Home Forums Reloading Varmint Rifles 8" twist 223 is not accurate with heavy bullets

My shooting buddy had a 223 built to shoot heavy bullets (70 to 80 grain) but can not get the accuracy expected. The rifle loves 50 grain bullets and holds them to less than 1/2 inch. With 55 grain on up the groups open up as the bullet weight increases. The 1 in 8 twist likes the lighter weight bullets. 70 to 80 grain bullets open groups to 1 1/4 to 1 1/2 inches! Any thoughts?

<img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

Jim

Need to check if it really is a 1:8 twist barrel.

How many rounds down the tube? Is it broken in yet?

I agree. My 1:9 twist barrel doesn't start getting really tight groups until I start using 68, 69, or 70 gr. bullets.

As described it sounds more like a 1:12 twist barrel....

It's broken in with around 90 - 100 rounds.

He says he verified the twist.

Damnit..........

How's it throated? Are the heavies pole-vaulting to the lands?

Is it an AR?

Kiss lands and carry on....................

Could still be a lot of things.

Box ammo or handloads? If handloads, which powder and primer?

How long of barrel?

Barrel length would have zero bearing,unless velocity was so compromised,that boolits weren't stabilized..................

That is why I asked the question.

Unfortunately...or fortunately....98% of any problem...is solved by the basics.

So..if you ask the basic questions...the problem will be found sooner.

This rifle is a re-barreled Sako ( L-46? ) with a medium sporter weight barrel. Powder is Varget and Benchmark with Sierra and Hornady bullets in weights of 50, 55, 60, and 69 gr. I do not know charge weights or primer data.

It is not my rifle so I don't know all the details of his loads. Sorry.

Jim

Barrel length 100% of the time,means dick on 100yd paper...................

The Baby Sako's have an itty-bitty mag box and my guess is that the 8" twisted tube's throat is cut for heavies and he's pole-vaulting them to the lands.

I'd go to kissing lands,disregarding mag confine COAL,as a barometer of performance evaluation.

The 64gr PP will probably shoot very well via mag confines(ogive friendly to the Sako),but the BC is [bleep].

Hammers Deer though.............................

I've got a box of the factory Win PP 64grainers sitting on my bench... explicitly for deer ... havent tried them at all yet ... still, I figure they'll do alright out of my 24" 1:9 twist pacnor 3 groover .... <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

They'll do nicely outta a 12" twist.

Have killed alotta Deer with them.

They dig deep....................

my .223 is twisted 1:9", so I've no hessitation in using them ... Just haven't gotten 'round to it yet ...

Well..you are not subtle.

no ... he's not, unless you get one of his posts in "stick language" that might be hard to interpret ... but even then, it's not subtle ... just a little harder to figure out, if you're not used to his style of writing ...

EDIT TO ADD: Regardless of the above, he's full of good info, as he shoots everyday, and has (or has had) a rifle in just about every reasonable chambering and style ... I can't speak for anyone other than myself, when I say that I've learned a lot from him ... a whole lot ...

What in the world is his pen name-- i gotta check out some of his stuff.

My AR in a 1-9 does not like heavy bullets either. I think the 223 is at its best in the 40-50 grain. And the Swift and 22-250 is best with 50-55. Not based on barrel twist, just based on case size and charge. The 223 in not a burner anyway, so I cannot see slowing it down with heavier bullets. That is just my preference though, I just never understood why people want to shoot heavy bullets from a small gun.

Well said! If I want a heavy bullet I use a larger cal. My .223's like 50 gr. and I don't use anything else.

To each his own.

Jim