243 pressure issues


February 17, 2012, 05:19 PM
i apologize for the long post, and let me thank you in advance for taking the time to help/share your knowledge. i want to clearly explain every little detail in order to help narrow down the cause of this problem. i am fairly new to reloading as i have only been in it only one year and have only gotten my information through reloading manuals as well as forms like this. i understand that despite hundreds of hours researching the subject of reloading, it doesnt leave me much more than tired and having to sort through the true and speculated information. i have reloaded a few thousand rifel/pistol rounds without any issue but have recently run into an issue while trying to reload 243 win for my girlfriend's savage 99e. I started reloading for this rifel when the reloads (unknown recipe) she was shooting from an experienced family friend started splitting the cases in half approx .365" up from the base of the cartrige on two occasions.

load #1) I started with clean mixed once fired brass (primarily rp and win) all trimed to 2.035" and used a rcbs 243win die, and started loads straight out of the hornady reloading manual 8th edition for the correct bullet (100 gr sp interlock 243). All these loads used fed 210 primer per hornady. I started with 31.5 gr imr 4064 and a col of the published 2.630" with a very very slight crimp. when i went to test these rounds, i found that on occasion some cases were again separating in half in the same spot as the other reloads, and sometimes the primers would back out or flatten or both. other times the cases seemed fine, other than a shiny stress line all the way around and sometimes a fracture 2/3 or all the way around the case would show in the same spot the cases were splitting.

after this i measured the headspace using a resized trimmed case that i cut a slit into the neck and just slightly seated the 100 gr interlock and chambered the uncharged/unprimed round to measure where the bullet be pushed back in the case and would contact the lands. the col of this test was 2.810" which i assume to be a bit long.

I then reloaded a few different loads of different amounts of imr 4064with several col for each change of powder weight. all of these loads produced similar results indicating high pressure. all loaded brass was checked and the correct size in all dimensions. each powder charge was hand weighed on a rcbs manual scale calibrated correctly. none of the following reloads had any crimp.

all loads used once fired mixed brass cleaned and trimmed (after resizing) to 2.035" using imr 4064 and fed 210 primers in the same rcbs dies on a single stage rockchucker.

#2) 31.5gr, col 2.710" fired 3 rounds, one primer flattened and backed out slightly, the other 4 had slightly flattened primers and all 5 have small dimples rising up from bolt face and all are slightly cratered around firing pin dent

#3) 31.5 gr, col 2.805" fired one round, flattened primer with cratering and split the case in two separate pieces. didnt want to fire the rest of these.

#4) 32.6 gr, col 2.633", 3 rounds. backed out primers with very slight cratering. all had stress line all the way around cases.

#5)32.6 gr, col 2.710", 3 round. all backed out primers. two with slight cratering and one with more obvious cratering, all had lines around case which were less visible than load #4.

#6)32.6 gr, col 2.810", 3 rounds. one backed out primer and cratering with stress line around case, two flattened primers with cratering, one with cracked case 2/3 around and one with two stress lines all the way around case. the first was in the same .365" up and the second was .665" up from the bottom.

#7)34.2 gr, col 2.633" 3 rounds. all flattened primers with cratering, all with stress lines at .365"up from base

#8)34.2 gr, col 2.710" 2 rounds. two flattened primers with cratering, one of which was backed out.

#9)34.2 gr, col 2.810" 2 rounds. both had flattened primers with cratering and one had cracked case all the way around in same spot as others, the other case had a stress line around case in same spot.

the min published load with imr 4064 per hdy is 31.0 gr and i started with 31.5 gr. and went up from there to max load of 34.2 gr. my original thought was that the .2" gap the bullets traveled was causing a pressure spike when they would hit the lands but changing the col didnt help even with the col set to 2.810" where the bullet is just touching. or for some reason there was some sort of under pressure issues causing the backed out primers. i got confused by the flattened primers and the backed out primers as well as the splitting cases as t thought they showed contradicting signs. before i start over with cci primers and/or different powder and risk blowing myself up anymore i'll wait to see what you kind folks can come up with (which i should have done in the first place). and yes i realize that this was dangerous testing these loads now that i know my original suspicions were incorrect.

thank you so much and any help would be greatly appreciated as well as needed. dont be afraid to hurt my feelings as i am open to learn any way i can.

