Ramshot TAC - Waste of Time

[Mike_Honcho]

I put this here only because when I was looking I did not see this info on TAC and it might save someone the time and money.


Pacino says it best:

Dont waste my motherfucking time! - YouTube


Simply put, TAC is not temp stable and is therefore (IMHO) a waste of time.

Freshly annealed Lapua, trimmed to length; Win LP, 175 SMK, mag length; AIAW.

I ran 5 rounds of loads from 41.4 - 43.2 in 60 degree weather; then took the three most promising loads: 42.2, 42.5 and 42.8 back out for 10 round testing in 80 degree weather.


60 degree average velocities:

42.2 - 2,603 fps
42.5 - 2,641 fps
42.8 - 2,658 fps


80 degree average velocities:

42.2 - 2,777 fps (still a very accurate load, but temps will be near 100 degrees soon enough making this a non starter)
42.5 - 2,855 and 2,879 fps - two rounds only as both pierced primers / destroyed brass
42.8 - did not attempt

Two rounds of 42.5:



The second round actually pushed enough crap back into the bolt that it would not fire. The fix was simple - cycle the safety one time.


Conversely, my standard load of 43.5 of RE15 was 2,611 and 2,617 respectively during the two tests. Fortunately I came across a small amount of RE15 yesterday so I am back in business.

 

[lte82]

So you saw a 200 fps swing? Hmm...

 

[KYS]

That powder should not be that unstable. We run that a lot in our bolt gun loads here in Kentucky and I have never seen it swing that much. Did you check your powder scale?
On another note we are all now trying out the Hodgdon CFE223 powder and it seems to be doing really well. A very clean powder for AR platforms and in the bolt guns I find it to be really stable.

Also, check your primers. What are you using?

 

[catgunguy]

Have you contacted Ramshot?
I believe something is defiantly wrong and will be anxious to hear the reason.

 

[roggom]

I have not used tac for precision loads, but it is my goto for plinkers / minute of ipsc target, no more than 500Y. In all reality 1-1.5 moa is about the norm anywhere from 30 degrees to 108 degrees up at 4800 feet. Although I am using 147 pulls or 150 sierra SP over 43.2 Tac 2.800. All in all with surplus bullets and brass, the cost of Tac is reasonable, I can crank out rounds for fun gunnin'.


Ramshot manual does list for use up to 190 smk's, but maybe its just better for the lighter ones.


For precision, I stick with 175SMK over RE15, inside some RP brass.

 

[bkw1911]

I experimented with tac and cfe 223 last year and both shot half inch at 5am-7am. As soon as the sun was up half way and temp rose slightly the same loads opened to almost 2in. I said the same thing and switched to benchmark and varget.

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[Mike_Honcho]

That powder should not be that unstable. We run that a lot in our bolt gun loads here in Kentucky and I have never seen it swing that much. Did you check your powder scale?


Also, check your primers. What are you using?

Scale is fine. Primers are Win LP - same lot I have been using for some time….

 

[.50 Cal Cow]

Stupid question. Were the loads left in the sun to bake at 80deg before they were fired? If not that's pretty wild.


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[Assault116]

I experimented with tac and cfe 223 last year and both shot half inch at 5am-7am. As soon as the sun was up half way and temp rose slightly the same loads opened to almost 2in. I said the same thing and switched to benchmark and varget.

Sent from my SCH-I605 using Tapatalk

I've been seeing similar issues with the group opening up with TAC in a gas gun as the barrel heats up. I'd been questioning the rifle since it's a fluted barrel and I hadn't had much luck finding a good load with H335 in it. Now I'm questioning the powder. I think I'm going to look at something a bit different and give it a try.

 

[Mike_Honcho]

Stupid question. Were the loads left in the sun to bake at 80deg before they were fired? If not that's pretty wild.


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No they were shaded

 

[ZombieMonkey]

I haven't used TAC in 308, but I've used it extensively on 223 bulk loads and precision loads here in Arizona where it's not uncommon for me to shoot when it's 50 degrees out or over 100 degrees out in the summer. I've never seen that kind of temperature sensitivity to the powder. This all from the same lot #?

