Optimizing Case Life in Belted Magnums

[whitefish]

Okay, bear with me as I'm getting into reloading and like any newbie I have alot of questions and I am worrying about nothing . I have a .300 Winchester Magnum A-Bolt II and I'm looking for ways of maximizing case life. I read alot on the essentials of minimizing headspace and thereby stretch at the belt. As a result, I'm looking for methods and the tools necessary to measure headspace to aid in extending case life.

I should say first that I'm not striving for BR accuracy or a tack driver. I can't shoot well enough to bother wringing that type of accuracy out of my A-Bolt. For now, I'm looking for reasonable accuracy, reliable ammo and easy cycling for hunting. To do this, I plan on FL resizing, but only so far as to bump back the shoulder enough to allow for reliable cycling (I've read anywhere between .001 to .003 of an inch). The trick is how to do this. I've read and been told everything from the bolt feel test to the use of comparators and gauges like those from Stoney, RCBS, Sinclair and Redding. I was leaning to the Redding Instant Indicator, before I read this from Chris Matthews in the Long Range Hunting forum:

"there is no guage for the shoulder measurement on a 300 Win Mag....what Redding made is just their version and could vary a bunch from my reamer (Pacific Tool and Guage Match finisher). So the Redding guage can't tell you tht they are 5 short or 6 long....but you can use the indicator to get them all the same...."

Here is the full thread:
http://www.thefiringline.com/forums/...=newthread&f=9

I apologize in advance if I've missed the point of Chris' post. Being the number junkie that I am, I DO want to know that headspace is .001 or .003 and that is how much brass stretch I will have. If I understand Chris right, no gauge or comparator will tell you this. Will this mean I will still have to chamber a round to determine the right headspace and use the Instant Indicator for comparative purposes only?

[T. O'Heir]

Headspace isn't measured. It's checked. It's a rifle manufacturing tolerance that allows all ammo made by all makers to be used in all like chambered rifles. Headspace is the distance between the bolt face and a spot in the chamber. In the case of a belted magnum, where the space for the belt is in the chamber.
Headspace guages are precision made tools used to check a rifle to see if the bolt/chamber are within tolerance.
You don't need to worry about headspace.
A cartridge, loaded or not, won't tell you anything about headspace.
Case life is entirely dependent on the load used. Hot loads reduce case life.
For a bolt action, you can set up your sizing die to neck size only. You can only do this with cases fired in the same rifle.
To load good ammo, meticulous techniques are required. Starting with weighing each charge on a scale until you have a loaf your rifle shoots well.
Beginning with the starting load, load 5 rounds only. Go up by half a grain of powder, loading 5 of each keeping them separate until you get to the max load in your manual.
Then go shooting. Shoot at 100 yards, for group only, slowly and deliberately off a bench.
Change targets between strings of 5 and allow time for the barrel to cool.
When you find the best group, sight in

[whitefish]

Thanks T. O'Heir

Headspace isn't measured. It's checked. It's a rifle manufacturing tolerance that allows all ammo made by all makers to be used in all like chambered rifles.

If this is the case, what is the purpose of a RCBS Precision Mic or a Redding Instant Indicator? These measure something rather than providing a go/no go reference.

[T. O'Heir]

Separating you from your money. Those are for measuring case dimensions. A $20 dial vernier calipre will do that.
Having all your cases the same length is a good thing, but it has nothing to do with headspace. Cartridges don't have headspace.

[oldscot3]

You can extend the life of belted cases by causing them to headspace off the shoulder instead of the belt. Neck them up one caliber (for example to 338 from 30) then use your 300 die to neck them back down. Go a little at a time, inserting the case into your rifle, then stop when you can just get the bolt to close. You will see a short "bubble" at the intersection of the neck and shoulder. This is where the case will headspace now. Lock the ring on the die at this point, then reload the case as usual. Fire the cartridges in your rifle and you will have perfectly fireformed cases for your rifle. Reload as usual from then on and you should see an increase in case life.

