Home Forums Hunting & Shooting Ask The Gunwriters reduced loads with TAC

I see tac has a burning rate very similar to 4895, and I want to use reduced loads for practice. There is no 4895 to be found in either Alberta or Saskatchewan. {the store shelves are completely bare of all powders} I do have some TAC and want reduced loads for 308, 3006, and 270 win.Is it safe to use in these cartridges for somewhat reduced loads. Thank you in advance for your responses.

Contact the distributer for that info.

TAC isn't really one for reduced loads. I haven't tried it that way, but in normal load development in 223 and 308 it showed a preference for running near or at full throttle.

Exactly.

Like a lot of newer powders, TAC was designed to burn most consistently at pressures around 60,000 PSI.

When it was first introduced many handloaders didn't get this concept--but it's common with spherical powders, which aren't as "flexible" as extruded powders, due to requiring deterrent coatings to control the burn-rate. In extruded powders burn-rate is at least partially controlled by granule size: Larger granules burn slower, because they have less surface area. But sphericals have very similar granule sizes, so require coatings to change burn-rate.

Also, ALL spherical powders are double-based, meaning they have added nitroglycerin, which also affects burn-rate compared to single-based extruded powders. (Not all extruded powders are single-based, but many are.)

Consequently, spherical powders usually burn less consistently and completely in reduced loads. This was one of the early "problems" with TAC. When loaded to pressures around 60,000 PSI it burned VERY cleanly, which was unusual for spherical rifle powders at the time. But even with "starting" loads, say around 55,000 PSI, it didn't burn as consistently or as cleanly. Consequently quite a few handloaders tried it, and when starting loads left visible powder-fouling in the bore, and often didn't shoot very accurately, they didn't even try maximum loads.

Don't know how many handloaders contacted me about this, basically whining that it didn't burn cleanly or result in very good accuracy, but it was quite a few. I advised them to add more powder--and all reported fine results.

What all of this comes down to is that just because TAC has a similar burn-rate to IMR4895, it doesn't act anything like 4895 with reduced charges.

Less surface area relative to their volume.

Surface area grows with the square of the dimensions, volume grows with the cube.

What mathman and Mule Dear said.

TAC is a great max pressure powder for yielding higher velocity with midweight .223 Rem and .308 Win bullets. Not really at all intended for reduced loads.

Yeah, of course. But I don't know of ANY small-granule extruded powder that has as little surface area as just about any spherical powder--regardless of volume.

I use Big game for 06 and 308. Lighter pills in 06 and heavier in 308.

Hunter for all of 270 or 06 with heavier pills

https://accuratepowder.com/wp-content/uploads/2018/11/WPHandloading-Guide-7.0-Web-REV.pdf

Do not run reduced loads of TAC. All kinds of unexpected things can happen. And most any ball rifle powder this applies to.
Charlie

I'll back what's been said. I have had nothing but good results with TAC under 223 midweight bullets, loaded firmly. In short, TAC is everything H335 was (or is, I guess), without the temper tantrums. Run TAC like it was designed and you'll be a big fan.

My first experience with TAC supports the conclusions in the above posts. It burned clean and accurately at the upper range of performance in my 1895 Winchester .405 and pushed a 400 grain Weldcore very effectively. The Woodie shot through 40+ inches of Cape buff internals, including the heart, and out between the front legs; bullet not recovered. MV about 2100 fps and peak chamber pressure of 49,000 psi.

It measures beautifully.

^^^^^^^^^

THIS

Try finding some 4198.. either Hodgdon's/ADI or IMR's version...

RL 7 is also a good reduced load powder.

Recent (last 15 years) H335 is NOT the same as the "old" H335. I've used a lot of the "new" in both my .45-70s amd .458 Win Mags, and it's "magical" in those as well as the .444 etc. TAC is similar, and true that they work best at max, or close to max. Check Hornady for H335 in the .458 and .458 Lott. And Barnes for a comparison of TAC with H335 in the .458. Yeah, I know thats not in the .223, .308, etc. But it does show how close they might be, and NO, I'd not use either in reduced loads!

Bob
www.bigbores.ca

H4198 is one of Hodgdon's EXTREME powders, one of the best. IMR 4198 is NOT. RL-7 is subject to variable psi in temp changes from summer to late fall-winter.

Bob
www.bigbores.ca

TAC works fantastic in the 35 Remington and it can’t be running 40,000 psi in that cartridge.

OK, but is the case packed full?

I'm seeing this, too. I just cleaned my 308 after close to 200 full-pressure rounds loaded with TAC. I made a couple of dozen passes with a brush and solvent, then went to Sweet's. The patches had just the lightest traces of blue.


Okie John

That's been my experience as well, but a LOT of hunters apparently aren't concerned about temperature-sensitivity because it doesn't vary all that widely in their area. I have generally found that just about ANY modern smokeless powder won't vary much in pressure/velocity at temperatures from about 20-85 Fahrenheit.

But I happen to live and hunt in Montana, which has the widest range of recorded temperatures of any of the 50 United States, from -70 to +117--which is why I tend to prefer temp-resistant powders. I suspect Ontario has a pretty wide range as well!

Interesting stuff, which I thoroughly enjoy learning. But, in my neck of the woods the temperature curve has been flattening over recent years. Still the same nasty highs in summer, with attendant humidity, but the winter temps are definitely warming. It's kind of moot to me as I don't venture out much to the range at the extreme ends of the spectrum, and the distances in the winter deer woods are invariably short-ish so a slight loss in velocity/bullet drop is immaterial to me. I've never paid any heed to powder temperature sensitivity but it's nice to be cognizant of it. Thanks.