Challenges of loading belted cases?
- Thread starter thefitter
- Start date
Personally I would build a 300 WSM. The Norma brass is really good and lasts a long time. No sizing issues like with a belted mag. Not quite the velocity but not that much short either. The WSM doesn't seem to be near as fussy as the WIN mag. The 300 WSM pretty well has taken over as the dominant 30 cal. cartridge in 1000 yard benchrest. Especially in the heavy gun class. It is winning the aggregates for the year and setting a lot of records. You can take H4350 and pretty easily get it shooting. I use Fed. 210 primers also. Another real accurate powder is 4007SSC. I think the barrels last longer because you have less powder to get almost the same velocity. With a belted case once you shoot it on the warm side a few times or real hot, the case swells in front of the belt and you cannot size it. Sticky bolt from then on. On the WSM case I can size the whole case right to the extractor groove.
CatShooter
thefitter said:
I currently load for and shoot 3 belted cartridges (264 WM, 300 WM, and 375 H&H).
In spite of all the rumors, I find no challenges.
I love them
I built myself a 300WM a year or so back. I've come to think that much of the fuss about the belted rounds stems from oversized chambers/reamers. I used a PTG Tac Match reamer for mine and case life seems pretty good, considering the fact that I'm pushing 200 grain hybrids at 3040 out of a 28 inch barrel.
It depends on what you want to use your .300 Magnum for. If for precision shooting, go for a rimless case any day. The problem with a belted case is that the case is supported in / headspaced on the fit of the belt in its chamber recess. With full-pressure loads, the relatively shallow belt does change dimension and that changes its relationship with the chamber and hence the rifle. Apart from the tight fit / extraction issues after a number of firings mentioned by Dkhunt, none of this is of great importance to sporting shooters, and many belted magnums are inherently good performers in a well built rifle.
But, for the long-range precision shooter, this changiong dimension / relationship issue caused by the belt injects a possible inconsistency into the ammunition and its chambering fit - anything such is undesirable. When the .300 Win Mag and .30/338 Win Mag wildcat were widely used long-range match cartridges, shooters had their rifles built and sized their brass such that the case-shoulder was just off the front of the chamber and the front edge of the belt had a tiny gap between it and the chamber belt recess. In effect, the cartridges were converted to rimless headspacing. This generally, not always, gave better results than setting it up for normal belted case operation.
Remember what Holland & Holland's original objective was back in around 1912 when it introduced the first belted designs and rifles. British big game rifle builders liked rimmed cases (flanged as they called them in that place at that time) as they gave a very positive headspace even when the front end of the case had a lot of clearance around it in the chamber. Lots of clearance is decidedly desirable in big / dangerous game rifles as it gives reliable chambering and extraction even when the African sun has heated everything up to the point where metal is too hot to touch with bare skin. The conditions a lot of hunters, especially professionals, lived and worked in during late 19th / early 20th century was also often primitive so rifles and ammunition could suffer dust, dirt problems and ammunition see surface corrosion. Rimmed cases were great with break-open doubles, but presented all sorts of problems when bolt-action magazine rifles made by German and Austrian gunmakers challenged the English gunmakers. They of course used rimless cartridges. H&H married the two forms by creating the belted design of bottlenecked case cartridges. In effect, it headspaces like a rimmed design, but feeds as easily and reliably as a rimless design without having to have the fairly close relationship with the chamber that the rimless variety needs. This is such a successful concept, it's why the belted design has survived a full 100 years and nearly all dangerous game cartridges designed for turnbolt rifles still use it.
Cartridges for non dangerous north American and European game and for target shooting are a different matter entirely, and the widespread use of belted designs during most of the 20th Century in 'magnums' was never technically warranted and was a triumph of marketing-speak over good rifle and cartridge design. Yes, the 7mm Rem Mag and series of Wichester magnums that kicked off with the .338 in 1956 (I think) worked fine, but they'd have worked equally well with a similar case shape and capacity rimless case without the belted case's extra cost and potential problems. This was very much a US issue - continental European gunmakers produced some very large and high pressure / performance hunting cartridge rimless case designs and belted cases saw little use in Scandinavia and France / Germany etc. (They did in the UK though as after the huge post WW2 contraction in the English gun manufacturing industry, we Brits tended to look to the US for rifles and cartridges, not to our European neighbours.)