[whitefish]

This is the type of resizing I was considering (from Sierra Bullets Exterior Ballistics website):

"Adjustment of the full length die calls for the die body to be screwed down in the press until it contacts the shell holder at the top of the ram’s stroke. If the ammunition is to be reused in the same gun the cases were originally fired in, back the die off 1/2 to 3/4 of a turn and size a lightly lubricated case. Wipe the case dry, and chamber it in the gun. If any resistance is felt, lower the die body another 1/8 of a turn (or less), and repeat the process with another fired case. This is repeated until the action will just close without resistance. When this has been accomplished, set the lock ring to secure the die in place. This method will ensure that the fired cases are resized with a minimum amount of headspace. This case has now been “custom fitted” to that particular chamber.

This will normally provide the best case life and accuracy, but does require that the ammunition only be used in the gun in which it was originally fired. If the ammunition is to be used in a different gun of the same chambering, of course!, the sizing die should be adjusted down until it just contacts the shell holder at the top of the ram’s stroke."

I was trying to avoid checking headspace by feel, opting for a more repeatable method - i.e. headspace gauge. I looks like going by feel may be the best?

[oldscot3]

Every firearm is a unique and individual specimen. Reload your ammunition for your firearm.

[cdoc42]

I was just doing this tonightwith my .270 WSM!! I'm logged on to ask a related question, but I'll put my two cents in here first.

I use a Stoney Point "Cartridge Headspace Gauge" that affixes to my digital caliper. There are 5 bushings, labeled A to E. You might be interested to know that bushing "E" is used for 9 calibers, one of which is the .300 Win Mag. You measure a fired case; the bushing contacts a spot on the shoulder. Set your die as you described but do not take the play out of the system, i.e., you should not have a "bump" when the handle is at the end of the stroke. I generally have the die touching the shellholder, then back off about a half a turn. Resize a clean, lubricated case. Measure it with the headspace gauge. Often it will be exactly the same size as it was before you resized - so the shoulder did not move back and when you chamber it, you'll feel some resistance when you close the bolt. Turn the die down about 1/8 and resize the same case. Measure it. Continue to turn the die down until you have resized it 0.002" from the fired dimension (or, as you read, 0.001 to 0.003). It should now chamber noticeably more smoothly.

I do this with all my cases, not just the belted ones. Of the 5 bushings I mentioned, none are listed for the WSM. But I matched them up until it appeared that "D" located itself on the shoulder pretty much where other listed cases are located. I was able to set the shoulder back 0.002" and the case chambered easily.

Now, here's MY question. After 30 years of reloading I STILL have not found a way to easily lock the ring on the resizing (or seating) die. After I set the die as described above I turn the brass lock nut into the threads of the die body. If I set it tightly, I can't turn the die out. If I set it lightly so as to be able to turn the die out, the lock ring usually slips and I must start my measurement all over again. Invariably, I strip the lock nut with the allen wrench and ruin the lock nut. I traded two nuts from other unused die sets tonight, but after 3 tries, I finally did it. I was able to turn the die slowly out, retighten the lock nut, turn out again, tighten again, until I had it adequately locked.

Does anyone have any technique to share that makes this easier?

[whitefish]

Thanks cdoc42,

I tried typing out a response and got "timed out" - so I'm shortening my second attempt.

If I understand the use of the Cartridge Headspace Gauge (L.E. Wilson?) correctly, its really for comparative purposes. It won't tell you whether your brass is above or below a SAAMI spec, but will tell you when you brass is getting bumped back and by how much. I would assume that the accuracy of this measurement will depend on how uniform the brass is.

A more accurate measurement may be one off of a reference (or datum) on the shoulder itself. I believe that this is how the Redding and RCBS gauges work. That said, this is probably way more precision than I need in a hunting rifle, even a long range hunting rifle.

BTW, when you test you brass by chambering, do you remove the firing pin? I was told that this may be important to remove tension that may be confused with tight brass. I thought simply cocking the firing pin would work as well.

