In my never ending quest to find my next rifle, I started thinking. (Scary, I know.) I'm sure this has been done, but can't find much on it. Has anyone necked a 300 WM (not the wsm or rum) up to a 338. How would it compare to the 338WM? Would it be worth doing? Mainly used for deer and elk. Or would you be better off sticking with the 300?
338-300??
- Thread starter Jumpalot
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JCM
Member
Jumpalot,
I dont think you would gain much by necking up the 300 win mag to 338, possibly 150fps or so more than the 338 win mag depending on barrel length. IMO the 338 RUM would do the same job without the case forming jobs.
I dont think you would gain much by necking up the 300 win mag to 338, possibly 150fps or so more than the 338 win mag depending on barrel length. IMO the 338 RUM would do the same job without the case forming jobs.
JCM
Member
What ranges do you plan to shoot elk and deer at?
Trooper21986
Well-Known Member
I am just now starting to do load development in a 338-300 improved . Went to the range today and with a 25-1/2 inch barrel am reaching 3072 with a 230. Still no pressure signs and using a slow for caliber powder , 4831. I will pass the Lapua , no doubt . Can't wait to see what the heavier bullets do.
If you just want some extra performance I'd say there are better/easier options available. Wildcats always bring the challenge of using custom reamers and having dies made (which may be enjoyable to some). But just to get another 100 fps I would personally grab a 340 Weatherby and hit the range. 200 fps? The 338 RUM is ready and waiting. I think there's a reason the 338-300 WM has not gained as much popularity as other wildcats such as the 338 edge and 7mm-300 WM. In order to realize the full potential of a 338-300 you need to seat the bullets long. Which thing you can also do with a 338 WM and gain some performance. And with other readily available cartridges in that performance range there's just not a huge demand. By going with a 340 Wby or 338 RUM you don't need a different bolt face or anything. Maybe an extended box for the 340 is all. If you plan on single feeding anyway I'd be interested to see what the 340 would do when using a custom throat and seating the bullets long.
jumpalot
I noticed your post right-a-way because of the combo of the two rounds.. The only
main difference in yours and what I have planned for mine is... I want to go the other way around 338 down to a 300??? Making a 338 x 300, to start with H4350 and start with 70 grains and work up on a tree with the custom throat and seating the bullets long.. with the Hornady ELD Match .308, (30 CAL) the 208 gr. ELD Match bullet.. I have used the Hornady products for a long time and very rarely use anything else.
I want to work up a good group at 400 to 500 yards and the tweek it some..
Your (or any ones) thoughts
Knapper
I noticed your post right-a-way because of the combo of the two rounds.. The only
main difference in yours and what I have planned for mine is... I want to go the other way around 338 down to a 300??? Making a 338 x 300, to start with H4350 and start with 70 grains and work up on a tree with the custom throat and seating the bullets long.. with the Hornady ELD Match .308, (30 CAL) the 208 gr. ELD Match bullet.. I have used the Hornady products for a long time and very rarely use anything else.
I want to work up a good group at 400 to 500 yards and the tweek it some..
Your (or any ones) thoughts
Knapper
Trooper21986
Well-Known Member
Knapper
If I'm reading this correctly, your building a 30 Cal with necked down 338 ? If so that's the original 308 Norma . I had one built on a 03a3 and it was great ! Shot 185 Berger's ( just because I had them ) past 3000fps ! I think a 200 eldx or eld match would shine in that cartridge !
If I'm reading this correctly, your building a 30 Cal with necked down 338 ? If so that's the original 308 Norma . I had one built on a 03a3 and it was great ! Shot 185 Berger's ( just because I had them ) past 3000fps ! I think a 200 eldx or eld match would shine in that cartridge !
JCM In reply to your post..I read yours and jumpalot's with great interest, but i want to go the opposite direction, Start with the 338 Caliber and neck down to the 300 Cal.
I now have a 300 Win Mag, necked down to a 7 MM that I REALLY enjoy shooting in
competition.. I don't know which 338 would be best?? ( dislike weatherby) but I am open to most any of the the others???? Your thoughts knapper
