Rub mark on cases/projectiles

Sparkypiper · September 7, 2011, 04:39 AM

hi all.

I have a .243 which i have made up some reloads.

Now the OAL says no longer than 68.83mm.

My loads are 68.30mm in length , and shorter than factory rounds.

When i chamber my rounds , im getting a little wear mark about 5mm up the projectile , however this is only 1/2 way arround the projectile and looks more like a wear mark than anything else. Does not look like rifling.

Im wondering if its when i close the bolt that this is happening......update just tryed that and that what it appears to be.......the bolt is gripping onto the base of the cart and when the bolt is moved up and down , its turning the whole shell in the chamber.....causing the little ring arround the projectile just up from case neck.

is this an issue? or it just because i got a new gun?

Cheers!

Craig.

243winxb · September 7, 2011, 11:04 AM

I dont think it will hurt anything. It might go away if you seat the bullet .005" deeper. Shorter COL.

oneoldsap · September 7, 2011, 01:00 PM

Milimeters , we don't use no stinking Milimeters !

Doyle · September 7, 2011, 02:57 PM

Take out your bolt and see if there is any imperfection in your chamber. Maybe it has some built-up gunk there that is marking your bullets.

**Unclenick** · September 7, 2011, 04:50 PM

That doesn't sound quite normal. The bullet should be touching nothing until you shoot, though some bullet shapes are stubby enough to need shorter COL's as suggested.

It is possible, however, that it picks up the mark from the corner where the neck meets the shoulder of the chamber on the way in or out. The way to tell is to push a round into the chamber with your finger as far as it goes, maybe turn it a little then drop it back out. If it doesn't just drop out and you need to bump it out or push it out with a cleaning rod, then there is definitely an interference issue and you may need to get a gunsmith to take a look with a bore scope. If there is no mark, then the ejector spring pressure is probably creating it by pushing the round to the side with extractor hook as pivot.

The chamber ideally should not be rough enough to cause the scrape, but many new ones are, and have to be burnished in by shooting. You can remove the bolt and run a bronze cleaning brush in and out (always go all the way out the muzzle; never reverse a bronze brush in the bore as this marks the steel). You can then take an undersize brush and wrap a patch on it and put Flits on the patch and push it in until it centers in the chamber neck and just turn it to lightly polish the metal in the neck area. See if that doesn't help.

September 7, 2011, 04:39 AM	#1
Sparkypiper Junior Member Join Date: September 4, 2011 Posts: 7	Rub mark on cases/projectiles hi all. I have a .243 which i have made up some reloads. Now the OAL says no longer than 68.83mm. My loads are 68.30mm in length , and shorter than factory rounds. When i chamber my rounds , im getting a little wear mark about 5mm up the projectile , however this is only 1/2 way arround the projectile and looks more like a wear mark than anything else. Does not look like rifling. Im wondering if its when i close the bolt that this is happening......update just tryed that and that what it appears to be.......the bolt is gripping onto the base of the cart and when the bolt is moved up and down , its turning the whole shell in the chamber.....causing the little ring arround the projectile just up from case neck. is this an issue? or it just because i got a new gun? Cheers! Craig.

September 7, 2011, 01:00 PM	#3
oneoldsap Senior Member Join Date: September 16, 2009 Location: I live in the foot of the Green Mountains of Vermont Posts: 1,602	mm Milimeters , we don't use no stinking Milimeters !

September 7, 2011, 04:50 PM	#5
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	That doesn't sound quite normal. The bullet should be touching nothing until you shoot, though some bullet shapes are stubby enough to need shorter COL's as suggested. It is possible, however, that it picks up the mark from the corner where the neck meets the shoulder of the chamber on the way in or out. The way to tell is to push a round into the chamber with your finger as far as it goes, maybe turn it a little then drop it back out. If it doesn't just drop out and you need to bump it out or push it out with a cleaning rod, then there is definitely an interference issue and you may need to get a gunsmith to take a look with a bore scope. If there is no mark, then the ejector spring pressure is probably creating it by pushing the round to the side with extractor hook as pivot. The chamber ideally should not be rough enough to cause the scrape, but many new ones are, and have to be burnished in by shooting. You can remove the bolt and run a bronze cleaning brush in and out (always go all the way out the muzzle; never reverse a bronze brush in the bore as this marks the steel). You can then take an undersize brush and wrap a patch on it and put Flits on the patch and push it in until it centers in the chamber neck and just turn it to lightly polish the metal in the neck area. See if that doesn't help. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

September 7, 2011, 11:04 AM	#2
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	I dont think it will hurt anything. It might go away if you seat the bullet .005" deeper. Shorter COL.

September 7, 2011, 02:57 PM	#4
Doyle Senior Member Join Date: June 20, 2007 Location: Rainbow City, Alabama Posts: 7,167	Take out your bolt and see if there is any imperfection in your chamber. Maybe it has some built-up gunk there that is marking your bullets.