I have been successfully reloading for many years but have recently had problems when making 22-250 bullets for an M12 Mauser. After I run the brass through a full length sizing die, the bullets fit very tight inside the gun and some of them will not chamber. The gun chambers factory rounds very well and will chamber neck sized reloads, but after I run a brass that will chamber in my gun through a sizing die, it no longer fits well. I tried three different brands of sizing dies and even tried two different presses and they all have the same problem. I have have already checked to make sure that the sizing dies are screwed down all the way and have tried just about everything that I can think of to fix the problem. I tried trimming the case length, seating the bullet deeper in the brass, and even test fitted just brass with no bullets, and nothing that I have done has fixed the problem. I have narrowed the problem down to full length sizing because I can take a brass that chamber very well and if I run it through the sizing die, it will fit very tight inside my gun and sometimes not fit at all.
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22-250 bullet won't fit after sizing
- Thread starter pb101
- Start date
603Country
New member
Must be that you are crunching the case in the FL die, causing the case to bulge slightly at the shoulder. The NK die won't do that. That's my guess.
condor bravo
New member
If I am reading the problem correctly, it sounds identical to what I had with a .22-250, Remington Mdl 700. What apparently is happening is that upon full length resizing, the case elongates to the point where the round will not chamber, thereby requiring some shoulder set back to shorten the case to normal. First try as 1stmar suggests by screwing the sizer die down past shell holder contact and see if cam-over sizing will provide the necessary shortening of the case. If not, trying a different sizing die would be next in order. But you say you have tried three with the same results. The sizing die needs to be screwed down farther than what the shell holder and caming-over will allow. With my .22-250 and several other calibers to follow, the solution was to grind some metal off the mouth of the sizing die, thereby allowing the die to be screwed down farther to privide case contact with the shoulder. This is easy to do with a small grinding wheel attached to an electric drill. Using a file takes a little longer. This may sound like you are ruining the die but certainly not. Others might suggest grinding down the shell holder instead but I find it more preferable to shorten the die.
WHERE is the contact?
I do not know what is causing your problem - never experienced this myself. Case length after sizing is easy to check and should be the first step - probably not the issue since you have trimmed the cases, but still a simple check. Next would be neck OD and neck thickness after sizing, again probably not the problems since you said neck sizing does not cause the problem, but still easy to compare between a case that fits and one that does not. You could also spend time with a micrometer comparing various other points of the case trying to stumble onto the difference after sizing, but why bother...?
Sounds to me like you have skipped the most important step in trying to fix this - you do not seem to know just WHERE the resized brass is contacting the chamber. Without that information, you will just waste time and money modifying things in the dark just hoping to stumble onto a fix.
You need to coat a resized case with something that will rub off under contact. Black marker often works just fine for that, or you could use Prussian Blue (used for checking helical gear contact patterns). After running the test case into the chamber and finding a tight fit, you should know immediately where the problems is happening and be able to work out a fix. I doubt seriously that trying to mash the sizing die down harder is the right solution. But if the problem turns out to truly be insufficient shoulder setback, consider just changing your shell holder. Different brands are often different thickness, so they may not perform well with mismatched brand dies. I only neck size my .22-250 loads, so that has never been an issue for me, but maybe it is for you?
I do not know what is causing your problem - never experienced this myself. Case length after sizing is easy to check and should be the first step - probably not the issue since you have trimmed the cases, but still a simple check. Next would be neck OD and neck thickness after sizing, again probably not the problems since you said neck sizing does not cause the problem, but still easy to compare between a case that fits and one that does not. You could also spend time with a micrometer comparing various other points of the case trying to stumble onto the difference after sizing, but why bother...?
Sounds to me like you have skipped the most important step in trying to fix this - you do not seem to know just WHERE the resized brass is contacting the chamber. Without that information, you will just waste time and money modifying things in the dark just hoping to stumble onto a fix.
You need to coat a resized case with something that will rub off under contact. Black marker often works just fine for that, or you could use Prussian Blue (used for checking helical gear contact patterns). After running the test case into the chamber and finding a tight fit, you should know immediately where the problems is happening and be able to work out a fix. I doubt seriously that trying to mash the sizing die down harder is the right solution. But if the problem turns out to truly be insufficient shoulder setback, consider just changing your shell holder. Different brands are often different thickness, so they may not perform well with mismatched brand dies. I only neck size my .22-250 loads, so that has never been an issue for me, but maybe it is for you?
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Most common problem is not enough shoulder set back, but if that's not the case.....and assuming that both, you've never (successfully) reloaded for this particular rifle before, and your Mauser M12 is a tightish chamber designed for top accuracy.......
Then try a small base sizer. I know that's not usually needed especially for bolt guns, but it just may be, that the chamber is cut close to minimum at the base.....therefore factory works fine, but regular full length sizers don't size the base area above the extractor groove down enough to allow the base go all the way in a tight chamber. SBS's only squeeze them one or two thousandths, but it can make all the difference.
As Mauser 69 suggested, first a test is in order.... a sized case painted with black magic marker & carefully run into the chamber worked well for me to trouble shoot where my problem was. Magic marker showed the base was just a tad too big around.
My problem was with a Remington R-25 in .308. I know, not a bolt gun, but it ran Winchester and Remington factory fine, but then I tried a box of Federal Power Shok (blue box) and it would chamber the first round, but the next auto-loaded round wouldn't go into battery.... Same with reloads until I bought a small-base die. Just depends on the rifle.
One positive: A tight chamber is often a more accurate chamber.....turned out to be so with my Remington R25. Reloads using even a SBD is still a little tighter than factory. They don't squeeze clear down to factory.
Then try a small base sizer. I know that's not usually needed especially for bolt guns, but it just may be, that the chamber is cut close to minimum at the base.....therefore factory works fine, but regular full length sizers don't size the base area above the extractor groove down enough to allow the base go all the way in a tight chamber. SBS's only squeeze them one or two thousandths, but it can make all the difference.
As Mauser 69 suggested, first a test is in order.... a sized case painted with black magic marker & carefully run into the chamber worked well for me to trouble shoot where my problem was. Magic marker showed the base was just a tad too big around.
My problem was with a Remington R-25 in .308. I know, not a bolt gun, but it ran Winchester and Remington factory fine, but then I tried a box of Federal Power Shok (blue box) and it would chamber the first round, but the next auto-loaded round wouldn't go into battery.... Same with reloads until I bought a small-base die. Just depends on the rifle.
One positive: A tight chamber is often a more accurate chamber.....turned out to be so with my Remington R25. Reloads using even a SBD is still a little tighter than factory. They don't squeeze clear down to factory.
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condor bravo
New member
pb101 & mauser69:
Another media that can be used to check shoulder contact within the chamber is powdered graphite, either white or black. Apply a layer around the neck of a tight fitting case and chamber, or attempt to chamber, the case and upon extraction see if the graphite is smudged on the shoulder. If so, an indication for the need of shoulder set-back. I've had at least four sizing dies over different calibers where a reduction in sizing die length was required in order to attain shoulder set-back within the die. Grinding off a small portion of the sizing die cures the problem and is certainly not a disastrous or big deal solution.
Another media that can be used to check shoulder contact within the chamber is powdered graphite, either white or black. Apply a layer around the neck of a tight fitting case and chamber, or attempt to chamber, the case and upon extraction see if the graphite is smudged on the shoulder. If so, an indication for the need of shoulder set-back. I've had at least four sizing dies over different calibers where a reduction in sizing die length was required in order to attain shoulder set-back within the die. Grinding off a small portion of the sizing die cures the problem and is certainly not a disastrous or big deal solution.
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