Hello,

Will this stabilize a 168 grain Barnes LRX bullet? What about heavier bullets like the 175 grain Partition? Anybody with real world experience? I'm being offered a Mark V Ultra Light Weight that will be going to an estate sale at a good price. Thanks in advance, appreciate any feedback.

My rebarrel to 7 mm Weatherby was a Lilja with 1-9 twist, specifically because I intended using 160-grainers. It shoots great, including 168-grainers. Don't count on 1-10 twist to do the same.

2 cents

I have a 7MM Weatherby accumark that drives tacks with 160 gr. partitions at 3250 FPS.
I have not tried anything heavier. It just shoots those so well.

I haven't run across a 7mm bullet that a 1-10 twist won't stabilize. But then I don't use any monometal bullets which are very long for their weight and have other issues that cause them to act differently from jacketed lead core bullets.

Whether a given bullet shoots well in a particular rifle is another question. But, except in extreme cases, factors other than the rate of twist are the culprits.

The short answer to your question, BighornBreath, is that the 175 Nosler Partition will definitely stabilize with a 1-10" twist, but the 168 Barnes LRX likely will not. 7 mm. bullets longer than about 1.42” will likely be under-stabilized or of borderline stability. The 175 Nosler Partition is 1.36” long, whereas the 168 Barnes LRX is 1.592” long. The latter bullet is solid copper, this accounting for its greater length. The 1-10” twist in your 7mm. Wby. Mag. would probably be too slow for most of the available boattail VLD bullets in the 160-175 gr. range as well.

How do I know this? For anyone wanting to explore bullet stability in greater depth, there are two JBM Ballistics sources. The first gives bullet lengths for a huge number of bullets from many bullet-makers. Here’s the link:

https://www.jbmballistics.com/...engths/lengths.shtml

Once you have the length of a particular bullet, you can enter the following JBM Ballistics stability calculator (along with the bullet diameter and weight, muzzle velocity, and barrel twist) to determine its likely stability with that twist:

https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

These days, I believe that most of the various 7mm. magnums have 1-9”, 1-9¼” (Remington), or 1-9½” twists.

You might want to double-check the twist of the rifle in question unless you know for certain that its twist is indeed 1-10".

Great information. Thanks for all of the responses. Looks like I will pass on the Weatherby as I'm more inclined to use a mono which my current rifle should handle. Thanks again.

Good Morning Bighorn,

I wouldn't lose a second's sleep over it.

Figure out how far you're capable of humanely killing big game and go from there.

My max Rocky Mountain shooting distance was 400 yards under perfect conditions. I've shaved a 100 yards off that. I probably should shave another hundred yards. Perfect conditions close to timberlines are rare.

When I was younger, cockier, and confident, I've made longer shots. Wisdom has taught me to close distance if possible. I'd rather shoot big game at a 100 yards than farther.

I'm not sure if this will help: I use 160 grain Partitions out of my 24" barreled 7MM Rem Mag. I can write from personal experience that they'll one-shot kill the largest bull elk in North America. I've cited bull elk because they're purportedly the toughest big game animal in North America to kill. I've found that they'll die just as dead as other big game animals if bullets decommission parts necessary for sustaining life.

I wish you success in your hunting seasons.