Loading for a short barrel 308

[Xscream]

I have a good 308 load for my 24" 308 Ar but recently acquired a short (16.5"), 1/10 twist, 308 win break action for deer season. In preparation for the season I'm going to load up a couple different loads to see which works best in this application. The shots won't exceed 200 yards. I'll start with my standard 45gr of Varget and a 150gr bt. and play with the charge.

I'm looking at some of the faster burning IMR powders (not sure how much this will help) or if going heaver or lighter on the bullet would yield a better result. Are there any other suggestions for a good 308 load in short barrel applications? Any projectile suggestions for white tail?

[OldmanFCSA]

try 42.0 grains of IMR3031 behind a 150 grain bullet,
or try 45.0 grains of Win748 for same,
I use Nosler Ballistic-Tip 150's for deer.


Reference Powder Burn Charts - then refer to published load data.

Or as Sam Says "RTFM" !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Pinnacle]

^ This

[Seismic Sam]

Got a chrono?? Unless you do, trying to find better loads for a very specific .308 rifle is simply groping in the dark. In partucular, going to faster burning powders just to try and compensate for the 16" bbl could be a real recipe for disaster, and I'd just stick with the reccomendations of a Lyman #49 or Speer #14 manual as to the most accurate or best powder for .308 150 grain loads. For the record BL-C(2) was the powder that was specifically DESIGNED to work with the T-65 experimental cartridge that becaome the .308/7.62 x 51 NATO, and it's generally accepted that Varget is a better powder than BL-C(2). I'd just sight in the 16" bbl gun for your current load, and not tweak it unless it shoots like **** for some reason, which I think is extremely unlikely.

[Xscream]

I have access to a chrono although for this I was planning on loading by the book and not exceeding any suggested loads.

Correct me if I wrong, but velocity doesn't have an absolute relationship to accuracy. So two loads with the same velocity may have different accuracies depending on variables such as the burn rate of the powder, bullet weight, etc.

[Seismic Sam]

I have access to a chrono although for this I was planning on loading by the book and not exceeding any suggested loads.

Correct me if I wrong, but velocity doesn't have an absolute relationship to accuracy. So two loads with the same velocity may have different accuracies depending on variables such as the burn rate of the powder, bullet weight, etc.

You are absolutely right, although burn rate of powder is not really a factor in accuracy so much as it is a MAJOR factor in peak pressure. Primer brand, type of powder, exact bullet used (brand, type, weight), case mouth crimp, concentricity of round (i.e., bullet runout), and barrel twist can all play a role. One of the major factors is finding the "node" in a load curve, which is shooting a string of powder weights, and selecting the one with best accuracy, and more quantatively, the one with the lowest SD of the velocity for 5 or 10 shot strings. the theory is that a barrel can be viewed like an organ pipe, and have certain inherent frequencies at which it vibrates. If you get a load where the barrel is stopped for a millisecond WHEN the bullet exits the barrel, the accuracy should be better than when the barrel is in the middle of an oscillation. That's why chrono data is so important to have. To take advantage of a barrel node, your bullet has to exit the barrel in the same number of milliseconds every time.

[HeadHunter]

Bingo, When you load for best accuracy make sure that you document the entire process such as

Brass: Brand, Virgin/once fired, prep conducted (ie case length, primer pockets uniformed, weighted/sorted....ect)
Powder type, and charge
Velocity
Projectile

Now when you do this make sure you measure the group sizes as you go and watch your preassures. As you go through your selected charges you will see accuracy nodes. The groups will shrink as you go through your selected loads until it hits a point and your groups may considerably open up...if you keep going you see them start to shrink again and the cycle will continue....the most accurate points will be your nodes...document those velocities and the above listed items....now take those nodes, load up some more and shoot at distance....document which one preduces better results at what distance.....wash, rinse, dry, repeat.....

Also VERY IMPORTIANT!!!!
Remember that a safe load in YOUR rifle does not mean that it is safe in mine. Remember that chambers are a bit different between rifles and you WILL see different results. I had 2 300WM's at one time...one was a PSS with a factory barrel and one custom....the load for the factory rifle would probably blow up my custom.....just be careful and watch your preassures. Two factory cut rifles should be ok as they should be in Saami Spec.

[smurfman]

From experience in 7mm/08 using a Savage M-16 and a Savage Striker in the same caliber, I found what gave the fastest velocity in the rifle also gave the fastest in the pistol or at least pretty dang close. Accuracy was not far off with either with the same loads which made for ease of loading. My most accurate load was factory silver box 140 gr Winchester Power Points though it was the slowest factory loads I found. In any case, it killed deer fine out of either gun.

I feel bullet constructon is much more important as the somewhat lower velocity does not need a stoutly constructed bullet at close range and definitely at longer. I used plain Jane bullets such as Power Points, Core-Lokts, Interlocks, etc and they seemed to expand fine through the pistol. I can't say for certain as I never recovered a bullet but the exit holes were much bigger than bullet diameter out to a bit under 200 yards. I shot about a dozen deer with it before I foolishly sold it, it was a fantastic gun for farmland deer if one had a solid rest.