How do you test your reloaded 9mm rounds for accuracy?

[justeric]

I am embarking on a journey to reload 9mm ammunition. I have a few different powders, Select, Unique and Bullseye. I have 1000, 115 FMJ bullets ordered and should start reloading next week. I do reload for my 6.5 Creedmoor and I have done a lot of load development to settle on my current formula. That being said, I don’t know how to judge the accuracy of the handgun bullets since my hold is less stable than the bullets are accurate. I suspect I will use some sort of rest to test my pistol loads but is there much difference with different powder loads in 9mm pistol cartridges? Should I be looking for things like signs of the bullets tumbling? What distance should I test the loads? Any advice for the new guy?

Thanks,
Eric

 

[Traveler]

Basic 25 and 50 foot target shooting. There are pictures of keyholing.

http://hunting.about.com/od/guns/g/definition-of-keyhole-bullet-keyholing.htm

A basic benchrest shot could help sort things out. Unless your did a REALLY bad job with your reloads, they will do better than Winchester white box ammo.

 

[sgt23preston]

I am embarking on a journey to reload 9mm ammunition. I have a few different powders, Select, Unique and Bullseye. I have 1000, 115 FMJ bullets ordered and should start reloading next week. I do reload for my 6.5 Creedmoor and I have done a lot of load development to settle on my current formula. That being said, I don’t know how to judge the accuracy of the handgun bullets since my hold is less stable than the bullets are accurate. I suspect I will use some sort of rest to test my pistol loads but is there much difference with different powder loads in 9mm pistol cartridges? Should I be looking for things like signs of the bullets tumbling? What distance should I test the loads? Any advice for the new guy?

Thanks,
Eric

The simplest method is to use a bench rest...

First practice dry firing from the bench rest 10 - 20 rounds...

Strive for controlled breathing, perfect target alignment and perfect trigger control...

Your target should be a DARK vertical line & a DARK horizontal line where you aim for the dead center intersections of those 2 lines...

Fire 10 perfect rounds & discount any "fliers"...

 

[fa18hooker]

Concerns about tumbling? Not with any load in a load manual. Hell, even if you go below manual loads (as bullseye shooters often do), still not a concern. Accuracy for bullseye shooting is always measured at 50 yards. What kind of 9mm are you shooting? If it's an out-of-the-box retail pistol (Glock, XD, etc), 25 yards is a good test. Barrel fixtures routinely get 1.5" groups out of 9mm barrels (so it's an accurate round), but then fitting and, as you mention, testing in a finished pistol opens that up. The M9's the AMU and USMC teams use will group at or under 2.5" at 50 yards. Quite a few clubs have a Ransom Rest for pistol group testing...

 

[kalister1]

Start by comparing what you load to factory ammo.

 

[DocAitch]

I started off using a pistol rest and comparing loads but eventually came to the conclusion that since I was going to shoot the pistols off hand at 7 to 25 yds, and as you note, my hold is shakier than the pistol will shoot with almost any ammo.
I don't bother any more- I shoot the lowest charge that will cycle my pistols reliably and am happy when I can hit a 3/4 " sticker at 7 yds>50% of the time.
I think that every load that I've used will do that. If I were a bullseye shooter, it would be a another story and I like SGT Preston's advice for comparing loads, if you need to do that.
Loading 6.5 Creedmoor for long range rifle is a totally different animal, and that round definitely benefits from fine tuning.
DocAitch

 

[Magnumite]

I always bench tested my loads at 25 and 50 yards, while shooting over the chrono if I need to. After I find a load or loads that are acceptable for the intended application, I shoot 50 to 100 rounds in the intended manner from the pistol. If the consistency is apparent, I log it in my "list" for that caliber. Then I shoot it frequently and take any necessary steps to fine tune it.

Long term I monitor it under seasonal conditions to verify consistency.

 

[alucard0822]

You said in another thread you were loading for IDPA and various other matches, that simplifies matters. You have to load for power factor, which favors heavy bullets, so your 115 have to be doing near 1100fps, where 147gr only has to do 850fps to meet a 125PF, so a heavier bullet choice will reduce recoil, and help speed up shots. This also illustrates one reason for a chrono, they aren't very expensive, and the data is priceless in load development. Data doesn't always match real life, in some cases you might be over or under the published velocity for a given load, and being pressure relates to velocity, you can use velocity to infer your loads are running at safe pressures when loading hot, or you are meeting PF when loading for comp.