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Longhorn 76
February 17, 2012, 05:47 PM
You are not properly measuring the headspace with your method, but the freebore (or distance of bullet off of the rifling).

February 17, 2012, 06:07 PM
thanks for the heads up longhorn. thats something i read about on another forum but i guess it wasnt too accurate. the reccomended col from hornady was used in the origional load that first brought the problem to my attention. i forgot to mention that the rifle shoots fine with factory loads.

February 17, 2012, 06:15 PM
Headspace is not the distance to the lands with seated bullet. It is the distance from the bolt face to the datum line in the chamber.

You have issues with that rifle and I recommend you stop shooting it until you get them repaired.

Backed out primers can be a sign of a Low pressure round. Backed out primers can also be a sign of excess headspace in the rifles chamber. Split cases with mild loads is also a sign of excess headspace. IMHO that rifle has excess headspace issues and should not be fired again until it is checked out by a qualified Smith and repaired.

February 17, 2012, 06:26 PM
The rifle either has excess headspace OR the reloaded rounds have the shoulder set back too far. Regardless, the resultant issue is excess headspace which will cause all the the issues you have described.

February 17, 2012, 06:28 PM
thanks guys! anyone know of a decent smith in northern ca? the closer to the bay area the better!

February 17, 2012, 06:35 PM
Where did the brass come from? How many times has it been reloaded? The splitting could very well be from excessive resizing and the web of the case is thinning out. If you've got a bunch of reloads on these or it's range brass etc. this could be contributing to your problem. If the chamber was a bit on the generous side that would certainly exacerbate the problem.

February 17, 2012, 06:54 PM
You have issues with that rifle and I recommend you stop shooting it until you get them repaired.

I agree, you may have more to worry about than COAL. It may be the action is sprung and is showing headspace issues, or the lever lockup has wear. You need to have that checked.

If you combine that with brass that may have had the shoulder pushed back a bit too much when sizing, you'll experience consistent head separations.
Your initial loads do not even meet www.hodgdon.com start load specs of 33gr of IMR4064 under a 100gr bullets.
Something isn't right.


February 17, 2012, 07:03 PM
It probably has to do with how much head space is being created during resizing, which would be too much. You should only be resizing the case enough to bring the neck into spec. and no more than is necessary to facilitate normal chambering. If the brass will chamber normal after having been fired, only adjust the resizing die to allow for neck sizing. If it doesn't chamber normal and is too tight, adjust the die down in very small increments until chambering does not create unusual or abnormal resistence.

February 17, 2012, 07:31 PM
It's O.K. with factory loads.
Breaks cases in half & flattens primers with your reloads.

You are pushing the shoulder back too far with your sizing die adjusted like it is now.

SO, you have created artificial excess headspace.

The primers are backing out when the pressure builds in the primer pocket.

Then the powder lights, the pressure builds, the case expands, grips the chamber and stretches until it cracks & breaks.
That slams the rear of the case back into the bolt and flattens the primers.

You need to back off your sizing die until the rifles bolt will just close on a sized case with slight resistance.


February 17, 2012, 07:44 PM
Looks like a headspace problem. How to measure & adjust headspace of the 243 Win. > http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL

February 17, 2012, 07:47 PM
RC is absolutely correct.

Headspace is almost irrelivant if a handloader understands how to correctly adjust his FL sizer.

February 17, 2012, 08:01 PM
Case life is not very good on a Savage 99 under the best of circumstances.

The rear locking bolt allows a lot of action & case stretch even when the case is sized to fit the chamber.


February 17, 2012, 08:21 PM
thanks folks. and strongbad- all the brass was once fired im pretty sure all out of that same gun.

February 17, 2012, 08:41 PM
all the brass was once fired im pretty sure all out of that same gun. Then firearm needs to see a gun smith to have the headspace checked. There can be case head separations on the first firing of factory ammo, if there is excessive headspace.

Centaur 1
February 17, 2012, 09:46 PM
boardmstr, check out this website with instructions and illustrations on how to properly adjust your sizing die. I think that the pictures will help you understand what everyone is telling you about oversizing the brass. Good luck.


