Barrel twist and optimum bullet weight for a .308

[Mr. Rowdy]

( I searched, couldn't find what I was looking for)

My Howa has a 20" 1:12 twist barrel and I was surprised to find a HUGE POI change with different ammo.

I had a box of 150 grain Winchester and am getting ready for deer season so I was zeroing in the scope. Got it zero'd but wasn't real happy with my groups. I grabbed a couple 168 Nosler Match rounds and put one down range and had no idea where it went. I pulled it back to 50 yards and saw my impact 1.5 Mils lower than it was previously. Moved it out to 100 and checked again, this time it was damn near 3 mils lower than it was shooting with the 150 grainers.

I shot a couple more times with same POA and the group was fine but the POI change really threw me off.

What weight bullets are you guys using and what is your twist? I hope to start loading my own soon, but until then I need to figure out what factory loads will shoot best and throwing $25 at a load hoping it works is getting somewhat expensive.

 

[Whit]

Re: Barrel twist and optimum bullet weight for a .308

I have a 1:10 twist and mine loves the 175gr. pills (using HSM ammo)

 

[Dollman]

Re: Barrel twist and optimum bullet weight for a .308

Final twist 11.25
175 grain weight bullets.

 

[Mr. Rowdy]

Re: Barrel twist and optimum bullet weight for a .308

I've been shooting the 168 gr. Noslers with limited success, then the 150 gr. POI change really threw me for a loop. I've got some 165 gr. and 180 gr. loads I'll try today.

 

[AMM0]

Re: Barrel twist and optimum bullet weight for a .308

I'm still a n00b, but I'm wondering if the first thing I need to do after getting my bolt-action toy is to buy a box of varying manufacturers amm0... and see which one offers up the best grouping.

Is it a case where each and every rifle barrel has its own characteristics? In other words, if I shoot 150-gr. Winchesters from two identical rifles... same specs, should both rifles, in theory, offer the same results? Or is that not necessarily the case?

 

[Killbox Alpha]

Re: Barrel twist and optimum bullet weight for a .308

Mr. Rowdy-
There is a thread on here that outlines what your looking for but I am unable to find it. A few of the guys had outlined some different calibers and twist rates and referenced projectile weights.

As far as the 308 and twist rate. I have a 1:11 twist and I have excellent luck with the 168 grain Sierra match Kings.

 

[0481]

Re: Barrel twist and optimum bullet weight for a .308

1:12 26" tube and 175 smk

 

[Graham]

Re: Barrel twist and optimum bullet weight for a .308

http://www.riflebarrels.com/articles/longrange_shooting/ideal_barrel_308_tactical_rifle.htm

 

[seanh]

Re: Barrel twist and optimum bullet weight for a .308

what you're experiencing is normal. You can take the same "load" just from a different lot and it can print in a different location.

As to what is optimum? That would depend on what you're doing. If you're only shooting at 200 then a lighter bullet will be fine but if you're going to say 600 to 1000 then maybe a 175grn will work for you.

I'd suggest looking for group size not where it hits. It can get kind of expensive doing this with factory loads, you may want to consider reloading.

Try some of the hornady A-max match, Federal Gold in 168grn. Most likely they'll shoot very well.

I shoot a 1-12 twist as well but it's a longer barrel. For me the 168's work well but so does the 175's. The lighter 147's shoot ok and are only good for plinking where accuracy isn't an issue.

 

[Cascade Precision]

Re: Barrel twist and optimum bullet weight for a .308

Rowdy,

As posted above, try different mfg of ammo.

I have experience with Federal Premium 175gr ammo on a 20" SPS tactical with a 1:12" twist barrel. It shoots sub-moa, typically between 3/4 and 7/8 moa depending on me and the wind to 300 yards.

There are a few vendors on this site that have super deals on .308 match ammo. First that comes to mind is Southwest Ammo, but I believe that copper creek is also a good source, but have not looked there as I just found them last night.

I also have some experience with the Winchester 147 grain ball ammo. In my opinion, if you are looking to hit a "man size" (18"x36") steel plate, you could reliably hit it at 200 to 250 yards. That, btw, is a HUGE target.

May also look at Black Hills 168 match ammo. My rifle seems to like it just fine, producing similar results as the Federal Premium.

Another option, save some cash and buy a good reloading press (RCBS rockchucker, kit is $287.99 Midway USA

Save some money in the long run this way. Buy a good brand of brass (I like Winchester and Remington), but don't discard your once fired stuff. Save it and reload with it.

Buy a GOOD manual (I like Sierra Rifle and Handgun reloading data Sierra reloading , but also look at Hodgdon's data site Here ).

This site also has a great reloading section, and most ALL of the possible .308 loads are there. HOWEVER: Always start at 10% lower than the listed powder charge and work up. Find a friend to help you get started.

Where are you located?

Wally

 

[Shortdraw]

Re: Barrel twist and optimum bullet weight for a .308

My 10 twist shoots 178 Amax, 190SMK, and 185 Berger VLD's very well. My 11.25 twist likes 168 and 175SMK's. My 12 twist liked the 165 and 168's the best. POI shifts are the norm when switching ammo brands even with similar projectile weights. Find a hunting load that shoots good and a target load that shoots good. Don't assume it will be close enough to keep the same zero. The only two that were really close was in my dad's 308. He shoots Federal Gold medal match 168's for target and Federal premium with the 165 Sierra game kings for hunting with a repeatable inch shift in zero.

 

[jasonZ]

Re: Barrel twist and optimum bullet weight for a .308

Yep already been said, but every time you change ammo, your POI will change to. A friend of mine has a factory Savage 308 that he hunts with and it has 1-12 twist. I have a Savage with 1-10 twist. He was loading a 165gr Nosler ballistic tip for a hunting round and it was printing a nice group, under 1", so I thought I'd try them. After loading a handful with his recipe and then trying several different recipe's of my own, I decided my rifle just didn't like that bullet. I couldn't get the dam things to group buy maybe just over 1" at 100yds. So far I've had success with 168gr amax and smk, plus 175smk's and 180gr nosler. I haven't gone much higher then that, but my friends Savage doesn't like anything heavier than the 165 from what we've learned. Every rifle will be different on any given ammo load. Some can duplicate another, but it will usually not provide the same results, especially a factory unit.