breaking in my new M305

ColKurtz

ColKurtz

Regular
Rating - 100%
1   0   0
Location
Cucktoria
I had a chance to break in my new M305 this weekend (after stripping and thoroughly cleaning it).

It worked great, nice PING. Overall, seems like I got a good one. I shot 100 rounds of this ammo through it.
http://www.theammosource.com/index.php?main_page=product_info&cPath=1_108_110&products_id=2185

Out of the 100 rounds, the "necks?" (narrow part) of 2 casings had split. One is a clean split, but the other is a jagged fracture. The later one was the VERY LAST round out of the 100, so I didn't have a chance to shoot more and see if it was getting worse (I was check each casing for damage)

You guys think I'm okay to keep shooting this ammo?
 
ColKurtz said:
You guys think I'm okay to keep shooting this ammo?
Click to expand...

No. Your link to the ammo purchased does not work but I suspect it is copper washed and steel cased. Your headspace is excessive for this ammo.

see post #19 below:
http://www.canadiangunnutz.com/foru...2-Headspace-gauges/page2?highlight=head+space

from Gus Fisher:

MAXIMUM HEADSPACE: This is the amount of room necessary so the shortest cartridge manufactured to correct specifications will fit and will have enough room to expand to seal the chamber without expanding so far that the cartridge case will expand until it ruptures or a piece of the cartridge case breaks off. When that happens, you are going to get a good deal of nasty and hot gas coming back into the action and towards your eyes. God Help you if you aren't wearing shooting glasses, as you could very likely suffer permanent eye damage. Much of the gas coming back normally blows the magazine base out the bottom of the magazine well and cracks and splinters the stock along the sides of the magazine well at least. That usually isn't life threatening, but you may wind up with some good sized chunks of stock in your supporting hand/arm. I've seen up close one real, G.I. M14 blow up and while it didn't come close to killing the Marine, it would have taken out his eyes had he not been wearing shooting glasses.
 
Last edited:
By someone who has marginal knowledge of the M305......he will just tell you you have excessive headspace which is normal for 90% of these guns

Shoot a 100 brass and see where it sits.

If you buy the cheapest ammo you get the cheapest ammo.
 
tiriaq said:
Excess headspace could result in case separations, not split necks.
Click to expand...

I get what you are saying. You have a point provided the crack does not initiate at the base of the neck.

None the less, weapons engineers do not design cases (steel or brass) to fail in a rifle. The ammo in question is not made to spec and/or the rifle chamber is cut out of tolerance. Split necks are not normal.

Good luck to all and safe shooting.
 
Last edited:
Split or burned through? There is a difference. A split could indicated an improperly cut chamber. Run some commercial brass rounds though, ie Winchester/Federal. If the neck splits you may very well have chamber dimension problems. If the cases burned through then it's definitely a case manufacturing issue. I've encountered this with Chinese, Israeli and old Norwegian surplus ammo. It usually isn't a problem.
 
Go over to the AR forum and ask those guys about split necks with norc ammo.

From my own findings with gauges ect... Chinese copper wash 7.62x51 is on the "small" size. Meaning, it would chamber easily and with 1 or 2 thou clearance in a 1.630 chamber (match .308). The stuff I've measured averaged out at 1.628" before firing.
That coupled with a headspace over 1.638" (typical norc since 09= 1.636 to 1.638) and I could see that causing problems
 
In my experience with nork ammo which is more than a few rounds!! split necks is quite common!! I've seen it In a bunch of different rifles Chinese and Mercian made. 223 and 308.
Safety glasses and keep firing!
 
You must log in or register to reply here.
Back
Top Bottom