As dkhunt 14 points out, you have the .300WSM which although a smaller capacity design is a superb performer and it and the yet smaller Remington SAUM form the vast majority of .300 cal long-range precision custom rifles in use today.
But, for the long-range precision shooter, this changiong dimension / relationship issue caused by the belt injects a possible inconsistency into the ammunition and its chambering fit - anything such is undesirable. When the .300 Win Mag and .30/338 Win Mag wildcat were widely used long-range match cartridges, shooters had their rifles built and sized their brass such that the case-shoulder was just off the front of the chamber and the front edge of the belt had a tiny gap between it and the chamber belt recess. In effect, the cartridges were converted to rimless headspacing. This generally, not always, gave better results than setting it up for normal belted case operation.
Remember what Holland & Holland's original objective was back in around 1912 when it introduced the first belted designs and rifles. British big game rifle builders liked rimmed cases (flanged as they called them in that place at that time) as they gave a very positive headspace even when the front end of the case had a lot of clearance around it in the chamber. Lots of clearance is decidedly desirable in big / dangerous game rifles as it gives reliable chambering and extraction even when the African sun has heated everything up to the point where metal is too hot to touch with bare skin. The conditions a lot of hunters, especially professionals, lived and worked in during late 19th / early 20th century was also often primitive so rifles and ammunition could suffer dust, dirt problems and ammunition see surface corrosion. Rimmed cases were great with break-open doubles, but presented all sorts of problems when bolt-action magazine rifles made by German and Austrian gunmakers challenged the English gunmakers. They of course used rimless cartridges. H&H married the two forms by creating the belted design of bottlenecked case cartridges. In effect, it headspaces like a rimmed design, but feeds as easily and reliably as a rimless design without having to have the fairly close relationship with the chamber that the rimless variety needs. This is such a successful concept, it's why the belted design has survived a full 100 years and nearly all dangerous game cartridges designed for turnbolt rifles still use it.
Cartridges for non dangerous north American and European game and for target shooting are a different matter entirely, and the widespread use of belted designs during most of the 20th Century in 'magnums' was never technically warranted and was a triumph of marketing-speak over good rifle and cartridge design. Yes, the 7mm Rem Mag and series of Wichester magnums that kicked off with the .338 in 1956 (I think) worked fine, but they'd have worked equally well with a similar case shape and capacity rimless case without the belted case's extra cost and potential problems. This was very much a US issue - continental European gunmakers produced some very large and high pressure / performance hunting cartridge rimless case designs and belted cases saw little use in Scandinavia and France / Germany etc. (They did in the UK though as after the huge post WW2 contraction in the English gun manufacturing industry, we Brits tended to look to the US for rifles and cartridges, not to our European neighbours.)
As dkhunt 14 points out, you have the .300WSM which although a smaller capacity design is a superb performer and it and the yet smaller Remington SAUM form the vast majority of .300 cal long-range precision custom rifles in use today.
We have 60 to 90 heavy gun benchrest 1000 yard shooters every match. 6 to 7 years ago everybody in 30 cal. was shooting a 300 Win Mag or 308 Baer which is the 300 Weatherby IMP. Now there is hardly any. They just can't compete with the 300 WSM. The rifles have to be able to shoot 10 shot groups at 1000 yards in the 4 to 5 inch range and do that pretty consistently when the conditions are half way decent. The others can't do that. Some of the guys have shot the WSM case 40 plus firings. Can't do that with a belted case. We had 2 guys average in the 6 inch range for all 10 matches. That means 100 shots all under a 7 inch average at 1000 yards. Both of these were 300 WSM. The case is really accurate and lasts.
I load only for a 300 Weatherby and the only tip is to make the case headspace on the shoulder just like a non-belted case. If you push the shoulders back too far and the case headspaces on the belt only then in 3-4 loadings you're likely to get a case separation just in front of the belt. Buy a headspace measuring tool and only push the shoulder back during sizing the same as a non-belted case. Shoulder headspace is the only issue I find loading 300 Wea. cases.
