Belted magnums

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bacardisteve

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Really interested in picking up a 300 win mag but have never owned a belted magnum. I can get once fired military brass for a good price but was told i would need a special collet die as a full length die wouldnt resize it enough to chamber in another rifle. I know i can neck size and headspace off the shoulder with new brass thats been fired in my rifle but how many times can I do that before i would need to Full length size? What kind of brass life do you guys get with the belted mags? Sorry for the long winded post ive tried searching but seems like a lot of controversy over the belted mags.
 
When I first got my Weatherby 300 Magnum I full-length resized with firm contact between die and shellholder. I simply thought it headspaced off the belt. I was only getting 3-4 loadings with factory Weatherby brass until a stretch ring was obvious on the inside of the case. Found out you have to headspace off the shoulder too and I was pushing the shoulders back too far. The stretching and possible case separations are just in front of the belt. Buy a headspace gauge such as Hornady's Headspace Gauge Set to measure how much you push the shoulder back on cases fired in your rifle so the case will headspace on the shoulder 1st and also on the belt. You only want to push the shoulder back about .002" from fired dimensions. Some recommend a special belted case die by Larry Willis but I have no problems adjusting my full length sizing die with no chambering issues. Of course neck sizing for cases fired in your rifle will not cause case stretching but you will have to full length size after a couple rounds fired or possibly a few more with less than maximum loads. I'd recommend full length sizing for hunting rounds when you definitely don't want a failure to chamber.
 
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I am not a fan of the belted magnum cartridges. One of the first problems you run into is the issue that base to shoulder dimensions are not standardized. Only base to belt is standardized and that is the head space. Base to shoulder can be all over the place and thus you need gauges to control this dimension. I purchased the Wilson Adjustable Case Gage http://www.lewilson.com/adjustablecasegage.html for my 375 H&H. Though I could have used a Sinclair Comparator on setting up the dies for my 300 H&H. This page shows how to use the Wilson adjustable case gage.:

Extending Cartridge Case Life
http://www.realguns.com/Commentary/comar46.htm

If you size your cases without measuring just how much you are pushing the shoulder back, your case life will be short. Maybe three reloads. Because I did not want my $2.00 a pop 300 H&H cases to stretch excessively on the first firing, I lubricated the cases before firing. I either rubbed on paste wax, which melts and acts as a lubricant, or rubbed case lube on the loaded cartridges. This prevented the front of the case sticking to the chamber, the case slide to the bolt face without sidewall stretch, and the shoulders folded out to the chamber walls. After first firing, I think I used a Sinclair Comparator to set up the die. I did not want to push the shoulder back more than 0.003", and I did not want a crush fit case either. I only have about four reloads on my 300 H&H cases but there is absolutely no evidence of case head separation. I checked with a bent paper clip, as the article shows how to do.

As for a collet die, are you thinking of this collet die?

Reloading Belted Magnum Calibers
http://www.larrywillis.com/windex.html

The merchant has a lot of comments on reloading belted magnums:

Reloading Belted Magnums
http://www.larrywillis.com/answers.html

I suspect if there is a dimensional issue between the chamber and sizing die, this collet die may be needed. I have not encountered this (yet) but Larry Willis must have, and he has come up with a solution. I would get something like after I had chambering problems.

Another issue I ran into, which reinforces my dislike of belted magnums, was rim lock. Firing 235 grain bullets in my 375 H&H, the cases slide around in the magazine. The top round, the edge of the belt caught on the rim of the next round down. This prevented me from closing the bolt as I had "rim lock". I had to pull the bolt back, push on the stack with my thumb, to clear the rim lock, before I could get the cartridge to feed. I think for a cartridge whose primary purpose is hunting big game, the type that could crush you into a mass of hamburger meat, or shred you with their teeth, this is not a good case design. I would say, anyone hunting large game with one of these rifles ought to have a big stiff spear to grab incase the bolt locks up. Going retro with a Paleolithic spear could save your life.! I have not had this problem with my 300 H&H and I don't know why. Maybe the recoil is less, maybe the cases have less space to slide around. My 300 H&H is an incredibly smooth feeding rifle as the cartridge is very tapered.

I don't fire my 375 H&H all that much, maybe have five reloads on one box. There are elephants around, but they all hide out in Bryant–Denny Stadium on the weekends. https://en.wikipedia.org/wiki/Bryant–Denny_Stadium
 
If you are referring to the Fed pull down .300 Win brass that apparently had been military sniper rounds, by all means get some, good brass and good buy. But don't rush into the collet die situation unless determined that it is really necessary for switching between rifles. One hundred dollars says you will never need one. At last count I had 21 belted mag rifles, Mdl 70s and 700s, covering 13 calibers and never once ran into the necessity for using a collet die. This subject was discussed in a recent thread. My sizing method is simply to screw the sizing die down to the shell holder and then back off some. Simplistic and basic but always works. I used to use separate sizing dies and brass for repeat calibers but this turned out to be unnecessary. Brass used is mostly Rems and Wins with good case life; I have given up keeping count on the number of loadings. Occasionally a split neck will show up but never anything close to a separation. Never a problem using the same loads between rifles of the same caliber. Perhaps a lot of this is just good luck with no expertise on my part. And cannot really say if headspacing is mostly on the belts or the shoulders. If there isn't a problem, don't create one by trying to make everything identical.
 
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.300 Win Mag is loaded just like any other cartridge. Whoever told you a full length die wouldn't resize it is confused. Ask 'em how do they think it was done before collet dies existed.
 
