Gunsmithing remington 300 win mag chamber problem.

[keithtb1]

Need help with my rifle. As stated above I have a remington 700 in 300 win mag with about 1,000 rounds through it. 800 from the previous owner here on the hide and 200 from me. Upon receiving this rifle I gave it a good cleaning and have fired only factory FGMM 190 grain bullets through it. After the first 150 rounds started noticing that the bolt was getting hard to manipulate when extracting a round from the chamber after firing. I gave it another good cleaning and the problem still exists. I can manipulate the bolt back and forth with several unfired rounds and there is no problem extracting and feeding several unfired rounds, but when I fire a round I can manipulate the bolt upwards but cannot pull back with out both hands or placing the rifle vertical and slapping it back to extract the fired casing. I also tried switching to black hills factory match in 190 grain bthp's with the same results. We chrono'd the rounds and they were exiting on an average of 2900 fps out of a 26inch barrel with a brake attached. It should also be noted the rifle is able to maintain a .5 to .75 inch group at a 100 yds. and cold bore shots at 1000yds. It is the factory barrel with no work having been done to it.
I would appreciate any help or suggestions. I'm hoping I don't have to rebarrel the weapon with so few rounds fired through it. thanks.

 

[Hateca]

Re: remington 300 win mag chamber problem.

Since your rifle is chambering and extracting factory unfired ammo I suspect the following.

The chamber wall where the cartridge belt headspaces could have a raised area that is catching the brass.

After firing the bottom web of the cartridge will expand and will not relax enough and will catch on the raised chamber metal as you attempt to pull the cartridge out.

To check and see if you have this little raised ridge take a plastic cleaning pic or some other tool that won't scratch the chamber wall and run it along the camber wall from inside to out and see if it catches on the chamber right at the edge of the chamber where the belt headspaces. It can be very small and not seen with the eye but can be large enough to screw with extraction.

If it does you will need to have the barrel pulled and this area polished down to remove the raised metal ridge.

This little raised area can be caused over time by several things from shooting over pressure loads to a headspace issue to a tight or snug headspace and shooting nickel coated brass.

I have also seen factory rifles delivered this way so it could have been nothing you have done.

 

[keithtb1]

Re: remington 300 win mag chamber problem.

Thank you for responding to my situation. I will try to determine if that is the problem by the technique you suggested. If so, I need to find a gunsmith to repair the problem.
If anyone knows a good gunsmith in Broward County, Florida. Please let me know here or by PM.
Once again, Thanks HateCA for you help.

 

[Criver600]

Re: remington 300 win mag chamber problem.

Bet its close to being shot out. I have had 300 WM die at 800 to 1500 rounds. With a rough throat cases are harder to extract. You might JB/Flitz the throat and get a few hundred more rounds but I think its time for a new barrel.

 

[Al Nyhus]

Re: remington 300 win mag chamber problem.

Make sure and check how much primary extraction you have. -Al