Overloading the Powder

[Peter988]

Been going to post this for a little while now. I was holding back because it’s always difficult to tell everyone how you stuffed up. Little background. I have been reloading the 222 for 30 odd years so I’m no beginner. I recently upgraded to a 223 and was asking on another Forum about powder loads. In particular, because the online data differed a fair bit, the discussion was around how different some max loads were stated on different sites. Surprisingly, a number of members argued that you ignore the data and just keep increasing the powder till you see signs around the primer that it’s getting too much. I thought that was not the way for me.

So, after due diligence, I decided to stay with minimum of 23.5 gr to a maximum of 25 gr while I worked up an accurate load. And I am meticulous when measuring powder as in my dotage it’s easy to lose concentration and get it wrong. Found that 24.5 was perfect. This is with 8208.

Doing some more testing recently I had a major blow back. Face full of gas. The primer was blown out of the shell. The bottom was blown out of the magazine. The extracted claw broke off the bolt. The ejectors jammed back inside the bolt. Very depressing. Even more depressing trying to find a Brisbane gunsmith to fix it. A couple knocked me back before Kingston Bro’s took on the job. Very happy with Keith’s work and thoroughly recommend him.

What happened. Wasn’t till a few days later that we found I Had managed to slip a couple of the old 222 shells in among the 223. So I had loaded a 222 with 24.5gr and let fly in the 223. Trouble is the 222 case ain’t designed for that much powder. I have now gotten paranoid about checking my empty cases. But an interesting lesson learned about what happens when the powder charge gets too much.

[TassieTiger]

Thanks for putting this up. It’s all too easy to do and you learn more from mistakes than successes. Glad your okay - Pity about the gun.

I didn’t think there was that much difference in pressures from 222 to 223 but when you consider the Shoulder position in the chamber, I guess it’s easier to understand why the blow back.
Lesson learned.

[Oldbloke]

I guess you have now disposed of (or somehow isolated) all the 222 cases?

I have always filled all the cases and then, using a torch check they look like they are all filled to same level while in the loading block.

The one time I didnt do this I had a squib.

You can't take short cuts reloading.

[JimTom]

I do the same old bloke. Can’t ever be in a rush, steady as she goes.

[SCJ429]

Are you sure that shooting the 222 case is what caused your issue? If you are shooting a 40 grain bullet, the load should not have produced particularly high pressure. If you are shooting a 55 grain bullet, you should have noticed that the load was close to compressing the powder.

I have not shot 222 brass in a 223 but you seem to have experienced extreme amounts of pressure above what I would not expect from the load you described. I have been known to push the pressure limits on a few cases and have seen a few pressure signs. I would not have expected that a load of 24.5 grains of 8208 would produce the dangerous pressure that you produced when shooting 40 to 55 grain projectiles. The wrong cases being used aside.

I am sorry that this happened to you but you should check all the factors that may have contributed to this dangerous pressure situation.

[Oldbloke]

I Hear what your s saying scj249. No experience, but Im guessing the case split near the shoulder.???

[Peter988]

I guess you have now disposed of (or somehow isolated) all the 222 cases?

I have always filled all the cases and then, using a torch check they look like they are all filled to same level while in the loading block.

The one time I didnt do this I had a squib.

You can't take short cuts reloading.

You can believe that. The 222 is semi retired and all shells stored elsewhere. I had previously loaded 500 of the 223 rounds for a culling program I am involved in. And yes - they have all gone under the magnifying glass.

[Blr243]

Could we perhaps have a pic of the case that did the damage?

[Oldbloke]

Could we perhaps have a pic of the case that did the damage?

U read my mind

[Peter988]

Unfortunately it’s been chucked. There was no visible neck damage. Just the primer blown out and flattened.

[SCJ429]

Usually these type of over pressure events come from using too fast a burn rate powder while accidentally using a slower powders charge weight. I am suprised that it was caused by fire forming 222 brass to 223. I can only assume the OP was using 50 grain projectiles?

Seems like a survivable load to me. I am not willing to test my theory with my rifle though.

[Peter988]

55 gr pills behind 24.5 of 8208. Won’t get into a debate. I know the result.

[SCJ429]

If it were me I would be using 2208 or 2206H behind a 55. More speed and use the faster powders for lighter pills.