February 17, 2012, 10:09 PM
Once fired then NS or FL sized?

February 18, 2012, 07:33 PM
all brass was once fired and then FL sized to where the die was touchong the shell holder at the top of its stroke. actually when the shell holder had camed over from the top of its stroke. thanks Centaur 1. that was going to be my next question. it is a great feeling to have the assistance from so many people here. i wish everyone in the world was as helpfull to others.

my next questions are... when i resized these cases, i did about 300 of them at the same time and primed them as well so once i found an accurate load i could load up a bunch. i guess all those are trash now? or just give them to my girlfriends dad to shoot out of his 243s? i dont want to fire form them back with these kinds of pressure signs.

also, this 243 is a lever gun, which to my understanding has less mechanical advantage than bolt action. is it very dangerous to just neck size when reloading for a lever action? the last thing i want is to have a round not chamber all the way when a 300lb boar is charging my girlfriend? although that could be better than having chunks of metal and hou gasses flying in her face from too much headspace.

Striker Fired
February 18, 2012, 08:04 PM
Load up a small batch for your girlfriends dad that fit in his gun and see if they show pressure signs in there.That would tell you if it's your gun,the brass,or die set-up.I would try to make sure that the shoulder isn't too far back for his rifle though.Do you have a factory round that you could compare the shoulder placement with? Not a real good stand in for a headspace gage but it should get you very close.Mostly you would want to see if it is pushed back farther than the factory round. If it is DON'T SHOOT THEM.

Centaur 1
February 18, 2012, 09:56 PM
my next questions are... when i resized these cases, i did about 300 of them at the same time and primed them as well so once i found an accurate load i could load up a bunch. i guess all those are trash now? or just give them to my girlfriends dad to shoot out of his 243s? i dont want to fire form them back with these kinds of pressure signs.

also, this 243 is a lever gun, which to my understanding has less mechanical advantage than bolt action. is it very dangerous to just neck size when reloading for a lever action?

Look up how to make loads for fireforming brass. I've never done it, but you can find information how to do it. I'm sure that you could use the same procedure for this brass that you would use if you rechambered the rifle to an ackley improved caliber. I've read where guys will use a mild charge of pistol powder, and top it with stuff like cream of wheat. Just enough pressure to move the brass back were it needs to be without building excess pressure.

You won't be neck sizing unless you buy a neck sizing die. Use the full length die that you have, and use the instructions that I posted. Even if you don't push the shoulder back any, the FL die will still size the body of the shell. When I load for my lever action I adjust the die so it just kisses the shoulder and there is never any trouble with cartridges sticking in the chamber.

February 18, 2012, 11:31 PM
What kind of pistol powders do you have?

February 19, 2012, 06:08 PM
for pistol powders i have- titegroup, h110, only about 1/4 lb of win 296, tons of hs-6, blue dot, pistol power, an old 3lb can of Alcan Al-5, and an old 15lb cardboard drum of hurcules (now alliant) red dot which is still good

Striker Fired
February 19, 2012, 06:24 PM
Red Dot is a common fire forming powder, but I don't know what charge to use ,most likely somewhere around 5 to 8gr.

February 19, 2012, 06:36 PM
i just got done comparing these reloads to ppu 100 gr sp which was the only facory loads i have laying around. everything seemed dead on with those and i checked all dimensions given in the hornady reloading manual from the illustration with out anything being out of spec. the only measurement i could not take was to confirm that the angle of the shoulder was 20 deg. the only thing i could find is at the bottom of the case shoulder the ppu ammo was much more rounded where the shoulder starts where mine is not very rounded. more of a clean change to the shoulder angle.

I also compared the fired reload cases to some of the loads i didnt fire but from the same batch. everything was the same except the case body just before the shoulder starts was a few thousanths larger dia on the fired brass than the unfired, the neck of the case was quite a bit larger dia on the fired brass and the fired brass was stretched a bit but distance from the case head to where the shoulder starts and stops seemed the same although i was eyeballing it with a caliper.

February 19, 2012, 06:59 PM
Try 2 loadings with resizing in between loadings of ether 6gn Red Dot or 12gn Blue Dot with your projectile then measure the case again. You may need to neck size for the second loading.

