Where is the best seating depth to start load development? I have a 7 mm Remington Magnum hunting rig with a brand new 24 1/2 Douglas barrel. I have fired a total of 60 rounds of 140 grain Berger 140 gr. VLD's, new WW cases, Fed 215M primers, using RL 22 from 65 to 70 grains. A couple of groups showed promise in the 3125 (.838") and 3190 (.698") fps range. The seating depth that I've been using for barrel break in is .025 short of where the rifling marks are square shaped and .014 short of where the rifling marks begin. This week I hope to get to the range and begin some serious load development using fully prepped once fired cases. What seating depth should I use to begin with; at the "square mark" area? At the point that just kissed the lands? or some point short of that? My instincts say to stay up close to the contact point. Any suggestions or thoughts appreciated.
Seating Depth Starting Point
- Thread starter gilream
- Start date
L
Larry Elliott
Guest
Is this rifle going to be used for hunting or is it a match rifle? If it's a hunting rifle then reliability is more important than the last thousandth of an inch in group size.
For match shooting at the rifling is a good place to start. Bullets can be seated deeper if needed without increasing pressures. If you start the bullets off the rifling, and develop a good load then move the bullets into the rifling pressures are likely to increase, possibly dangerously.
For match shooting at the rifling is a good place to start. Bullets can be seated deeper if needed without increasing pressures. If you start the bullets off the rifling, and develop a good load then move the bullets into the rifling pressures are likely to increase, possibly dangerously.
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tome
Guest
if your rifle has a mag. & you want more than a single shot..aren't you limited on col by what would fit and feed properly..also if you are going to use the mag &/or stick ammo in your pocket when hunting.. then you should crimp
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ForneyRider
Guest
I'd experiment with a non-magnum primer. Across the board, whenever I have experimented with primers with 7mm Mag, the non-magnum fare better. Several manufacturers load data list non-magnum as primer used. But, I don't use ball, very low temperatures, or max loads in 7mm mag either.
Also, try IMR 4350 instead of R22. R22 has given me very fast velocities, but my more accurate loads are with IMR 4350 and even IMR 4064.
Also, try IMR 4350 instead of R22. R22 has given me very fast velocities, but my more accurate loads are with IMR 4350 and even IMR 4064.
sbindy
Steve B
Most people who shoot VLD bullets have them jammed, so you might want to start there. I think you are right in that the rifle should shoot much better with once fired cases. All of my belted mags did. I have had some brass (.300 Win Mag) that the shoulders were .040 short, and that does nothing for accuracy. Just set the shoulder back .001-.002 and go try it again the way it is now.