You can also see how large and varied the spread of velocity is, a round loaded faster than the rest will usually hit higher, so if a 10rd test shows a mere 20fps difference, then it will probably be fairly accurate, if it has a large standard deviation and extreme spread, like 80fps, it won't be, and a component or two aren't working together. If you find a low SD, but high ES, where say 7 rounds are within 20fps, the other 3 are more than 50fps, they will cause fliers, and are either from a loading problem, like powder clumping in the measure, or a component problem, like mixing in a case brand that is thick and heavy with one that is thinner.

For me, there are few handguns I will ever shoot from a bench or rest, so I don't test them that way, the group may change if you do. I test them with standing slow fire through the chrono at 25 yards, being that is the best spot to set up my chrono at my range. If you can't tell the difference in accuracy from a good factory load, then the target probably can't either. It also factors in things beyond raw mechanical accuracy, you might have a load that would group at 3" instead of 2, but the light recoil and blast help you shoot it very well, might have a load with good SD and ES, but your pistol just doesn't shoot that bullet well. It's not like a recipe, where if you follow something in a book you get good ammo, it's R&D, testing, and in many ways art and science blended into a process that helps create a completely unique load that functions best for you in your pistol.

 

[Magnumite]

Over 10 years ago, everyone, every writer, group tested handguns off the bench. The last decade or so this wave of not bench testing for the level of precision has taken over. It started in the gun magazines.

Knowing the mechanical/loading accuracy of a firearm establishes its precision. It can then be determined whether the measured precision is adequate for an application. We know bench testing reduces human error. I have yet to meet a flawless shooter without error. Without knowledge of a pistol/load precision how do we assess our shooting performance and skill level? If a pistol can shoot into 1" @25 yards off a bench it can shoot to that level of precision out of human hands. It is up to the shooter to approach that level of precision - approach being the key word. Sight adjustment in the shooting form is the end process in establishing the load as reliable and desired to be used.

No less than former world class shooter Brian Enos shot off the bags as a form of practice to refine those human factors which lead to greater consistency. His book will explain it more.

POI will change if the pistol is rested more so than if the wrists or forearms are rested, no dispute there. Changing grips and grip strength can change it as well. Gun fit to the shooter will effect group size. Using the standing handheld mode introduces all those variables as well as the wander, shake and trigger movement which effects all shooting.. Then the actual level of precision is not realized.

When I question one of my guns, me, or the load, I have to differentiate the cause. I go to a known good load and the bench. In my experience 10 yard groups yield little info with respect to greater distance performance. It indicates only if there are gross issues with the gun/load system. Yaw rates and some instabilities don't show up at that distance.

How one assesses their loads is up to them. If the load shoots into 1" off the bench (but doesn't realize it since they didn't bench test it) but the shooter can only get 3" out of it handheld then that shooter does not know its real capability, but more important, doesn't work to improve their form and technique. This is because they feel the load is 'a 3 inch load". They remain a 3 inch shooter at best.

One last thought...how many assess rifle load performance standing freehand? The same theory should apply as with handgun load development, correct?

 

[Biggfoot44]

First stepis to be able to test fire your handgun (with factory ammo) in a manner to be able to make a meaningful judgement about the mechanical accuraccy.

( other than actual machine rests) , a bench and sandbags are considered best. *For me* (method #2) and (method#3) have proven close enough results for me to eveluate ammunition. Experement on your own. if at this time you can't shoot your pistol so as to be able to make meaningful evaluation, then judge your ammo by reliability, and chronograph . Vel average as relates to your desired, and extreme spread and std deviation that doesn't totally suck.

 

[Blacksmith101]

If you are trying to reload ammunition for practice only, punching holes in paper so you can get better, then the primary considerations should be economy and reliability. Develop a reliable load that costs the least; powder, primer, and bullet then shoot a lot until you can tell you shoot better than the load. Lower power loads will stress your equipment less and are more pleasant to shoot.

If you need to worry about power factors and want to knock over steel then add those requirements to load development. The greater distance you shoot the larger the dispersion will be but at the same distance and the same amount of support the patterns will be comparable apples to apples. Actually a wider dispersion make it easier to see the differences.

