lesson learned...primer pockets

[danny]

I believe the reason for the light strikes was the firing pin driving the primer somewhat further into the case. I didn't notice an appreciable difference in primer depth between unmodified and modified cases. I believe the deeper indent in the second group of cases was because the primers were completely bottomed around their circumference and therefore couldn't be pushed deeper.

Posting removed

 

[1lnbrdg]

It's called "Fire Forming" If you don't have the bullet jammed into the lands or a false shoulder, you are going to get the occasional light strike on your primers because you are making the case "longer" in certain dimensions when it is fired since you are firing a piece of brass that was formed for shorter dimensions.

 

[Lone Hunter]

You have either too much headspace, not enough firing pin protrusion or not enough spring power .
If your fp protrusion was 50 and your headspace was correct ( crush for fireform) your primer would be indented the amount of your firing pin protrusion.
How are you eliminating the military crimp to begin with ?

Old_Dude, Try this and just see if it will work. Your way or anybody else's way is not always the right way. If you ask for advice you need to be willing to take and use that advice. Not trying to be a Smart Azz but if you ask for advice try it. It may just work. Ggmac gave you some sound advice.

 

[Deleted old_dood]

Old_Dude, Try this and just see if it will work. Your way or anybody else's way is not always the right way. If you ask for advice you need to be willing to take and use that advice. Not trying to be a Smart Azz but if you ask for advice try it. It may just work. Ggmac gave you some sound advice.

actually, I'm going to order a 223ai nogo gauge from Manson reamers since they are who provided the go gauge. That would allow me to sell my regular 223 gauges. And just for the record, I didn't ask for advice. I only stated what worked for me. In addition, no one has yet answered the question of why two rounds failed to fire in another conventional 223. All primers were properly bottomed out with my adjustable priming tool like I'd done thousands of times. IMO, the fact of having high spots in the bottom of the primer pocket reduced the force with which the fp struck the primers. The pictures I posted prove it. When those high spots were eliminated and the primer was supported around its entire circumference, they all fired even if they were slightly lower. I'm an experienced shooter and reloader who has 2 Savage 12s and have changed barrels using the proper methods and tools multiple times on both rifles. If some want to think I'm stubborn that's fine. I will continue to do what works for me.

 

[1lnbrdg]

actually, I'm going to order a 223ai nogo gauge from Manson reamers since they are who provided the go gauge. That would allow me to sell my regular 223 gauges. And just for the record, I didn't ask for advice. I only stated what worked for me. In addition, no one has yet answered the question of why two rounds failed to fire in another conventional 223. All primers were properly bottomed out with my adjustable priming tool like I'd done thousands of times. IMO, the fact of having high spots in the bottom of the primer pocket reduced the force with which the fp struck the primers. The pictures I posted prove it. When those high spots were eliminated and the primer was supported around its entire circumference, they all fired even if they were slightly lower. I'm an experienced shooter and reloader who has 2 Savage 12s and have changed barrels using the proper methods and tools multiple times on both rifles. If some want to think I'm stubborn that's fine. I will continue to do what works for me.

The rounds fired in the .223 chamber because that was the chamber length the cartridge was designed for. In case of the .223AI, the headspace of the chamber is actually longer which allows the cartridge to go forward when the cartridge is fired since the headspace of that chamber is longer (reference Guffey, did I get that right?). <ok, now I went and done it>

 

[spife7980]

You dont need to buy a no go. You could just put a layer of scotch tape on the end of your ackley go gauge to add ~.002" to it. If it still closes do another until it doesnt. Measure with a comparator to see how far over the go gauges measurement you are out.

 

[Deleted old_dood]

The rounds fired in the .223 chamber because that was the chamber length the cartridge was designed for. In case of the .223AI, the headspace of the chamber is actually longer which allows the cartridge to go forward when the cartridge is fired since the headspace of that chamber is longer (reference Guffey, did I get that right?). <ok, now I went and done it>

I SAID THE ROUNDS DID NOT FIRE IN THE OTHER RIFLE.

 

[GrocMax]

Use 400's or WSR primers for fireforming. Don't use 450's until case is fully formed. 450's in particular are too thick and insensitive, just shoves the case forward. Keep in mind 400's can pierce/blank in upper pressure loads.

Been there done that got the t-shirt on fireforming 223 based AI's. Shallow shoulder angle, thin annealed brass and 450's = FTF proper headspace or not.

Keep in mind new brass is often undersized to go in a minimum chamber. Add it all up you get problems. Use 400's for fireforming.

Make a comparitor bushing of approx. .256" ID and measure neck length before and after a new FF case 450 primer FTF- the amount of new neck length will shock you.

Can only speculate that uniforming the primer pockets worked to increase primer sensitivity somehow.

 

[Deleted old_dood]

Use 400's or WSR primers for fireforming. Don't use 450's until case is fully formed. 450's in particular are too thick and insensitive, just shoves the case forward. Keep in mind 400's can pierce/blank in upper pressure loads.

this makes sense; thanks. Still have the issue of FTF in a different rifle though.

Make a comparitor bushing of approx. .256" ID and measure neck length before and after a new FF case 450 primer FTF- the amount of new neck length will shock you.

don't understand. if it fails to fire the neck length won't change at all, will it?

Can only speculate that uniforming the primer pockets worked to increase primer sensitivity somehow.

my belief entirely. better support of primer in the pocket.

 

[mikld]

If I were old dood, I think I'd give up on this thread, as every possible problem/cure has been guessed at even after dood has he has already checked and OKed the method/cure suggested. I don't "fire form" brass for "improved" cylinders so I can't comment on that but dood has explained, a few times, his case sizing is OK. Seems like lots of fellers will read one or two posts in a thread and in a hurry to add their 2 cents skip over the rest...

