bending case rim on extraction

[danb]

my garand is bending the case rim on extraction is there a common cause for this, do I need a new barrel? gun is new to me and I was test firing it .

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[Gus Fisher]

Dan,

You didn't mention what the ammo was you were shooting, but yes it is not unusual to the rims to get bent even on some new ammo some of the time.

Military rifles were not designed to ensure the brass was good for reloading. They were designed to get the case out of the rifle in all kinds of conditions.

[JimF in CT]

Actually. the case rim gets this "ding" upon chambering. . . . not extraction.

Some extractor springs are a bit strong and allow the extractor to snap over the rim only "grudgeingly".

Some here will tell you the rims get bent by the forward movement of the op-rod. . . not so in my experience. --Jim

[Gus Fisher]

Yes, there is some slight dings caused during feeding, but the worst bends/gouges/dings are caused from ejection after firing.

I have been using some G.I. dummy cartridges for years and they go in and out of a WHOLE bunch of rifles before the rims really get damaged as much as when a case if fired and extracted and ejected.

[cary m2a]

You ammo is to blame. You got to stick to milspec or start reloading for it so you know what your feeding it. And a ding on the rim is normal on chambering. If that doesn't stop it check to make sure the gas port has not been drilled out, you never now who's been doctoring on it.

[Liftrat]

Whether the rim is bent forward or backwards should be pretty visible, and would guide your search for a solution. It could be your ammo, whether incompatible powder burn rate, or soft brass. It might also be your chamber; if it's very dirty, or rough, that would make it hard for the rifle to extract. Try giving it a good cleaning with a brass chamber brush. HTH

[Johnny Peppers]

I'm with Liftrat. If the rim is bent out during extraction, I would check for a dirty chamber. The Remington 740 family of rifles are bad about tearing the rim off the cartridge if the chamber gets dirty/rusty. The rifle's chambers are not maintained because they are not easy to clean, but like money in the bank for the local gunsmith. The gunsmith pulls the barrel, polishes the chamber, and they work like new.

[Jim K]

An oversize gas port can also cause that problem.

Jim

[Fick_2141]

The ding on the case rim and a bent case mouth is common to almost all Garands. They are for two seperate reasons and both occur after extraction.
The ding or bent rim is caused by the case hitting the boltface as the ejector plunger begins to flip the empty case out of the extractor. There is enough inertia or kinetic energy in the empty case to slightly bend the rim inward as it's engery is tranfered to the boltface as it stops it's reaward movement. It will only ding one side because of the angle created by the ejector plunger.
The bent case mouth occurs after the case has been ejected. As the oprod moves forward it hits the twirling case launching it to the 1 to 3 O'clock position, making the case mouth look like the letter D. Both of these phenonmenon are normal to Garands.
After a 50 rd match you will see the brass smudges on the oprod indicating where the contact occurs. It is nothing to worry about. Just wipe it off.

[mousegun]

The ding on the case rim and a bent case mouth is common to almost all Garands. They are for two seperate reasons and both occur after extraction.
The ding or bent rim is caused by the case hitting the boltface as the ejector plunger begins to flip the empty case out of the extractor. There is enough inertia or kinetic energy in the empty case to slightly bend the rim inward as it's engery is tranfered to the boltface as it stops it's reaward movement. It will only ding one side because of the angle created by the ejector plunger.
The bent case mouth occurs after the case has been ejected. As the oprod moves forward it hits the twirling case launching it to the 1 to 3 O'clock position, making the case mouth look like the letter D. Both of these phenonmenon are normal to Garands.
After a 50 rd match you will see the brass smudges on the oprod indicating where the contact occurs. It is nothing to worry about. Just wipe it off.

Ah HAH! Suspected as such. The ding on the rim has a straight line at the bend. If it were from the extractor during chambering, it would not be linear since the extractor claw has a radius. First time I ever saw anyone explain it. Also probably why using an adjustable gas lock screw seems to make it better. Kewl!