I'm building a .30 caliber magnum on a pre-64 or pre-war mod 70. I'm down to either using the pre war and .300 Win mag or the pre-64 (already magnum length) for the .30-8mm/.30 STW. From what I've seen, the .30-8mm has RUM velocities with 20gr or so less powder. Yet is it worth the extra few fps above a .300 Win?

Anyone have experience with the big .30 and how does it rate against the .300 Win.

P.S. I'm not interested in a .300 Wby or a .300 Dakota.

If you already know this, please forgive me for pointing out the obvious. What you're contemplating is, for all purposes, a 300 Weatherby. Minor differences in shoulder angle that mean nothing, and a difference from the standard Weatherby freebore notwithstanding, it's the same case. It might be easier to have the rifle chambered with a short-throated 300Wby reamer. That way you can use factory brass without the minor hassles of necking up/down to 30 cal.

[ 12-20-2002, 02:30: Message edited by: RickF ]

300 hh ackley improved
300 weatherby

same thing
jeffe

Frank C,

Do a search on this forum for 30-8mm, and you can look at some of the answers I received for the same question a couple of months ago.

The man who runs AR, Saeed, did some testing with a 30-8mm for long range target work and the data is posted in the Reloading Pages of the this site. I asked him what his opinion of the cartrigde was and he felt inorder to make a justifiable gain in velocity over the standard 300 mags you need a larger case, such as the 30-404 or 300 Ultra.

Good luck with your project, if you build a 30-8mm, please post your results here on AR. I know I am not the only one who has looked at this wildcat.

Saludos...Frank

I've built two and have kept one. One was a 30" heavy barrel,the other a #5 fluted and 26" long. I kept the shorter one. Both on Rem 700's and both twisted 1-10".

I think it is a fabulous cartridge and it is my favorite 30 and I've done quite a few of 'em(300Winny,300Wby,300H&H and 30-378Wby).

It is a definate upgrade in Ooomph over the Winny,brass is a snap to make too. 165XLC's are my favorite in it,for everything.

Mine isn't a light rifle,I designed it to be superbly accurate and that it is. I've other tools,for long trekks. The added weight does a nice job of soaking up some felt recoil and it is rather soft shooting.

It rides in a heavy fill McMillan Classic patterned stock in Urban camo,with a Decelerator. I poked a Leupie 3.5-10x 40mm on it,in DD's and Burris Posilign rings. As mentioned,I favor the 165gr XLC and this barrel likes them at 3475fps,for best accuracy(courtesy of Re-19 in R/P 8mmmag brass).

Pretty good medicine...............

All else being equal it will give the same performance as the 300 WBY. A solid 100 fps above the 300 Win Mag. There's nothing wrong with that. A nice round. But the RUM will add another 150 fps or so to that.

How big do you want to go? How tough is your shoulder?

I think the trouble with exceeding available H&H capacities,in that bore diameter,is longer barrels start to become damn near required.

Make mine 26" and punched Super............

I think that the 8mm Remington necked to .308 is available as a semi-propietary cartridge from Kenny Jarret known as the .300 Jarret. I don't think that the shoulder or neck has been altered in his round, but I'm not certain.

With all due respect, I feel this cartridge is significantly different from the .300 Weatherby, at least from the perspective of handloading it. It is without the Weatherby freebore, of course, and a non-freebored chamber is generally more conducive to good accuracy (after all, how many bench guns do you find with freebored chambers?). Also, the conventional 25 degree shoulder is easier to load for and headspace accurately off of than the Weatherby radiused shoulder.

Velocities from this cartridge will be slightly less but so similar to the RUM and larger cases as to be insignificantly different. It will provide the advantage of allowing one more round in the magazine than the fatter cases. I can't really see enough advantage in any of the super-.30's to go to the trouble and expense of replacing my .300 Winchester, but if I did it would be with the .30/8mmMag-.300STW-.300 Jarret, or whatever you wish to call it.

P.S. to Frank on the Model 70 action: I feel that the .300 Winchester is crowded in a standard length action, and you will have to have a "magnum" length action if you want to use any of the longer cartridges, anyway. The old factory Model 70 actions were given a longer magazine box by cutting into the feed ramp behind the lower (right hand) locking lug recess. This leaves very little metal supporting that locking lug. Many gunsmiths doing a custom lengthening of a Model 70 box lengthen to the rear rather than cutting away important metal from the locking lug support. My advice would be to acquire a standard length action and have your gunsmith lengthen to the rear instead of using an original long action. The standard action will cost you alot less than the "long" action and you will end up with a stronger gun, in my opinion. Good luck with your project!

