TAC Powder and Berger .308 175 grain OTM Tactical

[JimmyT]

I am working up some loads with this bullet combo for my AR 10s.

I am using prepped (Full resize, tumbled, anneal, primer pockets trued up) L/C brass and CCI BR-2 primers.

The RAMSHOT load data list 43.4 grains of TAC as the heaviest load with 175 SMKs.

I have backed off to 43.2 grains in loaded three rounds for each .3 grain step down to 42.0 grains.

Does anyone out there have experience with this combination, or with other Brass, and tried this with 16" AR 10s (LaRue PredatOBR, Noveske N6).

 

[DrewC]

I’d do a load work up starting at 40.8 going up to maybe 42.9 using .3 gn jumps. Most likely you’ll be around 42 gn area for your node using Tac with that bullet and those rifles.

 

[mgrs]

Good luck. I have never had good results with TAC and that weight class of bullet. I tried it a few times because 1) the burn rate should be good for short barrels and gas rifles 2) I could load on a progressive and 3) TAC is cheap.

I lost my older data when a hard drive failed and only have a more recent attempt with 175gr RDFs in FC brass with Tula primers and it was a disaster. I started at 39.0 and got to 41 at which point primers were flattening and cratering. Groups were all 1.5-2" and velocities were not that great. The same combination with 41.8gr IMR4064 or 42.3gr Varget was excellent.

I found TAC does do very well in .308 with the 110gr-150gr class of bullet though. Like it a lot with the 125gr SST.

Good luck and YMMV. Curious what you come to.

 

[DrewC]

43.2 gns of Varget and 40.7 gns of AR Comp are my two loads using 175 smk’s in my 16” predatobr. Mv is around 2480 for both. Sd’s are outstanding with Ar Comp.

 

[XLR308]

43.2 gns of Varget and 40.7 gns of AR Comp are my two loads using 175 smk’s in my 16” predatobr. Mv is around 2480 for both. Sd’s are outstanding with Ar Comp.

AR-COMP is a great and very versatile powder and one I would allways recommend to anyone shooting 308 win.

 

[JimmyT]

Found an interesting combo with 42.3 grains of TAC under a Berger 175 OTM. Delivered a sub MOA 3 round group at 100 yards. My go to load of 41.8 grains of 4064 under a 175 grain SMK was much more stable in an 1 MOA 5 round group. TAC may not be the ticket for my short AR10s, the other 9 groups were garbage. I’m going to get a pound of AR Comp and try again

 

[mgrs]

Too bad on the TAC. It stacks the lightweight flat base bullets.

Would like to see how the AR-Comp turns out. I never gave it any thought before reading this thread and it looks pretty good for a heavy/bullet gas rifle powder.

 

[XLR308]

Too bad on the TAC. It stacks the lightweight flat base bullets.

Would like to see how the AR-Comp turns out. I never gave it any thought before reading this thread and it looks pretty good for a heavy/bullet gas rifle powder.

Since I started using it Varget has pretty much just been collecting dust on my powder shelf, another cartridge I have found that AR-COMP excells in though I dont think you will find it in any manual is the 68spc.
I'm running the 120sst at 2730fps with it and it hammers pigs, haven't finished building a 224V yet but I expect it to perform well with bullets in the 75-80 gr range.

 

[mgrs]

Displacing varget is high praise as far as I am concerned. 4064 has been my go-to in .308 but I am tired of the extra time loading 4064 (it will still bridge or over-throw) 30% of the time in a modified chargemaster) and would be all about a shorter-cut powder that delivers good performance for heavy bullet applications in .223 and .308.

This guy's video below has some good load development data and groups for ARCOMP and 77gr in .223. I've done the same load development he has with TAC, 8208, and 2000mr and got almost identical results as far as accuracy nodes and velocities. He does a whole series trying to find what powders will roughly duplicate mk262 performance:

 

[JimmyT]

I had some great results today with a load of 40. 6 grains of AR Comp. I was able to get a 3 shot group that produced an average velocity of 2523 FPS witn and SD of 7... loading a bunch to test out!!!

 

[JimmyT]

Success at 600 yards this morning! The 40.6 grains of AR Comp under a 175 grain SMK allowed me to get 14 10 and x rings out of 23 shots fired. 3 were sighters and rest of the non 10/X was positioning on my part and trigger squeeze. Now I will see what the same load will do in my Bergara HMR.

