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Right Caliber, Wrong Ammunition? What a Difference a Grain Makes

Experienced and new shooters alike may find their pistols not performing as expected.  While there are many things that can cause malfunctions, sometimes it’s the ammo.  Proper caliber is an easy choice; get what’s labeled on your chamber or barrel, but what about grain?
Sometimes misunderstood as the weight of powder, the grain measurement you see on a modern box of ammunition is actually the weight of the projectile.  There are 437.5 grains (gr) in an ounce.  They are important to us though as they can be indicative of the way a bullet will perform.  Lighter bullets are often loaded to fly faster (measured in feet per second or fps) and heavier bullets fly slower.  After testing 9mm rounds as light as 50gr and as heavy as 158gr, I can attest that there is a strong difference. 

Mass x Velocity = Energy
115gr bullet flying at 1,150fps = 338 foot pounds of energy
147gr bullet flying at 1,050fps= 360 foot pounds of energy

Not only will the weight effect total energy, but it often leads to different overall lengths, some of which may not work properly in your handgun.  The picture above has seven different loads of 9mm varying from 85gr to 147gr.  Examining them closely you can see that they all have different lengths.  Some bullets also have different shapes to them that may or may not feed well in your particular gun.

Different heights and starting diameter among ammunition of the same caliber

 

This is why it is so important that before trusting your life to a defensive round you try at least one magazine’s worth through your gun.  Another concern is pressure and recoil.  Unless your handgun is specifically rated for +P or +P+ loads these are best avoided.  The Sporting Arms and Ammunition Manufacturer’s Institute (SAAMI) has established and agreed upon levels of pressure that ammunition can generate.  If this is exceeded the round is labeled +P, or +P+.  This method is often used to squeeze a little more velocity out of a round.  You may have seen “CIP” stamped on European arms and ammunition.  This is the Permanent International Commission for the Proof of Small Arms, a similar organization to SAAMI, but international.  A combination of SAAMI and CIP markings makes me feel best, which is why I support many European arms and ammunition companies like Fiocchi because I know their goods to be dually approved.



About Graham Baates
“Graham Baates” is a pen name used by a 15-year active Army veteran who spent most of his time in the tactical side of the Intelligence community including tours in Afghanistan and Iraq. Post-Army Graham spent some time in the 3-Gun circuit before becoming a full-time NRA Certified defensive handgun instructor and now works as an industry writer while curating a YouTube channel on the side. Visit Graham on Youtube .