Two Question on powders

[ReaperDriver]

OK, so I'm trying to settle on a "go to" powder for .308 precision shooting (600 yd F-class, some tac matches, shooting steel at 500+, etc) with my SPS-T 20" and I feel like I'm chasing my tail. I've tried RL-15 with good luck so far and have some IMR-4895 on the way. I'm also thinking of trying TAC and Vargay based on word of mouth recommendations.

But here's my 1st question: Does the brand of powder matter? I mean, as long as I'm using a type of powder that is compatible with the type of bullet and rifle i.e. a medium rifle powder - what difference does it make as long as you are getting the desired muzzle velocity? If two different loads are getting the same bullet out the tube at exactly 2700 fps - how does the powder affect the ultimate accuracy? I would think at that point - the bullet itself has far more to do with accuracy than the powder that gets it moving? Given the exact same conditions of gun, barrel, MV, temp, etc - how is one powder more accurate than another throught the same gun?

2nd Q: With a short barrel like my 20", am I better off with faster burning powders like IMR-4895, 4064, etc than slower powders like Varget or RL-15? I wondering if all the powder is getting burned effectively in the shorter tube with a relatively slow powder like RL-15 and I wonder if that is part of what's accounting for my slower than expected velocities.

 

[Victor N TN]

Re: Two Question on powders

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">
But here's my 1st question: Does the brand of powder matter? If two different loads are getting the same bullet out the tube at exactly 2700 fps - how does the powder affect the ultimate accuracy?

2nd Q: With a short barrel like my 20", am I better off with faster burning powders like IMR-4895, 4064, etc than slower powders like Varget or RL-15?
</div></div>

Question #1 Yes it does matter. I know it doesn't make rational sense to say that. But it does. Some people argue podwer column density and ingition rates. I just like the simple side. Yes it does matter.

Question #2 It could. I would suggest trying different loads with the powders you mentioned and see for yourself what shoots best from your rifle.

Here is a link to an interesting article that may help you:

http://www.shootingtimes.com/ammunition/ST_burnchart_200907/

Good luck with your choices.

 

[cinosbus]

Re: Two Question on powders

Just pick a popular one and shoot. If there's nothing wrong with the load you've developed so far, why waste time and money to mess with it? The .308 is not picky, many powders will work very, very well. My guess is that you will not be able to find a repeatable difference from your best load with all of the powders you've mentioned, except that 4895 is not a "great" choice compared to the others, but will still work acceptably well. TAC meters the best if that matters to you.

 

[cinosbus]

Re: Two Question on powders

To answer your 2nd question, your 20" barrel will work fine with all of those powders. You don't need a faster powder with a shorter barrel.

 

[akula702002]

Re: Two Question on powders

Varget works best for me and is very stable across temps, altitude, etc...

 

[HOGGHEAD]

Re: Two Question on powders

After I decide which bullet I prefer to shoot in a rifle I then pick my powder with care. I decide the target velocity I want, and then I pick my powder accordingly. What I look for is case fill first. IMO a full case of powder gives stability under all circumstances. I do not like to have a cartridge case 1/2 full of powder. I want the case to be full or as close as possible. This has constantly produced more accurate loads for 35 years for me.

Filling the case with powder can be more expensive because you are using more powder. However my main concern is accuracy, not saving a dime. Tom.

 

[Victor N TN]

Re: Two Question on powders

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HOGGHEAD</div><div class="ubbcode-body">After I decide which bullet I prefer to shoot in a rifle I then pick my powder with care. I decide the target velocity I want, and then I pick my powder accordingly. What I look for is case fill first. IMO a full case of powder gives stability under all circumstances. I do not like to have a cartridge case 1/2 full of powder. I want the case to be full or as close as possible. This has constantly produced more accurate loads for 35 years for me.

Filling the case with powder can be more expensive because you are using more powder. However my main concern is accuracy, not saving a dime. Tom. </div></div>

)1...

I agree. Most times for me a full case works better than a partial case. It has better ignition as well.

 

[jrob300]

Re: Two Question on powders

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">But here's my 1st question: Does the brand of powder matter? I mean, as long as I'm using a type of powder that is compatible with the type of bullet and rifle i.e. a medium rifle powder - what difference does it make as long as you are getting the desired muzzle velocity?

2nd Q: With a short barrel like my 20", am I better off with faster burning powders </div></div>

I shoot a short-barreled 300WM so I can relate to your struggle. One thing you might consider at first, is contacting Mike @ TacOps since he is a short barrel fiend. He might be able to get you knocked off dead center.

Other wise...

Question #1: I agree with Victor, I've loaded several different powders at a velocity that really shoots with Powder A. No two powders seem to group the same. Interesting observation though, in my gun at least, the most accurate load for each powder seems to fall in a fairly tight velocity range.

Question #2: you will find yourself limited on the fast side by pressure and on the slow side by velocity. But again, like Victor said, try stuff. You may be surprised what works.

Not sure if that helped.

 

[willsnipe]

Re: Two Question on powders

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">But here's my 1st question: Does the brand of powder matter? </div></div>

Yes. Some powder/primer combinations produce more UNIFORM velocities, which can affect accuracy a great deal. They may average the same velocity, but the extreme spread between velocities is quite important in long range shooting.

As a rule, most loads are not sensitive to using too hot a primer, but too cool can be a major issue. I'd recommend starting with BR or Magnum primers as they're a little hotter.

 

[ReaperDriver]

Re: Two Question on powders

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cinosbus</div><div class="ubbcode-body">Just pick a popular one and shoot. If there's nothing wrong with the load you've developed so far, why waste time and money to mess with it? The .308 is not picky, many powders will work very, very well. My guess is that you will not be able to find a repeatable difference from your best load with all of the powders you've mentioned, except that 4895 is not a "great" choice compared to the others, but will still work acceptably well. TAC meters the best if that matters to you.

</div></div>
I'm curious, why do you say that "IMR4895 is not a great choice"? How does it differ from the others?

ETA: good thoughts everyone, thanks!

 

[Downzero]

Re: Two Question on powders

4895 is a fine choice.

I wouldn't waste your time with any ball powder. They're fine for FMJs in the semi-autos, but they really have no place in a precision rifle.

I use ball powders in my ARs, but for .30 cal cartridges, 4895 and Varget are all I use (stick powders).