Belted Magnums

[Kachok]

"My _____belted magnum isn't very accurate."

Translation

"I cannot tolerate the recoil and flinch terribly when I shoot my magnum."

No I have shot belted magnums for years, and my Model 70 7mm Rem Mag just would not shoot for $#!^ but that was not the fault of the caliber but the rifle, and yes my other hunters tried to shoot it as well it never would group any better then 8" at 50 yards no matter what we tried. I could drive tacks with my Rem 700 7mm RM and my Savage 270 WSM so defiantly not a recoil issue.

 

[Slamfire]

I remember seeing the picture of shooter and his target which set the 1000 yard long range record, and the cartridge was a 300 Win Mag.

However, I think the belted magnum cases are a very poor design.

It is questionable whether the belt really adds any strength to the case, as there will always be some non belted sidewall, hanging out of the chamber.

The edge of the chamber that transitions between the sidewall and the belt has a sharp edge and I am of the opinion that it would increase sidewall stresses in an overpressure event, making case rupture more likely at that location.

Because base to shoulder length is not controlled, rounds fired in one chamber may stretch something awful when fired in another chamber cut with a different reamer. Or it may be a crunch fit. Bring your hammer.

The only controlled dimension is the belt headspace. The shoulder headspace on these things vary wildly. And that will contribute to short case life. You have to buy special gages to properly measure how much you are setting the shoulder back each time you size. Even so, the first firing may stretch the case so much that you may only get a couple of reloads out of the thing even if you use gages to set up your dies.

And then I have experienced rim lock in my 375 H&H. Several times. The recoil was enough to shuffle the cartridges in the magazine and the belt on the top magazine locked with the rim of the cartridge below it. I had to retract the bolt, push on the cartridge stack to clear the jam.

For that reason particularly, I would not use a belted cartridge against hazardous game. They might eat me before I got a second round off.

Something like the 416 Rigby, no belt, no rim, that is a good design.

 

[Jdillon]

The difference in headspace in some of the 300 Mag I have loaded between new and fire formed brass is approximately .015 which is a significant amount. Once fired, I will neck size to the point where I need to resize then bump the shoulder approx. .002 which allow the case to space off the shoulder. There is an excellent chapter in the book Precision Shooting Reloading Guide that deals with belted magnums. The biggest problem causing shortened case life is over sizing the brass. This is no different than adjusting proper headspace in non-belted cases. The difference in my 300 WSM between new and fire formed cases is approx. .007 using Norma brass and there is a significant difference in accuracy between new brass and fire formed cases. Obviously, brass sized in this manner should only be fired through that particular rifle.

 

[Loosedhorse]

However, I think the belted magnum cases are a very poor design.

It is questionable whether the belt really adds any strength to the case,

There's about 100 years worth of agreement on its being a good design.

As stated above, its purpose is bolt-action, magazine-fed rifles for dangerous game. The idea of the taper, narrow shoulder and belt was to allow the bolt to close and the rifle to go bang even if the chamber and round were not ideally clean. The belt was for proper headspacing, not strength.

One can argue whether that's really needed; the .375 Ruger, for example, is developing a good reputation, even on dangerous game, despite no belt. And, as you mention, the .416 Rigby has a great reputation.

And then I have experienced rim lock in my 375 H&H. Several times. The recoil was enough to shuffle the cartridges in the magazine and the belt on the top magazine locked with the rim of the cartridge below it.

This to me sounds more like a problem of magazine-length/cartridge-lenth mismatch rather than of cartridge design. I'd expect a possible problem with rim-belt lock if I'm firing, for example, .458 WM from a .458 Lott magazine; but it shouldn't happen from a .458 WM magazine.

They might eat me before I got a second round off.

Might happen anyway--make that first shot count!

 

[Slamfire]

This to me sounds more like a problem of magazine-length/cartridge-lenth mismatch rather than of cartridge design.

That is one way to look at it. However with no belt, I don't have to worry about magazine length-cartridge length issues with rimless cartridges.

I also have had rim lock with Nagants even though that mechanism has an interrupter that holds the next cartridge in the stack down, to avoid rim lock. Sometimes you get tolerance stackup on things with fins and rims and they interfere with each other.

Belted cartridges are another example of advertizing induced behavior.

 

[ladytrapper44]

Belted Magnum

Thats just not true the guy who said that the belted mags aren't accurate needs his glasses Rx refilled my hubby swears by his & he shoots his a lot

 

[Art Eatman]

Whee! My post-64 Model 70 in .264 Maggie was sub-MOA from the git-go. It was definitely a fun-gun, but it was a bunch more gun than I needed for hunting CenTex deer. Had I been in bigger-critter country I'd likely still have it.

At one time the 7mm RemMag held the record for 1,000-yard competition. It took lots of R&D to beat it out...

 

[BADUNAME37]

I had a new Model 70 338 Win Magnum with Leupold Vari-X-III which I had glass bedded myself and had trigger work done by a gunsmith.

