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SST and Interbond annealing tutorial

The following video details how to anneal an SST or Interbond projectile as described amongst the cartridge texts of the knowledge base.  Annealing can produce two benefits. In the first instance, it helps the frontal area of both the SST and IB to swage back after expansion, the frontal area folds back against the bullet shank and the reduced frontal area allows for much deeper penetration- but without sacrificing wound channel diameters.

In the second instance, at long range, the softer ogive gives faster expansion, imparting energy more readily, improving wound channel diameters. This helps the Interbond to create broad wounding at ranges of around 400 yards in various calibiers (as an example) while allowing the SST to produce admirable performance out to ranges exceeding 1000 yards.

Regarding the SST, please bare in mind, a high sectional density (long for caliber) SST is required for any increase in penetration at close ranges.  For example, annealing the .277" 130 grain SST does not improve performance. Annealing the .277" 150 grain SST is a boon, making for a potent load in the .270 Winchester.  Yet there is a catch. Annealing the 154 grain 7mm SST which has almost the same SD as the .277" 150 grain bullet, helps improve expansion at extreme ranges but does not help penetration at close ranges if fired from a 7mm magnum and used on stout bodied game. Magnum muzzle velocities and close range hits are hard on conventional bullet designs.   On the other hand, annealing the .277" 130 grain Interbond or 7mm 154 grain Interbond helps both projectiles to achieve deeper penetration and faster expansion.

There is a lot to consider. For example, a 7mm user may decide to use an annealed 154 grain Interbond for close to intermediate range work on Mule Deer, using the annealed 154 grain SST for long range work on the same game.  Yet, another hunter may decide to choose the annealed 162 grain SST for all situations.  As always, matching bullet weights to game body weights along with intended ranges and conditions is the first step in decision making.

It is counterproductive to say, "annealing the 162 grain 7mm SST is effective, therefore annealing all SST projectiles is effective".  As mentioned, the same goes for velocity, any major changes in velocity will effect performance. Each caliber /weight SST must be studied on an individual basis (just as I have done with other projectiles throughout the knowledge base). Annealing certain SST and Interbond projectiles can radically optimize cartridge performance and many examples of this are given within the knowledge base.
 


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