308. 180gr sst. accuracy ?

[hammer33]

General accuracy question. Shooting 180gr SST.s in the 308. Went with the heavy bullet for pass through performance on hogs. . 5 gr below max according to the sierra reloading book a recipe a buddy with the same rifle suggested. Best I can do off the bench with this load is 2-2.5"
Before I spool up a half dozen different loads and use up all my bullets, does the 308 in general throw a heavy 180 gr bullet well ? Or is it (in general) happier with a lighter round?

 

[Jcalder]

Drop a grain and try again

 

[Lone Hunter]

What is the twist on your barrel? You should always start low then work up to max. Just because it was safe in his rifle doesn't mean it will be in yours. I have not had good luck with accuracy with SST's in any caliber. I shoot Berger 185 Juggernauts and Sierra 175 MK's out of my .308 with a 11.25 twist. Most factory barrels are 1-12 with some going to 1-10. If it were me if you had different powder and bullets I would try a different combination.

 

[hammer33]

Its a 1:10 twist. The load Im using was a last minute deal. Bought the rifle last season and a buddy I hunt with has the same one. He was using this load and said it was accurate in his rifle so I gave it a try. Accurate enough for our hog hunt where shots of 10-75 yards were expected but I would like to tap into that legendary 308 accuracy.
Didn't want to spend a bunch of time and powder chasing the 180gr around if the heavy for caliber bullet is typically not accurate in the 308.

 

[philsanchez76]

ive had much better luck with 150 grainers in my 1:10 twist barrel. But ive not tried super hard on the 180's either.

 

[jlanecr500]

I can get you real close. 1) Weigh a piece of fired brass, then fill with water and weigh again. I need the difference in grains. 2) barrel length breech face to muzzle not including brake. 3) bullet manuf and model. 4) powder you'd like to use and others that you have in the 308 burn range. 5) coal touching the lands ( if you don't have a comparator, just insert a bullet in the case a little long and chamber it. If the case is not too tight but snug enough to hold it then you can measure the coal. Measure the mag internal length to make sure it will fit.

 

[backyardtndeer]

I run 178 grain eldx in my 308's with great accuracy. I don't have my data in front of me, but best as I recall I was loading them near max of imr4895.

 

[Lone Hunter]

Its a 1:10 twist. The load Im using was a last minute deal. Bought the rifle last season and a buddy I hunt with has the same one. He was using this load and said it was accurate in his rifle so I gave it a try. Accurate enough for our hog hunt where shots of 10-75 yards were expected but I would like to tap into that legendary 308 accuracy.
Didn't want to spend a bunch of time and powder chasing the 180gr around if the heavy for caliber bullet is typically not accurate in the 308.

1/12 twist will handle the 180 gr easily. There are several powders that work well with the .308. I would look at the Interlock 150-180gr, Sierra 150-180 grain. I use Sierra 165 SBT in my .308 and it hammers plus is very accurate. My buddy uses same bullet ( Sierra 165 SBT) to hunt hogs in S Georgia and it kills great. I would look at a bullet change and possibly a powder change too. If you can, do what jlanecr500 says two post above you. He apparently has Quickload and it will get you in the ball park and real close. If not, look at different powders and bullets.

 

[hammer33]

Thanks for all the help! Doing the easiest first, Ill make up a few test loads and see if a lower powder charge tightens up the groups.
Im having a hard time finding IMR4064 so a powder change might be in order during the off season.
If I don't find a load giving me better groups, Ill pull all the data and send it to Jlancer500. I wouldn't mind going to a slightly lighter bullet for a bit flatter trajectory but don't want to open that can of worms with season so close.

 

[Lone Hunter]

Where are you located? There are several online companies that have IMR-4064 in stock. 4064 is a good powder in the .308. I would try a different bullet too. For hunting with a .308 I would use a 150 gr or a 165 gr. I use Sierra 165 gr SBT. Unless you are planning on shooting past 500 yds you don't need the boat tail a flat base will be sufficient. The Interlock is a good option also. Like I said I have never in any caliber had good groups with SST's. Other folks use them and like them though. You also might try adjusting your seating depth along with the powder charge but do one thing at a time so you know which one worked.

 

[jlanecr500]

I'd at least start at .020" off the lands if your magazine can handle it. Cup and core bullets tend to like that