Whom would you recommend for making a reamer for a 7mm Remington Magnum? I want a reamer that does not cut oversized chambers like a lot of the factory chambers. I will be using Winchester brass, so I would like a reamer that is made accordingly.

Thanks, Erik

Erik,
how do you mean? ALL reamers, even benchrest, cut an oversized chamber... "tight" chamber is usually .001 oversized... but all are a +.00X size...

you could call dave manson and ask for a minimum saami chamber

jeffe

I believe I read on reamer rentals website that all there reamers are made to SAAMI minimum specs. If that suits your needs you might contact them. Cheaper than buying one.

I should add that I shortened the chamber on my 264 WM to make it fit new Winchester brass. All that requires is cutting the shoulder, breech face, and belt recess on the barrel to shorten the chamber. I will also have to shorten the resize die if I need to push the shoulder back on fired brass. I don't know if it is advisable to fire factory ammo in a shortened chamber but I don't use factory ammo.

Thanks for the reply. I realize all chambers have to be bigger than actual case, but some factory chambers appear large compared to custom chambers. I like a chamber that is close to actual brass size so I don't work the brass any more than necessary.

I will let the gunsmith figure it out for me anyway, just getting ideas and input at this point.

Thanks

I buy custom reamers from Dave Manson.
http://www.mansonreamers.com/pricelist.htm

It is $95 for a 7mm Rem Mag, and $160 for wildcats.

$30 extra for a tighter neck and $30 for a shorter throat would total an extra $60, but for $65 you could change even more.

If someone offered to buy me any 7mm rem mag reamer in the world, I would take a Manson with 311" neck, instead of the SAAMI .317+" neck, for a cost of $95 + $30 = $125

You are asking for perfection.

Even the most match super duper reamers out there are going to have some small amount of tolerance so you brass will chamber.

A magnum reamer will be no more 'out of spec' than any other non-magnum caliber, it is just that the body of the case can afford a little more tolerance because the case headspaces on the belt.

Whoever is putting it in your head to get a 'custom reamer' should rethink the problem a little more. This is usually what happens when you read too many magazines/internet posts.

FWIW, 90% of my reames are Clymer and I have had hardly a problem with them.

Now refer to Jim's following post.

-Spencer

Reamers don't cut oversize chambers! People that don't know how to use them do. Jim

Belted magnum chambers are not "oversize", the brass is undersize! I think the manufacturers are trying to save money on brass by making the cases short. Heads separated in my 264WM in three firings. The case walls were so thin after one firing that I probably should not have used them again and I didn't for hunting loads.

My full length size die still works the shoulder more than necessary in my shortened standard chamber but the heads aren't coming off the cases any more.

There was an article in Precision Shooting magazine about some fellows that used 7mmRM's for match rifles. They shortened the chambers by .050" IIRC to deal with the short magnum brass.

quote:

Belted magnum chambers are not "oversize", the brass is undersize! I think the manufacturers are trying to save money on brass by making the cases short. Heads separated in my 264WM in three firings. The case walls were so thin after one firing that I probably should not have used them again and I didn't for hunting loads.

When I was attending gunsmithing school (CST-43 years ago), two instructors whom I admired very much (Dick Kroeckle and Eldon Adams) said that the headspace specifications on the belted mags, if followed, built in excessive headspace. We were taught never to use the No-Go (.224") gauge at all and to chamber the barrel using the Go (.220) gauge as a No-Go. I have never had a problem losing brass or not being able to chamber any factory cartridge/case doing it that way.

Masterifleman, that was certainly the case with my rifle. I shortened everything the same amount and then found out a friend of mine has a no go gauge. The bolt closed easily on that gauge although I think it is a .226" gauge. Given that I have measured belts on some cases as small as .214" things can get real sloppy in the chamber!

Looking at SAAMI specs, measuring reamers, chambers, and ammo.... they are all at the small end of the permisable range.

Because the range is quite wide and chmambers and ammo do not overlap, the chambers seem too big for the ammo.

If you want to sell guns, make the minimum SAAMI chamber. If the gun is for yourself, and you know what you are doing reloading, you can get a custom reamer for longer brass life, benchrest competition, etc.