[tuck2]

I have gotten the most reloads from belted cases from the case being fire formed to the rifles chamber the first time they are loaded. After the first fireing I only neck size the case . I neck size the case untill the empty resized case will not chamber in the rifle. There is a die that will reduce the case diameter in front of the belt but I have not tried it. After a number of reloads the case body expands so that it will not chamber ,the cases are then full length resized . One has to check for insept(SP ?)case seperation when reloading a case a number of times.

[cdoc42]

Whitefish, I think you are correct about the measurement being a reference rather than an actual number. If the chamber was truly measured by firing a case you'd not get the case out. Once it rebounds after fire-forming it is no longer exactly the chamber dimension, but you can either resize to fit any chamber or resize just enough to assure it will fit your particular rifle (i.e., 0.001-0.003"). That move is an attempt to improve accuracy since the case expansion and resultant pressure becomes a relative constant. But thinking about it, does it really matter except between rifles? If you fully resize a case for your rifle, every time you fire, it will adopt the dimension of your chamber, so size becomes a constant. Then you adjust pressure by changing the powder charge. So ultimately you end up with the same accuracy potential. Resizing to fit your chamber, then, is a move to increase case life more so than accuracy.

I don't think messing with the firing pin is necessary. Remember you're measuring a resized case so the primer is gone.

[whitefish]

Resizing to fit your chamber, then, is a move to increase case life more so than accuracy.

Yup, that's what I'm striving for, increase case life over some accuracy.

But this brings up an interesting dilemma that I hadn't thought of. I plan on using most of the rounds for target practice and the rest for hunting (varmints and big game). For hunting, I need the guarentee of a round that will cycle and no stuck cases. Therefore, just neck sizing or bumping back the shoulder won't due - I would have to either full length resize or use new or once fired brass. A sticky case is no big deal if I'm target practicing, so I can use that brass for multiple reloads. Also, because its a hunting rifle, I can't have a stuck case, so I don't think.

Hopefully if I practice with brass thats been reloaded multiple times, the point of impact will not change when I ues the same brass/load/bullet combo in once fired or new brass for hunting. We'll see.

tuck2, you mention Larry Willis' resizing collet for belted magnums. Have you used this? Does it work? If you minimize brass flow/stretch by just neck sizing or bumping the shoulder back, how many reloads do you get before you have to full resize? How many before the rounds will not chamber no matter what?

[cdoc42]

I've been "partially resizing" -either just neck or as described earlier for about 15 of the 30 years I've been reloading. I have not had a stuck case or difficult cartridge chambering. If you want to be certain, though, just run however many rounds you plan to take hunting through your chamber while at the range. Take those rounds hunting. Re: accuracy of resized vs new or once-fired rounds for hunting, I don't think you'll consistently put all your shots inside a quarter with a load in a new case vs a fired case but you certainly shouldn't miss your target. If I have a load that shoots under 1 inch, that spread may go to 2 or 3 inches in a new case but even that's unusual.

I suspect my question got lost in the dicussion. I'll try again:

Now, here's MY question. After 30 years of reloading I STILL have not found a way to easily lock the ring on the resizing (or seating) die. After I set the die as described above I turn the brass lock nut into the threads of the die body. If I set it tightly, I can't turn the die out. If I set it lightly so as to be able to turn the die out, the lock ring usually slips and I must start my measurement all over again. Invariably, I strip the lock nut with the allen wrench and ruin the lock nut. I traded two nuts from other unused die sets tonight, but after 3 tries, I finally did it. I was able to turn the die slowly out, retighten the lock nut, turn out again, tighten again, until I had it adequately locked.

Does anyone have any technique to share that makes this easier?

[whitefish]

Thanks again...

With reference to

I have not had a stuck case or difficult cartridge chambering.

, was this with any belted magnums?

With respect to your question, I can't offer any suggestions. I've just started reloading and don't have my own press yet. I'll ask my buddy who has been helping me out. Also, I would suggest starting a new thread with this question - you may get more responses.