Yes, normal full length resizing dies will work, but for long (and safe) use, don't use the belt for headspacing. Find a fired case that won't chamber, then set the resizing die about 1/16" from the shell holder. Size and try to chamber, if it won't chamber, screw the die down another 1/4 turn and try again, repeat as necessary. Once it chambers, screw the die down another 1/4 turn and it's set.

My 7mm Rem. magnum, .300WM and .338 Rem. magnum brass lasts 10 loadings using this method.
 
I have case forming dies for belted cases, I have RCBS BAR dies. I form belted cases to wildcats. I do not have a collet die for belted cases. I have two lathes with collets just in case. I am the only reloader that understands the case that expands in front of the belt has other problems.

Sorry for the long winded post ive tried searching but seems like a lot of controversy over the belted mags.
Click to expand...

Your are kidding, I have no ideal why:rolleyes: all the questions about the digitial head space gage:eek: sound like they were posted by the same person.

F. Guffey
 
The person that told me a full length die wouldnt work is actually the online vendor that sells once fired military 300 win. Im starting to think they are trying to get people to puchase the larry willis collet die that they also sell.
 
I bought the Larry Willis collet die. Turns out I did not need it, my Forster Bench rest full length resizing die takes care of any bulge problems,,so it sets on the shelf lookin on with other bad financial decisions I've made...
It does make a decent case Guage though, I guess....
 
What is this, "...once fired military brass...", that the original poster is refering to? What does the military use .300 Win. Magnum brass for? It's sniper program?
 
IF continually fired at absolute max loadings, the case section just above the belt will gradually expand to an
interference [non]fit with the chamber. And because it's belted the "normal" resizing die cannot fully resize through
this section as would ordinarily be the case... so it will grow over time. [Therefore the seller's not pulling your leg.] ;)

However once-fired brass should not ordinarily give you a problem unless the chamber was overly large to begin with.

Second, loading below absolute max will alleviate the belt/case sizing problem.

Third, partial sizing to shoulder fit -- as with normal non-belted cases -- will solve the case stretch problem.





ps: get a Stoney Point/Hornady case headspace gauge set.
(Don't leave home without it) :D

pps:
SLAMFIRE said:
I lubricated the cases before firing. I either rubbed on paste wax, which
melts and acts as a lubricant, or rubbed case lube on the loaded cartridges.
This prevented the front of the case sticking to the chamber...
Click to expand...
+1
I just leave on the [RCBS/Imperial] case lube/don't wipe it off.
[You and I are now going to get a lot of doomsday hatemail. :D]
 
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Dahermit you are correct the military uses sniper rifles chamberd in 300 win. You can purchase once fired brass online. Its $450 for 1000 pieces. Its not crimped like 7.62 nato and 5.56 nato are.
 
Thanks for all the replies guys many mentioned the stoney point case length gauge and im very familiar with that tool. I use it on all my other rifles and i aslo have the hornady comparators and head space gauge. Im gonna take the plunge and drop down the cash for the rifle soon.
 
When I put together my R700 in 300wm I was also concerned about the cnflicting methods of proper case sizing. Now after about 600 rounds of handloading ive realized its not super critical. There is however a few extra steps you need to take for reliable 300wm shooting. I use rcbs FL dies and really dont have any chambering issues. I bought the LW headspace gage and spent the time to accurately caculate and size my brass to precisely fit my chamber. I also bought the LW belted mag collet die but in hindsight its really not needed. Yes I do get a very slight bulge at the base near the belt but after a typical FL resize my casings always chamber . My only additional suggestion is to always perform the "paper clip test" to avoid a case separation. I check all my casings and ive still experienced two case separations so be wary of this. Good luck!
 
Belted magnum chambers are SAAMI registered at 0.220 -0.227".
Belted magnum brass cases are SAAMI registered at 0.212 -0.220"

Typically with all cartridges we see factory gun chambers are at the small end of SAAMI range and factory brass is at the small end of the SAAMI range. Belted magnums are no exception [One exception is that old Glock 40s&w chambers are LARGER than SAAMI specs.]

Anyway, for me I see a loophole. I can buy a lifetime supply of belted magnum brass, measure them and not the longest is 0.215" long.
I have done that in 7mmRemMag, 300WinMag, and 338WinMag.
I can then chamber MY rifles at 0.215" headspace for the rim.

My factory rifles in belted magnum cartridges still suck, err stretch.
 
Trying to recall from earlier reading, I think the military usage of the .300 Win sniper rounds was with Remington Mdl 700 rifles. The cases will come with a variety of headstamp dates, and, as would be expected from bolt rifles, do not have crimped primers. I have not used any of the once fired cases, but recently from Graf & Sons obtained a quantity of pull-down cases, meaning that bullets were pulled from new rounds and sold as non-fired primed brass, not requiring a hazmat fee for shipping. I just checked with Graf and of course these are now out of stock. I'm partial towards Federal brass and of course have found the cases to be totally satisfactory. Unless you are forced to buy 1000 at $450 per an above post, by all means get some of the once fired cases.

But don't get the collet die. I'm one who maintains that with proper die adjustment and proper loadings, the need for a collet die can be completely avoided which is what I intended to convey with the numbers game (see post #4).
 
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Pogy:

I suppose they say that opinions are a dime a dozen, or something like that, but go ahead and express yours anyway. We all do that. :)
 
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