I worked up 210g Nosler Partition bullets to an extremely accurate load. At 100 yards, I was putting the bullets nearly in the same hole, every shot (off a solid bench).

To say that belted magnums are in some way not accurate is not an accurate statement to make.

If the person stating that has had problems with belted magnums, that does not mean that every one out there is a poor-shooter.

 

[Zak Smith]

Between a couple buddies and I we've shot out two 7mm RM barrels and one .300 WM barrel in long-range competition and accuracy was excellent until the barrels were toast. By excellent I mean approx 0.5 MOA or better. These were AI rifles.

 

[hardluk1]

US F-Class shooting team's choice of caliber ??? 7mm rem mag
http://usfclass.com/

 

[Slamfire]

US F-Class shooting team's choice of caliber ??? 7mm rem mag

We will see how they do with them. Without a doubt they are looking at Bergers and the highest velocity they can get in 7mm.

I met Mo Defina once at a Long Range match at Camp Perry, Mo is a wealth of shooting history. He mentioned the year someone won Long Range with a 7mm Remington Magnum, and "it set shooting back for several years". I don't know the specifics but the 7mm Rem Mag has not won as many Long Range matches as the 300 Win Mag, at least that is my memory.

If the teams makes a clean sweep this year, and I wish them the best of luck, then 7mm Rem Mag is going to be popular for a while.

 

[highlander 5]

IIRC didn't the 300 H&H cartridge win a boat load of matches back in the 20s or 30s..
The only 2 cartridges that need a belt are the 300 and 375 H&H as they don't have much of a shoulder. All the modern belted rounds don't need them but they do look pretty on them though. There's also the 8X68 magnum and that has no belt either.
My .02 cents most of the modern magnums burn huge amounts of powder for a relatively small ballistic gain over standard rifle cartridges. I was a magnum fan and decided to go to non magnum to save my shoulder and keep more money in my pocket for reloading supplies.

 

[Loosedhorse]

Under the "don't have much of a shoulder" label, you may want to include .400 H&H, .416 RM, .450 Marlin, .458 WM, .458 Lott, and .470 Capstick; maybe others.

 

[Slamfire]

IIRC didn't the 300 H&H cartridge win a boat load of matches back in the 20s or 30s..

I don't know about a boat load, but there is one that was won, and it was by Ben Comfort. Might have been about 1937.

The gunwriter Charles Askins used to periodically claim the 30-06 was obsolete, basically to rile up the readership, a sort of “Gorgeous George” technique, he would claim that the 30-06 was obsolete as a target round since Ben Comfort won the 1000 yard match with a 300H&H.

This of course was horse hockey, just designed to get attention for Charles Askins.

I don’t know how many long range matches the 300 H&H won, but I remember reading the 30-06 still had the most long range championships.

There were real advantages to using the 30-06, you got free match ammunition from the DCM at matches, you got to shoot your across the course rifle at long range, the recoil was less, the expense was less.

The 300 H&H was only in the more expensive M70, the brass was hideously expensive, you had to roll your own, and according to a grey beard who was there, case life was not that good. The advantage of the 300 H&H was 200 fps more velocity, which is good, but that improvement is almost insignificant compared to going from a 0.473 ballistic coefficient bullet to a 0.674 http://www.bergerbullets.com/Products/Target Bullets.html, which is obviously why the F Class team is trying 7mm’s.

I am certain a number of long range events were won with 300 H&H’s, but once something like the 300 Win Mag came out, which pushed bullets even faster, the 300 H&H faded from long range competition target line.

A 300 H&H pre 64 M70 target rifle is a real collector's item.

 

[snakeman]

My weatherby 257 shoots a half inch group.

 

[H&Hhunter]

Belts and short necks have evoked urban legends about accuracy issues. They are myths and nothing more. The belt is an outdated design, no doubt about it. But it doesn't negatively affect accuracy.

 

[MachIVshooter]

Belts and short necks have evoked urban legends about accuracy issues.

Short case necks in and of themselves don't hinder accuracy, but the inability to play with freebore much does. That, and often a short case neck is the result of shoehorning a cartridge into a shorter action, which also makes it nigh impossible to use long, high BC bullets, and this leads to a reputation for being less accurate. Doesn't mean they can't be in the right rifle, just that most rifles so-chambered cannot realize that potential.

 

[hardluk1]

slamfire1 Today if you want to win you would be better with one of the short pudgy 6.5mm cartidges. Get 3000 fps out of it with a high SD and they do better than the 7mm and 30's today out to a 1000 yards.

 

[Clark]

Wimpy loads will work ok reloading for more than one rifle with belted magnum, but any hot loads will expand the case in front of the belt.

So one can either 1) keep buying brass, 2) buy Larry Willis's collet belted magnum die, or 3) segregate the brass to a particular rifle.

Here is a 1908 Brazilian Mauser that were $125 from Century in 2009.
I put on a $33 Rem700 take off barrel from Ebay [back when they sold barrels].

The 7mm Rem Mag reamer wobbled .005" all the way, as I forgot to deburr after parting off the Rem700 threads.

The rifle is ugly and poorly put together by me.

