Posted: 12/4/2016 7:57:32 PM EDT
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Cliff notes. I have no experience with precision/long range rifle shooting or reloading. How many rounds should I make in each charge weight since it's probably going to be hard to tell the difference between my marksmanship and the ammo? Should I find a friend who already has the skill set and ask them to fire my test loads? And I don't have a chrono yet so I'll be going 100% accuracy and pressure signs for now.
I'm just starting out with precision reloading. I've been loading for 5.56 and 300AAC plus most common pistol calibers. Let me start with, I don't have the funds right now for more reloading equipment. So concentricity gauges and the like are out. I just had a 308 built (I'm not even sure what barrel) and put a viper pst on it. I'm such a noob in that arena that I just trusted my smith to do right by me and he delivered. The smith suggested that 168 and 178 would be a good match for my barrel. I'm trimming to 2.005 +/- .003 because that seems to currently be the closest consistency I can get with my Lyman trimmer. Using Hornady custom grade does and my lock and load progressive for now. Thanks for the help |
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I generally load 5 cartridges with the same powder charge. Â 5 Shot groups, and make notes if I feel like I pulled one. Â I also record chronograph results for each shot.
If you find a skilled friend to shoot with you, then load 10 each charge and compare 5 shot groups. If you have a 1:10 twist, 178s / 180s should shoot fine. Â I have really good results with AMax 168s, too. Â (30-06) Â Have fun. |
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To further your education, here's one method of finding a good load: OCW: Optimal Charge Weight. Tells you the theory behind it, and how to execute.
For your 308, buy a box of Federal Gold Medal Match in 168gr or 175gr. If that shoots well - and it's very likely it will - the powder used there, IMR4064, will be a very workable powder for you. The bullets are Sierra 168/175gr Match Kings. The powder charge is 41.75gr for the 175gr, 42.75gr for the 168gr. If you play around in the appropriate range, you can likely improve a bit on FGMM performance in YOUR rifle. IF FGMM ammo doesn't shoot well from your 308, talk to your gunsmith. |
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Thanks for the replies guys. The rifle was tested with FGMM and it shot .4 something 3 round group I believe. I know it's going to take a while for me to get to that point. As I was breaking my press while attempting to make my first batch it occurred to me that I just need to find a reasonably accurate load to practice with and once I refine my skill set I'll start working on making exceptional ammo.
PSA. Don't overtighten the mechanism that seats the primers on the Hornady LnL progressive, it is not overly sturdy. And now I am hand priming until I can call them tomorrow and have them send me a new one. And a spindle and decapping pin that I broke yesterday too while prepping brass. |
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A skilled reloader can take any Match grade bullet, any set of matching cases, any <suitable> powder, and any set of primers and build a nice accurate loading from these. The key here is that the reloader needs for find where that bullet, in those cases with that powder and primers performs well. It is VERY possible that some other bullet, powder, primer cases will perform BETTER at some other load recipe, but finding out how much better is <basically> HARD the BEST loading may only outperform an otherwise excellent loading by 0.05 MoA.
Finding a long range load is a bit different than finding a benchrest load. The benchrest load one simply wants the smallest most consistent groups. The long range load wants the smallest most consistent groups at the highest pressure that remains inside the envelope of sanity under all conditions. High pressure is giving you MV with translates into lack of drop and lack of windage as the projectile goes down range. You stay inside the sanity window because you value your eyesight. To find the benchrest load, you basically try everything (several times) looking to shave that 0.05" off the average group size. By the time you have tried out all the possibilities, the barrel s shot out and you start again. To find the long range load, you start with a quick survey of pressure. Here one loads up 1 case in 0.5gr increments 3-4 steps over the max in the reload book. You will expect to disassemble 2-3 of these, but you want to be sure to find where pressure rears its ugly head. These are not fired for accuracy, but fired as an examination of pressure--so don't do this part in the cold of winter. You find the point where pressure is visible, drop back 1.5 Gr and then survey -1.5gr through -0.2gr. There WILL be an accuracy node somewhere in this region. The second step is to make 5 cases at 0.5% steps between -1.5gr and -0.2gr. Weight the powder with extreme diligence, measure stuff multiple times (shoulder position,...), seat bullets to the ame jump distance across the whole set. Color code the cases so you can examine the cases afterwards for pressure signs. Take the 5-6 sets of targets and examine the patterns. Small groups sizes are good, but there is additional information in the groups that are not so good. Ultimately choose the best group size. The third step is to survey the area around the best group size at very high level of precision. Take the survey from -0.3gr through +0.3 gr in 0.1gr increments (of finer if your scale can be read to higher accuracy). Shoot this set of 7 cases for record using your best technique. What you are looking for, here, is the window where the group sizes are all good, and where the groups start to fall apart. If the window is narrow (0.1gr-0.2gr) you are likely at an antinode and these are frustrating nodes indeed. If the window is wide (0.3gr or wider) you have found a good accuracy node. With the good accuracy node found, it is now time to run jump distance experiments to finish dialing the load recipe. These are most easily accomplished with a micrometer bullet seating die. |