[cdoc42]

Yes, my experience includes belted magnums in 7mmRM, .300 WM, .338WM and 7mmSTW.

[whitefish]

How many re-loads would you safely get in your 300WM?

[The Lovemaster]

Now, here's MY question. After 30 years of reloading I STILL have not found a way to easily lock the ring on the resizing (or seating) die. After I set the die as described above I turn the brass lock nut into the threads of the die body. If I set it tightly, I can't turn the die out. If I set it lightly so as to be able to turn the die out, the lock ring usually slips and I must start my measurement all over again. Invariably, I strip the lock nut with the allen wrench and ruin the lock nut. I traded two nuts from other unused die sets tonight, but after 3 tries, I finally did it. I was able to turn the die slowly out, retighten the lock nut, turn out again, tighten again, until I had it adequately locked.

Does anyone have any technique to share that makes this easier?

Two solutions: remove the set screw, put a single lead shot BB in the set screw hole, and reinsert the screw. The soft lead will form to the die threads and hold the ring in place better.

The second and better solution is to invest in better lock rings like the Hornady ones that truly clamp the die by means of a tangential set screw similar to a hose clamp, rather than having the set screw dig into the die body. These better clamps exert force around the entire circumference of the die when tightened, rather than a single point load as the set screws you have.

[brickeyee]

"Separating you from your money. Those are for measuring case dimensions. A $20 dial vernier calipre will do that.
Having all your cases the same length is a good thing, but it has nothing to do with headspace. Cartridges don't have headspace."

Sort of tough to measure shoulder location with just a caliper.

Headspace is technically the distance from bolt face to the datum defined for the cartridge.
Some point on the shoulder for bottle necked cases, the front of the belt on belted cases, etc.
Headspace clearance is the difference between a case and the chamber it is in.
This has come to be called headspace and just about everyone understands what is meant.

Case length has nothing to do with preventing repeated stretching and case head separation.
To limit stretching you want to not move, or move as little as possible, the shoulder of a fired case for use in the SAME gun.
The various tools sold allow you to measure the case shoulder dimension so dies can be set for as little movement as possible.
This is the reason there are also neck dies.
By sizing only the neck the fired case shoulder dimension is not disturbed.

In many cases after a number of firings the case may become difficult to chamber.
A body die is then used to barely bump the shoulder back without affecting the neck.
After a body die bump the case is then neck sized.

Reloading belted magnums so they headspace on the shoulder instead of the belt is one way to extend case life.
If you full length size you will push the shoulder back, then it will be blown forward, then back, etc.
The brass can work harden and then splits show up.
Case head separation can occur, but the brass is usually pretty thick just above the belt.

Full length sizing of regular bottle necked cases results in stretching just above the case head.
Firing pin drives the case forward, front of case grabs the chamber walls, even higher pressure pushes the case head against the bolt.
Separation can occur in only a few loadings if the clearance of the case in the chamber is significant.

[whitefish]

Thanks brickeyee! That was just the detailed and concise answer I was looking for.

I suspect that for my needs, testing headspace through experimental sizing of fired formed brass will tell me where I need to set my dies to bump the shoulder just far enough back to allow reliable chambering in my 300 WM - again, I willing to give up some accuracy for the reassurance that a round will chamber when the elk of a life time is in range!


cdoc42, I was checking out Hornaday's Sure-Loc lock rings just before Vincent_Vega posted his response. They look like they might do the trick.

[brickeyee]

For hunting loads I have always used once fired brass that has been full length sized.

Having a chambering problem hunting is just not worth the risk.

Another problem to watch for is seating bullets long for better accuracy and then having one stick.
A shells worth of powder ends up in the action (thogh most gets dumed inthe mag well), but the bullet is left in the leade.
Sometimes they can be bumped out with a solid drop onto the but, but sometimes you need a cleaning rod.
Not something I carry for anything but varmint shooting from a table.

