such a bewildering array of powders...

[cleardatum]

i'm working on loads for my savage 10 pc .308, with a 20 inch barrel. it's now shooting consistently under moa, but i know it can do better ( they always can, right?). that short barrel would prefer a faster burning powder, yes? i've determined my next step to be trying a lighter bullet (i've gotten the groups down to where they are with 168 grain speer ballistic hollow point boat tail boowets), and i've been using reloder 15 (all that was available). is this a fast burning powder? am i correct in assuming that faster burning is better in a shorter barrel? the barrel is 1 in 10, btw.

 

[Rick Courtright]

Hi,

For "how fast is my powder" questions, you need a burn rate chart. Hodgdon's has one here: http://www.hodgdon.com/burn-rate.html

There you'll see that Rel15 is just a touch slower than the 4895s, which have been good choices in the '06 and .308 for target use for a long time. It's worked well for me in a 22" barrel using 150 gr bullets in my '06. I don't have any 165-168 grainers, but suspect it might be a touch better with the extra 10% weight. However, minute of Bambi is my goal, so 2" groups are just fine in my book...

Now, I heard this a long time ago, and some of it's been documented, but not all: rifle powders are generally completely burned in a 16" barrel, shotgun powders in an 18", and no mention was made of pistol barrels. That part's probably pretty much spot on. The part that isn't so certain is what followed, that "fast" rifle powders are pretty well lit off and "maintaining" after about 8"-10" or so, while slower ones might take 12"-14" or so. What that means is while they're past their pressure peak they're still burning, and perhaps gaining a little velocity, very soon they're only maintaining enough pressure to keep the bullet moving at whatever velocity it's already achieved. Makes for fascinating barstool conversation but how much truth there is in that idea shall remain unproven!

However, the concept can be used by the handloader in tailoring his loads to a particular barrel. When the trigger's pulled, and things get moving, there's a harmonic wave that moves down the barrel as the bullet travels thru. The idea for greatest accuracy is to have the barrel in the same place as the sights say it is time after time. Not as easy to do in real life as on paper! I don't know how to "tune" that, but do know that the more accurate loads ARE more "in tune" than the less accurate ones. What that tells me is once you've found a load that works really well, similar loads using different powders in the same general burn rate may prove to work as well.

The interesting part of such conjecture comes when we remember every gun is a law unto itself regarding the loads it likes best, so some experimentation must be done. if you're already "close" with a particular recipe, as it sounds you are with the Rel15, sometimes moving the charge up or down a couple of tenths of a grain or so will wring that last little bit of accuracy the load's capable of out of it. Which means even more experimentation. A change in bullet may do something, but remember the general rule of faster powder-lighter bullet and slower powder-heavier bullet.

But that'll keep you busy while you're trying to locate the next powder to use in your "lab work." Have fun, remember to document all your work well, and maybe you can tighten those groups up even more...

Rick C

 

[jsh]

" it's now shooting consistently under moa, but i know it can do better"
If that is true, I would be more inclined to tinker with oal.
I have never used any of the reloader series other than 7.
The fast powders in a short barrel is a myth that won't die. Go have a look at what guys are using for the 12-14" pistol barrels in rifle calibers. My 15" 308 uses the same varget load as my rifle.
Jeff

 

[contender]

Hopefully you have several manuals to read & especially the ones with the burn rate charts, as well as all the safe loads you could try.

 

[cleardatum]

i've been using the speer manual so far (episode 14- it came with my press), and (unfortunately for my shoulder) the hotter loads are the most accurate in this gun, which is what got me thinking about maybe a slightly lighter bullet? a little more velocity? i've got the oal dialed so the bullet is ~.020 off the rifling. i could play with that as well. i also verify length further down the ogive (that measurement is consistent within .0005- i'm an engine builder, so i'm way anal about dimensional accuracy). i'll be getting another manual (or two) this weekend. i am thoroughly enjoying this endeavor. my only regret is that i don't have my own range. that could change in the next few years (i have an empty nest).