 

[bkw1911]

I haven't used TAC in 308, but I've used it extensively on 223 bulk loads and precision loads here in Arizona where it's not uncommon for me to shoot when it's 50 degrees out or over 100 degrees out in the summer. I've never seen that kind of temperature sensitivity to the powder. This all from the same lot #?

I was using it in a bolt gun and the accuracy suffered in the heat with the 68s and 75s. bulk ar it probably works just fine. It metered easy and had good velocity. I've still got a full unopened lb if you want it and still use it. Just pm me. It's just collecting dust.

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[mtrmn]

I'm a TAC-loving knuckledragger myself. Never seen this much change in TAC or any other powders for that matter. Surely not with just 20 degree change.

 

[buffybuster]

I've shot thousands and thousands of 42.8grs of TAC with 168's from 40F to 110F and never had that kind of pressure swing.

 

[Mike_Honcho]

I rechecked the scale with a check weight - it's on. Bad powder is about the only thing left. I have @ 18#s of it too (different lots). If the consensus is hat this is pretty far outside of the norm I guess my choice is to switch lots and try again or see if I can trade off the unopened 8's for something else.

 

[Pat M]

? your pushing 175gr bullet at 2850-2880 and wonder why your brass is destroyed and primers pierced

 

[mtrmn]

? your pushing 175gr bullet at 2850-2880 and wonder why your brass is destroyed and primers pierced

Perhaps you need to re-read the OP with a little more comprehension. He knows full well this load was too hot at 80 degree weather, but it was fine at 60 degrees.

 

[BoilerUP]

No they were shaded

Shaded in a closed box in direct sun...or shaded as in totally obscured from the sun?

I've had a similar experience with RL17 swinging 100fps+ when the cartridges were left in direct sunlight...even with the MTM box top closed.

 

[Rprecision]

I have had good luck with Tac. Shot it in .308 from 20 - 100 degrees.

Just because a scale reads correct with a test weight doesn't mean its accurate at other weights.

 

[Mike_Honcho]

Just because a scale reads correct with a test weight doesn't mean its accurate at other weights.

What? I am not following the logic. You're saying if someone tests a scale with a series of known quantities and it checks out, the scale still can not be trusted? Not sure I agree with you there.

 

[Mike_Honcho]

BoilerUp - obscured

 

[Rprecision]

What? I am not following the logic. You're saying if someone tests a scale with a series of known quantities and it checks out, the scale still can not be trusted? Not sure I agree with you there.

I watched a fellow shooter pierce primers and lock up a gun. Funny thing, they were all loaded to the same specs, some worked fine, the latter did not.

Pulled down the remaining lot and checked his charges which showed a 4 grain + difference, which in a .204 sized case is a lot of extra powder.

The electronic scale he was using included calibration and test weights. The scale performed fine with the test weights. We cross checked a known weight and started noticing the discrepancy grow on the lower end of the scales measurements. (32 grain bullet that weighed 38) The only explanation he received from the maker of the scale was that it had a damaged load cell. They suspected it was dropped at some point. According to the test and calibration weights that scale was working properly....................

The quick one line statement above doesn't explain this point, electronics are not always perfectly linear, what works at one end of that range may not be the same as where your working. This is usually averaged out by two different calibration weights, but when things go wrong its not a guarantee things are perfect.

This isn't to bash electronic scales, start a brand war or piss off your third born child. Fact is delicate electronics go tits up in the most unpredictable ways. If one experiences a overpressure incident it would behoove one to carefully diagnose what caused it.

There's the logic

From my range notes I found with 5.56 stuff, I observed somewhere around 1.6-2.7 FPS change per degree of ambient temp change. The higher number being in 96 degrees. This is of course not taking into effect the variables in my crappy chronograph, changes related to mixed brass, Etc. My number, although just my own limited data, seems fairly consistent with what others have reported.

With my numbers extrapolated to a .308, you shouldn't have seen more then 60 FPS increase in MV, which leads me to believe there was something else going on here. What that is, well is up to you

 

[dariof]

I'm a TAC-loving knuckledragger myself. Never seen this much change in TAC or any other powders for that matter. Surely not with just 20 degree change.