 

[Biggfoot44]

25yd is the long time standardized test distance, that way you can compare your apples to most people's apples.

 

[Scottfs]

I can shoot my 9mm reloads from my Glock 19, Gen 4 two-handed at 7 yds at very small targets (5 targets on a 8.5x11 sheet of paper) and quickly get a feel for how the particular loads are doing. For me this tends to translate proportionately into bench rest and further yardage shooting.

A change of .1 or .2 grains of powder can make a difference of a one inch group at 7 yds to 1 1/2 inch or more group.

 

[Magnumite]

A load that sensitive is unstable and certainly not optimum. I don't think 25 ACP would be that sensitive.

 

[coopermania]

Awwwwwww come on magnum... That 20 to 30 fps will make a world of difference.

 

[Magnumite]

Yah....

 

[Scottfs]

Wow, sarcasm and ridicule towards someone trying to make a helpful suggestion in answer to a question.

A couple tenths of a grain of powder DOES matter, and if you reload you know that.

I know for a fact that .1 or .2 grains of powder in a minimally powered load will make the difference in whether you get several malfunctions per magazine or you get none.

I know for a fact when I load 124gr plated with WinAutoComp powder, 5.0grs is the most accurate. I have shot hundreds of rounds loaded between 4.8 and 5.2, and 5.0 hits a quarter at 7 yds and the others don’t. I didn’t say a tenth of a grain difference will spray bullets all over a target…I said one powder load will shoot maybe a 1” group and another a 1 1/2” group—a very small difference.

Finally, if you do reload and have been doing it for any length of time you have favorite recipes for your different calibers, and, further, I would bet you have specific recipes to specific guns in the same caliber. I would also bet your recipe is x.x grains of powder in that recipe, not a range of x.x to y.y. And why is that? Because you found a very specific charge that you felt was the most accurate for conditions and worked well in your gun; or you’re just lazy and it’s the same load you use in all your calibers and you don’t want to adjust your drop between different loads.

Oh, btw, I’m not naive enough, either, to believe my powder drop and my scale are exact to +/- 0.0 grains. That’s why you shoot more than 1 shot in a particular load.

 

[Magnumite]

Truly, no ridicule was intended. I have been reloading for well over 30 years...mostly in handgun. I do have several pet loads. Many are specific charge weights, some in ranges. It has been proven many times the charge volume consistency has as much to do with accuracy as does the actual weight. I have seen small variations of charge weight...not much, not often....from lot to lot of powder. A good load will not deviate from established good performance with 0.1 to 0.2 grain charge deviation., that is normal variance of thrown charges from a good measure. I don't even use any charge that sensitive. I have one 44 Magnum load that will give pressure indicators with a .5 grain increase. I don't load it anymore....but the accuracy was still great at 100 yards.

If you see a group size increase of 50% at 7 yards, it will be worse a longer more telling distances.

 

[noylj]

Reloading has always been a +/- 0.1gn activity. Factory ammo varies even more.
Tumbling/Keyholing:
Be sure to have a firm target backing. Many folks who think they are getting keyholing actually are getting oval holes 'cause the target moves.
9x19 seems to be the single most likely round for keyholing, other than milsurp rifles with worn barrels. Be sure to slug the barrel and match the groove diameter to the jacketed/plated bullet diameter. In many cases, simply going to .38 Super or .38 bullets will eliminate the problem. Before the "Wondernines" came out, 9x19 was not popular in the US and finding 0.355" bullets was very hard. All the reloaders I knew used 0.357" jacketed bullets and, usually, 0.358" cast bullets. Never had any pressure signs, but I always start load work up for any bullet at the starting load. All the guns I have ever fired are rather indifferent to slightly oversize bullets and, in many cases, actually shoot better with the oversize bullets.
Accuracy testing:
Any testing at less than 25 yards tells you about the shooter and not the gun or load. Shoot load at 25-50 yards, over a rest, and take your time. Be sure to fire 5-10 rounds through the barrel first to "season" it (remove oil and get the barrel into a stable condition).
I find that 9x19 is not that accurate with fast powders (good enough for up-close and personal action pistol shooting, but not for real accuracy). Best powders have been Power Pistol, Silhouette, True Blue, AA5, AA7, Herco, N340, and (according to some) WSF. For me, Power Pistol has been the #1 powder for accuracy in 9x19 (2" or less at 25 yards).