CCI Standard Velocity Study

[918v]

I have this old High Standard 106. It shoots CCI standard velocity as well as Eley Tenex, about .75" at 50 feet from a rest. So I got a 500 round brick of the CCI stuff and weight sorted it in .1 grain increments. The lightest round weighed 50.2 grains while the heaviest weighed 51.2 grains. The weights were almost evenly split between 51, 50.9, 50.7, 50,7 and 50.6 grains. There were a few 51.1 and a couple of the lighter weights.

This ammo, weightsorted, immediately started to shoot .5" or less at 50 feet and I finally got my quarter inch group yesterday.

Today I pulled apart the heaviest and the lightest round:

The heavy, weighing in at 51.2 grains, was composed of a 40.2 grain bullet, a 10.1 grain case and .7 grains of powder. I lost .1 grains in there somewhere... I dunno where.

The light, weighing in at 50.2 grains, was composed of a 39.4 grain bullet, a 9.8 grain case, and .9 grains of powder. Again, I lost .1 grains in there, possibly due to my electronic scale's inaccuracy.

So it looks like some bullets weigh almost a grain less than others and the powder charge varies by 20%!!! I disassembled these rounds inside a ziploc bag, so I did not lose any powder.

Just food for thought.

 

[Nebraska]

Re: CCI Standard Velocity Study

Very interesting......thanks for taking the time to run the test and pass along the info.

 

[One-Eyed Jack]

Re: CCI Standard Velocity Study

Yes, that was very interesting. I thought the overall mass difference was remarkably small, but then the differences in the components were pretty surprising, especially the charge.

 

[918v]

Re: CCI Standard Velocity Study

I was shocked at how little powder those 22's contain. I wonder if powder positioning is an issue there?

 

[kirkhamg]

Re: CCI Standard Velocity Study

I have done about 1500 rounds of ammo testing over this last summer. Weight-sort, lube, you name it. It is kind of surprising the wide range of results.
There should be enough priming compound to get the projectile to exit the barrel, and the powder is a very fine grained fast powder, so position shouldn't be much of a factor.
Example: the M1906 Guard load used something like 8 or 9 grains of Bullseye pistol powder in a 30-06 case.
The 0.1 grain lost is surely in the tolerance of the scale.
My findings were weighing good ammo, and culling the high and low out-liers improved results. Weight-sorting bad ammo resulted in wasted time, and weight sorted bad ammo.
Thanks for sharing your results.

 

[noname]

Re: CCI Standard Velocity Study

the consistency if the primer mix, because it goes in the outer rim of the case and not the center, and the technique used to get it there-- determine accuracy more than the other variables

 

[918v]

Re: CCI Standard Velocity Study

I weightsorted some Eley Sport. The weights ranged from 49.7 to 52.2 grains, surely all in the bullet. I think a 2.5 grain variance in a 40 grain bullet is alot.

 

[kirkhamg]

Re: CCI Standard Velocity Study

Just for the sake of argument say half of the 2.5grains is distributed on each side of the 40 grain ideal weight equally, so plus or minus 3% for 6% total. Not that much really. Now at what velocity range are they launched? And how much does the extra weight (and therefore size) affect the BC? Answer: not much... but the killer is when all of these things add-up/compound against you.

I just ran a quick calculation, and if one can assume the BC is constant, and the projectile exits the muzzle at the average velocity, the difference in total drop at 100 yards is less than a bullet diameter.

But we all see the one low shot dropping out at 100, or the occasional high one, or some other 'flyer'.
I have found weight-sorting the 'pretty-good' ammo, and just removing out-liers improves groups. Weight sorting to a greater degree does not significantly improve results. Because of the many variables, some 'fliers' or other inconsistency will still occasionally ruin a group, score, target, or opportunity on game.
Just part of the fun of rimfire?
I would be interested if someone has found differing results.

 

[HotRod9mm]

Re: CCI Standard Velocity Study

Very nice post.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">...........This ammo, weightsorted, immediately started to shoot .5" or less......</div></div>

What weight shot the best or did all shoot well as long as the weight was the same?

 

[918v]

Re: CCI Standard Velocity Study

All batches shot the same, but the quarter-inch group came from the 50.9 grain batch.

 

[One-Eyed Jack]

Re: CCI Standard Velocity Study

I wonder how the waxy lube on some 22LR rounds would affect the weight matching? Perhaps that's part of the 0.1 grain "missing mass."

 

[HD1911]

Re: CCI Standard Velocity Study

The CCI Standard Velocity's you speak of shoot great out of my 10/22 Target Tactical. About .75 groups at 50 yards

 

[SOLO LOBO]

Re: CCI Standard Velocity Study

My Kimber svt shoots the CCI as will as Ely 10x also. And as will or better than the Fed. Gold Metal Match.
I read on the net that a gun test using the Kimber svt had the same Results with the CCI MiNi Mag.
Thanks for sharing ur info

 

[TOP PREDATOR]

Re: CCI Standard Velocity Study

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">I was shocked at how little powder those 22's contain. I wonder if powder positioning is an issue there?</div></div>

i've read an article from some rimfire guro somewhere lately where he did a bit of an experiment about powder positioning, apparantly lifting the muzzle of the rifle before shooting to put the powder to the back of the cartridge is not the way to go as the firing pin dropping on the rim causes a vibration which pushes the powder forward in an uneven fashion, leaving unconsistant results compared to barrel down....

...he found out that putting the muzzle down before a shot increased the consistancy as the powder went to the front and apparantly stayed somewhat even toward the front of the cartridge, which supposedly gave better consistancy.

whether it is true or not, i have no idea, but will give it a try eventually.

nice post 918V, i got to add it to these..22 ammo threads

 

[Teryx]

Re: CCI Standard Velocity Study

I've had the same experience with the standard velocity CCI. The accuracy is basically very good but there will be flyers in the mix. CCI makes a "green tag" version for competion that is basically the same round but made to higher tolerances, and much more expensive. They shoot to the same POI, but the green tag rarely has a flyer. I use the regular ammo for practice, sightin, etc, and then use the green tag just for hunting or serious shooting. That way I have no culls to deal with and keep my cost down.
Teryx