 

[memilanuk]

Nice!

At first I thought that seemed awful slow, but then I saw it's a 16" gas gun. Probably a good safe n stable load!

 

[XLR308]

Success at 600 yards this morning! The 40.6 grains of AR Comp under a 175 grain SMK allowed me to get 14 10 and x rings out of 23 shots fired. 3 were sighters and rest of the non 10/X was positioning on my part and trigger squeeze. Now I will see what the same load will do in my Bergara HMR.

Nice sounds like you are getting it dialed in.
Just for info purposes 40.7gr in Lapua Palma brass and cci450 runs 2650 with the 178amax in my 26" 1-12 barrel loaded long 2.885".
I would think you will be pretty close to that with your Bergara, 40.7 was the node in my barrel and it shoots so good I haven't bothered to go any higher.

 

[newguy2k3v2]

My 175gr blasting load for my 16" Mws is 40.5 tac, Lc brass and #34 primer. It gets me around 2475-2500 iirc. I started getting swipes and other brass damage when I went higher. I was surprised considering load data showed up to about 43gr.

It shoots fairly well in my bolt guns too.

 

[JimmyT]

I just went back to the drawing board with 3 powders, AR Comp/IMR 4064/TAC.

With IMR 4064 I had an accuracy node between 42.4 grains and 42.6 grains with a velocity around 2505 fps.

With TAC, 43.0-43.2 grains with a velocity of 2515 FPS.

With AR Comp, 41.2-41.4 grains with a velocity 2507 fps.

This barrel seems to give some velocity (pressure) flat spots when the speed hits slightly over 2500 fps. I was using the Scott Shatterly method of ten rounds seprated by .2 grains of powder, going from book maximum on down. Just reloded 10 rounds of each in the sweet spots I identified and will shoot for groops on saturday.

 

[XLR308]

Just an observation and maybe it's just a typo but you had stated that you found a good load at 40.6 gr of AR-COMP with an average of 2523fps that help up well to 600 yards.
Now your at 41.2 - 41.4 with a drop in velocity, I think you may have overshot your accuracy node unless I'm reading something wrong.

 

[DrewC]

You have a consistency issues somewhere. Either your chrono or loading procedure. Or a mix of both. You shouldn’t drop 20 FPS while going up .6 to .8 gns. Shoot an OCW test to find your load then chrono it. Confirm it and shoot away. If there any issues with consistency in reloading or your chrono, you’ll never find the right load by doing that Satterly test.

Your 40.6 load of Ar comp had basically the same mv as my load which is 40.8 at 2526 fps. If I go up to 41.2 to 41.4 I’m around 2545-2550 fps. I’d also concentrate on one powder. Maybe two at a time.

 

[918v]

My 175gr blasting load for my 16" Mws is 40.5 tac, Lc brass and #34 primer. It gets me around 2475-2500 iirc. I started getting swipes and other brass damage when I went higher. I was surprised considering load data showed up to about 43gr.

It shoots fairly well in my bolt guns too.

Ramshot’s data is based on thin Winchester commercial brass. You cannot use it in thick heavy military cases. They have less volume and require a reduction.

 

[JimmyT]

Played around with 175 grain SMK and Berger OTo with 41.7 grains of IMR 4064 and 40.7 grains of AR Comp. this is about as good as it is getting with. My N6 at near MOA and occasional sub MOA. I am saving TAC for 168 grain or lighter bullets. Varget is still out there, but I’m having fun shooting other loads.

 

[DrewC]

Well if you’re shooting right around 1moa pretty consistently then that might be what the rifle is capable of. You can always play with seating depth if you haven’t yet and try 210 primers. I’ve never used br-2’s so I have don’t know if that’ll change anything. How is your Es / Sd on the ar comp? And maybe shoot an ocw an post a pic. It’ll sure help others on giving out advice.

I do know with the 4064 powder lot I have 41.7 is not even close to my node. I want to say it’s around 42.5 out of my gas gun.

You can always try Varget. Definitely works great but in my experience and all the dudes shooting around me using 308 gas guns, Ar Comp gets lower Es / sd’s but not by much, plus an average of 20 fps more. It also seems to give out less gas / pressure but I could be talking out of my ass on that opinion. I just wished someone would stock 8# jugs of Comp in my area.

 

[JimmyT]

I have a pound of Varget to play with... but i need to wrap up with AR Comp/IMR 4064 first...