One of the best options still remains running every round through the gun beofre leaving home for hunting.
Point in a safe direction and keep your finger off the trigger.

[cdoc42]

Thanks, Vincent Vega!! I never thought to try Hornady rings over RCBS dies, but I know of which you speak as I have a set of Hornady dies.

[cdoc42]

Whitefish, I reload all my cases until the necks split or I can see a hint of a ring near the base of the case. I used to count a long time ago but then I got into 17 calibers over the years and found it wasn't worth the time and space to count and separate cases.

You'll find as you resize your cases if you lube the case mouth with a Q-tip or brush dipped in graphite you'll pick up a gleam of light coming through a split in the case neck. Early on I used to physically check every case after cleaning. You might miss some, but these can be picked up when you pay attention to how the bullets seat. If one seems to seat with very little resistance, check that case for a split. I don't think split necks present a hazard, just an inaccurate round since there is less pressure upon firing.

When I first started reloading I had a Remington Model 700 that had a throat so long I could see California from Pennsylvania. The bullet jump was a quarter of an inch. There was no bullet made that allowed me to seat it near the leade. Neither did I know about partial resizing and within 3 reloads my cases would separate at the head. It came to my attention one day when the whole case split and I ejected the base, leaving the rest of the case in the chamber. No problem other than needing a cleaning rod and the experience sent me to the books as places like this forum didn't exist. Local reloaders I came into contact with had no idea what In was talking about when I asked about seating to touch the lands, so I did a lot of reading. You're way ahead with forums like this.

If you're not certain a case is likely to separate, curl the end of a thin paper clip into the shape of a "L" and slowly run it back and forth over the area you think shows a ring at the base. It's not an exact exercise, and to get the idea you may have to saw a case apart length-wise to see what it really looks like inside. Of course, if you're not sure, toss it.

Since I've been partially resizing and neck resizing I have not had a case completely separate for the last 25 years. Occassionally I see rings and more rarely a case will actually start to split, making itself very obvious. But I'm guessing those cases have been reloaded at least a dozen times.

[whitefish]

Thanks for the help cdoc42! The advice I received in this forum has been tremendous - its definately going to save me time and point me in the right direction.

[SST]

I've been reloading belted cases since 1969. Fortunately, I started out dealing with a custom rifle with a minimum spec chamber. Reloading factory ammo wasn't a big deal. Handloading belted cases that have been fired in a normal factory chamber is a different story. Thanks to the oversized chambers and excessive headspace in so many factory rifles, belted cases sometimes stretch beyond salvation upon the first firing. By excessive headspace, I don't mean beyond SAAMI tolerances. I mean beyond what is conducive to long brass life. I've seen case head separation on belted cases on their second firing. The only way to eliminate this in overly long chambers is to use only new component brass that has been necked up and then back down in small increments until the bolt just closes with slight pressure. The fireformed case will then be as good as it's going to get. The brass is new enough that it has plenty of springback for easy chambering with just neck sizing, so for the next reload, I neck size only. These are what I use for hunting cartridges. I will neck size only until I have difficulty chambering. Then I partial full-length resize, again incrementally adjusting the die down till just beyond a slight crush fit. There should be a small amount of the neck not resized. That will help align the cartridge with the bore. If primer pockets start to open up, I simply scrap the cases. Unfortunately, sometimes primer pockets are loose on new unfired brass. That's just the price we pay for mass production.

[whitefish]

Thanks SST....

The only way to eliminate this in overly long chambers is to use only new component brass that has been necked up and then back down in small increments until the bolt just closes with slight pressure

When you say "necked up", are you referring to moving the shoulder forward and then back just enough to close the bolt?

Also, could you use this same process for once fired brass that has hardly stretched? I was looking at some of my once fired winchester brass with a caliber and was surprised to see that most of the brass had stretched very little as compared to my new winchester brass. I did find a few cases that had stretched quite abit, but these were obvious and could be tossed.