 

[WIL TERRY]

It is the size and shape of the chamber [ the EXACT cartridge ] that determines the proper burning rate needed [ of many...] for any specific weight projectile, NOT EVER the length of the BBL.

 

[sixshot]

Making accurate loads is always interesting but if your gun is consistently shooting under 1" groups (you didn't say 3 shots or 5 shots) then you probably can't gain much more with what you have. Barrel length really has no bearing on accuracy, a short barrel will usually shoot as well & many times better than a long barrel. I think Jim Carmichael recently shot a new world record with a light varmint class (20", 10 1/2 lb gun)
Probably the best thing anyone can do is prep their brass, if you don't then tweaking the powder charge & seating depth will only take you so far. If you really want to see what the gun is capable of doing you have to gauge the flash holes, ream the primer pockets to a uniform depth, turn the necks, use a run out gauge to see if your loaded ammo is in perfect alignment with your bore.... there really is a lot going on if you want your gun to shoot the very best it can. BUT, if its a sporter/hunting type gun how much accuracy is needed to whack a muley, a whitetail or an elk? Still, its fun to see what they will do, I've spent a lot of money, & wasted a lot trying to make them shoot bug hole groups.

Dick

 

[cleardatum]

5 shot groups, consistently around .9 inch with the hotter loads. thanks for all the input, guys. i appreciate it!

 

[jsh]

I am absolutely not arguing with Sixshot. But, opinions are like elbows everyone has a couple, you can do a whole bunch of case prep and end up with worse than you had to begin with. You need to match the brass to the chamber. Very very few factory chambers will see much if any difference in case prep. Been there done that.
You wNt to play that I would suggest forming from a 06 family of cases and then do the neck turning, that fits your chamber, weighing cases, flash holes primer pockets etc. then you might see some results in the accuracy department.
Your an engine builder and I admire that. Raced a bit off and on from 82-95. Got out and went back to shooting.
You can't put a cam, intake and carburator on an engine and expect a whole lot on a consistent basis.
Jeff

 

[Jimbo357mag]

Sounds like you have the 168gr hunting load nailed. I would stop there and label that load #1.
Now pick another bullet for target/sport shooting and start over. Maybe a 150gr flat base and a reduced charge of H-4895 as that powder is known to work well in reduced loads. Drop back 20% or 10% from Max. and see if you can get it to group.

 

[krw]

I'll bet a Lapua case, SMK175gr, and about 43.3gr Varget will shoot lights out. This is my favorite 308 load.

 

[Rick Courtright]

Hi,

Just for giggles, whenever the topic of "absolute accuracy" comes up, dare we ask one more question:

How good is the SHOOTER?

There are a lot of guns out there which, right out of the box and using off the shelf factory ammo, CAN shoot far better than the loose nut behind the butt can do! Of course, that loose nut is always the OTHER guy, right?

Rick C

 

[cleardatum]

Hi,

Just for giggles, whenever the topic of "absolute accuracy" comes up, dare we ask one more question:

How good is the SHOOTER?

There are a lot of guns out there which, right out of the box and using off the shelf factory ammo, CAN shoot far better than the loose nut behind the butt can do! Of course, that loose nut is always the OTHER guy, right?

Rick C

point taken, and being the introspective type, that's the first place i look. i do shoot much smaller groups with other guns, but that doesn't mean there isn't something about this gun that causes me to be the "problem". my scope has a mildot reticle that i don't care for, and the stock doesn't fit me just right, so those items are on the list to investigate (they give me a "legitimate" excuse to buy more stuff).

 

[sixshot]

Jeff, you are correct, when dealing with factory chambers, which are "genorous" preping brass is pretty much a waste of time. If you are dealing with a factory rifle & are getting 1" groups or less you have a very good rifle, actually 1 1/2" groups will work on big game with great success. Still, its fun to work with accurate guns, thats where custom barrels with tighter tolerances come into play but the shooter has to take advantage of everything available to really make it all come together. Tight chambers, good quality brass thats been fine tuned, good handloads & a shooter thats up to the task makes for a fun day in the field or at the range, been doing it for many years & it never gets old.

