Hi,
made a 250 grain bullet cartridge for my 338 and used crimping for the first time with the result that half of the batch didn't feed propery in my BAR semi-auto. I tried measuring a finished cartridge but couldn't find any apparent problems. Made the same number of cartridges with another 250gn bullet, this time without crimping and they all fed normally.

Shot all of the feeding problem cart. (loading them manually and then closing the breech worked) and them reloeaded them with the same bullet, this time without crimping and they all worked.

Any ideas of what happened here?

Maybe a much too hard crimp, possibly making a small bulge in the brass either just below the crimp, or where the sholder meets the case side.

Hello,
Sounds like you are using the "roll crimp" method or pressing the case into the die and forcing the edge/rim of the case neck to be squeezed inward, but if the cases are not all trimmed to same length, different pressure point and each crimp will be different or more than is needed and force outwards the case neck, as in "bulge." If you feel you must crimp, suggest you take a look at the Lee Factory Crimp die. Not that expensive and does a fine job and not so dependent upon the cases being trimmed to the exact same length. Many reloaders do not crimp at all other than your strong, hard kicking calibers. Perhaps others can further advise you on your problem. Good Luck.

I had the same problem with a 308 semiauto before I learned that a crimp wasn't necessary. The cartridges looked fine but obviously, there was a wrinkle somewhere that was causing interference in chambering.

If the bullets of the cartridges in the magazine don't move at all in their respective cartridge necks when the gun is fired, then you don't need to crimp. If you do need to crimp, as dsiteman said, use a Lee Factory Crimp Die.

Does the bullet have a crimp cannelure? Or are you trying to crimp a smooth sided bullet? You don't have to crimp unless you have a tubular magazine or the bullets move under recoil.
Even then, just enough crimp to hold the bullet is enough.
It sounds like you are applying enough to even crush the whole case down, let alone a bulge on the neck.

You will also have problems with feeding if you dip your finished ammunition in boiling pine tar. So why are you crimping? What problem are you seeking to solve by crimping? Does your ammunition try to fall apart if you do not crimp?

There are few instances in which rifle ammunition benefits by crimping. Use in your BAR should not be one of them.

The solution is - stop crimping. All crimping gets you is ammo that won't chamber. I reload a fair bit of hard kicking stuff and never crimp, not even the large nitro expresses. If bullets move under recoil, it's because of an oversize expander ball, not lack of a crimp.
-----------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Thanks all, your posts where all in line with my suspicions. Crimping is now skipped.

Your crimp is too heavy and is bulging the neck so that the case won't feed, back off the crimper. It doesn't take very much at all.

Don't stop crimping, just do it right and use a Lee factory crimp die.
Do a slight crimp just enough to stop the bullet in the last cartridge in the magazine from moving under recoil of the prevously fired 2 magazine full of shots. Keep the last ctg in the mag and load and fire the rifle twice, them measure this ctg that has been pounded by two mags worth of shots.

quote:

Originally posted by greenjoy:
Don't stop crimping, just do it right...

Keep the last ctg in the mag and load and fire the rifle twice, them measure this ctg that has been pounded by two mags worth of shots.

Thats a nice test, will do that and then see if I do need crimping.

quote:

Originally posted by GE:
Hi,
made a 250 grain bullet cartridge for my 338 and used crimping for the first time with the result that half of the batch didn't feed propery in my BAR semi-auto. I tried measuring a finished cartridge but couldn't find any apparent problems. Made the same number of cartridges with another 250gn bullet, this time without crimping and they all fed normally.

Shot all of the feeding problem cart. (loading them manually and then closing the breech worked) and them reloeaded them with the same bullet, this time without crimping and they all worked.

Any ideas of what happened here?

Get a lee Factory Crimp Die!!