I have been trying to load 9mm largo with hard cast lead bullets. The cast bullets mic @ .356 and are 124 gr. It seems the olgive and being the the bullet mics @ .356 will not chamber in my M400 Astra. Loading FMJ bullets is no problem at all. Has anyone else run into this problem?
problems W/ 9mm largo +cast bullets
- Thread starter joem1945
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Blue68f100
Member
Paint up the bullet with a marker and see where the contact is. Then you will be able to make a knowledgeable decision. Sound like the bullet is contacting the rifling.
Tried that already. Seated bullet way shorter than spec and about .125 shorter that the FMJ that fit and shoot. The chamber was cut with a finish reamer so I know it's correct. I think if the dia was .355 it would fit. My FMJ loads fit very well and it looks like all the cast bullets are .356.
chris in va
Member
I've reloaded thousands of 9mm Luger using various FMJ and LRN profiles. It's been my experience LRN has to be loaded shorter, depending on bullet ogive profile and chamber leade.
For example, I can use a 124gr FMJ AT 1.10, but the same weight in LRN has to be at 1.07 before it passes the plunk test. My loads cannot approach max charge due to this so I back it off a bit.
I know nothing about 9mm Largo except for what I've read. It appears there is a bunch of extra space available using approximately the same powder charge as Luger. I would ass-u-me you could load Largo fairly short and still have considerable space left to not worry about overpressure.
Again, just an assumption.
BTW, you want at least .001 over bore diameter with lead bullets, preferably .002.
For example, I can use a 124gr FMJ AT 1.10, but the same weight in LRN has to be at 1.07 before it passes the plunk test. My loads cannot approach max charge due to this so I back it off a bit.
I know nothing about 9mm Largo except for what I've read. It appears there is a bunch of extra space available using approximately the same powder charge as Luger. I would ass-u-me you could load Largo fairly short and still have considerable space left to not worry about overpressure.
Again, just an assumption.
BTW, you want at least .001 over bore diameter with lead bullets, preferably .002.
Blue68f100
Member
0.125" shorter OAL is a lot. You may be getting down into the case where it starts getting thicker. Also if your using mixed brass you will run into different wall thickness and internal volume. Particularly if you have some IMT or Ammoload brass that has the internal step. See if the problem is related to a particular MFG.
TimSr
Member
I'm not familiar with the 9mm Largo, but I ran into an interesting situation with .380, in that while it is the same diameter as 9mm Luger, many of them wont chamber .356 bullets due to the case profile, or something of that nature. The question was asked as to why .380 load data called for .355 in jacket or cast bullets while 9mm called for .355 jacket and .356 cast, which made no sense to me. A little investigation revealed that the extra .001" was critical in some .380s while nnot so in 9mm Luger.
I'm wondering if you are having similar issues.
I'm wondering if you are having similar issues.
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