7mm Remington Mag

K

KEVELDER21

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Need help. I am an avid reloader and just started reloading for a 7mm Remington Mag. I used a oal gauge to get mesaured length from bottom of case to ogive bullet. It's about .055 longer than a factory Remington Load. I measured this 5 different time and came up with 2.784 oal to the ogive of the bullet. The factory Remington load is 2.729 to the ogive. Does anyone have any info on whether .055 jump is o.k. Just seems like that's an awful far jump to the lands. Any thoughts on this would be appreciative.
 
I assume you set your seating depth up to reach the lands. The factory load is most likely much shorter than yours because the factory must take all guns in to consideration when producing ammo. There are most likely a wide variety of seating depths out there from many different manufacturers and their loads must fit them all.
 
I have a federal load and remington load and they are .001 difference in length. Then when I measured the oal with the gauge, it was .055 in difference. The factory loads are very inacurate. Just wondering if that's due to the major jump to the lands.
 
Initially I set the oal to the exact configuration as the factory loads. 2.729 oal. My gun is 2.784..... I haven't reloaded to 2.784 spec yet. Just thought that was big difference.
 
It's been a while since I loaded for the 7RemMag. There are powders today that show faster muzzle velocities, but max loads of IMR 4831 always gave me excellent accuracy.
 
My 7mm Rem Mag is a precision barreled long range workup. I seat the 168 grain Sierra MK bullets to just touch the lands, at 3.325" AOL, but you need to remember that this is not a good idea for hunting rifles as it can leave a bullet stuck in the chamber while the case pulls free, if you try to unload without firing. The length of most factory bullets also vary by several thousandths as they are produced by several different dies and blended into the same packaging, which can exacerbate the problem if the OAL is set up tight with a short bullet. Also, it depends on the length of the magazine, my rifle was built on a long length magnum action for the .375 H&H. Experimentation is the only way to determine what works best. The .055" jump may shoot okay. I use H 4831SC and H1000 with Federal 215 Gold Match primers with good results.
 
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Seating Depth

I just started reloading, so I can't claim years of experience, but the first thing I did was to play with seating depth. Seemed to make a noticeable difference in my Savage BVSS 308. A difference of 0.005" made a 2.625" groups at 200 yards shrink to a 1.00" group (four of those shots were within 0.50").

I found the Stoney Point "fake" cartridge guage inconsistent. Maybe user error, but I could never get consistent readings. So I used a dremel to splits a few case necks and I measured "full jam" on my bullet of interest (base to ogive). These readings were always consistent to within 0.001"...usually spot on.

I somewhat agree though with the "no reloading for hunting" comment. Tight handloads in field conditions can create risk of jamming or sticking...which is not what I need when hunting elk at 12,000'. Also, if you forget, lose or damage your handloads, you are screwed in the field. Moreover, shooting off sticks, wind and temperature, heart rate after climbing to within range, moving target...all have much more impact on my success than the difference between a factory load and a hand load. When it comes to target rifles and little groups on papers than I am all about wringing every little bit out of the equipment.

K
 
A little out there, but, has anybody noticed that factory 140 gr ammo shoots right through whitetails like hardball? Or is it just me. I went to 120s in order to get some terminal effect, but haven't shot a deer with it yet. A couple times I shot a deer with 140s and they stood there looking at me and then trotted off. I didn't loose either of them but had to shoot them again. Both first round hits would have knocked them down with a 30-06. I like the 140 weight maybe I need the Nosler partition to get the shock.
 
jump to lands

.055 jump to lands on factory round is pretty normal.

I would either go with either .010 to .020 off lands or .010 to .020 into lands.
If you seat just touching you will have some out .001 some into .001, this will give you some groups that are way worse than .055 jump.

Most consider +/- .005 of lands off limits. On bench most will seat into lands, for field most will seat off. I seat into lands .020 tight neck and have never pulled bullet from case, but am aware this could happen.


RC
 
I would start .005 off with a 140gr. Ballistic Tip, then try the following powders: RL-19, RL-22, and IMR 4831. I have had the best luck with RL-19 (with 3 rifles). You may want to try 140gr. Pro Hunters also. I would be a bit surprised if you can't get a good load out of those 3 powders and 2 bullets.
 
H-1000

I load for a dozen different 7 mm rem mag's (factory and custom) with bullets ranging from 140 ballistic tips to 180 JLK's. All....again....ALL of them shot best AND fastest with H-1000. RL 22, and RL25 for the heavy bullets come in a very close second!! Most bullets like it up against the lands, but for hunting we use .02 off. Like was stated above..check your mag well to make sure there is room for a long OAL.

just my .02 worth
TOD
 
How far the bullet jumps with factory ammo in factory barrels can really vary with the caliber and the make of ammo and the rifle.

They have to make factory ammo safe in all factory rifles so there will always be some excessive tolerance somewhere... even with that some combinations shoot very well...

In the older Weatherby's the jump was over .500"... :eek:

The advantage of reloading is to keep the jump down and the accuracy up...
 
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