Help - 7mmUM Load Development

[Mike Liane]

I wonder if any of you 7mm UM owners would be willing to share your pet loads. I'm having difficulty getting the accuracy I want. I've been messing with some Sierra 168 Match and Hornady 162 A Max bullets and H-1000 and Retumbo powders. I hope to get at least 3200 fps. and would sure like to see an inch group at 200 yards. I'm shooting a Rem. 700 Sendero with the original barrel. Seating depth is frustrating with the short magazine. Anything I seat just off the lands won't fit in the magazine and has to be loaded singly.
Any tips you could share would be greatly appriciated.

 

[257speed]

I went throught his recently as well so you are not alone. As far as overall length, you can have a local smith put in a wyatts extended mag box, which will allow you to seat out and still stay in the box. I believe that the factory barrels came with a 1/10 twist, which I believe was another factory mistake. Remingtons vision, obvious by the majority of factory loads, was to be able to shoot the lighter 140 to 160gn bullets at very high velocity. I think that Remington screwed the pooch on this, as the Ultra Mags really excell with the heavier bullets, which require faster twists. First of all though, check your twist and let us know, as that will help us help you. Mine has a 1/9 twist and loved 175gn partitions with H-1000. Would not shoot the 162 A-Max's or the 175 SMK's, so now it is getting a new barrel.

 

[7Rumloader]

168 grain match king over 94 grains of Retumbo with Rem 9 1/2 mag primer seated to fit mag. 168 match king over 100 grains of H-50 BMG with same primer and seated the same. The Retumbo will get faster velocities but the ES and SD will be a little higher which will increase your vertical the farther out you go. I was getting a little over 3200 with retumbo and just under 3200 with 50 BMG powder. These are max loads so reduce them a little and go from there.
I found that mine shoots better when seated to a mag fit rather than trying to get closer to the lands.
They have a 1n9 twist barrel. Those loads I listed shoot an average of 1/2 moa out to about 400 yards from my gun and about 3/4 moa to 700. I shoot a factory Sendero as well with a bedding job and muzzle brake.
I have some more hunting loads as well with a variety of bullets and powders if you would like them just let me know.

 

[mrultramag]

My load might not be the best for the 7 ultra but it has bagged a couple bull elk for me. Rem Case, Fed 215 primer, 95 gr RL25, 150 gr partition, oal 3.670 or as long as your magazine will allow if shooting a mod 700 rem. Check to see if you throat is long. Mine is way long. Don't worry about getting close to the lands with the bullet. Velocity is 3450 @ 15 ft chrono'ed. 3 shot groups .75 in. @ 100 yd. Work up from well below. RL25 can be different from lot to lot.