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Discussion Starter #1
So I just loaded up some m855 pull downs with bl-c2 and had flattened primers. I'm not sure what the problem is. I loaded with cci small rifle primers and 24 grains of bl-c2.

The only thing I can think of is I used load data for 63 grain bullets since that was the closest published data. I assumed that this would be fine as long as I started at the minimum listed load but apparently not. Can anyone point point out what I am missing?
 

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What kind of brass are you using?
 

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Discussion Starter #4
I am using mixed brass. My notes say I was loading to 2.250 but I just measured a couple and They are closer to 2.235, although that still puts the cannelure at the case mouth and that seems pretty close to magazine length.
 

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Min OAL is 2.25" for 62gr if I recall correctly (look that up to be sure, my memory isn't always right) and you're under that. I would start by moving them out a little if that turns out to be correct.
 

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Discussion Starter #6
I will try that, I will have to figure out what went wrong with my dies, I must have tighten the plug down on accident. That would make sense, since one of the primers looked good. I Must have loaded one, and then goofed up my die. Will using data for 63gr bullet cause any problems since this is a 62gr. They seem so close that I didn't think so (and I never had a problem using 63gr data with varget in the past) but I figure it is worth asking.
 

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I will try that. Will using data for 63gr bullet cause any problems since this is a 62gr. They seem so close that I didn't think so (and I never had a problem using 63gr data with varget in the past) but I figure it is worth asking.
I would not think so. All other things equal, a 63gr bullet would use less powder than a 62gr so you're on the conservative side of that. Make sure the bullet that you're using data for is the same shape as the one you're loading at least. boat tail or whatever. That would affect the volume inside the case.
 

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weight your bullets just to make sure they aren't heavier, 1 gr in bullet weight is insignificant. I run mine H335 loads a lot shorter than that with out problem.
 

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Keep in mind, the M855 has a lighter-than-lead steel penetrator in it, so it's going to be longer than a 63gr FMJ lead core round, and going to take up a little more case capacity when loaded to the same length.
 

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Discussion Starter #11
are you trimming the cases?...are you crimping the bullet?....is it chambered for 5.56 or 223?
I did trim the cases, I didn't apply any crimp, and my rifle is chambered in 5.56

weight your bullets just to make sure they aren't heavier, 1 gr in bullet weight is insignificant. I run mine H335 loads a lot shorter than that with out problem.
I'll check the weight, but I haven't had any problem before.

Keep in mind, the M855 has a lighter-than-lead steel penetrator in it, so it's going to be longer than a 63gr FMJ lead core round, and going to take up a little more case capacity when loaded to the same length.
Do you know where I can get any load data specifically for M855? Hodgdon didn't have any data, and my sierra load manual didn't either
 

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your not going to find data for military bullets on a commercial site, only commercial, reloading isn't an exact science, thats why it is always advised to start 10% below the minimum load. The data for 63 Sierra sp is 24 gr at 2.200" see if you can get the dimensions for that bullet and compare it to the length of what you have and adjust appropriately, start with a load of 22.5 grains and work up. OR start at you current length and start at 22.5 grains
 

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Do you know where I can get any load data specifically for M855? Hodgdon didn't have any data, and my sierra load manual didn't either
If you know the length of the 63gr bullets, add the difference between those and the M855 bullets to your COAL and you should have the same case volume.
 

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Found this stuff on the web

Duplicating NATO cartridges (cloning) - 223 / 5.56 / 9mm reload central database

M855 5.56 mm
62
3020±40
27 grs of 748 or BallC2

Recipe for the SS109 62 grain bullet - AR15.Com Mobile
I used the start loads for the Speer 62 gr FMJBT (lead core), and worked up.

In my rifle these loads are safe, and are 1/2 gr below the first signs of pressure.

All these loads use LC brass trimmed to 1.750, neck deburred inside and out.

Primer pocket swaged, Win SR, pulled SS-109 62 gr FMJBT seated to mid cannelure.

Crimped with a Lee FCD (factory crimp die).
BLC2, 26.0 grs. My favorite SS-109 load.
 

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Min OAL is 2.25" for 62gr if I recall correctly (look that up to be sure, my memory isn't always right) and you're under that. I would start by moving them out a little if that turns out to be correct.
I've never found it under 2.260 and I've emptied many many cans
 

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Discussion Starter #20
It's been kind of a crazy week so I haven't posted back. I bumped the col out to 2.25 some of the came out a little long, but none were over 2.26. Even at this col I was still seeing some flattening of the primers. I wound up dropping the powder down a total of 3 grains to 21. With 21 grains the primers looked good. I'm not sure why I had to go so low to keep from getting pressure signs though. I only loaded a couple at 21 grains so I still need to see.how they hit. I don't see a problem with this but does anyone else?

I will post some pics later of the primer pockets. I am pretty sure I have them all seperated still
 
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