Approved-2015-12-14-Posting-Copy.pdf

The max cartridge / minimum chamber drawing is page 116/375 of the pdf document. The min chamber drawing shows the .3084" diameter freebore section.

Ok.

I thought that Weatherby has reduced the free-bore in their rifles from their original design.

Is that true?

If so, which is the standard?

If so, has SAAMI shown the decreased free-Bore?

That drawing shows a 1 degree 2 minute slope, I didn’t see a maximum length of the straight portion? I guess that’s the rifled bore and the length of the free bore is dependent on the slope and the two end diameters.

Bugger,

Care to share the details of the 200 Partition/RL26 load?

I've run 150's to 208's in a Sako 300 Bee, all right at or sub 1 MOA with using either RL-22 and RL-25 for five shots (when I didn't mind the recoil). The powder could have been I4350 or H870.

Like you stated on sub MOA, (a bit facetiously), your RL-26 loads are probably doing just fine and if you need to try five different powders you're probably not going to find a one-holer but once in 500 tries....and it won't be repeated in a factory rifle or with a human shoulder behind it.

I once had A 7 shot group from a factory 338 that measured .765. I quit at seven because I knew I'd jack it up. It used Sierra 215's at 2,985 fps.. It shot so good I pretty much wound up shooting game with 250 Partitions and PT Golds and 230 FailSafes.........

78.2 grains RE 26, 215 primers, 3.69” LOA, 200 grain new Partitions.

.95” 4 shot group, round in shape.



PS: I have on hand 3 different styles of 180 grain Partitions. I suspect that the 200 grain bullets went through the same “improvements”.

Also
83 grain H1000, 215 primers, 180 grain new Partitions .8” group - horizontal dispersion - no measurable verticals dispersion.

MD

Just curious, your chapter in the 300 WBY in Gack. You stated, I believe, that you had three 300 WBY’s.
I think you had a very early WBY built on a Mauser action, correct?
Which rifle(s) did you use for your loads? Did you notice a difference in “free bore length” with your rifles?

Thanks.

PS: The 200 grain Partition is likely the bullet I’ll be using for the same reasons you stated in that chapter.

Thank you.

Have you had a chance to run those over a chronograph?

Bugger,

Yes, I owned a mid-1950's Weatherby, one of the first "production" rifles based on the FN 98 action. Its throat was very similar to those in the later .300 Weatherbys I owned.

There's no reason for Weatherby to change the originally developed "freebore," and as somebody else has already mentioned, a good reason not to. It's been standardized for a long time.

My most accurate load I tried in my 338’s was with 250 grain Partitions and H4831/H4831sc, that was my go-to elk rifle/load. My last 338 - a classic model 70 seemed to kick harder than the others (age had nothing to do with it!!!🙄) and I thought that I could get by, by going smaller. Now I’m wringing our my 300 Win Mag and 300 WBY’s - all Remington 700’s.

Pure and simple, a 300 WBY will push a 180 grain NBT or Accubond at 3200 FPS with 7828 powder and kill anything you point it at. 7828 is a great powder for accuracy and velocity, forget anything else you hear about what works best as nothing will work better...

Nyrifleman

As I recall both loads were close to 3,000 fps

I've used MRP/RL22 since day one back in the 80s, because the old Weatherby Guide had a reloading section in the back with a "factory equivalent load" and that is what I use. 80.5gr, F-215s gave be right at 3200 and half MOA. I also had good luck with 7828, but my mainstay remains the former. Over 17 head of African game, one elk, black bear, LOTS of hogs. I used 180 Partitions way back when but have since switched to TTSXs 180s.

Here you go. 3280 ft per second 180 gr accubond. Please disregard the fouling shot. 82 gr 7828.