beavis_m305
Regular
- Location
- New Zealand
The above things I learned the hard way by toasting an M305
One more thing, please make sure your muzzle is pointed at the butts when you release that bolt and let it go forward. If, for some reason you had a slam fire, your round would have gone over the backstop.
It looks like you had a pierced primer, by the way.
Scott
Double checked, the firing pin is fine!Pierced primer is what I was gently trying to say earlier. He should also check his firing pin tip now (with a magnifying glass). A pierced primer can chip a bit off the firing pin tip. That is a bad thing, as with a chipped, now sharply pointed firing pin,you will tend to get more pierced primers if you don't replace the firing pin. I'm not tacticool, I'm old and been there, done that.
"...without resizing it..." Most like cause an instant failure to feed. Semi-autos require FL resizing every time.
You're seeing normal smoke from 'smokeless' powder. If there was a headspace issue or any other issue you'd see smoke on every shot.
Most semis do but the m305 you can neck size. I know it's a safe argument to make that you have to do it every time on a semi, but it's just not the case for these rifles.
Good to have a long chamber thenanything that prevents a round from chambering easily could contribute to a slam fire. That is something best read about.
You do not cure slam fires by under sizing the brass, that’s just ridiculous.
When you have a chamber that is too large for the brass you have 3 options.
1) Fix the rifle so the chamber is the correct size
2) Obtain brass that fits the oversize chamber
3) Bury your head in the sand and keep on shooting cheap ammo.
For the purpose of this discussion, let’s forget about option 1 and 3.
So… How do we obtain brass that fits the oversize chamber?
Answer: That’s easy shoot it. Once fired brass will expand to fit the chamber of the rifle it was fired in.
When you resize this once fired brass you leave the full length resizing die unscrewed just enough to produce the desired headspace. Forget about saami spec! If your rifle is .015” over saami then size the cases to saami plus .015”. This is not complicated.
Since we are talking semi autos here, there does need to be a certain amount of clearance so the round can feed and not stick during extraction. Since we are talking about FL resize that will not be a problem because the round IS being resized.
When you FL resize the brass the body diameter will be squeezed down so you will not have a failure to feed. You will also need to set the headspace just a few thousandths of an inch shorter than the chamber. I assume most of you don’t have proper headspace gages for the brass, so for many of you, this may be the tricky part.
If you know the headspace oversize amount of your rifle from a formal measurement being taken just float the resizing die above the shell holder by the same amount using feeler gages. My guess is for most of you guys you should probably go somewhere between .010” and .015”.
You can prove to yourself that the headspace is not oversize by taking the operating rod and trigger group out of the rifle and cycling the bolt with your resized brass. If the bolt closes without resistance you do not have excessive headspace.
If you are not confident of the amount, just start somewhere. You can increase the feeler gage thickness a little at a time. Load a few and test a few until you get it just right.
When the cartridge goes off, the brass normally expands under pressure and creates a seal against the chamber. Since you probably have excessive headspace some of the smoke from the burning powder leaked out before the brass created a seal.
To correct this you have 2 options
1) Save your once fired brass and reload it without resizing it back to sammi spec. Size it to the same headspace as the fired round. This way the round wll fit perfectly next time you fire it.
2) Change the bolt and maybe the barrel to correct the headspace.
You do not cure slam fires by under sizing the brass, that’s just ridiculous.
When you have a chamber that is too large for the brass you have 3 options.
1) Fix the rifle so the chamber is the correct size
2) Obtain brass that fits the oversize chamber
3) Bury your head in the sand and keep on shooting cheap ammo.
For the purpose of this discussion, let’s forget about option 1 and 3.
So… How do we obtain brass that fits the oversize chamber?
Answer: That’s easy shoot it. Once fired brass will expand to fit the chamber of the rifle it was fired in.
When you resize this once fired brass you leave the full length resizing die unscrewed just enough to produce the desired headspace. Forget about saami spec! If your rifle is .015” over saami then size the cases to saami plus .015”. This is not complicated.
Since we are talking semi autos here, there does need to be a certain amount of clearance so the round can feed and not stick during extraction. Since we are talking about FL resize that will not be a problem because the round IS being resized.
When you FL resize the brass the body diameter will be squeezed down so you will not have a failure to feed. You will also need to set the headspace just a few thousandths of an inch shorter than the chamber. I assume most of you don’t have proper headspace gages for the brass, so for many of you, this may be the tricky part.
If you know the headspace oversize amount of your rifle from a formal measurement being taken just float the resizing die above the shell holder by the same amount using feeler gages. My guess is for most of you guys you should probably go somewhere between .010” and .015”.
You can prove to yourself that the headspace is not oversize by taking the operating rod and trigger group out of the rifle and cycling the bolt with your resized brass. If the bolt closes without resistance you do not have excessive headspace.
If you are not confident of the amount, just start somewhere. You can increase the feeler gage thickness a little at a time. Load a few and test a few until you get it just right.
I reckon your face is worth more than getting a few extra loads out of your brass