[ 12-20-2002, 20:29: Message edited by: Stonecreek ]

The 300 Jarrett is a an improved version with a 35-degree shoulder and less body taper. It is a very good round. I helped develope it years ago when I was at Jarrett's and I build quite a few of them. Despite what anyone says, the .30-8mm, the .300 Wthby, and the .300 Jarrett are about as efficient as you can get in a sporter length (26") barrel. The .300 RUM doesn't add enough velocity for the amount of extra poder to justify it's existence.Now with a 30" barrel it is a slightly different story.

Jon A - That is comparing the .300 Win to the .300 Ultra. Not the .300 Wthby or the .300 Jarrett. I can promise you that on average, you won't see 50fps difference in the .300 Jarrett and the .300 RUM. And the RUM uses over 10 grains more powder to do that. That is over 10% more powder for @ 1.5 % increase in velocity. And a corresponding increase in blast and recoil for no real world performance increase. The figures aren't opinion but facts and thay don't add up favoribly for the RUM.
If you have one and you're happy with it, great. Keep it and enjoy it. But if someone is asking for the facts, I'm gonna tell them so they can make up their own mind based on the truth, not advertising rhetoric.
And before your think I'm just down on the RUM, I have a .30-378 on a Ruger #1 with 28" barrel. It uses even more powder than the RUM and is even less efficient and makes no sense whatsoever. I just wanted to play with it. So, go enjoy your RUM and please don't be personally offended by anything I say, I'm just trying to give the best advice I can based on 21 yrs. of building hunting rifles. Oh, and yes, it is my opinion.

My 30" barreled 300Super(30-8mmRemmag)would out run my 26" barreled 30-378Wby with 180's.

In my opinion when constructing a Big30,the focal point should be accuracy. With it,everything else falls nicely into place. Another reason I favor the 30-8mmRemmag,is that it just excells at demonstrating fantastic accuracy potential. Both of them shot better than my pair of 7STW's and that isn't because the 7's shot poorly,just that the 30cal version was even better.

I think the 300Ultra case,with .350" of length removed from it's body(to yield a 2.500" case),would make a "perfect" Big30. The capacity would be there to make good things happen in a 26" tube and the abbreviated length would allow more latitude in throating geometry,while still staying within the confines of the 700's mag box. Especially for those wanting to play the fast-twist,high BC,VLD game.

Letting the belt go(as compared to the H&H Clan)wouldn't hurt my feelings either. It would sorta mimic Dakota's offering,but do so with more mainstream brass and no boltface mods.

No flies on the 338Ultra either,as issued.............

John Lewis is right. My 300 Jarrett (built on Weatherby mark V, 26" #5 barrel)with 200 Noslers and 76 grain MRP gives about 3050 ft/s. And groups about 0.3 MOA whenever I do my part. I use 200 Sierra Matchking with same load, clocked over 3030 ft/s, with same result, same point of impact at distances closer than 250 meters.
Enough for "controverse" Mark V actions, and "obsolete" belted cases.

I had just about got the 30-8mm out of out of my system and was going to rebarrel a 700 to 300 Win Mag or 338 Win Mag for a dedicated elk rifle. But insanity is rearing it's ulgy head again. I do not know if I should cuss you guys or thank you.

Saludos...Frank

John,

I agree that there is a point of diminishing returns in efficiency (but not as bad as most people think) and where you draw the line is up to whatever makes you happy. Some feel that any case bigger than the 30-06 is a complete waste of powder. That's fine for them if it makes them happy but it would bore the hell out of me!

I do question that 50 fps remark, however. Are you saying 2900-2925 fps is possible from a 300 Jarrett with 240's from a 26" barrel? What's the case capacity in grains of water for that round, anyway?