Glad you did not hurt yourself and you have been able to repair your rifle.

[JimTom]

BM8208 goes well behind a 55gn pill. Will be trying some 2206H in the not to distant future.

[Oldbloke]

ADI list 25.3gr of 8208 as the max with a 55gr bullet for 223. Seems to me there must be more to this.

Have you checked or disasembled the other case(s)?

Too long a case?
Incorrect coal?
Scale set wrong, not zeroed, or faulty?

[Peter988]

ADI list 25.3gr of 8208 as the max with a 55gr bullet for 223. Seems to me there must be more to this.

Have you checked or disasembled the other case(s)?

Too long a case?
Incorrect coal?
Scale set wrong, not zeroed, or faulty?

Yes - but what is the max load for a 222 case?

[SCJ429]

The manual says about 23.2 grain which they say is a compressed load. You are a little over one grain more but as the pressure is not particularly high, you would think that it would not do the damage you experienced. You would think a very fast pistol powder would be needed to make that type of pressure.

[Oldbloke]

Am I wrong? 222 case fired in a 223 chamber. Case would just expand to fit the chamber? Would it not?

Well under the 25.3 max for 223. Id have thouvht it would be ok. Perhaps someone with more experience can comment.

[TassieTiger]

I would have thought the 222 case wouldn’t be able to fill the 223 chamber without giving way...thus the back blast. If you look side by side at cases, that’s a lot of shoulder to fill...it’s going to get thin in areas...

[Oldbloke]

I would have thought the 222 case wouldn’t be able to fill the 223 chamber without giving way...thus the back blast. If you look side by side at cases, that’s a lot of shoulder to fill...it’s going to get thin in areas...

Thats why in one of my earlier posts i asked if the case split near the shoulder. But that isnt the case

On second thoughts, perhaps the charge was slightly compressed rapidly increasing pressure. Just a guess. That would be back to the original theory, an over charge.

[animalpest]

The .222 case could not expand enough to fill a .223 chamber and still stay intact when using full power loads. I would think a case head separation would be inevitable.

Headspace would be extreme resulting in a blown up gun.

Mike

[marksman]

The .222 case could not expand enough to fill a .223 chamber and still stay intact when using full power loads. I would think a case head separation would be inevitable.

Headspace would be extreme resulting in a blown up gun.

Mike

after reading this thread that is what l thought myself
"Headspace"
its just a bad accident and lucky the op is ok
and could have the bolt repaired

thanks for posting it up

[Oldbloke]

The .222 case could not expand enough to fill a .223 chamber and still stay intact when using full power loads. I would think a case head separation would be inevitable.

Headspace would be extreme resulting in a blown up gun.

Mike

Bloody he'll so obvious once pointed out. Doh.

[Peter988]

Explain this one to me please. I am a bit of a dummy. I thought the base of the 222 and 223 shell were the same and the 223 was a bit longer? If the base is the same, wouldn’t the headspace be the same?

[Oldbloke]

Deleted. Double post

[Oldbloke]

Mmmm, no expert here. MM is probable more experience here.

For rimless cases the head space is the gap between the shoulder of case and shoulder in the chamber. If you look the 222 is a lot shorter than the 223. (At the shoulder)

For rimmed cases it is created at the rim.

Could easily be corrected here but when fire forming normally fairly light loads are used. Because of the head space.
Just guessing but if there is a lot of head space the case may not grip the chamber in the normal way increasing the pressure onto the bolt face.

MM?

[Peter988]

I thought headspace was the gap between the bolt face and breech?

[Blr243]

I thought headspace was the distance between the boltface and where the shoulder of the case touches the chamber

[Blr243]

And for that I mean for a case like my 243 that has a shoulder. A 45 acp headspace is measured from the case mouth back to the bolt face because it’s the case mouth that stops the case being chambered too deep. So I think people who crimp the mouths too much on their acp may be messing with their headspace a bit. Not sure. Have not loaded for pistol in over a decade For safety and for case life and for perhaps accuracy I like to size my cases in my 243 so that I can feel a slight compression as I close the bolt completely. Then I know it’s tight and there’s no slop slop. It just feels right to me

[Blr243]

Accidental double post