Not condemning, just pointing out human behavior and "forum thread thinking"...

 

[alinwa]

If I were old dood, I think I'd give up on this thread, as every possible problem/cure has been guessed at even after dood has he has already checked and OKed the method/cure suggested. I don't "fire form" brass for "improved" cylinders so I can't comment on that but dood has explained, a few times, his case sizing is OK. Seems like lots of fellers will read one or two posts in a thread and in a hurry to add their 2 cents skip over the rest...

Not condemning, just pointing out human behavior and "forum thread thinking"...

Well, no, not even close to "every possible problem/cure" has been approached. We're only scratching the surface at this point.

Opinions vary.

The problem exists, the "fix" is illogical and while (as often happens) dood DID find improvement, causality is flawed.

period.

And some of us refuse to believe in magic, I'm typing here because of PHYSICS, not cuz magic gremlins in thee box.

You're right, you don't understand "improved" cylinders but still assume his case sizing is OK.

I'm pointing this out only to illustrate that YOU are "one of those fellers" and

Not condemning, just pointing out human behavior and "forum thread thinking" ....


(Even though I have no idea from whence your concept of "forum thread thinking" has been formed)

 

[ShaneG.]

The headspace of the rifle could be spot on and if set with the go gauge probably is. The cases you said were new and unfired could have a shoulder dimension that is shorter than normal or just a few short ones. The first time you stated they were loaded with cci450 and after tearing down and repriming you stated you used cci 400 then they fired. The harder cup of the 450 and a case a little short on shoulder length could cause it. Also if the shoulder was short that could be the reason the other rifle misfired as well. I got about 3 rifles that will hangfire Wolf SRM primers something scary and a couple of them fire them off no problem.

Try to find a way to hold the case back against the boltface just like a jammed bullet would and see if your firing pin make a deeper indention. Also measure cases base to shoulder to see how consistant the are with each other.

I have seen cases short enough that a bottomed out primer was shoved back out noticeably after being fired, a jammed bullet might have stopped it.

I agree if your cutting the pocket deeper to uniform it should make the problem worse.

 

[alinwa]

And BTW...... the REAL PROBLEM hasn't even been mentioned yet. The somewhat dangerous problem of head separation. Elsewhere on site someone just experienced a head separation..."nick in safety glasses, blood on face" as I recall......The problem with short brass and long chambers is that when you finally DO get them to fire, then the dangerous problems start.

Any assumption that all "forum peeple" here are just a mindless bunch of jagoffs speculating wildly on the innertube in a failed attempt at self-validation is flawed in it's face.

 

[paperpuncher]

I also think this may be an excessive HS issue. I am not convinced that your rifle has excessive HS but is it possible that the brass you are using is creating an excessive HS situation? Do you have a device that will allow you to accurately measure from the case head to the datum ref. point? If so measure the 223 cases you have and compare them to a known standard such as a 223 rem go gauge. You can quickly eliminate a variable. I have a possible explanation as to why your results are better after you uniformed the pockets, this will sound counter intuitive but I observed last week loading 223 ammo and was surprised. You said that you took the cases that did not fire and decapped them uniformed the pockets reprimed them and they worked. I will assume you de-primed them with a FL sizing die and offer the following explanation, and then Ill put my nomex suit on. I made a simple device by partially reaming a piece of barrel and fashioning it in a way that it could be fastened to my caliper to measure the base to datum of my cases when I was sizing them. Start with a fired case from my rifle measure and set caliper to 0. Now I slowly lower the sizing die checking my results as I lower the die. I expected to observe that as I lowered the die the shoulder would bump back and I would see a -.001 ect. What actually happened surprised me a bit the case actually "grew" a little before the shoulder started to push back. I suspect that some dimensional differences between my dies and the chamber caused the cases to be squeezed a little causing the shoulder to get pushed forward a bit before the die could come in contact with the shoulder to move it back. So if you had cases that created excessive HS then you decapped them and your dies like mine squeezed that shoulder forward a bit it could correct the HS enough to make the FP strike OK. Short HS on your cases would explain why they would not fire in your buddys rifle. Im just throwin some against the wall YMMMV

 

[Dusty Stevens]

Does your brass have a crush fit? Can you feel them when closing a stripped bolt on them?

 

[6MMsteve]

I quit uniforming pockets along time ago, because I cut them to deep plus the pocket needs to be concave some for the blast from the primer to gather thru the flashhole, I could be wrong though

 

[mr45man]

A full length die can absolutely "stretch " brass.

 

[sawcarver]

Take a piece of brass neck it to 6mm then back down to .224 until the bolt closes with some resistance, crush fit, load that round and fire it then measure that piece of brass vs the rest and see how much of a difference it is

 

[Homerange]

If I were old dood, I think I'd give up on this thread, as every possible problem/cure has been guessed at even after dood has he has already checked and OKed the method/cure suggested. I don't "fire form" brass for "improved" cylinders so I can't comment on that but dood has explained, a few times, his case sizing is OK. Seems like lots of fellers will read one or two posts in a thread and in a hurry to add their 2 cents skip over the rest...

Not condemning, just pointing out human behavior and "forum thread thinking"...

Yep and a potential clue was raised earlier and a question was asked about crimping that old dood overlooked to mean neck crimps. In fact if I understood the question that IIRC was asked after brass pics were posted that showed what appeared to be a existing primer crimp. Working with brass without uniforming that existing crimp can make primer insertion difficult and stress primers so the anvil is not properly located............hey presto........misfires !

 

[mr45man]

In theory new brass should have the same head space in a Ackley chamber.