Dick

 

[Mobuck]

"Hopefully you have several manuals to read & especially the ones with the burn rate charts, as well as all the safe loads you could try"
Multiple manuals is good advice. Data from both bullet makers and powder companies plus a Lyman gives you a wider view of what/how to achieve your goal. I don't have a current Speer manual since I don't often use Speer rifle bullets but all my other manuals have a burn rate chart. I wouldn't call Re15 a "fast" powder. I use this powder in .308 accuracy loads by choice-not simply because it's the only thing on the shelf. Literally "cloverleaf" accurate in my most often used .308 heavy barrel.

 

[contender]

Both Jeff & sixshot are correct.
Factory chambers are often a lot "looser" than a custom barrel etc. Working brass over to where you are trying to duplicate match grade accuracy with a production gun could be considered a waste of time & efforts.
However, even the factory barrels & all can often benefit from such work. You may get one of the first barrels cut with a new reamer, and it be tighter than the ones before the tool change.
Like sixshot, I get a lot of pleasure out of working up my brass, tweaking my reloads, experimenting etc with all the mechanical factors to squeeze out the best accuracy in that gun. I also keep notes to let me know if my work was worth it or not. I also accept my factory production guns limitations once I determine I can do no more.

 

[sixshot]

Actually a new reamer will cut the biggest chamber, as the reamer wears (gets smaller) it will cut a smaller chamber. At one time I had 8 different custom pistol barrels (single shot) that would shoot under 1/10" at 50 yds. The biggest problem was scope power. But still its fun working up loads with any rifle/handgun & seeing what it can do within reason, its when we get accuracy crazy that things can get out of hand. Back in the 70's & 80's I did a lot of experimenting with Remington 40X & 40XBR's, mostly in 222 & 6X47, fun, expensive & time consuming.

Dick

 

[contender]

sixshot is right, I was thinking backwards. I knew better.
Still, my point is that even a factory production gun can give excellent accuracy, and doing all the little things to improve it can pay off. Sometimes. You just never know until you try!

 

[SweetWilliam]

I'm on board with sixshot about scope power. You can't shoot a ragged one hole group if you can't see the hole in the 1st place.

 

[Mobuck]

"You can't shoot a ragged one hole group if you can't see the hole in the 1st place."
I disagree. When shooting "groups", the placement of the group has little to do with the aiming point (other than it has to be "on the paper"). A few years back, I was bragging about several very nice groups shot by my blind Son and one of the guys pipes and asks "what was he trying to hit?". The groups weren't centered on the target face so this guy couldn't understand the significance of the group size. As an interesting side note, I discovered later that this guy had traded off several expensive scoped rifles because "they didn't hit the bullseye" (they'd never been sighted in).

 

[SweetWilliam]

So if your rifle is capable of shooting one hole groups at 100yrds. but you have a 4x or even a 3x9 on it how do you go about shooting those one hole groups?
You need the magnification to see what your shooting at.

 

[cleardatum]

So if your rifle is capable of shooting one hole groups at 100yrds. but you have a 4x or even a 3x9 on it how do you go about shooting those one hole groups?
You need the magnification to see what your shooting at.

i may be a neophyte when it comes to target shooting, but when it comes to optics, i know a bit more. magnification is WAY over rated. image quality is king. crank the magnification up on a hot day and you'll see what i mean, eh? i see the target better (and shoot better) at 4x with my leupold, than i do cranked up to 16 with my nikon. when i'm gazing at the stars, often times less magnification is better. if the "seeing" is bad as we say in astronomy, magnification is your enemy (well, the air is, but i think you know what i'm saying).

 

[SweetWilliam]

Well sure image quality is all so needed. but when you look through your 4x leupold at a 1/2" dot a 100yrds. How clear can you see it? You still need the magnification.
I have a Nikon Monarch 2.5x10x42 on my 308win & it's has a pretty damn clear image.