I've shot thousands and thousands of 42.8grs of TAC with 168's from 40F to 110F and never had that kind of pressure swing.

I use TAC out here in Vegas for my .223. Temp swings are all over the place out here.

I shoot 1/2 MOA with TAC at 100 yards, 55 Gr B/T, 24.5 TAC,
Lake City Brass, Win primers.

 

[Mike_Honcho]

Rprecision - thank you for explaining. I am a cheap knuckle dragger that still uses a manual scale and a manual lock on my strong box.

I said F it and cracked open a fresh 8#er - gonna give it another go. Powder is too scarce to just write TAC off, esp considering that by yourall's anecdotals this must be a fluke, and I am sitting on a reasonable amount.

 

[EddieNFL]

I use a lot of TAC. I don't think the term temp insensitive existed 40 years ago. We summer and winter loads.

 

[260shooter]

I shoot 24.0 in the winter and 23.4 in the summer.

 

[mtrmn]

Rprecision - thank you for explaining. I am a cheap knuckle dragger that still uses a manual scale and a manual lock on my strong box.

I said F it and cracked open a fresh 8#er - gonna give it another go. Powder is too scarce to just write TAC off, esp considering that by yourall's anecdotals this must be a fluke, and I am sitting on a reasonable amount.

Us cheap knuckledraggers will fare much better in the coming apocalypse than those who aren't. I don't trust electronic scales nor electronic locks on gun safes---never bought either of them.

 

[ZombieMonkey]

Just curious, but did they happen to be different lot numbers between the testing you did? While I have had good luck with TAC in the past, I finally am making it to a new lot # after using the same one for the last few years. Lot to Lot variation is the one thing I have not tested with the TAC yet, but the temperature has never been a big concern even on 100+ degree days with the same lot #.

 

[leadbullet]

I have burned unknown number of 8lbs kegs of TAC, all in plinker loads .5 gr below max, they are good to go year round around here but temps never get too hot or too cold to create problems at the range.
Cheers

 

[USMC-FURY]

If you are worried about temperature sensitivity then use AR-COMP, per Alliant it is RL-15 that has been reformulated to be temperature insensitive and burn closer to Vargets burn rate, you also need a lot less:

308 Winchester
•Sierra 175 gr HPBT

Federal 2.8 24 Fed 210 2000-MR 47.7gr 2,720 fps
Federal 2.8 24 Fed 210 AR-Comp 41.4gr 2,719 fps

 

[USMC-FURY]

Amonette, Ben
Oct 2, 2013

----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Tuesday, October 01, 2013 10:42 PM
To: Alliant Reloading
Subject: Alliant Powder - Ask the Expert Form


USMC FURY
to [email protected]

Formulas reformulated to be temperature insensitive (BE-86 flash retardant)


AR-COMP (slightly faster than RL 15)
1200-R (similar to RL 10x)
Varmint (similar to our discontinued RL 12)
BE-86 (in-between Unique and Power Pistol)

Me ----- Forwarded Message ----- From: "Amonette, Ben" <[email protected]> To: "[email protected]" <[email protected]> Sent: Wednesday, October 2, 2013 1:53 PM Subject: RE: Alliant Powder - Ask the












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

 

[tom30calglassburn]

I have use tac powder for a year here in Indiana were one day its 20 and the next it could reach 65. And last year I was shooting on the pararie with 223 in ar and bolt both, in 98 degree weather and I have never had an issue with the extreme range of variation.

 

[glock63]

So you saw a 200 fps swing? Hmm...

Yeah something else is going on here.

 

[MarinePMI]

I have a sneaky impression that some ball powders, when used with heavy bullets, show some erratic ignition signs (strange ES and SD's). I know CFE223 was this way with heavy bullets in 223.

Methinks, like Lil'Gun, some of these fine ball powders do strange things under high initial pressure spikes.

My suspicions are completely anecdotal, but figured I'd toss it out there...

Strangely enough, 2000MR has the opposite problem (excessive non-obturation of the case mouth and neck, leaving sooty cases); fine with heavy bullets, but problematic with lighter ones.