Mikefromyu, that's a nice load but it is a good 150-200 fps behind what the RUM can do.

i may not have the experience a lot of folks here due, but i am on the 3rd barrel in this cartridge, 300 stw. current barrel is 26" walther stainless by brockmans and it will shoot way under in inch at 100 yds. favorite load is 180 scirrocco,reloader 25 and 3240 fps. have taken several elk and a few deer with this. also i shot the first barrel out in 1200 rounds of 190 hornady boattails and aa8700 for 3260 fps in a shilen barrel. at 1200 rounds velocity was down 100 fps and bore scope revealed severe fire cracking and very ugly throat,this a very good cartridge IMO , especially with a long magazine box in a 700 remington.feeds good and no free bore, thats what sold it to me.

John A,

I saw a nice load in Saed's Reloading Pages (one of them is 94 g. H1000, 200 Sierra MK, 3277 ft/s), but there is 18 grain more powder, increased recoil, shorter barrel life and I'm almost certain much higher pressure. I tried 80 gr. MRP in my Jarrett and got over 3220 ft/s, same bullet,0.4 MOA accuracy, but could use cases only twice. I would like to say, there are many variables that have to be considered in order to compare all these things properly. I do agree, all these experiments make our shooting world much more interesting.

I agree experimenting is where the fun is for me. Also comparing different rifles, etc doesn't make for a controlled experiment. I guess my case is probably the exception to the rule since I was using the same rifle with the same barrel for both rounds.

Saeed's data is interesting. He got over 3300 but accuracy wasn't as good as the load you cited--however it was better than the load that only got 3193. I guess the load you mentioned was the "sweet spot" for that rifle.

I'm going to give the new 200 AccuBonds a try this year and see how they do. I'm hoping somewhere in the 3250 range will be achievable with decent pressures and accuracy using Retumbo. I think the burning rate of Retumbo is better suited to this case with that bullet than H1000 so it should keep the pressures lower for the same velocity. There's only one way to find out....

JonA - I've never tried the 240s in a .300 Jarrett, and probably never will. I've always felt that if you want to go over 200 grains, go to a .338. However, if you are going to shoot 240s in a .30, the 300 RUM will probably work well, the extra case capacity will make a difference then. My point, is that for the most commonly used bullets, 165 -200 grains, the difference between the 300 Jarrett and the 300 Ultra is not very much in a 26" barrel.
I recently did a 300 RUM for a customer with a 30". With 180 Ballistic Tips, he was getting 3600fps and sub-1/2" groups at 300 yds. I was impressed. That is probably 150 fps faster than a 300 Jarrett with a 30" tube.
You just won't start seeing any major difference in the two cartridges until you get a longer barrel in the mix. And, imho, 26" is as long as is practical for a sporter.

John Lewis: Thanks for correcting me on the shoulder of the .300 Jarrett. And you were kind not to mention that I had misspelled "Jarrett". My apologies to Mr. Kenny.

I think that you are absolutely right that the 8mm Remington case represents as much capacity as you can practically use in a .30 caliber sporter limited to a 26" barrel. I'm certain that I would rather have one extra round in the magazine than to push the bullet another 50 fps faster.

Dang John, I hope your friend doesn't want to eat anything he shoots with that load!

Stonecreek, I hear that a lot so I'm just asking (I really don't know)--just what brand/model rifles hold more standard mags in the magazine than the fatter ones? My A-Bolt held 3 Win Mags now it holds 3 RUMs. It looks like both the Rem 700 and Win Model 70 will hold 3 of either. It seems the only time you can get more is with a 30-06 sized case. To which models does this apply?

Big Stick,

The 300 RUM case cut to 2.500" does exist, it's the 300 Dakota. Probably the ultimate 30 cal. mag round. I have toyed with the thought of the Dakota round but the brass and factory ammo is just to expensive given the other 30 cal. rounds out there. If 3100fps. with a 180gr. 30cal. bullet won't get the job done, more speed isn't the answer, you need to move up in caliber.
Elk Country

How does the recoil of a 30-8mm or 300 Jarrett compare to a .338 WinMag.?

Daryl

Anyone try or shoot the 7.82 Warbird from Lazzeroni? I am toying with the idea of a Sako in this chambering. As far as moving up to the .338, why? A .308 with 240's will have significantly better SD than the .338 with 250's which theoretically mean deeper penetration, you have to go to a 300gr .338 to surpass these figures, and a 300gr in a .338Wm is not the flat shooter it is with a 250. Not really bashing the .338, just don't see it as being the "hammer of thor" some folks do.