Too much powder?
- Thread starter D3vin
- Start date
Here's a couple theories that can be useful for anyone shooting steel in their M305's.
As steel is not as malleable as brass it can tend to split when trying to expand in the slightly larger chambers of these battle rifles.
Another reason could be, combined with the stretching, possibly weaker steel in those cases. As the case expands it sticks to the chamber walls to create a seal and if the steel doesn't retract enough, it can be "stickier" than brass. So as the bolt unlocks, it cams the "sticky" case out of the chamber and the weak or stretched steel is giving out at the web.
The face full of powder is the residual pressure in the barrel, even though that bullet is long gone, there's still lots of pressure until that case is extracted. If this was an overpressure or detonation, I think the outcome would have been worse.
This is purely theoretical.
Personally I'm not a straight steel ammo fan, just personal preference!
I do trust brass flashed or copper washed steel though, as this adds lubricity to the steel to function more reliably.
As steel is not as malleable as brass it can tend to split when trying to expand in the slightly larger chambers of these battle rifles.
Another reason could be, combined with the stretching, possibly weaker steel in those cases. As the case expands it sticks to the chamber walls to create a seal and if the steel doesn't retract enough, it can be "stickier" than brass. So as the bolt unlocks, it cams the "sticky" case out of the chamber and the weak or stretched steel is giving out at the web.
The face full of powder is the residual pressure in the barrel, even though that bullet is long gone, there's still lots of pressure until that case is extracted. If this was an overpressure or detonation, I think the outcome would have been worse.
This is purely theoretical.
Personally I'm not a straight steel ammo fan, just personal preference!
I do trust brass flashed or copper washed steel though, as this adds lubricity to the steel to function more reliably.
Hi.
Today i was firing off some tula ammo via my norc 305. Fired off a round, get a face full of (not hot) smoke and find this casing. Too much powder or what out of curiosity?
Looks like this is a heat-treatment issue combined with the slightly-larger-than-USGI-spec chamber on the Norc M305's.
Case head failure is often the result.
Normally, the solid casehead does not expand. This case failed through the extraction groove, where a case will always be unsupported. It would be interesting to dismantle a few rounds, and section the heads, to see how much solid casehead there is.
Two flash holes means Berdan primers. Neither good nor bad unless you want to reload.
Steel cases are not heat treated. They're mild steel. That one likely had its extractor groove cut a bit too deep. Apply 50,000 psi and it lets go.
Steel cases are not heat treated. They're mild steel. That one likely had its extractor groove cut a bit too deep. Apply 50,000 psi and it lets go.
Not necessarily. some Berdan only has one off center flash hole.
Often wondered why, certainly can't be a cost cutting measure, one would think.Grizz
Brutus
CGN Ultra frequent flyer
Looks like the rim was partially pulled off on extraction - not high pressure. The M305 can be tough on rims, but usually just the rim is scarred, not the casehead separated like that. That ammo might be ok in a bolt gun, but you should expect more of the same in your M305.
If the breech tried to open while residual pressure was still too high, case damage could occur. Ripped rims occur in AG42Bs for that reason. However, that doesn't explain the missing primer.
I would be interested in how thin the solid portion of the casehead is - how close it gets to the extraction groove.
I would be interested in how thin the solid portion of the casehead is - how close it gets to the extraction groove.
That was the point I was going to make . Generally , a blown primer like this indicates excessive pressure , though there can be other causes . Long story short , I wouldn't use this ammo anymore .
