7mm rem mag COAL

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hunter7mmRM

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So I am not totally new to reloading, have been reloading fr a few years now and have gotten some good loads. I bought some new bullets and want to make up a load for my older savage 111, but I figured I would start by finding out roughly where I should seat the bullet in comparison with the lands. Previously I just loaded to book length, 3.290 ish. I coloured a bullet and seated it loosely in a fired case, and came out to about 3.395-3.4 inches. Loading data says max 3.290. I do have room in my mag for longer than SAAMI spec. Bullet is a 150gr nosler ballistic tip with IMR4350.

So where should I start for my COAL? With a longer COAL would I typically start with a lesser powder charge, or more? I would prefer getting some insight from more experienced reloaders than burning through a pound of powder doing an experiment that others might have an answer or advice for.
 
SAAMI coal is what is used for book values. Measure the max for your magazine but leave enough room for recoil and reliable feeding. Savage 7mm mag throats on two of my savage rifles are reasonably tight. The mags allow for a lot of room. However, I manage well with 60 jump for most if not all hunting rounds. And for this round I feel no real need to seat really long. So by your measurements 3.330 should work well. You will find your load increments to be within 0.5 gr for practical hunting loads. Tweak finer if you are shooting 300m or beyond. And if you have the means measure bullet run out. Affects from this will show up at distances 300m or beyond.

Bullet feeding is most important for a hunting round IMO. No need for a jam up when under the gun in a second shot opportunity. I have found seating too long in the savage mag could lead to some issues. So my recommendation for 60 jump was offered. You may be able to seat past 3.4" for optimal accuracy but it may not feed reliably. Test it and see as you go.
My 2c.
 
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I start .010" off of the lands with cup and core bullets, and .050" off of the lands with monometal bullets, if the magazine allows. Start with the recommended starting load, and work up from there.
 
stubblejumper said:
I start .010" off of the lands with cup and core bullets, and .050" off of the lands with monometal bullets, if the magazine allows. Start with the recommended starting load, and work up from there.
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This!! You may find "tweaking" a bit from these figures will yield positive results,
but for most hunting applications, it will work just fine. EE.
 
I usually start lightly touching the lands with conventional bullets, or jammed .015" with VLDs as measured with the rod method, which gives very similar results as the Stoney Point tool. That way if I want to experiment with COL there's only one way to go.

The reason why I mention the measuring technique is I've proven to my satisfaction that the fired case with dented neck method consistently results in .030-.040" jam. A bullet just dropped the barrel will jam about the same distance.

That has me thinking that about a century's worth of advice of setting .030" off the lands was in actual fact instructions to seat lightly touching.
 
Dogleg said:
I usually start lightly touching the lands with conventional bullets, or jammed .015" with VLDs as measured with the rod method, which gives very similar results as the Stoney Point tool. That way if I want to experiment with COL there's only one way to go.

The reason why I mention the measuring technique is I've proven to my satisfaction that the fired case with dented neck method consistently results in .030-.040" jam. A bullet just dropped the barrel will jam about the same distance.

That has me thinking that about a century's worth of advice of setting .030" off the lands was in actual fact instructions to seat lightly touching.
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Intresting point. I use the rod method with the bullet taped (tape only touching the boat tail or very base) to a kabob skewer. I can kinda push the bullet into the lands, then with the rod push it off them. Go back and forth to find the spot and its not really an exact spot. Do all the measuring, then grab another bullet and its different again.

I write that "touching measurement" on the box of bullets then if I make changes it's referenced to that number since it's an arbitrary number anyway. It's an attempt to have consistency.
 
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I had always thought that the bullet was only touching the lands if it was placed there. I didn't think I could physically jamb it into the lands unless it was attached to a loaded case and pushed/cammed in by the bolt.
 
Purple shoulder said:
Intresting point. I use the rod method with the bullet taped (tape only touching the boat tail or very base) to a kabob skewer. I can kinda push the bullet into the lands, then with the rod push it off them. Go back and forth to find the spot and its not really an exact spot. Do all the measuring, then grab another bullet and its different again.

I write that "touching measurement" on the box of bullets then if I make changes it's referenced to that number since it's an arbitrary number anyway. It's an attempt to have consistency.
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That sounds like what I do, with the push in and out and feel method.I use a pencil for the bullet pusher; the sharp point gives a bit more feel. The results can vary from bullet to bullet, with some makes being better or worse than others. The way I deal with that is to set the seating die with the test bullet. Following bullets will seat off the ogive.
 
Good info! Thanks. I will try to make some rounds about 40-50 back from where I did my test, to be very roughly 10-20 off the lands and shoot some loads over a chrony to figure out where the max pressure would be. And then start with some load development. I would like to see accuracy but I would like to get some speed too. No use shooting a rem mag if I can only get 7-08 speeds.
 
Buckmastr said:
I had always thought that the bullet was only touching the lands if it was placed there. I didn't think I could physically jamb it into the lands unless it was attached to a loaded case and pushed/cammed in by the bolt.
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I figure that if it can fall out under its own weight its touching, and if its stuck there it must be jammed.
 
Depending on the rifle, there are some in which the throat is so long that you
will never get close to the lands, even at maximum magazine length. But Savage
is usually a bit shorter, so you should be able to make it work. The 7mm Rem Mag
is an excellent chambering, IMHO. EE.
 
hunter7mmRM said:
Good info! Thanks. I will try to make some rounds about 40-50 back from where I did my test, to be very roughly 10-20 off the lands and shoot some loads over a chrony to figure out where the max pressure would be. And then start with some load development. I would like to see accuracy but I would like to get some speed too. No use shooting a rem mag if I can only get 7-08 speeds.
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Chronograph is your friend with 7 Rem. Its not hard to end up with a load that makes a 30-06 look like a speed demon, and factory loads are a leading cause of calls to suicide hot lines.
 
Dogleg said:
Chronograph is your friend with 7 Rem. Its not hard to end up with a load that makes a 30-06 look like a speed demon, and factory loads are a leading cause of calls to suicide hot lines.
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Soooo true, Dogleg!! I chronographed some 160 grain factory loads that barely made 2800, and some 150 grain factory loads that were slightly slower.
I consider decent 160 grain loads in most 24" 7mm Mags to be around 3050 or a bit more. My present 7mm Rem Mag, an early production 700, will make
3050+ with 5 different powders, and no adverse pressure signs. 2 of these loads are sub-moa as well. EE.
 
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