7-300wm chamber needs coal lengthened

[Mram10]

I have a 7-300 reamer that has a short throat. Wondering if I could use a saami 7mag reamer to touch up the neck to lands section to allow for seating the bullets out further. Thanks

 

[Mike Bryant]

Which 7-300 WM do you have Weatherby Mag, Win Mag or WSM? If it's a Weatherby Mag, you'd never get to the throat before the belt on the reamer hit the chamber's belt. Same thing if it's a .300 Win Mag based cartridge. As Francis said, if you want it throated longer, use a throating reamer. Using the correct tool for the job, usually saves money in the long run.

 

[alinwa]

I have a 7-300 reamer that has a short throat. Wondering if I could use a saami 7mag reamer to touch up the neck to lands section to allow for seating the bullets out further. Thanks

Sure, jam it in there and see what happens......if it don't fit, grind the back down until it does.

You can do this!

 

[Mram10]

Win mag. Dumb question on my part. Didn’t even think of belt. I’ll get a throating reamer. Thanks guys. Any chance a 7stw reamer would work?

 

[brickeyee]

Win mag. Dumb question on my part. Didn’t even think of belt. I’ll get a throating reamer. Thanks guys. Any chance a 7stw reamer would work?

See if you can rent a throating reamer.

Even with that it is delicate work.
It does not take all that much force to cut rifling away.

The slightest alignment error will wreck the chambering.

 

[Mram10]

Got it! I lightly ran the 7stw reamer in until the shoulder face just touched. Worked perfectly. Took my time to make sure I didn’t go to far.

 

[brickeyee]

Got it! I lightly ran the 7stw reamer in until the shoulder face just touched. Worked perfectly. Took my time to make sure I didn’t go to far.

Congrats.

It is one of those things with few ways to do correctly but hundreds of ways to screw up.

 

[Mram10]

I see your point. It cut like butter till it touched the shoulder than felt very different. Shot it today and seemed to function correctly. I was worried I’d screw it up. Next time I’m getting a throating reamer like others advised. No chance to screw up shoulder

 

[brickeyee]

I see your point. It cut like butter till it touched the shoulder than felt very different. Shot it today and seemed to function correctly. I was worried I’d screw it up. Next time I’m getting a throating reamer like others advised. No chance to screw up shoulder

You can always treat a chamber with minor deviations as a custom chamber and reload around many 'issues.'

It mostly means you must keep brass for that gun segregated. from other guns of the same nominal chambering.

 

[brickeyee]

No. No. No.
Do it right and you don't need to segregate brass.

Everyone knows that.

Segregating brass by rifles still allows a better case to chamber fit.