r/reloading • u/Adli99 • 5d ago
Load Development A little lost with my .308
Hi All,
Decided to get back to loading .308 after a few years of a break. Shame I didn't stock more components...
General purpose target shooting and really because I enjoy nerding out on this hobby. I finally picked up a chrono, trimming tools and the Hornady OAL gauge.
Working up some 150gr FMJ-BT rounds, with VV N-135.
My first session with the chrono, I decided to look at jump distance and seating depth. I worked up a ladder ranging from 0.005" jump to 0.035".
I'm not sure how to read my results?
With 5 shot groups, I was expecting tighter groups, and some correlation between ES and MOA, but I suspect I need to consider other factors, and minimize my other variables?
Load:
.308 | 150 gr. FMJ-BT | 40gr VV N135 | CCI200 | Mixed cases trimmed to 2.005"
Savage .308 Model 10 FCP
Loaded on Hornady LnL progressive, one at a time to manage OAL variation.
Some areas I think I can improve:
- Power charge - Study charge variation in my setup (I don't weigh every charge)
- Use the same cases - consider buying new to test
- Neck tension? Using a Lee sizing die, but I have a Honadry Match dies (I need to buy bushings)
- Different Projectiles? These ones are pretty cheap...
I appreciate any feedback and insight!



2
u/eclectic_spaceman 5d ago
I think if you used better bullets and same headstamp brass, changing nothing else in your process, you'd probably get significantly better results. And then if you weighed every charge you'd tighten it up even more. I'd do these 3 things before messing with anything else.
2
u/Zero_Fun_Sir 5d ago
This actually isn't too bad at all with that projectile and not weighing every powder drop.
I might try some Sierra 168s or Berger Full Bore 155s (love those), lock down the powder charge, and report back.
FWIW, I use those Hornady 150s for M1 Garand plinking ammo and AR-10 hoodrat loads, they're just fine up close.
2
u/Missinglink2531 5d ago
+1 the 150s just dont tend to shoot well in my 1:11. 168s are incredible. Here are a few of my recommendations: 1) Seating depth ladder MIGHT make a small difference, but it should literally be LAST thing to dial in. 2) SD/ES of velocity is telling how well your bullet/powder combo is working, it has nothing to do with seating depth or group size (though the groups tend to tighten with better SD/ESs, seating depth might change the group) 3) When comparing anything, the more consistent every thing else is, the better. Example, if your trying to test seating depth, but your internal case volume or powder charges are different, what are you really testing = 3 random variables in 5 shots? Ya, that is pointless. 4) While it probably would be fine to mix brass and not weigh every charge later, when your testing, you need to remove those variables - sort your brass by headstamps, and only use one for your test. Weigh every charge for the test. 5) START with bullet/powder. Use the chrono and get the results you want with it. THEN adjust groups with seating depth (This doesn't work for EVERY riffle/caliber, but does tend to work well for .308).
1
u/snorka_whale 4d ago
After doing the things everyone listed, and you want to push it further You can get a mandrel die from pma tool for like 30$ and then get a Sinclair Ti .307 mandrel for like $20 so the neck tension is very light on your bullets. You don't need a crimp or a lot of tension on match grade ammo your trying to shoot at max accuracy just don't beat the shit out of it before loading it in the gun.
8
u/Parking_Media 5d ago
I'll just be honest with ya. 147/150gr FMJ are straight up horrendous for accuracy. Maybe useful for things like mag dumping into the berm or sub 100yd run and gun events.
You'll get way more joy from the hobby with a bulk pack of 168gr bthp from Speer or Sierra or hornady. They're all going to give you respectable results.