I load my 7mm weatherby and have no problems. I full length sized the casings, trimmed to length, then I fire form them to the chamber. After that I just neck size them. Basically im indexing off of the shoulder now, not off the belt.
I've had no buldging issues, and the accuracy is excellent for a "hunting" cartridge.
5 Shot group. 100 yards.
I've had no buldging issues, and the accuracy is excellent for a "hunting" cartridge.
5 Shot group. 100 yards.
I've had nothing but problems with my 300 WM. A look in the chamber with a bore scope revealed a small un supported section near the belt caused by the belt recess. This has caused bookoo extraction issued. . causing big time extraction issues.
BoydAllen
Gold $$ Contributor
Some years back, I helped a friend with a .300 Weatherby project. He wanted a tight neck short thoat chamber that would allow seating 180 grain bullets into the rifling at a length that would fit in the magazine of his custom stocked Weatherby. (He is a meticulous loader and very bright, or I would have never agreed.) Looking at new and fired brass from his factory chamber, I could see (with proper tools) that the shoulders of new cases were being blown forward about .021. Putting aside the neck (which required a clean up turn for proper loaded round fit) and the freebore shortening , addressing the reamer body design, I used the stock Weatherby diameters up through the shoulder, but I located the shoulder such that a new cases shoulder would only be blown forward .006 when fired. After the barrel was fitted, we took the whole reloading and chronograph setup to the range and started our testing well down from the maximum book load, not being sure of what effect the short throat and loading into the lands would have on pressure. I used a single case, for our pressure investigation, and although we had a FL die, the neck die worked perfectly all the way through. We did one shot per load, a half grain apart, and went up past where we were getting a bright circle from ejector hole, to the point where the belt diameter showed an increase for the second time, the first being on the initial firing. After the pressure test, I could easily chamber the case. I attribute this to not having too tight of chamber body dimensions. Shooters tend to think that tighter is better, and in some dimensions it can be, to a point, but I have seen more than one instance where a chamber was too close to fired brass's size, where tight extraction came at a pressure level that was lower than it would have been in a looser bodied chamber. The rifle shot well, and on its first hunt after rebarreling, dumped and large bull elk at about 600 yards with a high withers shot.
bigedp51
The Belted Magnum designed cartridges dates back the early 1900s and like the rimmed cases the shoulder location was not critical. Meaning due to poor manufacturing practices anything forward of the belt could vary in tolerances a great deal.
If you read the story of the "Enfield Inch" and the problems Pratt and Whitney had setting up the Enfield manufacturing plant in Lithgow Australia you would be amazed. The British inch was so many grains of barley, so many kernels of corn, etc. Pratt and Whitney could not set up the manufacturing of the British Enfield rifle until they found out how long the British inch really was and standardize British blueprints.
You need a belted magnum case like you need another hole in your head, the word "Belted Magnum" today is nothing more than a sales gimmick. And no one today measures headspace with barley or corn.
As you can see below Remington use immature barley or corn to set the shoulder location on this new .303 British case. (and you think a belted case would be better?)
The British used Cordite powder that looked like long spaghetti noodles inside the case, the powder was loaded into the cases before the shoulder and neck were formed. With rimmed and belted cases the shoulder location was not critical during manufacture and tolerances became meaningless.
Below, the rimmed and belted cases did not depend on shoulder location, and is a leftover from the dark ages of crude cartridge manufacturing techniques.
If you read the story of the "Enfield Inch" and the problems Pratt and Whitney had setting up the Enfield manufacturing plant in Lithgow Australia you would be amazed. The British inch was so many grains of barley, so many kernels of corn, etc. Pratt and Whitney could not set up the manufacturing of the British Enfield rifle until they found out how long the British inch really was and standardize British blueprints.
You need a belted magnum case like you need another hole in your head, the word "Belted Magnum" today is nothing more than a sales gimmick. And no one today measures headspace with barley or corn.
As you can see below Remington use immature barley or corn to set the shoulder location on this new .303 British case. (and you think a belted case would be better?)
The British used Cordite powder that looked like long spaghetti noodles inside the case, the powder was loaded into the cases before the shoulder and neck were formed. With rimmed and belted cases the shoulder location was not critical during manufacture and tolerances became meaningless.
