Performance vs. Reliability
by Bob Londrigan, published in Front Sight Magazine, May 2006
Everyone interested in competing to the best of their ability looks for ways to improve their match performance. One way to maximize match points is to get the best performance out of your equipment. However, sometimes better performance from your equipment can result in decreased reliability and, in the end, your match scores may suffer. How to balance performance against reliability is the subject of this article.
I cannot stress enough that reliability is the most important factor in setting up a gun. One jam will cost you approximately 15 match points (same as a miss). It may cost you much more depending on when it occurs and if it causes enough confusion. It will also distract you from your purpose at hand and make you doubt your equipment for the rest of the match. None of these things are conducive to peak match performance.
The first priority when you make any change to your equipment is that you make sure that you measure the change in performance somehow. This sounds like a simple concept but it is often ignored. How often have you changed something on your gun and after shooting it a few rounds, decided it felt better, and then promptly forgot about it? Then a couple of weeks later when you were having problems you suddenly remembered that you changed “X” a couple of weeks ago -- right before you started having problems. Improvements should result in measurable increases in hit factor under all match situations. This will result in more match points and higher placement. You have to be disciplined about changes that you make to your equipment. Make only one change at a time, and keep a detailed log of exactly what you have done. Fully evaluate that one change before making any others. This will make it easier to isolate problems if they occur as a result of a change.
Once you have decided that a particular change results in a gain in performance then you have to check reliability. The ideal situation is that the change produces better performance results and there is no effect on reliability. This is seldom the case and you must weigh the performance benefits against reliability changes and do a cost-benefit analysis. It would go something like this – I make change “X” to the gun and I get 0.01 second better splits on each index on targets 15 yards or farther away. In a typical big match this might be 40 shots out of 300. For the match you will save 0.4 second. If the average hit factor for the match is 7.5, then the points saved equals 3.0. If the change you made results in one jam every 1,000 rounds, this will cost you about 2 seconds. At the average hit factor of 7.5 your jam will cost 15 match points. If you average out the chances of a jam for the 300 rounds of the match it works out to 4.5 points per 300 rounds shot. For this change you would actually be in worse shape because your change resulted in one jam per 1000 rounds.
You will not have hard and fast figures to work with so you have to make your best estimate but in most cases unless there is a marked increase in performance even a small reduction in reliability will negate the performance gain. Let’s look about some specific applications of this concept. Changes to equipment that I see most often are: magazine tuning, recoil springs, different loads/bullets, and weight distribution changes.
This would include magazine springs, followers, basepads etc. You can usually increase capacity another round by cutting coils off the spring but this usually results in reduced reliability. Really be careful here – any changes should be made with reliability in mind before performance. Changes to the follower or basepad can actually improve reliability and performance and that is usually a winning combination. Be careful trying to get that last round in the magazine. It can put undue pressure on the spring causing it to fail early. If combined with a lighter recoil spring, it can also cause failure to feed problems on the first round.
Changes here can sometimes result in better performance but be careful as you get to the extreme ranges of spring rate, both high and low. For instance a 6 lb spring might feel real good in that limited gun but what it does to the long term survival of your gun would not be pretty, and it is probably not going to feed when the gun gets dirty, etc. Make sure when you compare setups with different springs that you are using new springs so that you are comparing apples to apples. Comparing a new 14 lb. spring to that old 12 lb. spring that has been in the gun for 15,000 rounds does not make much sense.
This one is tricky because the main issue with loads is that you must be sure that you are not using an over pressure load (especially in open guns). If your load is over pressure you will stress your entire gun and eventually this will result in increased parts breakage. Some of that will likely happen in the match resulting in a zeroed stage or worse. Watch carefully for pressure signs and try to use a load that is recommended by your gunsmith for your gun. Don’t just pick a load that someone else is using because it feels good in your gun. This is a particular problem in open guns because a high pressure load with a fast powder will work the comp just as well as a low pressure load with a slow powder. Sometimes the high pressure load will feel better but the long term consequences to your gun are not worth it. You want to work your comp lots of gas volume at lower pressure, not low volumes of gas at high pressure. It is not as much of a problem in limited guns but you still have to be careful about using a really fast powder with heavy bullets. Your setup will be very susceptible to bullet setback, small changes in powder weight, and temperature changes. Any of which in the wrong combination can have catastrophic consequences.
Weight Distribution Changes
You are usually pretty safe with these type of changes – heavier magwells, steel mainspring housings, extended dust covers, and tungsten guide rods. The tungsten guide rod is the only one that might cause a reliability problem (breakage of the rod).
Make sure you are honest with yourself about the performance enhancements you make. Always look for reliability first and you should be able to set your gun up to suit your style of shooting and enhance your match scores in the process.