Today I believe to have ran into my first hurtle with ramshot tac. Being a ball powder and not temp stable how much of a temperature swing cause issues. 5, 10, 20 degrees. I never took temperatures on my first load development this summer. Va hot and humid. Today was 60 degrees when i was shooting. This tells me i need info at certain temperatures if i am thinking correct. Also had my first run in with mirage. Hats of to those compete in shooting or just having fun. Stay there for a got while just watching the mirage affect my glass. Oh and shooting 69gr smk out of a 16" WOA spr barrel.
Ramshot TAC questions
- Thread starter Kangbeef
- Start date
My experience is that in a good barrel, and the Hornady 68 BTHP, it will produce some small groups. I built an AR with a 14.5 Daniel Defense lightweight barrel for my wife. She never had an issue with hitting 2MOA targets from 100-500 yards, in weather from 50-90F
That said, I know it is temperature sensitive but if you factor for it, the loads will perform.
That said, I know it is temperature sensitive but if you factor for it, the loads will perform.
- Nov 3, 2010
- 10,241
- 22,121
I loaded quite a few 223 over the summer that I haven’t shot yet. The temps had dropped a few degrees so maybe have to see how bad it affected the loads one day
What did your groups look like?
Getting 3/4" groups out of an AR isn't easy
It takes a lot of effort by the shooter to be consistent.
There's a chart out there that has Ramshot Tac at 0.91 fps per degree from 50*F on up.
GRT numbers come out to be about 0.895 to 0.93fps per degree change from 70*F to 140*F
0.504 to 0.54 fps per degree change from -4*F to 70*F
Up to you to decide if you want to track powder temp.
GRT numbers come out to be about 0.895 to 0.93fps per degree change from 70*F to 140*F
0.504 to 0.54 fps per degree change from -4*F to 70*F
Up to you to decide if you want to track powder temp.
FWIW: This table went around a while back. The footnote says the units are in fps per degree F.
So for example, it shows TAC at 0.91 fps/degF, which roughly agrees with the above posts.
Lets assume the OP was doing his work in 90 degree summer, and got 3000 fps.
If he shoots in 60 degree weather, then the math looks like 3000 - ((90-60)*0.91) = 3000 - 27.3 = 2972.7 fps
If the OP is shooting at say 300 yards, it would most likely be negligible. If he is shooting at 600 or beyond, then it barely starts to show.
The WOA SPR bbl is a pretty good one and not real sensitive to small changes like this one from a harmonics view. It would amount to roughly 0.3 MOA vertical difference at 600 yards.
I would make two suggestions. One would be to go ahead and keep range notes along with your reloading diary and note the climate and any differences in target performance. Second would be to also take some velocity data along with those in order to see if your batch to batch consistency is partly to blame as well as to see the effects of temperature on your loads.
It takes some discipline in loading to keep the average velocity of a batch the same as well as keep the ES/SD tight. Keep the faith and work on the discipline and you will get there. YMMV
So for example, it shows TAC at 0.91 fps/degF, which roughly agrees with the above posts.
Lets assume the OP was doing his work in 90 degree summer, and got 3000 fps.
If he shoots in 60 degree weather, then the math looks like 3000 - ((90-60)*0.91) = 3000 - 27.3 = 2972.7 fps
If the OP is shooting at say 300 yards, it would most likely be negligible. If he is shooting at 600 or beyond, then it barely starts to show.
The WOA SPR bbl is a pretty good one and not real sensitive to small changes like this one from a harmonics view. It would amount to roughly 0.3 MOA vertical difference at 600 yards.
I would make two suggestions. One would be to go ahead and keep range notes along with your reloading diary and note the climate and any differences in target performance. Second would be to also take some velocity data along with those in order to see if your batch to batch consistency is partly to blame as well as to see the effects of temperature on your loads.
It takes some discipline in loading to keep the average velocity of a batch the same as well as keep the ES/SD tight. Keep the faith and work on the discipline and you will get there. YMMV
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@RegionRat Tyvm for the tip. I took notes on they days weather and have velocity data from my garmin. Will keep chugging along and gather more info.
I've shot a lot of TAC in my semi-autos. I was familiar with the temp swings as there are a couple of charts like the one posted above. However, I saw it personally during load development in a .308 pig rifle of mine that was totally fine with the arbitrary load I threw together for it during the winter. Then I got some nasty swipes when I shot that same load ~40 degrees warmer.
I have since switched to doing all load development with anything that is moderately sensitive to the summer months. It is easier to check for accuracy/velocity degradation in the winter later than it is to pull a bunch of bullets.
I can't really speak to the pursuit of potential accuracy, because I don't usually try to load precision ammo with TAC. I HAVE tried...I just haven't had the initial accuracy that I was getting with extruded powders. As long as my pig rigs will shoot 1.5 MOA or better, I'm happy and TAC delivered just fine for that.
I have since switched to doing all load development with anything that is moderately sensitive to the summer months. It is easier to check for accuracy/velocity degradation in the winter later than it is to pull a bunch of bullets.
I can't really speak to the pursuit of potential accuracy, because I don't usually try to load precision ammo with TAC. I HAVE tried...I just haven't had the initial accuracy that I was getting with extruded powders. As long as my pig rigs will shoot 1.5 MOA or better, I'm happy and TAC delivered just fine for that.
