Preparing Match Ammo
by Bob Londrigan, published in Front Sight Magazine, July 2007
One of the most common causes for reliability problems that I see at big matches concerns ammunition. You have spent a lot of money to get to the match, and you’ve spent a lot of time and money practicing. Now spend the final extra effort to be sure your match ammo will not let you down.
To be match ready, your match ammo must meet several criteria: it must be accurate in your gun, it must be reliable, it must feel good to you (e.g., sights return quickly), and it needs to make major (or minor depending on your division.) Your role in ensuring you have good ammo starts well before match day. Begin by testing some loads both for accuracy and for power factor (you must use a chronograph). Narrow things down to a few loads and then test for feel. Settle in on one load so you can do more testing.
Next you will load a batch of ammo that you will test in practice. Even though you may have the perfect recipe, there are many things that can go wrong when actually loading ammo. Get a good start by always using new brass (or once fired in your barrel) for major matches. It will be much more consistent dimensionally and in terms of velocity. Also check each loaded round for the following problems: (If you use factory ammo check it the same way as if you loaded it yourself.)
· High primers – this is one of the most common problems. A high primer will cause a light hit from the firing pin and may result in a misfire. Primers should actually be set a little below flush with the case head (about 0.003 inch.) You should be able to set the rounds on a flat surface with the primer down and you should not be able to rock the round back and forth. I find the flat edge of a caliper is a good tool to check for this.
· Not enough crimp – If the case mouth has not had all the bell removed it can cause feeding problems. Light crimp can also cause misfeeds from bullet setback.
· Overall length (OAL) problems – Find out what overall length ammo works best in your gun and make sure your match ammo is +/- 0.005 inch of this length.
· Primer flow - Make sure you have no signs of primer flow. Primer flow can cause light primer hits because small metal chips build up in the firing pin hole.
You should be able to shoot at least a couple thousand rounds of this practice test ammo and have no malfunctions that trace back to ammo. After your ammo passes this test you are ready to make some match ammo. Once you settle on a final load, do not change bullet type or brand without retesting. Plan ahead so that you can load your entire batch of match ammo from the same canister of powder that you used for testing. If you change any of your components (bullet, brass, powder, primer, powder canister), then retest.
Once you are ready to start loading the actual ammo you will use in the match you must do final chronograph testing to be sure your ammo will make the proper power factor. The only way to do this is with a chronograph. I am fortunate in that I have a chrono set up in the shop and can test loads right there. I shoot over the chrono and then make adjustments to the powder measure until I get the velocity I want. This is the easiest method to get it right but most people don’t have access to that kind of setup. You can get the same results, but it will take a little more work. Load some test batches of ammo with your match recipe and then plus and minus 0.1 gr. and plus and minus 0.2 gr. This will give you five batches to test. Load about 25 rounds of each, bag them separately, and mark the charge weight on the bag. Now it’s off to the range to chrono your loads.
The big question is what velocity are you looking for? The way I make that decision is to first determine the minimum velocity I need to make major. For example, to make 165 power factor with a 125 gr bullet, I need 1320 fps. (165000 divided by 125). My benchmark for velocity is an extra 40 fps for a safety cushion. What I want is to take 5 shots and have the average be 1360 fps. I also want the slowest shot to be in excess of 1320 fps. This benchmark gives me plenty of safety margin without sacrificing performance because the loads may be too hot. You will have to set a benchmark that makes you comfortable but this one works well for me. Now test your ammo and select the batch that just makes the benchmark. Hopefully +/- 0.2 gr. was enough to get you in the target range but if it was not then adjust the load and try again. I have seen different lot numbers of powder vary as much as 0.5 gr. to get the same velocity.
Once you identify the batch that has the results you’re looking for, go home and start loading for the match. I load at least twice as much ammo as I think the match will require and usually three times as much. I can always use it for the next match. When the ammo is loaded, it is time to quality check it. Chamber check each round first. Reject any rounds that don’t slide in and out of the chamber checker easily. You should also check for OAL and high primers while you are doing this. Run your finger over the top of the round while it is in the chamber checker. You should feel that it is below the level of the chamber checker. Also feel for any high primers.
As I check each round, I load it into an ammo box. I use the plastic 100 boxes that you can get from Dillon or Midway. Once you have a box filled, look at the tops of the rounds from the side – the rounds should all be the same height and you should be able to spot any suspected high primers. If you see any suspect rounds, pull them for the practice bin.
Next mark that box with the date loaded, the recipe, and lot # of the powder. This is a good practice so that you can rotate your match ammo and, if you have a problem, you can cull all of the bad batch. As one final check, I would take this match ammo to the range once more and test a few rounds out of each box at random to see if they hit your target velocity. If not, pull the box and make some more ammo. One final hint - use your match ammo for your final sight-in of your gun before the match.
If you follow this procedure you will be confident in your ammo and gun on match day. This will significantly reduce your stress level, especially at the chrono stage.