Suitable off the shelf reamer for an accurate 7mmMag rifle?

V

VaniB

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Hi guys. Geees.....this websight has gotten ghostly quiet ever since it was altered. I hope somebody out there besides the "visitors" will read my thread and respond. ( ...nothing against the visitors, other then they have become the 60-80% "majority" in every forum and can't participate.)

Ok, the question;

I want a new barrel reamed in Remington 7mm Mag. I intend for my Remington brass and 162 AMax handloads to deliver 1/2" MOA or better groups, but I don't wish to turn the case necks. I don't know how the readilly available 7mmMag reamers out there are designed to headspace. Do they headspace on the belt? Will they produce too much free bore like the Ruger 204 Ruger or the Weatherby? I'm just not familiar with it and the chamber they produce.

Dave @ PTG is always a great source, but frankly, I'm not too crazy about having to pay $150 for a reamer and the one barrel that I will ever make with it. (But, if I have to keep going that route again, I will)

Midway adverstises a slew of PTG reamers for $97, but I don't know the specs or what I'm getting.Can anybody recommend a good off the shelf 7mmMag reamer that's suitable for precision shooting?
 
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Well if you want 1/2 inch groups, I do not believe the Remington brass will deliver.

However the inexpensive no spec reamer will be compatible with the Remington brass.

Half inch groups will required a trued action, top of the line barrel, top bedding job, and quailty brass or just plain luck.

Head space on the shoulder, just like any other cartridge.

I'm shooting 160 gr TSX, Norma Brass (neck sized with a Lee Collet Die), H4831SC, Fed 215 at 3000 fps over wind flags with a 6.5x20 Leupold and get 3 shot 1/2 inch groups.

The rifle is a trued 700 with a Hart SS 26" barrel, bedded in a H&S.
 
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I have a run of the mill solid pilot Clymer 7mm Rem Mag reamer that I removed the throat on so I can throat separately and shorter... I have built many excellent shooting rifles with this reamer. I think the key is as short a throat as required and the chamber well lined up...
 
Thanks for the input gents. John, if it is possible to derive sub 1/2 MOA from a 7mmMag, then I'll be doing it, as I will be using a Krieger barrel and custom smithing to have a precision rifle built. While there is no Lapua brass to be had, I'll simply cull out the less then perfect Remington hand loaded cartridges I've made and use only the better rounds when doing precision shooting. This is why I'm fussing trying to start out with the right reamer and not just any chamber.

Dennis, I'll take your advice about a short throat.
My smith also emailed me to tell me that he has a reamer with a .315 neck. He said: "I have .315 reamer with a target lead and throat in it. I usually cut the headspace depth.001-.002 over minimum, that way when you resize cases they can be made to head space on the shoulder and not the belt."
In your opinion, does this sound like all I will need? Because I'm suspicious of the .315 neck, and wonder if he may simply just be trying to have me settle on the only one 7mmMag reamer that he has on hand. While I don't doubt that it would work for most normal applications and hunting rifles and MIGHT even turn in tight groups, I think I would be better off with a tighter neck....perhaps .311- .312 for target shooting applications. (??) I bought 300 pieces of once-fired brass and measured the expanded necks to see it all measures between .315-.316. I measured a Federal case and Remington case with a bullet seated in them to see that they are between a .307-.308 measurement ...... and NOT a .315 neck.
Thus, would you agree that a reamer with a tighter .311 to .312 neck would be preferable? (....and a .315 neck may be too large) I'm coming to the conclusion that I would be better off ordering from Dave at Pacific. Even if it costs me $150 for a reamer in order to make me just one barrel, I know his expertise will be invaluable compared to my guessing games. As long as I hand my smith the new reamer but he gets the job, his feelings will not be hurt.

Until I speak to Dave to place my order, does my thinking that a reamer with a .311 neck sound right to you?
 
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My old Clymer reamer has a .316 neck.

I would go on what Dave recommends...
 
It seems from the info I've gathered, a .315 neck may not be so excessive for a no-turn case. But, yes, there are other important aspects to concern myself with when choosing the right reamer specs for precision shooting. I'll consult with Dave and let him sell me a reamer. But, I'll first buy a Redding Body die, Lee Collet die, and the 162 Amax bullets, and put a dummy cartridge or two together so I can mike it for specs and be prepared to talk to him.

Thanks.
 
Vani......I wouldn't worry about the initial expense of a properly ground reamer. You repeatedly mention a one barrel use of the reamer.
Either you ain't going to be shooting that rifle very much, ( ? ) or if you are; that 7 Mag will burn up barrels at such a fast pace that your 'smith will probably wear out a new reamer........ At your accuracy requirement of 1/2 inch groups, I would expect a barrel to last maybe 1500 rounds before is starts edging towards 3/4 or 1 inch patterns...........Grant.
 
Order the reamer. As you probably know belted cases' headspace specifications are from the front of the belt, not the shoulder. Years ago when I checked unfired cases against fired from a couple of factory 7 Mag chambers the shoulders on the fired cases had blown forward about .021 from where they started. This situation makes setting up FL dies for belted cases something that requires more attention to detail than just running it down to touch the shell holder, a practice that I understand was in the factory directions for some dies, and which has been responsible for more than a few case separations, at low numbers of firings.
 
I have the Manson $110 reamer in 7mmRemMag through Brownells.

I have never done better than 0.75" at 100 yard, but I am building 9 pound rifles and putting 2x7 scopes on them.

If I were to build a 30 pound rifle with select match barrel and 40X scope, I think I might get below 0.5" and even average 0.5" with my reamer and Remington brass.

The idea that the type of reamer or the brand of brass would hold me back from getting 0.5" groups seem inconstant with the hundred rifles I have taken to the range.

But that is a hypothetical.
I have won another elk tag for an area that does not even have sage brush.
For the past couple years, I could easily get within 1000 yards of the elk there.
Getting with in 400 is the trick.

I will not be stalking around with a 30 pound rifle.
I am going to take one of my inaccurate light weight rifles that only occasionally gets 0.75".
 
PTG Reamers can also be had through Grizzly Industrail, not sure if they offer at a better price or specifications you are asking about.

Bob
 
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