I was able to chronograph those primer modifications I made to my basic 9mm plinking load recipe. I had previously collected some performance data on that load, and that somewhat influenced how I did things on this go around.
I shot these the morning of 5 July 2010 @ the Austin Rifle Club. It was about 75º out, 94% humidity, altitude was 449′ above sea level, winds calm and the day generally pleasant.
I used a PACT MKIV XP timer/chronograph to record the data, with the chrono set about 10′ from the muzzle. All shots were off a heavy steel benchrest. I shot two guns: both Springfield XD-9’s, one with a 4″ barrel and one with a 5″ barrel. I did that because most of my previous data was out of the 4″ barrel and I wanted to get more data on what that extra inch of barrel would give me. I shot 10 rounds out of each gun over the chronograph screens, however not all strings recorded all 10 shots for whatever reason the chrono didn’t get it. Still, I feel enough shots went over the chrono to give me enough of an idea of how the load and modification performed.
The point of this exercise was to test out primer modifications. The say every time you change a component you need to retest to ensure all is good, thus here we are. My basic recipe is: Berry’s 9mm TMJ RN 115 grain bullet; 4.5 grains Titegroup; mixed used brass cases; 1.135″ overall length; and Remington small pistol primers. Previously I tried out changing the bullet, and as expected there wasn’t much difference. This time around I have another bullet change (Precision Delta) but more importantly a primer change. So I ran 5 different loads:
- The base original recipe (with 11 secret herbs and spices)
- The base original recipe, but swapping a Precision Delta 115 grain FMJ ball copper jacket bullet.
- Base + PD bullet + Winchester small pistol primer (WSP)
- Base + PD bullet + Federal small pistol primer (#100)
- Base + PD bullet + Wolf small pistol primers
I also wanted a baseline factory load that was closer to the sort of load I was going for, so I ran some good old Winchester White Box (9mm 115 grain FMJ’s) for that purpose. And since I had some carry ammo that I needed to cycle out, I ran some Gold Dots over the chrono just because I could.
Winchester White Box
|Avg. Velocity (mean)||1160.9 fps|
|Std Dev Coefficient of Variation||1.575%|
|Mean Absolute Deviation||13.45|
|MAD Coefficient of Variation||1.159%|
|Avg. Velocity (mean)||1217.04 fps|
|Std Dev Coefficient of Variation||1.474%|
|Mean Absolute Deviation||14.392|
|MAD Coefficient of Variation||1.183%|
|Avg. Velocity (mean)||1149.689 fps|
|Std Dev Coefficient of Variation||1.291%|
|Mean Absolute Deviation||12.104|
|MAD Coefficient of Variation||1.053%|
|Avg. Velocity (mean)||1201.45 fps|
|Std Dev Coefficient of Variation||1.131%|
|Mean Absolute Deviation||9.97|
|MAD Coefficient of Variation||0.83%|
Base Recipe + PD Bullet
|Avg. Velocity (mean)||1137.97 fps|
|Std Dev Coefficient of Variation||1.303%|
|Mean Absolute Deviation||11.79|
|MAD Coefficient of Variation||1.036%|
|Avg. Velocity (mean)||1193.012 fps|
|Std Dev Coefficient of Variation||0.831%|
|Mean Absolute Deviation||7.562|
|MAD Coefficient of Variation||0.634%|
Base + PD Bullet + Winchester Primer
|Avg. Velocity (mean)||1149.967 fps|
|Std Dev Coefficient of Variation||0.96%|
|Mean Absolute Deviation||9.17|
|MAD Coefficient of Variation||0.797%|
|Avg. Velocity (mean)||1199.289 fps|
|Std Dev Coefficient of Variation||0.833%|
|Mean Absolute Deviation||8.452|
|MAD Coefficient of Variation||0.705%|
Base Recipe + PD Bullet + Federal Primer
|Avg. Velocity (mean)||1135.66 fps|
|Std Dev Coefficient of Variation||0.885%|
|Mean Absolute Deviation||8.412|
|MAD Coefficient of Variation||0.741%|
|Avg. Velocity (mean)||1189.257 fps|
|Std Dev Coefficient of Variation||0.821%|
|Mean Absolute Deviation||6.661|
|MAD Coefficient of Variation||0.56%|
Base Recipe + PD Bullet + Wolf Primer
|Avg. Velocity (mean)||1134.871 fps|
|Std Dev Coefficient of Variation||1.407%|
|Mean Absolute Deviation||13.147|
|MAD Coefficient of Variation||1.158%|
|Avg. Velocity (mean)||1187.511 fps|
|Std Dev Coefficient of Variation||0.835%|
|Mean Absolute Deviation||8.057|
|MAD Coefficient of Variation||0.678%|
Speer Gold Dot 9mm 124 grain +P
5″ gun (15 rounds)
|Avg. Velocity (mean)||1248.571 fps|
|Std Dev Coefficient of Variation||1.1%|
|Mean Absolute Deviation||11.89|
|MAD Coefficient of Variation||0.952%|
I’m quite pleased with the results.
Last time I did tests, the only factory load I had to compare to was 124 grain American Eagle, which due to the bullet weight difference wasn’t apples-to-apples comparison. But based upon what I saw then I figured that my load just a hair under a factory load and the above data bears that out. I’m fine with that, it’s close enough.
The 5″ barrel gives about 50 fps more than the 4″ barrel. Due to this consistent behavior, in the future I’ll just test with one gun and do a little math if I really want to know how the other barrel will do.
Overall, the results were as I expected they would be: the changes didn’t amount to much.
Changing to the Precision Delta bullet didn’t change much, which is good. I’ve got a lot of PD bullets to use, and given that they’ve been running well and load well (compared to the troubles I’ve had with the Berry’s bullets) and are about the least expensive bullets to buy (especially in bulk), I’m sure I’ll stick with PD bullets for the foreseeable future. Consider my plinking load recipe officially changed. 🙂 One thing to consider on that front is I explicitly was trying to stay under 1200 fps because of the limits of the Berry’s bullets; but now that I’ll be using not-Berry’s bullets, I could start to change the load up for more velocity… but given the purpose of what this load is for? I see little reason to do that right now. This load is working well so why mess with it?
Changing primers didn’t seem to amount to much. One could argue the Federal primers gave me the most consistency, but this is such a small data set (20 rounds with each primer, 10 of each out of each gun) that I’m not ready to say “Federal primers are more consistent” as a general statement. I will say that now that I’m out of Remington primers I’ll probably use the Federal primers because the box they come in is HUGE and I wouldn’t mind reclaiming some shelf space. 😉
It was nice to see the load, on the whole, performed very consistently (look at the MAD CV), even more consistent than the factory loads. It’s also interesting to note that out of the 5″ barrel there was even more consistency. I’ve been wanting to move to the 5″ gun in general, and this just nudges me further in that direction.
Accuracy was acceptable for the guns and the intended purpose of the gun and these loads. Nothing here is “match grade”, I don’t expect to put ’em through the same hole at 25 yards. It was all good enough for the intent.
All in all, I’m pleased with the results. Onward!