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7mm Rem Ultra Mag w/ 1in8 twist
Thesteeleboy
Member Posts: 5 ✭✭
I built this rifle with a 1 in 8 twist to shoot 168 gr Berger VLDs and it shoots them well but their too long to fit into the magazine and that's not to appealing to me. I'm going hunting Grizzly bear in Alaska and was wondering if anyone had any load recommendations for me with this 1 in 8 twist barrel.
Comments
I guess I'd like to ask a couple of questions first.
Why do you have a 1:8" twist for these bullets?
According to Berger and my own tests, these bullets only require a 1:10" twist at the velocities you will be shooting. Even the 180 grain VLDs only need a 1:9" twist.
Why are they too long to fit in the magazine?
Are you trying to touch or jam into the lands?
Have you tried testing them seated to magazine length?
Best.
What velocities are you recording for these bullets?
Have you tried shooting these bullets at ranges longer than 100 yards?
You might see an improvement in group size at longer distances with designs like this.
But none of this makes any difference if you can't get them to shoot at magazine length for hunting. At this point, you might want to consider another bullet rather than the VLD-style Berger or the almost VLD Sierra bullets.
The Barnes 160 grain TSX will pack plenty of punch for a Grizzly bear. They also like to seated significantly off of the lands which will only help in your situation. I think Retumbo or V V N-170 will work fine. That's what I remember from the tests I shot.
You might also consider the Nosler 175 grain Partition.
Best.
ADDED:
Push comes to shove and you really want to shoot the Match bullets, you could have the barrel set back and use another reamer with a shorter throat or leade to get the cartridge back to magazine length and still be close to the lands with these bullets. You should make up a dummy cartridge for each bullet seated to magazine length to check where the bullet is seated in the case neck. The Sierra has a fairly short body length and you need it to be in the case neck not below.
Setting the barrel back can affect your bedding so check the contour and position of the barrel diameters to see what adjustments have to be made.
Best.
Thank You
Excellent! Looking forward to the report and your assessment.
Best.
{edit:} Welcome to the forum!
In my shooting of the Berger VLD's I've found they almost always need to be seated 'into the lands' in order to shoot most accurately. I have found I do just fine with my .280 Ackley with a 1-9" twist, shooting 180 Bergers loaded to about 2670. To me that's always been the secret loading VLD's, put them into the lands. However, in your situation this isn't going to work as you need to fill a magazine.
This is a good opportunity I feel to branch out and try some other bullets. I feel that while I wouldn't have too much problem shooting at deer or elk with a Berger, I would have a problem with shooting at Alaskan grizzly with one. This is definitely the hunting situation that requires a better constructed bullet. I suggest either Nosler Partitions (160 or 175) or Barnes. Both have excellent expansion qualities. I will also recommend Nosler Accubonds and Hornady Interbonds. The core is bonded to the jacket and expansion is very good. Better I think than the Partition. The question is whether you need more penetration or more expansion in the bullet after initial entry. The partition will likely go through more backside bone than an Accubond/Interbond will. Either though, will produce a much better effect than a Berger. I do like shooting them. I just wouldn't go after big bear with them.
As for loads I've found a lot of success with RE-22 for velocity and H-1000 for velocity and accuracy in the .300 WM, .300WSM and 7WSM. You would need to work up what gets you where you need.
Thesteeleboy