Loading with AA #7

Reloading info for the 5.7x28mm

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termite
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Loading with AA #7

Post by termite » 11 Mar 2015, 13:37

I'm just getting back into loading and shooting due to back trouble. Can someone/anyone chime in as to what's going on? I'm loading with 5.9gr of AA#7, trim to 1.130, AOL is 1.580, WSP primer, 40 gr VMax.
On first run of 20 of these I shot them out of my "Mac type" 5.7 pistol, forgot manufacturer name, but was getting about 1640-1660 fps. Felt ok enough to try another batch in my FN 5.7, first round, 1660, 2nd was 585 with funky low toned pop, no squib, next was 1445, and they kept easing down in fps to when I stopped after 10 rounds.
Could the bullets be setting back? I miked the id of the neck before loading and they are running about .215-.2165, this is using my RCBS dies, the Lee die gave me .220-.221 in the neck. I would think that that's plenty of tension.

Any and all help would be greatly appreciated.

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grimmond
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Re: Loading with AA #7

Post by grimmond » 11 Mar 2015, 14:35

Sometimes you don't always get the right amount of tension when sizing. The easiest way to see if your bullets are shifting in the case is to seat one then push the bullet tip against your table. If it goes in you do not have enough tension and I would suggest you look into getting a crimper. You could also measure the OAL of the rounds you had left in the mag to see if they are shorter, which would suggest that they are loose enough to shift from the recoil. Other then a crimper you could polish down your expander/decapper to get a tighter crimp.
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termite
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Re: Loading with AA #7

Post by termite » 11 Mar 2015, 16:11

Thanks Grimmond, I did that with a round, I squished the tip all the way down and bullet didn't move. I've got a die in the 4th spot on press to crimp with. I miked the bullets and got .223, with the neck being .215-.216, that should give me .007-.008, so that should be plenty. I Loaded 5 more, same load, but used Federal primers, had 2 that didn't extract, and only 1 that sounded funky. It was getting too dark for chrono to read right. The FTE may be from dirty gun, but that funky boom with a small flash/fireball is what's concerning me.
I've got 4lbs of tru blue, so may try that next, to see if I get the same results.

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grimmond
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Re: Loading with AA #7

Post by grimmond » 12 Mar 2015, 07:00

How are you measuring your powder for your loads? Based on what you are describing it's sounds like your loads are not equal across the board. If you are using a powder drop, I suggest you stop until you can verify each drop every time with a digital or beam scale. Most powder drops are not accurate enough for the 5.7.....
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termite
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Re: Loading with AA #7

Post by termite » 12 Mar 2015, 12:33

Nope, not powder drop. Using RCBS digital scales that get calibrated every time they are turned on.Can't test any this afternoon cause it's raining, and the wife would get really upset if I did it out the basement garage door.

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grimmond
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Re: Loading with AA #7

Post by grimmond » 12 Mar 2015, 13:47

About the only other thing that comes to mind could be a moisture/humidity issue when you are loading powder. But your results are pretty baffling. As for your wife just tell her it's a critically important experiment that you have to run. Lol
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Rapier1772
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Re: Loading with AA #7

Post by Rapier1772 » 12 Mar 2015, 14:49

grimmond wrote:As for your wife just tell her it's a critically important experiment that you have to run. Lol
Yeah cuz that always works

:p
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termite
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Re: Loading with AA #7

Post by termite » 12 Mar 2015, 19:04

When you say moisture/humidity are you meaning that the powder may be moist and possibly not burning completely?, but it's got me stumped. I haven't used this can of powder in over 2 years, but it doesn't smell funny. From what I remember, powder that is bad with have a weird, funky, maybe even acidic smell, but as far as my old nose can tell, it smells like plain old powder.
And if "momma ain't happy" I sure as crap won't be happy, and "testing" rounds in the basement won't fly, although I have "tested" some CCI 22lr standard velocity with the can into some sandbags a while back, she didn't quite see the humor in that, I did have the door up, but it still scared the crap out of her, so if I have any testing to do, I go out on the back deck and she "allows me" to rattle the windows all I want, but really, my wife is cool with me shooting, even crows out the back door, i got a good one this time around.

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grimmond
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Re: Loading with AA #7

Post by grimmond » 13 Mar 2015, 06:34

Yep moisture and humidity can wreck havoc on loads. When I first started reloading years ago I stored my powder in the garage which was not climate controlled. I started noticing my load data was starting to fluctuate. Another reloader suggested I monitor and record the temp and humidity. And sure enough it was the cause. Now I store my powder in a climate controlled room and keep dehumidifiers where I reload. My loads became more reliable and consistent from batch to batch.
"Let us never forget that good intelligence saves American lives and protects our freedom."
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