I was not very specific in my earlier posting, when I said they manufactured them to the same specifications I was only talking about the Government model & Government Target model pistols with the 6 7/8ths inch barrels. Not the 5 1/2" bull barrel models. They also laser bore sighted each pistol prior to testing and shipment as part of the contract. One of our conversations, in the early 1990's, was concerning the tighter chambers on the government pistols as these were causing some issues with the commercially produced pistols. Since the military contract was fulfilled they were considering altering the chamber dimensions of the later produced pistols to facilitate operation with a wider variety of commercial ammunition brands.
R,
Bullseye
That's good information to have. In general, with good quality ammunition, my Mk II Target with 5.5" barrel will shot under 1.5" at 25 yards.
I have a box of CCI green tag with nothing to do, so perhaps I'll shoot some test targets with it. I have no doubt I can demonstrate 1.5" at 25 yards.
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When it comes to test targets though I am a realist and am well aware of the limitations of that marketing ploy. I lived near two high end gun makers for several years. Both sold rifles that were promised to deliver 1/2" at 100 yards accuracy, and both companies would shoot at our private club range when their respective indoor ranges were down for maintenance. I won't name either company as they both make very good quality rifles and I suspect every other company has similar test protocols to produce the required targets for similar accuracy claims, but they will serve to illustrate the fallacy of the test target:
Our range was in a canyon with trees to either side so winds were not an issue especially on calm days, so it was the default choice when a 100 yd indoor range was not available. Basically when they were testing a new rifle, they'd fire a group, and if it looked good in the spotting scope they'd move to the next rifle, if not they'd fire another group until they got a good one. In most cases 2 or 3 groups was enough to get a suitable 1/2" group, but obviously the rifle would not do it every time.
The other shooting that was done at the range was with problem rifles that had been returned by the shooter/buyer, or that had failed to shoot a suitable group previously. In most cases their in-house expert had looked at them and tweaked them. Some would again get a 1/2" group in 2 or 3 groups, while others would eventually get a suitable test target and get sent out the door.
So... after watching that several times and talking to the shooter, who were up front about it and made no bones about hiding anything, I put no faith in test targets. Statistically, a single test target tells you nothing at all, except that any rifle can get lucky now and then.
For example, I have shot sub 1/2" 5 shot groups with my CZ 453 and Model 52R Winchester sporters at 100 yards using SK Standard Plus .22LR ammo, and I have the targets to "prove" it. But statistically, having fired many 100 yard groups with them over time, I know they are 1.0 MOA to 1.25 MOA rifles at that range, not 1/2 MOA rifles.
In a similar fashion, I know many of those "1/2 MOA" rifles I saw tested were instead 1 MOA or even 1.5 MOA rifles with test targets that represented 2nd or 3rd SD performance in the right hand tail of a normal distribution.
They get away with it as 1) they are not being dishonest - it did produce a 1/2" group at 100 yards at least once, and 2) most people won't shoot that well, or they'll get a serious shooter who'll work up a load that will shoot better than the Federal Gold Medal ammunition they used for testing. Consequently, very few customer send those 1.0 MOA or 1.5 MOA rifles back. In many cases, if they are sent back it's an issue of playing with action screw torque and getting a half inch group and then telling the shooter "we have no problem getting half inch groups with this ammo and these action screw torque values. Even if the customer can't replicate it, few customers are willing to send it back given the implication that the problem is the shooter, not the rifle.
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The US military accuracy standard for ammunition requires a sample of the ammunition lot to be tested with a test barrel at 200 yd or 600 yd with three 30 round groups with a maximum horizontal and vertical standard deviation. If only two out of three groups meet the standard they get to retest the lot. If only one of three makes it, or if it fails the second test, the whole lot gets rejected. (Can anyone say "civilian white box ammo for sale".)
As an example, the acceptance criteria for M855 requires both a vertical and horizontal standard deviation no greater than 6.8" at 600 yards or alternatively no greater than 1.8" at 200 yards using an indoor range. Three 30 shot targets are fired and averaged out of a fixed test barrel.
What it means is the maximum allowable average distance from the center of the target would be 1.8" at 200 yards. This means that 68.2% (61) of the rounds will impact within a 3.6" circle at 200 yards, 95.4% (a total of 86) will impact within a 7.2" circle at 200 yards and 99.9% (for all practical purposes all of the 90 ound sample) will impact within a 10.8" circle at 200 yards.
Two minutes of angle is 4.19" at 200 yards, so the accuracy standard for 1 standard deviation is essentially 1.7 MOA and it is 3.4 MOA at the 95% confidence level.
That 90 round sample is much better than relying on a single 3, 5, or 10 round group to meet a 3.4 MOA accuracy standard, as with enough attempts you could get eventually get any lot of M855 to print a sufficiently small group, but it would not tell you anything about the consistency of the lot as a whole.
Similarly, weapons acceptance requires accuracy determined by the mean radius from the point of aim (calculating the average distance of each hole from the center of the target. This approach thus considers the entire distribution of shot, including the expected number of fliers, rather then just relying on a single 3 or 5 shot cold barrel group.
