Home Forums Reloading Big Game Rifles 7mm Remington magnum.he lands check

My dad recently bought a Remington 700 bdl in 7mm Remington magnum we was curious if it was shot out cause he did buy it used so I took a fired case sized it enough to hold.bullet put it in chamber and closed the bolt I looked in my lyman book at the oal it was 3.290 so I miced the case I closed in chamber and it reads 3.315 to 3.320 I did use a hornady ballistic tip to.check with I know there will be some variance in the tip but I figured it would get me pretty close . So.based on the reading I did get.is there.any life left it in my opinion is its pretty close to factory and hasn't bin shot.to much but when I took a magic marker colored the bullet and case rim and pulled the bullet out of the case and looked at how much was actually in the case it didn't seem.like too much and that was with the bullet seated to the lands . Am I doing it right for what I have in hand opinions and info would be great thank you

Take it to the range.

You'll learn more there.

A hunting rife isn't a bench gun.

If it shoots, hunt it.

DF

Factory rifles have long throats to start. I agree with Dirtfarmer, shoot it and see how it does. Your post is pretty hard to follow with the periods strewn about randomly, but from what I can make out I doubt the rifle's shot out.

And I'll add that good, straight ammo helps things even more, the further you get from the lands. I had some really wonky ammo a while back (I noticed it when I got a concentricity gauge) but it shot well enough, being very close to the lands. My own 7mmRM has a rather long throat, but it shoots quite well with a substantial jump and straight ammo.

Reloaded or factory ammo could benefit from a run out eval. with a Sinclair concentracity tool, correcting R/O with the TruAngle.

Groups will shrink.

http://www.trutool-equipment.com/TruAngle%20Guide.pdf

DF

Don't mind the periods it's close to my space button but is there a way to check the lands cause even if it shoots good now it might not after 20 rounds I wanna know how close it is from.being burnt up if it is close

I don't think this one measurement will tell. Even brand new throats will vary in depth. With a measurement at only one point in time you can't tell if or how much a throat has eroded.

A bore scope would be appropriate here.

shoot it.

I'm being serious and not critical.

I think too much emphasis is placed on finding lands.

Too MANY factory loads shoot pretty good and they are set to SAAMI c o a l, regardless of freebore to the lands.

However, some barrels are finicky and bullets have to be seated farther our OR deeper.

I'd set the COAL to work trouble free in the magazine and see what you get.

Jerry

Shoot it. Quit looking for meaningless shortcuts.

Clean it and look at it.With a bore scope if possible.

If it's shot out the throat will look "shot out", frosted and dark just forward of the throat,and lands will look flattened, not sharp,after cleaning. It's not hard to tell.But easier to tell through a bore scope.

It's a used hunting rifle and the overwhelming majority of them are not shot much except by a few loonies.

I've cooked several 7mm magnum barrels. Accuracy will begin to deteriorate and then accuracy will sour ....fast...there won't be much doubt about it.But it won't happen in 20 rounds either,unless the barrel is right at the very end of its life.

What you are trying to do won't tell you much of anything.

I had one that the throat was 3/4" long and still shot well. Then one day it started opening up the groups. I rebarreled it and went back to shooting again.

Run it. Don't need .23 inch groups to fill the back of a pick-up...

My last 7rm was partial cooked 'bought used from another loon' and I got 2 good years of hunting with the ol' girl till it turned into a scatter gun.

That partial crispy barrel filled the pick-up a few times, fixed some coyotes and such It was close to being done I could tell by the 2 inch groups and getting larger each bench session.... I knew it was done when keeping 3 shots on the burris sight in target@ 100 was as good of group it could muster. Which was around 150 shots from the time I had acquired it. Faster death than I thought, but I knew it was getting close looking down the barrel when I bought it.

Got a brand new 7rm now, life is better than good

Reason for doing so is it don't wanna go putting money into scope and stock cause it's gonna be a Colorado gun. When knowing it's gonna be toast in say 100 rounds. Doesn't hornady make a gauge u can get a accurate reading of the lands... but then what do you compare it to is there a set depth to go buy. Amy deer rifle I'd work up a load and go with it but I just wanted to be safe and know how long this gun was gonna last and of it was worth putting the money into .

What weight bullet were you using?

Not sure that I follow your line of reasoning....what makes you think that the barrel will be shot out in 100 rounds? Also, if that's what you believe, why even bother to measure the distance to the lands?

If you search this forum, there are guys who deliberately build their custom 7mm RM's with a long throat.

As many others have advised here, just go out and shoot it. A lot. Rifles were meant to be shot, not "not shot" because you're worried about wearing them out.

I had a .300 WinMag that still had .120" jump to the lands when seated as far as the magbox would allow.

It shot bugholes.

I sold it because I thought a .308 was better suited for 40 to 60 yard shots at Whitetail deer.....

Gasman im not saying it will be shot out in 100 rounds but I wanted to see how it was in case it would be as example. Basically I wanted to check and see how much life it still had before messing with it cause I did buy it used

Most factory rifles tend to come with long throats, so how would you know a) how much a rifle had been shot, and b) how much life is left in a barrel, just from measuring the distance to the lands?

Haven't read everything, even though I don't think it will matter much to your accuracy. Here is the easiest method to find the rifling. Take a sized unprimed case, cut a slot in the case neck all the way to the shoulder junction with a hacksaw or cut off wheel in a dremel, de-burr all edges. Take a bullet and just let it sit in the case mouth, chamber it, close the bolt, then lift and close the bolt a couple of times. Done. Measure it, take note.
Keep this case to check as you shoot, the throat will erode roughly .020" per 200 rounds on most magnums.

Cheers.

There is no way you can gain the information you seek with the method of measurement you propose.

As mentioned above, there are two way to learn something about the conditions of the barrel.

1. Look at it with a bore scope
2. Shoot it.

I would start with option number 2, it's cheaper then buying a bore scope.