February 19, 2012, 07:49 PM
Fire Forming. The case will headspace on the false shoulder, which will hold the case against the bolt face when fireforming. This will prevent the case from stretching/thinning and prevent case head separations. The actual false shoulder location will depend on your chamber headspace and the location of the shoulder of the case.
The case mouth is opened with a tapered expander to the next larger caliber. Then run up part way, not fully, into a full length sizing die. The bolt should close with a little resistence. This fire forming is needed when the case headspace, distance from head to datum line on shoulder, is under .010" or more when compared to the chamber of the rifle. This will not help factory ammo brass that has been damaged on the first firing. http://i338.photobucket.com/albums/n420/joe1944usa/Firearms%20%20and%20%20Reloading/falseshoulder.jpg

February 20, 2012, 03:42 PM
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
Bad day at the range shooting a 243 10 years ago, but I got 30,000 downloads on the picture.

The .243 is SAAMI registered at 60,000 psi max and 78,000 -84,000 psi proof test.

The 243 has the same case head as the 270 registered at 65,000 psi and the 8mmMauser registered at 35,000 psi, but they all have the same case heads with the same strength.

That case head is made out of C26000 brass (cartridge brass)Temper - H06
Tensile yield strength - 65,300 psi.
That brass can be formed into a weak shape, like a 10mm pistol cartridge, or a strong shape like a 38 Special case.
But no matter how beefy around the primer pocket, it is still going to have problems somewhere around it's tensile yield, but that could be over 80,000 psi in the 6mmBR with small primer pocket.

When a rimless brass case fails from pressure, the primer pocket gets loose.
This is the limit that drives the SAAMI registration.
If primer pockets got loose at 100,000 psi, most cartridges would be registered at 90,000 psi.
If primer pockets got loose at 50,000 psi, most cartridges would be registered at 45,000 psi.

The foundation of load data is not built on sand, it is built on tight primer pockets.

The 243 case head can get long brass life in a individual rifle at ~ 67,000 psi with margin for load to load variation, temp variation with powder, dirty chamber, etc.

I have noticed that Varget is not only temperature stable, but it is also very accurately characterized in the Quickload library. No adjustments required.

The extractor groove growth of .001" in one shot will occur at 75,000 psi with Varget in 243.

I can tell you that the difference between 60kpsi and 67 kpsi in 243 is about 1 gr of Varget.

Striker Fired
February 20, 2012, 04:20 PM
What did the bolt face look like after that little "experiment"?

February 20, 2012, 06:17 PM
The last batch of 100 .243 cases I purchased had cases as short as .009 below minimum headspace. Add this to your actual headspace and you can easily have .012 head clearance or "air space" between the bolt face and the rear of the case.

The average full length resizing die is setup to push the shoulder back .002 smaller than minimum headspace, this allows the resized cartridge to fit in any chamber. By using the resizing dies instructions you can be "OVER" resizing these cases and be causing premature case head separations.

I set the full length resizing dies up per the instructions "BUT" I use headspace control shims to "CONTROL" how far the shoulder is actually pushed back (if at all) during resizing.


By placing these shims under the dies lock ring "YOU" control your cartridge case headspace and "WHERE" the shoulder of the case ends up after resizing.



Having some simple gauges and measuring tools can virtually stop any case head separations from happening.



February 20, 2012, 07:58 PM
Rossi in 243? Pick the cases that don't have the shiny line close to the case head, use the paper clip on the inside to see if there is a groove. Use a mild load and shoot them. It will blow the shoulder back out without separation. Make sure the chamber has NO oil in it. Use a once fired factory case to do the partial N/S thing. When the lever closes easily, your done. Smoke and size one of your questionable cases with the SAME die adjustment to see if the shoulder is still too far back. You can check a once fired factory case with a partially seated USED primer to check the H/S, use a pencil or something to fully seat the case in the chamber, close the lever fully. Slowly extract the case and measure how far the primer sticks out. Check against SAAMI specs to see if rifle work needs to be done. You are using a 100 grn SP for piggies, right?

February 21, 2012, 12:05 AM
Striker Fired
What did the bolt face look like after that little "experiment"?

10 years ago I was bending bolts and truing bolt faces.

But that was before the above pic.

I do not think the gun has been shot since.

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