Good Standard Deviation for 9mm 147g?

[pdjms1]

I am developing a load for IDPA purposes so I should start off by saying that precision/consistancy is not my absolute goal but I would like to know if my variation is considered decent or if I should strive for better controls in my loading process. Feel free to slap me and tell me that good enough is good enough. Also, feel free to let me know if any of my components tend to lead to more variation and make recommendations for replacements. Hopefully, i have captured enough data to help with recommendations and haven't done anything too idiotic...

My primary goals-
-Meet power factor 125 min 129 to 130 ideal. (FPS Goal 877)
-Minimize felt recoil
-Maintain as much consistency/accuracy as possible understanding that most 9mm loads perform better at higher powder charges
-Reduce cost of buying factory ammo (going through about 1200 rounds per month at this point)

Constants -
Ambient Air 97 F
Gun - 5" STI Eagle
Chrono - 10 ft from muzzle
Brass - Mix
Primers - Federal
Bullet - 147 gr LC (Moly) Cimarron


Freedom Munitions 147gr Remanufactured Factory- Control:
Avg FPS - 915.2
Stdev - 5.3
min - 911
max - 924
MV - 915
note - seemed to feel about the same as 4.0 True blue but slightly less. Tightest group

4.5 True Blue -
avg FPS - 980.4
Stdev - 9.0
min - 970
max - 991
MV - 980
note - most felt recoil but also the largest load group was tighter then 4.0g of true blue

4.0 True Blue -
Avg FPS - 879.8
Stdev - 6.2
Min - 869
Max - 885
MV - 880


3.0 Bullseye -
Avg FPS - 895.2
Stdev - 8.2
min - 881
max - 901
MV 895
note - felt like snappier then freedom munitions and 4.0 true blue


Thanks in advance!

Edit: here is a link to a photo of the groups (Shot standing, handheld, unsupported, somewhat quickly .5 SPS) http://www.thehighroad.org/attachment.php?attachmentid=222897&d=1471192046

 

[MtnCreek]

All of those loads have Excellent SD numbers.

 

[carbine85]

Deviation is excellent but the velocities are on the lower side.

 

[pdjms1]

carbine85, Thats right about where I want them for IDPA as I stated in the post. I am not at the point I am comfortable with reloading my carry/self defense rounds for those I would want the velocities to be higher as well. Thanks

 

[carbine85]

I trust my reloads but I carry and practice with Ranger SD rounds, so I understand where you are coming from. I use the reloads for the fun guns.

 

[rdtompki]

I don't chrono a lot, but standard deviation in single digits seems like a very good result.

 

[LiveLife]

Low SD numbers are good indications but sometimes don't translate to smaller shot groups.

I think you may need to do comparison range testing next to see which load produces consistently smaller shot groups.

Have you considered testing 3.5 gr of W231/HP-38?

Keep us posted with a range report!

 

[ArchAngelCD]

To me it looks like the 4.0gr True Blue load will fill all your criteria but you didn't include any accuracy information.

I also think W231/HP-38 might be a better choice or Zip which is a lot like W231. Zip is sold by the same company as True Blue.

 

[pdjms1]

bds and ArchAngelCD, They all shot about the same with a slight advantage to the 4.5g. All shots were standing, hand held, for practical accuracy not really to test "intrinsic accuracy". Once I narrow down the recipe to my favorite 3 I will do some more precise test but for now these Practical accuracy tests will be my go to. Attached are the 4 5 shot groups... I did have one flyer that I eliminated on one of the groups and reshot.

Thanks for the suggestions

 

[Chuck R.]

Low SD numbers are good indications but sometimes don't translate to smaller shot groups.

I think you may need to do comparison range testing next to see which load produces consistently smaller shot groups.

Have you considered testing 3.5 gr of W231/HP-38?

Keep us posted with a range report!

Agreed, I normally don't even bother worrying about chrono stats for normal handgun rounds, because a lot of what the stats tell us come into play at a much greater distance than the pistol will ever be shot. I go for a MV to make sure I'm making power factor, or replicating defensive rounds, but the group trumps the stats in my book.

BTW, my favorite 147grn practice load is 3.5 gr of W231/HP-38!

Chuck

 

[Jim Watson]

A PhD of my acquaintance looked hard at velocity uniformity.
He concluded that the best measure was Coefficient of Variation, which is the Standard Deviation as a percentage of the average value.
A CoV of less than 1% indicated "match grade" ammo. So the OP's stuff is very good to excellent.
That sort of consistency is not necessary for good accuracy at pistol ranges but it shows good quality control and matching of powder to cartridge. It is also reassuring if you are trying to shade JUST over the power factor requirement.