Below, the rimmed and belted cases did not depend on shoulder location, and is a leftover from the dark ages of crude cartridge manufacturing techniques.
XTR
F-TR obssessed shooting junkie
I would argue that belted magnums are not around today as a sales gimmick but as an artifact of very successful past sales. Compare the number of 7mm Short whatevers to 7mmRMs in the world. If you make bullets you better be making 7mmRMs and if you are buying a rifle and are not a reloader, like 90% of the shooters out there, then you buy one that you can get ammo for.
As for the tirade on head-spacing on the belt, if you're a competent reloader you don't do that with anything other than new brass.
I'm not saying that belted cases are better, the only thing I think they offer today is more capacity and more top end for standard chamberings with readily available components than what is available in non-belted cases. Case in point, both the 7mmRM and the 300WM can be loaded to higher velocities than their short magnum counterparts.
As for the tirade on head-spacing on the belt, if you're a competent reloader you don't do that with anything other than new brass.
I'm not saying that belted cases are better, the only thing I think they offer today is more capacity and more top end for standard chamberings with readily available components than what is available in non-belted cases. Case in point, both the 7mmRM and the 300WM can be loaded to higher velocities than their short magnum counterparts.
Thanks for all the info. I decided against the 300 wm.
I might go with the 300 wsm in the future. But for now I think the next build will be a 6.5 CM bolt to go with the new JP gas gun I have being built in 6.5 CM.
Thanks again, saved me some headaches and disappointment...and I learned something!!
I might go with the 300 wsm in the future. But for now I think the next build will be a 6.5 CM bolt to go with the new JP gas gun I have being built in 6.5 CM.
Thanks again, saved me some headaches and disappointment...and I learned something!!
bigedp51
XTR said:
You poor uninformed people who never read anything by Jack O'Conner.
Anyone who is smart, good looking and reasonably modest, ;D that has read books by Jack O'Conner knows that the .270 Winchester is the absolute best non-belted magnum in the world.
7mm Remington magnum my gluteus maximus.
The match results do speak for themselves, however, it didn't seem to me that the poster was building a rifle for benchrest or f class.
Cartridge characteristics that provide a decisive advantage in a competition rifle may or may not amount to much in a gun intended for informal shooting.
I would add that he mentioned this was to be a custom rifle, meaning that he would have some control over the chamber dimensions.
Cartridge characteristics that provide a decisive advantage in a competition rifle may or may not amount to much in a gun intended for informal shooting.
I would add that he mentioned this was to be a custom rifle, meaning that he would have some control over the chamber dimensions.
Raythemanroe
Bullet Whisperer
I just built one on a custom action and I don't get the brass movement dkhunt said he got. Gun is pretty accurate although I haven't pumped that many rounds threw it to know case life.
Anyone who is smart, good looking and reasonably modest, ;D that has read books by Jack O'Conner knows that the .270 Winchester is the absolute best non-belted magnum in the world.
100% true. Add in a number of similar cartridges such as .280 Rem, 6.5-284, 8X68mm RWS. Any and all of these could have been as reasonably given the 'Magnum' title by the manufacturer and its marketing people. The truth is that the belted design stems from H&H's dangerous game cartridge design decisions, excellent and still valid today in that specialised role, but which were cleverly then adopted by people making cartridges for US non dangerous game hunters. A belt became almost synonymous with 'Magnum', a linkage that started to be weakened when it was applied to revolver and other pistol cartridges.
All the reasons that pro-magnum advocates have given in their posts don't change the fact that people chose rifles in these chamberings to get a particular level of performance, but that level would have been achieved by a similar sized case without a belt and lacking its problems.
Thanks for that comment - it makes the case (no pun intended) against the use of belted cartridges in precision and non-dangerous game roles perfectly. If you use handloading practices to negate the intended role of the belt why have it in the first place? Its existence solely adds cost and potential disbenefits by complicating case and chamber design / manufacture while you're then sizing cases to remove its function! A bit like buying a five-wheel car then putting extra high springs into the suspension to lift the fifth wheel off the road surface!
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