Guys,

The old "beater" M7400 Remington in .308 Win has after many years finally started to have extraction problems.

I have it apart ... the barrel is out. Chamber seems to be a bit rough ... that is, a light mist of rust on it.

What is the "right way" to polish out a chamber? I do have lots of tools including a big lathe (13x42).

The rifle has never been a problem and given that it shoots 1 1/2" at 100 yards with handloads, it's too useful a piece to junk.

Thanks!

J & B bore paste. Get a chamber brush and a big patch saturated with J&B, chuck it up in a cordless drill and polish away.

For really stubborn problems, tap a case fired in the rifle, attach a rod, coat case in J&B, chuck in cordless drill and polish away.

Just don't overdo it and you'll be back to reliable extraction in no time.

After a small amount of polishing with the JB, switch to Flitz. You can get it from Sinclair. I use that to smooth up Redding reloading dies. No measurable dimensional changes, just a much smoother metal surface.

ld

A little 000 steel wool around a chamber mop and some hoppes should do the trick. Don't get carried away with polishing. A too shiny chamber will not "grab" the case upon firing.

Just chuck a tight fitting chamber mop in your tailstock or a drill with a dose of JB's and give it a whirl. Carefull not to overdo it. Use a fairly low RPM and some patience, check at regular intervals and stop when it looks good.

It shouldnt take long to smooth it out with the bore paste, then you can switch to bore bright or flitz. I think that making sure that all residue is cleaned out afterward is more important than having too high of a polish. Your brass should also have no traces of polish when it is done so you have a good "squeaky clean" metal on metal seal in the chamber.

Good information. I have a chamber that sticks with remington factory brass only. A "barrel" man polished it at tone time, but didn't help. I am going to have a go at it before ai rebarrel or set the barrel beck.
Judge Sharpe

OK Guys,

Took the barrel out of the rifle and hit it with Butch's, Sweet's, and then JB's. Cleaned it thoroughly with Shooter's Choice and reassembled with the new recoil rod and recoil spring that arrived today. (UPS actually lost the first shipment of parts!)

Test fired the rifle and it works like it used to ... nicely thank you. Running 43.7 gr of BLC-2 on LC cases with 150 gr Noslers. Will kill whitetails for sure.

In the meantime, I found an article in the American Gunsmithing Journal on 7400's that fail to eject. Main reason given was dirty and/or rusted chambers. Article noted that these rifles need to be cleaned when brought in from bad weather even if they have not been fired.

Thanks All!

quote:

Originally posted by DobleTroble:
J & B bore paste. Get a chamber brush and a big patch saturated with J&B, chuck it up in a cordless drill and polish away.

For really stubborn problems, tap a case fired in the rifle, attach a rod, coat case in J&B, chuck in cordless drill and polish away.

Just don't overdo it and you'll be back to reliable extraction in no time.

That's one way. Anothr is to use the J & B on an empty cartridge case that you've soldered onto a section of steel cleaning rod and chucked up in an electric drill. It only takes a very brief polishing to do the job, as long as the rust is very light!

It is more bother, but the fired case method with a rod soldered on should give the most accurate job. Also, and more importantly, it lets you apply the abrasive on only the side of the chamber and not to the headspace section.

I chucked the bbl into a lathe and used a 3/8" felt bob with the JB paste. Went very lightly trying to be as even as possible ... leaving the throat and neck alone. Then cleaned up with copius amounts of flood coolant.

Seems to have worked fine and left a good surface in the chamber.

I can't tell any difference in the size of the chamber based on measurements of cases fired before and after.

I realize that a 7400 is not a pretty rifle ... but this one has been a good working gun that I hated to see go away as it is often a loaner for folks I hunt with. I found it interesting that the AGI article indicated that cleaning of the chamber in this rifle is critical to its on-going functioning. I've owned and shot lots of semis over the years (Garand, M1A, SIG AMT, BAR, ARs, and a couple of buzz guns) and never had one do this before. Will be pretty obsessive about cleaning it in the future!