Uniform velocity IS needed for best long range and Long Range rifle accuracy.
BPCR shooters are going for single digit extreme spreads, SD in the low single digits. With the long flight time of a 1200 fps bullet to, say, 600 yards, velocity variation will give vertical stringing.
Bart B. can describe the effects on smallbore nitro rounds.

 

[pdjms1]

Hey Chuck, I only chromo to make sure I hit Power factor for competing in IDPA. Normal plinking rounds I am happy to just load min and see how it shoots and save all the hassle.

Jim, Thanks for calling my loads very good to excellent! As a newbie I appreciate knowing what is considered to be good enough... In my original post I was trying to chase the factory load thinking that my loads were inadequate from a consistency standpoint. I now know from your post and others that having a SD less then 10 is considered good and should work for my needs.


Also, looks like I am adding W231/HP-38 to my shopping list for the gun show at the end of the month.

Finally, with the original parameters in mind IDPA soft shot PF = 127k or so, does anyone have any experience with a VV powder they would recommend? 350, 320, 310?

Thanks for all the feedback and info!

 

[ArchAngelCD]

Finally, with the original parameters in mind IDPA soft shot PF = 127k or so, does anyone have any experience with a VV powder they would recommend? 350, 320, 310?

Thanks for all the feedback and info!

Walkalong uses quite abit of VV powders so if he stops by this thread he will have some advice as to which will fill your needs.

 

[Walkalong]

I haven't used any 147s, but THR member jmorris likes N310 with them. I have been meaning to try his load one of these days, but just haven't gotten around to it. I like a 124/5 Gr with N320 for 1050ish from a 5" barrel. I really need to try the 147s.

http://www.thehighroad.org/showpost.php?p=7711810&postcount=12

I keep N310, N320, N340, & 3N37 around all the time. Some other pistol powders as well, but those from Vihtavuori.

 

[Load Master]

pdjms1, how many rounds per each group measured? If it was in your original post I missed it. When measuring pistol I normally use 10 to 20 rounds for each measurement sets. With 9mm and 45acp my standard deviation is normally around 12. I find rounds of these groups to be very accurate.

 

[pdjms1]

Load Master, keep in mind that I did this standing from 10yrds unsupported so don't laugh too hard. http://www.thehighroad.org/attachment.php?attachmentid=222897&d=1471192046

Walkalong, Thanks for the info! I have some barry's 124 on the way. I was planning on making my wife a really light load for plinking since power factor won't be a factor for her with them but I might sneak a few for myself to tryout that combo.

Thanks again for all the info/help!

 

[Walkalong]

N310 or N320 will do that.

 

[pdjms1]

Got a buddy at Cabela's now checking out with N350. They didn't have any of the other VV powders in stock. I see it will be the slowest burning powder that I have in my now rather sizable collection and so I can at least test if slower burn translates into less perceived muzzle flip (as it has between bullseye and True Blue). I won't use it for 124's I think from what I understand that wouldn't be a good paring (not bad, just not good). Correct me if I am wrong.

I am adding VV N350, HP-38, Titegroup, and CFE to the collection for more range tests. In the next week or two I should be posting more data.

Thanks again!

 

[LiveLife]

Instead of N350, I would suggest N320 for lower velocity target loads and N340 for higher velocity full power loads.

 

[pdjms1]

Well crap... the N350 since that was the only VV powder they had in stock for pistol. No such thing as bad data so Its worth trying. Worst case scenario I will have the data point and powder for hitting Major if I ever decide to do USPSA . I will keep my eyes open for N320 at the gun show at the end of the month. I think at most I will add one or two more powders to this growing test and call that a good enough sample for my needs.

Thanks as always!

 

[LiveLife]

9 Major? Woohoo!

Now you are talking! - http://forums.brianenos.com/index.php?/topic/12740-9mm-major-load-data/

 

[longdayjake]

I love 147s. Im a recent convert to them. If it wasnt for the fact that I make a ton of 115s myself, I would shoot 147 exclusively. Your sd numbers look really good. Your velocities look good. Keep at it.

 

[rfwobbly]

My experience tells me 2 things...

Any SD less than 10 is really an excellent result in 9mm

The use of mixed brass is your major cause for not being able to lower those numbers.

 

[Walkalong]

9 Major? Woohoo!

Now your talking 3N37 IMHO, but I don't load 9MM major. I do load hot .38 Super with it.

I am adding VV N350, HP-38, Titegroup, and CFE

Titegroup or W-231 will make a soft 124/5 Gr 9MM load.

 

[Dudedog]

I have had good results on target with both CFE-P and WSF. Since I was punching holes in paper I wasn't after MAX vels. 3.9 of CFE-P and 3.9 of WSF both worked well for me with RMR 147 plated Target HPs.

Maybe just me but I prefer the recoil feel of the slower powders over something faster like Titegroup or HP38, but some people prefer the faster powders.