Interesting .223 test results

[2ndtimer]

I previously posted a thread about trying to duplicate Nosler factory .223 40 gr Ballistic Tip Ammo. I decided to go ahead and test some handloads with 3 different powders, TAC (my personal fave), X-Terminator and Benchmark. All were loaded with LC brass, Remington 7 1/2 primers and Nosler 40 gr Tipped Varmageddon bullets. I shot a pair of 5 shot groups with each loading at 100 yards from a rest and chronographed all the shots and averaged the two groups. The most interesting result was the effect of the low temperature on the ball powder loads. Most of my previous workups have been in the spring/summer months in temperatures between 70 and 90 degrees Fahrenheit. (Since that is when the gophers and prairie dogs are most active.) But this test was started in just 30 degrees. Quite an eye opener, since in previous efforts, I could reliably push 40 gr bullets 3700 fps or better from my Remington 26" 1 in 12" twist barrel. Neither of the ball powders were able to break 3400 fps at this temperature. While the extruded powder hit almost 3500 fps at the lightest charge weight. Happily, none of the average group sizes exceeded one inch at 100 yards. Here are my results:

Powder	Charge WT	Velocity	SD	Group AVG
TAC	27.0	3260	41	1.00
TAC	27.3	3332	34	0.48
TAC	27.7	3368	46	0.67
TAC	28.0	3384	46	0.40
---	---	---	---	---
X-Terminator	26.0	3204	27	0.68
X-Terminator	26.3	3257	28	0.92
X-Terminator	26.6	3330	31	0.43
X-Terminator	27.0	3354	67	0.78
---	---	---	---	---
Benchmark	26.5	3482	33	1.00
Benchmark	26.8	3558	35	0.50
Benchmark	27.1	3609	48	0.72
Benchmark	27.4	3615	41	0.75

Another conclusion from this bit of data is that standard deviation does not equal best groups. I believe the loads have better SD's in warmer weather as well as higher velocity. I elected not to clutter up the post with pics of targets, although I have them available, if anyone wants to see photographic evidence. Scope is a an older VX-3 4.5-14X with A/O and a fine duplex reticle.
Edit: sorry for the crappy table, I couldn't figure out how to import the excel spreadsheet and manually typing out the table produced this lousy rendition.
Thank you to whoever fixed my original illegible data table.

Read More

 

[DizzyJ]

Nice write up!

Did you have any pressure signs at the higher loads?

 

[2ndtimer]

Nice write up!

Did you have any pressure signs at the higher loads?

None shown, primers nice and rounded edges, no marks on brass cases. None of my charges exceeded published data in a manual. ( I might have had to look at several to find one that listed a hotter load than I used, but I did find at least one for each powder).

 

[osprey]

While low sd does not automatically mean tighter groups it does show combustion is stable which is desirable for good groups. Often to get the best groups out of a low sd load you must fine tune seating depth which affects harmonics. Most of the time this process will give you the most consistent results over longer shot strings day in day out.

 

[Hueco]

Edit: sorry for the crappy table, I couldn't figure out how to import the excel spreadsheet and manually typing out the table produced this lousy rendition.

FTFY

(if you know some html, toggling into BBcode mode makes like easier, imo. )

 

[P7M13]

Awesome writeup - thanks for sharing.
Since you have velocities for the powders at higher temps and these numbers at 30°, are you able to calculate an approximate temperature FPS/°F factor?
I use TAC and it would be great to have this empirical info.

 

[The Heretic]

Are any of these powders the new (?) temp insensitive powders?

 

[2ndtimer]

Are any of these powders the new (?) temp insensitive powders?

Benchmark is labeled by Hodgdon as one of their "Extreme" powders. I used to think it was just a marketing gimmick, now I have to give it some credibility. I still have to give props to Ramshot TAC, as well. One of the reasons I switched over to it for my .223 loads years ago was some posts by John Barsness, a gun writer from Montana that commented that he shot 500 rounds of ammo loaded with TAC through his .223, without cleaning with zero accuracy fall off. My best group average in my testing came with the maximum load of TAC, averaging .40 of an inch, after 90 rounds had been fired without cleaning the barrel.

 

[Certaindeaf]

Benchmark is labeled by Hodgdon as one of their "Extreme" powders. I used to think it was just a marketing gimmick, now I have to give it some credibility. I still have to give props to Ramshot TAC, as well. One of the reasons I switched over to it for my .223 loads years ago was some posts by John Barsness, a gun writer from Montana that commented that he shot 500 rounds of ammo loaded with TAC through his .223, without cleaning with zero accuracy fall off. My best group average in my testing came with the maximum load of TAC, averaging .40 of an inch, after 90 rounds had been fired without cleaning the barrel.

Bench rest shooters never clean their barrels.

 

[DizzyJ]

Bench rest shooters never clean their barrels.

Never huh?

 

[Hueco]

Never huh?

Nor their lucky undies.

 

[Certaindeaf]

Never huh?

Close enough to get my point across. They're a little different than some dude in Montana with an AR though probably.

 

[osprey]

Most benchrest shooters don't clean until accuracy degrades on their particular barrel. Once they learn how many rounds it takes with their barrel for accuracy to fall off, they keep track off rounds sent downrange and preemptively clean in most cases. Most of us clean way too often.

 

[DizzyJ]

Close enough to get my point across. They're a little different than some dude in Montana with an AR though probably.

You say'n there's no Montana bench rest shooters who own an AR?

 

[pharmseller]

I pay zero attention to SD. Unless the sample size is 30 or larger, SD doesn't really tell us much.

Instead, I pay attention to Extreme Spread (ES). I find it to be a much more useful tool.