I shot 2 groups with it, here is one and a pic of the $158 belted magnum project. That is a 0.75" 3 shot group at 100 yards with 162 gr SST blems at around 2900 fps.

 

[Samclrk]

``CLARK``,,Quote``
Wimpy loads will work ok reloading for more than one rifle with belted magnum, but any hot loads will expand the case in front of the belt.```

Have you ever saw a case that DID`NT expand the case in front of the belt.???????Wheather belted or not??Maybe you need to get a better reamer..Have you ever fired or even saw a belted magnum??

 

[MtnCreek]

Samclrk,
Do a search on Clark's posts. He is the World’s Most Interesting Reloader. On days where I’m feeling particularly smart, I like to read a few of his posts about his reloading experiences. It humbles me.

 

[Clark]

This thread is about belted magnum accuracy, with some morphing into resizing in front of the belt.
I am no expert on accuracy, but I have researched Bart Bobbitt's posts about belted magnums.
A 1982 photo of him shooting at camp Perry, turned into a sketch, was a 1999 poster for Camp Perry. The NRA used that photo for something else.
He is an expert on accuracy, was a top competitor at the national level for many years, and has been posting on the internet about since before the www had a gun forum [rec.guns in the old usenet days].
From decades ago:

I've no idea why Lyman says belted cases last about 3 reloads. I've got
as many as 21 on one batch of cases and full-power loads were used.
.. Belted
cases when new often have their shoulders 25/1000ths of an inch back
from the chamber's shoulder when they are fired. Some stretching may
well occur with the first firing.

Backing off the full-length sizing die will solve the case stretching
problem, but it often exposes another problem. If the belted case is
loaded too hot (too much powder for the load), the case diameter in
front of the belt may not get sized down enough as the base of the die
doesn't touch it. That may prevent the case from easily chambering
in the normal, out-of-round chamber. So, to solve this problem, you
must screw the die down. But that sets the shoulder back too far.
..

Although neck sizing may extend the case life, it typically reduces
accuracy with belted cases.

BB

From recently:

March 20, 2012, 11:09 AM #8
Bart B.

The Willis collet die's probably the best reloading tool for belted cases since the reloading press was invented.

I've worn out 3 or 4 belted 30 caliber barrels in competion. The only way I got reloads for them to shoot sub 5/8 MOA at 1000 yards was to use brand new cases or resize fired ones such that the ridge in front of the belt got sized down to new case diameters. Folks used to cut the center part out of a standard full length sizing die then use it either before or after using a standard full length sizing die. That body die has to be set so the case body is sized all the way back to the belt; not 1/32 inch in front of it like standard full length dies do. Otherwise, that ridge prevents the case head from chambering the same for each shot; it causes interference when the bolt's closed.

The reason one should not feel any binding when closing the bolt on a chambered round is it makes the bolt head lock up in different places for each shot. Biggest cause of this is out of square bolt faces closing on previously fired cases whose heads are now more out of square; when the two high points align binding is at its worst. That changes how the barreled action whips around a bit when the round's fired. If the barrel doesn's whip the same for each shot, bullets won't strike very close to each other.

'Course if you can't shoot 20 or more consecutive shots of your belted case ammo into 1/4 MOA at 100 or 5/8 MOA at 1000, then you probably won't see nor appreciate what the Willis Collet Die will do. A great thing about it is it doesn't push body brass up against the belt like the old body dies used years ago do. One can probably get 20 or more loads per case instead of 10 to 15 we got with the body dies we used to make

 

[MCMXI]

Although neck sizing may extend the case life, it typically reduces accuracy with belted cases.

I've really enjoyed (and learned a lot from) Bart B.'s posts on this forum but I can't agree with his statement above based on my experience with neck sizing .300 Win Mag cases. The two groups posted earlier were shot using cases that were neck sized only. Those cases had been fired and neck sized twice. My approach with my .300 Win Mag rifles is to neck size only until there's too much resistance when closing the bolt. Then it's time to anneal the case mouth, bump the shoulder back a couple of thousandths and neck size. This will result in excellent accuracy and long case life.

 

[Kachok]

I don't believe there are cartrages that are accurate or inaccurate by nature, but there are cartrages that it is easier to stroke good accuracy out of. Sure the 7mm RM and 300 WM have a belt that makes accuracy just a hair harder to get, but they seem to have just about everything else going for them, hence some snipers and long range hunters still continue to use them even in this short mag era. Will the short mags replace them over time...maybe, but they have a long way to go before they replace field proven classics. That said my 270 WSM walked all over my three 7mm RMs, it is just a better rifle in every way for deer hunting. Flatter shooting, every bit as accurate, hits just as hard at range, and works in a light weight 24" short action, still a massive overkill inside 300 yards but all magnums are.

 

[Dthunter]

X2,1858!

I have been neck sizing my cases for at least 8 reloads.

My accuracy has been under MOA consistantly. I have shot this rifle out to 1760 yards an even 1900yds.

Hope to add the 2000 yard mark to my resume this summer!