Taper crimping?

One very big oops. I fired a round in my Polytech M-14s that hadn't been taper crimped. The bullet lodged in the barrel and Idiot Moron Trigger Puller failed to notice that little teeny fact. The loads I was using were running around 2900 fps and the next bullet blew out the side of the barrel. No idiots were harmed.

How much taper crimp is enough for a semi-auto .308?

Hooda Thunkit said:

All I can say is : Holy split barrel Batman ! You are lucky nobody was hurt !

Perhaps you should stick to axes Lizzie.

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I don't do axes. I do swords.

These are commercial reloads from Freedom Munitions in Lewiston Idaho. I pulled the bullets on 10 rounds to check charge consistency - they were okay for commercial reloads. I re-seated the bullets and taper crimped the rounds.

A short charge is a real possibility, I had two squib loads that cleared the barrel at a velocity of about 1100 fps. With the third squib load, I didn't check the chronograph. Bad mistake.

My only injury is my pride. I've never done something that stupid with a firearm. I was shooting prone and the barrel ruptured on the left side, so I was clear of the shrapnel and I was shooting in the back yard.

I suppose the smart thing to do next is weigh all the rounds, looking for light outliers.

MEHavey said:

The bolt actually cycled with the that first/stuck round?

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Thinking about it - no, it did not. Missed Red Flag number 3.

DocRock said:

Glad you were not injured. Sorry that your rifle was. A bullet obstruction like does not arise from insufficient crimp. An insufficient charge seems most likely.

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It's obvious a sign from above that I need to dump the Polytech and buy an SA M1A.

A quick weight check of 20 rounds was disturbing. The cases are all LC 17 and the weight variation was +/- 5 grains. I haven't weighed the powder, but I'm guessing the charge is supposed to be between 40 and 44 grains. If the variation is solely due to the powder, that's a 12% variation in the charge. I'm sure it's not just the powder; there's variation in bullet and case weight.

I think I'm going to be unloading and reloading a bunch of ammunition, because I'm not putting this stuff in my Savage 99.

n2omike said:

A SINGLE squib load is too many. If you had TWO that barely exited the barrel, followed by the one that didn't... you need to find a new ammo source!!!

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I've decided that I'm going to rely on my Lyman Turret press.

MEHavey said:

OOC: What "type" (appearance) was the powder when you dumped it -- stick or ball/spheroidal ?

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It's ball powder. Single cartridge charge was 44.7 grains.

Just to shame myself further, I should also have realized that something was terribly wrong when my chonometer was clocking some rounds at 2900+ fps.

DocRock said:

Check whether the LC brass will even chamber well in your 99. Mine did not like milsurp brass at all, even when resized with a small base die. At the time I mentioned this, several folks chimed in with similar observations about milsurp brass and their 99s.

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My 99E has been happy with a steady diet of milsurp brass and ammo. It particularly likes RA 64 brass.

Overall, I think we can all agree that I was stupid and unobservant. And I really appreciate having people tell me where I went wrong.