Bersa v.s. P3AT shootout

[oldgranpa]

Bersa 380CC v.s. KelTec P3AT Shootout, May 25, 2007 by og
In the previous Chrony test of four .380acp pistols on April 19, 2007  http://usrange.org/smf/index.php?topic=1044.0   
 (scroll down to the spreadsheet picture)
 there was an anomaly between the Bersa and P3AT with the P3AT having better FMJ velocity than the Bersa.
I decided to re-run the test and include a wetpack comparison. The velocities this time were more what one would expect, with the longer barrel Bersa showing higher velocity, except for the CorBon DPX. (The DPX numbers are so close as to not be significant.)
Velocity readings, average of 4 shots.....

Rem UMC 95gr FMJ.....................................Rem GS 102gr JHP
Bersa 933.7fps, SD 10.9                             Bersa 913.9fps, SD 8.1
P3AT 877.9fps, SD  1                                  P3AT 855.2fps, SD 2.5

CorBon DPX 80gr......................................Win SXT 95gr JHP
Bersa 1055.3fps, SD 10.2                          Bersa 822.9fps, SD 33.2
P3AT 1068.5fps, SD 20.5                           P3AT 791.3fps, SD 1

MagTek FD 77gr........................................ Hornady XTP 90gr JHP
Bersa 1001.9fps, SD 16.1                           Bersa 869.0fps, SD 15
P3AT 961.8fps, SD 15.8                              P3AT 807.5fps, SD 7.9

Perhaps the only explanation I have for the lower FMJ numbers with the Bersa last time might be the pistol was new, first time fired. The rifling in the Bersa is a little deeper than the P3AT and may have had some slight roughness that affected velocity when first fired. Of course I'm just speculating on that idea. Anyway, a longer barrel, 3.5", Bersa gives higher velocity, as it should, than the 2.7" P3AT barrel. (I thought the locked breach P3AT might make a difference, but that does not seem to be a factor.)

During warmup of the two pistols, I initially tried a small, soft plastic tube on the trigger of the P3AT thinking that might reduce the recoil "hurt" to my trigger finger. The tube actually made it worse by taking up space and then my finger hit the front of the trigger guard during recoil. Which hurt worse. The pistol feels better without the tube so I left it off. At that point I did a little accuracy comparison. The Bersa fires a tighter group but was off just a bit to the left as seen in the picture below. The long pull of the P3AT trigger causes me to be off in POA.

Following is the wetpack test picture. Interesting was the penetration was the same for the JHP rounds. Even though the P3AT velocities are lower, lower expansion made up for it and penetration was the same as the Bersa with higher expansion numbers. With good placement, the tradeoff would be insignificant. However, the Hornady stuff doesn't look too good in expansion, might as well just use FMJ instead of Hornady XTP. FMJ did reflect the difference in velocity with penetration into the plywood backing with the Bersa.

In all, both pistols have their place. There were no malfunctions of any kind with over 30 rounds fired with both pistols. The P3AT is the best for a deep conceal backup due to it's light weight and small size. But it's not a target gun for heavy range use and begins to hurt after about 10 rounds. If you can carry the Bersa  (concealed carry model) it is more
comfortable to shoot, light, easy trigger, and faster for follow-up shots

[Norfdet]

Great report OG, can you clarify for our new members what "standard deviation" is?

[oldgranpa]

hi, Norf

this test report was originally posted back in May 2007 here. But just checking today I noted that there was a glitch in the orginal post that must have occured back when the site suffered a major glitch. I was unable to correct it the way it was since it listed me as a guest. So I decided to repost the whole thing, which worked out OK. Guess I will do some checking of our other wetpack tests for any similar glitches.

Then to answer your question what "SD", standard deviation is. This is a statistical value that gives the most probable range, up or down, from the average number. Of course you have to have at least 2 data points to get the average in the first place. So SD gives an indication of the accuracy or 'closeness' of the data points that went into calculating the average. The smaller the SD number, the more accurate the average is. Average is simply the sum of the data points divided by the number of data points. We all know how to do that.
But to get SD takes a complex equation 'invented' by mathematicians years ago. Something like square root of the sum of the squares. Most decent pocket calcuators do the math for you nowadays and all you have to do is enter the data point values.
Normally, SD is just some extra frosting on the cake and I only put it there in case some of the 'experts' happen to read our reports. Several of these so called 'experts' who run several of the gelatin sites say that data presented without the SD value is invalid and 'void'.
So there you have it, I hope. By showing the SD number USRange is just as technically excellent as the sites run by the 'experts'!!

Cheers,
og

I went ahead and made this a sticky so members could get a feel for what SD is. And note, the values in this report were based on 4 data points for each round. It always amazes me how the 'experts' that do gelatin tests can get a SD from only 1 data point! But then, of course, they are the 'experts'!!
When I was at NASA, we were required to do 50 tests to obtain the average and SD before the results could be accepted. This was called an 'A-Basis'. We had to do that since the safety factor on most space parts is very low to keep weight down. For Chrony readings more is better since factory ammo varies a lot. But 4 readings is good enough for most purposes. To get decent expansion about 800fps is needed. Chrony readings help a lot to understand ballistics from your pistol.