How Different Can Identical Airguns Be?
Here’s a question that often exercises the minds of the HAM Test Team. How different can identical airguns be?
The reason for this question is that – like all other media – we review one sample of an airgun, then tell you all about it.
We know that there’s bound to be some differences between two individual samples of the same airgun. That’s known and accepted in the HAM pellet test reviews, for example, where we test 50 samples of each “identical” pellet and see the variation.
But how big is the variation between two “identical” airguns?
Recently we had an opportunity to test this for the first time ever. Umarex USA sent us two sample Ruger Mark IV pellet pistols to review. The guns were selected at random. They just happened to be next to each other when our order was picked in the Umarex warehouse and were not tested before shipment.
The test review for one of these guns – serial number 21H227954 – has already been published. But what about the other – number 21H227957? How different could that be?
To answer that question, we’ll compare some key performance metrics from both guns. They’re accuracy, muzzle velocity and trigger pull weight.
To compare the accuracy of the two Ruger Mark IVs, HAM Specialist pistol tester Doug Wall fired a 10-shot group from each guns successively at 6 Yards range. The pellets – RWS Meisterkugeln Pistols – were unsorted but taken from the same tin.
Here’s the results…
As you can see, the groups were slightly different shapes. However the actual sizes, measured by comparing vertical and horizontal CTCs were exactly the same: 1-Inch vertical and 0.8 Inch horizontal.
That proves two things. First, the accuracy of both guns is very similar. Secondly, Doug Wall is a very consistent shot!
2. MUZZLE VELOCITY:
Here again, the two guns were very similar. When shooting RWS Meisterkugeln pellets the results were as follows…
|S/N 21H227954||S/N 21H227957|
|Average Muzzle Velocity||365.3 FPS||361.6 FPS|
|Highest Muzzle Velocity||371 FPS||367 FPS|
|Lowest Muzzle Velocity||362 FPS||358 FPS|
|Standard Deviation||2.37 FPS||2.67 FPS|
The difference between the average muzzle velocities of the two guns was just 4.2 FPS. That’s slightly over 1%. Given that the test was undertaken with unsorted pellets, that’s effectively identical!
3. TRIGGER PULL WEIGHT:
Unfortunately, the trigger pull of the Ruger Mark IV is very inconsistent. That was true for both the guns tested. But more so for “954”.
|S/N 21H227954||S/N 21H227957|
|Average Trigger Pull Weight||10 Lbs 7 Oz||10 Lbs 14 Oz|
|Highest Trigger Pull Weight||11 Lbs 8 Oz||11 Lbs 0 Oz|
|Lowest Trigger Pull Weight||9 Lb 13 Oz||10 Lbs 5 Oz|
Overall, we can say that the trigger pull weight of “954” is about half a Pound lighter than that for “957”. That’s very roughly a 6% difference in average pull weight. But the variability of pull for “954” is so extreme that it makes a real comparison difficult.
However the triggers of both guns had similar characteristics – a long, gritty pull and waaaaay too heavy!
To be honest, we were surprised by how similarly these two air pistols performed. Yes, they obviously come from the same manufacturing batch but – given the low price of the Ruger Mark IV pellet pistol, we expected the differences to be greater.
Modern manufacturing and assembly techniques often minimize differences. They obviously have done so here.
So how different can identical airguns be?
From this analysis, it seems that they can actually be quite similar. Yes, there will always be differences of some sort between two samples of “the same” airgun. In this case, the trigger is the obvious area of difference.
However it’s clear that the general conclusions of the HAM review for 21H227954 also apply pretty well to 21H227957 when they are tested under identical conditions and with the same test methodologies. They would also likely apply to other samples of the same pistol.