The first group of three is loaded to the maximum length found above. I begin loading groups of three cartridges. You will actually see a benefit from keeping these records down the road. You are actually making your own reloading data for a given rifle, a given bullet, and of course all the other variations in components. After seating depth was found with the tool I use, the comparator is used to get comparator length from the ogive of the bullet to the case head and I then record that dimension for future reference. Bullet and case measurements that are touching lands came to 2.400”. This can be a reference point after the rifle is shot several times. First, I find the length where the bullet touches the lands, and make a “dummy” round with that specific bullet at that length. I use the starting load listed in reloading manuals, and the Sinclair bullet seating depth tool “59-4000” and # 09-600 comparator. What I need is for the ammo to be loaded in advance and shoot in almost any given condition. The type of shooting I do doesn’t give me the time to load for each match. This is fine for the bench rest game where the shooters are changing the load specifications to match the conditions of the day. The chamber will finish seating the bullet, or “soft seating”. The reamers that are cut with a lower angle in the throat are designed to seat the bullet a little long. When I look at the choices for reamers, the main change is in the angle of the throat. For instance the bench rest shooters love to jam the bullets in the 6mm PPC. I feel the reason for this is in the way the reamers are cut. The further off of the lands the better they shot. I tried to seat the bullet on the lands and tested different lengths similar to what I described above. 223 Remington I was working a load that I had the bullets seated at a max OAL of 2.260”. When seating off the “lands” this is the point you need to determine as a point of reference. Please approach with extreme caution!)Īn actual cut away view of a chamber showing the throat (left) and “lands” (right) of the rifling. (Note to reader: "jamming” or touching the rifling with a seated bullet will increase case pressure significantly! Use minimum published powder charges while working these loads up. My other varmint rifles like the bullet's ogive to be seated away from the rifling a bit. The group tightened up to 0.220” and when I tried a 0.010” jam, the group opened up to 0.270”. So not wanting to miss something I tried seating bullets into the rifling with a 0.005” jam. I felt that I should be able to tighten the group. I tried seating the bullet on the lands and worked off in 0.005” increments back to 0.020” and accuracy was 0.375-0.500” at 100 yards. One of these rifles is chambered in “.22 Cheetah” which is a notorious barrel burner. They each have about 500 rounds through their barrels. The two rifles that like bullets jammed into the rifling are chambered in wildcat cartridges, and their barrels are worn. I have two rifles in which jamming the bullet works, however on most of my rifles the bullets need some “jump”. Over the years many bench rest shooters have said that the rifle won’t shoot unless the bullet is jammed into the rifling. However it is what makes the rifle shoot best. What is the proper seating depth for bullets? There is no definitive exact answer to this. To learn more about techniques on determining seating depth click on the below link to read an article from our March, 2009 “Reloading Press”)
Utilizing the proper base design provides incredible in-flight stability for long-range shooting.(Editors note: This article focuses on the importance of seating depth, and how it can be different for various rifles. This allows the tip to build up energy before smashing into the core, causing dramatic fragmentation of the core and jacket. The swaging process allows precise formation of the core up and around the tip, with a cavity under the tip's stem. The V-MAX ® profile also provides the maximum bearing surface for added in-flight stability. Hornady ® combines the sharp, pointed polymer tip with the most aerodynamic profile for a high ballistic coefficient. Upon impact, the hard shaft builds up speed and energy before driving into the core, causing the entire package to rapidly expand to the point of violent fragmentation, even at low terminal velocities. The secret to the explosive terminal performance of the V-Max ® is a hollow cavity resting between the tip's shaft and the body of the bullet.