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Old May 27, 2007, 04:24 PM   #1
Glennster
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Blown out primers on my AR

I've had some trouble with the loads I just built for my AR ( .223 ). The brass (Lapua ) was used once in a bolt rifle, I ran the brass thru a full length die, reamed the primer pocket and loaded them at 1 grain under the max load. I have no problems with factory loads.
When I shoot my loads there are two problems.
1. The brass does not eject, I have to use a cleaning rod to bump it out of the chamber.
2. The primer either sticks out a little, or it just comes out of the case completly.

Any suggestions???
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Old May 27, 2007, 04:45 PM   #2
mc223
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I would say that reaming of primer pockets can be a bad thing. If the loads for the bolt gun were a max type load the pockets could have been stretched and reaming only exagerated an existing condition.
And the loads may be too light for the powder in your rifle. Are the cases sooty?
I have blown primers with max loads in hot weather with Win 748 and BL-C2.
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Old May 27, 2007, 05:17 PM   #3
Unclenick
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The sticking cases in combination with primer piercing seems almost certainly to be excess pressure. You should include the load, the bullet, and your C.O.L. so others can compare it to their own experience. In particular, a load developed in a Winchester case will be too warm for other brands of cases because Winchester makes their cases with more powder space than most. One grain under maximum for a listed load may not be safe in your chamber. Always use a suggested starting load. When one isn't listed, knock 10% the maximum and work it up slowly.

Primer pocket reaming is normally for removing military crimps. If these were NATO loads with crimped primers, you have no choice but to ream. Otherwise, it is an unnecessary step. Primer pocket depth uniforming (different tool) is commonly done for accuracy improvement.

Also, be on the lookout for cases made for use with lead-free primers. They can have bigger flashholes than normal. Too big for a normal primer, and that can cause primer blowout.
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Last edited by Unclenick; May 27, 2007 at 06:26 PM.
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Old May 27, 2007, 06:23 PM   #4
Glennster
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What is C.O.L. ?
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Old May 27, 2007, 06:32 PM   #5
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Sorry, I edited above: It is primer piercing in combination with sticky cases that seems like a sure indicator of excess pressure. Sometimes I curse cut-and-paste for editing, sometimes I don't know what I'd do without it.

C.O.L. stands for Cartridge Overall Length. You will also see O.A.L. and C.O.A.L., or anyone of the three without the periods. The latter two break the compound word "overall" into two words initialled "O.A.". I don't know why? "Overall" has been a compound word since Chaucer's day. The whole mess began when the NRA used to write out "Cartridge O.A.L.". Don't know who came up with that version? In any event, they all mean the same thing: the length of the finished cartridge from stem to stern. The distance from the tip of the bullet to the back of the casehead (where all the markings are stamped).
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Old May 27, 2007, 08:17 PM   #6
Slamfire
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Cut your loads. Reduce your powder charge by half a grain until you stop blowing primers. Does not matter how nice and sweet and pretty your loads are in another rifle. They are all different. Bottom line cut your loads. You have too much pressure.

And if you don't, expect to be changing out your firing pin soon.
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Old May 27, 2007, 08:58 PM   #7
Glennster
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Thank you gentlemen....
When you say C.O.L., do you mean total length of bullet or ogive to base of case length?
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Old May 27, 2007, 09:22 PM   #8
Tim R
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COL is cartridge over all length. Ogive has nothing to do with it. I would guess you are running your ammo to mag length.

I would never load 1 gr. under max without first working up. I shoot a lot of 223 in a AR and have never lost a primer. I've pierced 4 or 5 primers when I used Federal match primers in place of Remington 7 1/2's. The load was not all that hot either.

I shoot with a guy who was loosing primers out of his 223 during a match. He was using Federal brass and had loaded them 5 times before. The primer pockets had gotten larger and he should have tossed the stuff before it counted.

Lapua on the other hand, is the best brass out there, (wish I could afford to shoot it in a gas gun) but it is heavier than Lake City and Winchester brass and therefore has less case capacity. By using 1 gr less than a published max load and Lupua brass you more than likley are running WAY HOT! This is why we work up loads up first.
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Old May 27, 2007, 09:51 PM   #9
Glennster
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Again, thank you gentlemen......
GREAT help for a rookie loader....
Your help and good info is much appreciated ! ! !
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Old May 28, 2007, 09:09 AM   #10
Mach II Sailor
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i NEVER ream a primer pocket !!

swageing is the only way to reform primer pockets in military brass.
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Old May 28, 2007, 11:37 AM   #11
Glennster
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I mis-spoke, I did not ream the pockets. I used a Primer Pocket depth uniforming tool. Got it from Sinclairs.
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Old May 28, 2007, 11:58 AM   #12
Mal H
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Repeating Unclenick's question: What is the load you used? powder type and weight/bullet type and weight/primer type and mfg.

Now that you know the definition of COL, what was it for your rounds?

All of that info is very important before any good analysis can be given.
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